WorldWideScience

Sample records for rhizoctonia solani electronic

  1. Parasitism of Rhizoctonia solani by strains of Trichoderma spp. / Parasitismo de Rhizoctonia solani por linhagens de Trichoderma spp.

    Scientific Electronic Library Online (English)

    Itamar Soares de, Melo; Jane L., Faull.

    2000-03-01

    Full Text Available Rhizoctonia solani é um dos mais destrutivos patógenos de plantas cultivadas. Métodos alternativos de controle têm sido empregados com sucesso, particularmente, utilizando-se o fungo Trichoderma. Este trabalho visou, portanto, selecionar linhagens efetivas desse micoparasita contra o patógeno. Onze [...] linhagens de T. harzianum e três de T. koningii foram testadas in vitro com relação ao parasitismo de hifas e de escleródios e produção de metabólitos tóxicos. Todas as linhagens de Trichoderma spp. inibiram o crescimento miceliano de R. solani e as três linhagens de T. koningii produziram potentes antibióticos, que inibiram mais de 79% o crescimento do patógeno. Uma linhagem de T. harzianum, Th-9, reduziu a viabilidade dos escleródios em 81,8% e uma de T. koningii em 53%. Microscopia eletrônica de varredura revelou que todas as linhagens de T. harzianum parasitaram R. solani enquanto nenhuma linhagem de T. koningii interagiu com R. solani, possivelmente, devido à forte inibição causada pelos metabólitos que impediu o contato entre os dois fungos. T. harzianum, Th-9, cresceu ao redor, penetrou e destruiu as hifas de R. solani. A penetração das células hospedeiras parece ser acompanhada por atividade mecânica. Abstract in english Rhizoctonia solani causes serious diseases in a wide range of plant species. The fungus Trichoderma has been shown to be particularly effective in the control of the pathogen. Thus, this research was carried out to screen fourteen Trichoderma strains against R. solani in vitro. All strains tested in [...] hibited the growth of R. solani. Three T. koningii strains produced toxic metabolites with strong activity against R. solani, inhibiting the mycelial growth by 79%. T. harzianum, Th-9 reduced the viability of sclerotia of R. solani by 81.8% and T. koningii, TK-5 reduced by 53%. Electron microscopic observations revealed that all T. harzianum strains interacted with R. solani. Th-9 grew toward and coiled around the host cells, penetrating and destroying the hyphae. Penetration of host cells was apparently accomplished by mechanical activity.

  2. Parasitism of Rhizoctonia solani by strains of Trichoderma spp. Parasitismo de Rhizoctonia solani por linhagens de Trichoderma spp.

    Directory of Open Access Journals (Sweden)

    Itamar Soares de Melo

    2000-03-01

    Full Text Available Rhizoctonia solani causes serious diseases in a wide range of plant species. The fungus Trichoderma has been shown to be particularly effective in the control of the pathogen. Thus, this research was carried out to screen fourteen Trichoderma strains against R. solani in vitro. All strains tested inhibited the growth of R. solani. Three T. koningii strains produced toxic metabolites with strong activity against R. solani, inhibiting the mycelial growth by 79%. T. harzianum, Th-9 reduced the viability of sclerotia of R. solani by 81.8% and T. koningii, TK-5 reduced by 53%. Electron microscopic observations revealed that all T. harzianum strains interacted with R. solani. Th-9 grew toward and coiled around the host cells, penetrating and destroying the hyphae. Penetration of host cells was apparently accomplished by mechanical activity.Rhizoctonia solani é um dos mais destrutivos patógenos de plantas cultivadas. Métodos alternativos de controle têm sido empregados com sucesso, particularmente, utilizando-se o fungo Trichoderma. Este trabalho visou, portanto, selecionar linhagens efetivas desse micoparasita contra o patógeno. Onze linhagens de T. harzianum e três de T. koningii foram testadas in vitro com relação ao parasitismo de hifas e de escleródios e produção de metabólitos tóxicos. Todas as linhagens de Trichoderma spp. inibiram o crescimento miceliano de R. solani e as três linhagens de T. koningii produziram potentes antibióticos, que inibiram mais de 79% o crescimento do patógeno. Uma linhagem de T. harzianum, Th-9, reduziu a viabilidade dos escleródios em 81,8% e uma de T. koningii em 53%. Microscopia eletrônica de varredura revelou que todas as linhagens de T. harzianum parasitaram R. solani enquanto nenhuma linhagem de T. koningii interagiu com R. solani, possivelmente, devido à forte inibição causada pelos metabólitos que impediu o contato entre os dois fungos. T. harzianum, Th-9, cresceu ao redor, penetrou e destruiu as hifas de R. solani. A penetração das células hospedeiras parece ser acompanhada por atividade mecânica.

  3. Optimized protein extraction methods for proteomic analysis of Rhizoctonia solani

    Science.gov (United States)

    Rhizoctonia solani (Teleomorph: Thanatephorus cucumeris) is a basidiomycetous fungus which includes important plant pathogens, saprophytes and mycorrhizae. R. solani displays several hyphal anastomosis groups (AGs) with distinct host plant specializations. In order to facilitate studies on its biol...

  4. Reaction of melon genotypes to Rhizoctonia solani Reação de genótipos de melão a Rhizoctonia solani

    OpenAIRE

    Michereff, Sami J.; Egt, Domingos Andrade; Rui Sales Júnior

    2008-01-01

    The intensive exploration of melon (Cucumis melo L.) crops in the Brazilian Northeast favors the occurrence of root diseases such as the Rhizoctonia canker, caused by Rhizoctonia solani. Twenty melon genotypes were challenged against the pathogen isolates RS-9 and RS-10 aiming at selecting those potentially useful for breeding programs and/or integrated disease management. Seeds were planted in infested soil (50 mg of colonized rice grains kg-1 of soil). Disease severity was assessed 15 days ...

  5. Patogenicidade de Rhizoctonia solani em morangueiro Pathogenicity of Rhizoctonia solani to strawberry

    OpenAIRE

    Maria Aparecida de Souza Tanaka; Margarida Fumiko Ito; Francisco Antonio Passos

    1995-01-01

    O fungo Rhizoctonia solani Kuhen tem sido isolado com maior freqüência de mudas e plantas adultas de morangueiro com sintomas de subdesenvolvimento, declínio progressivo, avermelhamento ou arroxeamento dos folíolos, pecíolos e estolhos, além do apodrecimento do ápice da coroa, estipulas e base dos pecíolos. As plantas doentes apresentavam, com freqüência, raízes escuras ou com áreas necrosadas. Fusarium spp. e Pythium spp. também estavam, reiteradamente, associados às plantas do...

  6. Signaling in the Rhizoctonia solani-rice pathosystem

    Science.gov (United States)

    Rhizoctonia solani is a necrotrophic soil borne fungal pathogen known to be a serious crop killer worldwide. A better understanding of the molecular signaling will benefit the development of effective methods to control the pathogen. To dissect molecular signaling between rice and R. solani a combin...

  7. Interrelationships of Rotylenchulus reniformis with Rhizoctonia solani on Cotton

    OpenAIRE

    Sankaralingam, A.; Mcgawley, E. C.

    1994-01-01

    The interrelationships between reniform nematode (Rotylenchulus reniformis) and the cotton (Gossypium hirsutum) seedling blight fungus (Rhizoctonia solani) were studied using three isolates of R. solani, two populations of R. reniformis at multiple inoculum levels, and the cotton cultivars Dehapine 90 (DP 90) and Dehapine 41 (DP 41). Colonization of cotton hypocotyl tissue by R. solani resulted in increases (P ? 0.05) in nematode population densities in soil and in eggs recovered from the r...

  8. Reaction of melon genotypes to Rhizoctonia solani / Reação de genótipos de melão a Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Sami J, Michereff; Domingos EGT, Andrade; Rui, Sales Júnior.

    2008-09-01

    Full Text Available O cultivo intensivo de melão (Cucumis melo L.) no Nordeste brasileiro tem favorecido a ocorrência de doenças radiculares como a rizoctoniose, causada pelo fungo Rhizoctonia solani. Visando selecionar genótipos com potencial de utilização nos programas de melhoramento e/ou no manejo integrado da doen [...] ça, foram avaliados 20 genótipos de melão, em relação a dois isolados do patógeno (RS-9 e RS-10). As sementes foram plantadas em solo infestado com o patógeno pela incorporação de 50 mg de substrato (grãos de arroz) colonizado kg-1 de solo. A avaliação dos genótipos foi realizada após 15 dias, com o auxílio de escala de notas de 0 a 4, para agrupamento de cada genótipo em cinco classes e cálculo do índice de severidade da doença. Nenhum dos genótipos apresentou reação de imunidade a R. solani, independentemente do isolado. Os índices de severidade da doença variaram de 6,2 a 85,4% e de 7,8 a 85,2% para os isolados RS-9 e RS-10, respectivamente. Quando considerados os dois isolados do patógeno simultaneamente, os genótipos Sancho, AF-1805, Athenas, AF-682, Torreon e Galileo comportaram-se como altamente resistentes. Os genótipos Sancho e AF-1805 apresentaram os menores índices de severidade da rizoctoniose em relação a RS-9 e, o genótipo Gold Pride, em relação a RS-10. Esses genótipos diferiram significativamente dos demais, considerando cada isolado do patógeno individualmente e, portanto, constituem fontes promissoras de resistência a R. Solani, devendo ser preferidos para plantio em áreas infestadas pelo patógeno. Abstract in english The intensive exploration of melon (Cucumis melo L.) crops in the Brazilian Northeast favors the occurrence of root diseases such as the Rhizoctonia canker, caused by Rhizoctonia solani. Twenty melon genotypes were challenged against the pathogen isolates RS-9 and RS-10 aiming at selecting those pot [...] entially useful for breeding programs and/or integrated disease management. Seeds were planted in infested soil (50 mg of colonized rice grains kg-1 of soil). Disease severity was assessed 15 days after inoculation, by means of a disease scale from 0 to 4, used later to cluster genotypes in five classes. None of the genotypes presented immune-like reaction to R. solani, independent of the pathogen isolate. Disease severity ranged from 6.2 to 85.4% and from 7.8 to 85.2%, for isolates RS-9 and RS-10, respectively. When both isolates were considered simultaneously, genotypes Sancho, AF-1805, Athenas, AF-682, Torreon, and Galileo were highly resistant. Genotypes Sancho and AF-1805 had the lowest disease severity levels in relation to isolate RS-9, and genotype Gold Pride, in relation to RS-10. These genotypes differed significantly from the others, within isolates. Therefore, they are potential sources of resistance to R. solani and should be considered as a priority planting choice in infested areas.

  9. Resistência de cultivares de arroz a Rhizoctonia solani e Rhizoctonia oryzae Resistance of rice cultivars to Rhizoctonia solani and Rhizoctonia oryzae

    Directory of Open Access Journals (Sweden)

    Anne Sitarama Prabhu

    2002-05-01

    Full Text Available Isolados de Rhizoctonia solani e Rhizoctonia oryzae, agentes causais da queima-da-bainha e mancha-da-bainha, respectivamente, foram coletados em lavouras de arroz irrigado no Estado do Tocantins. O objetivo deste trabalho foi avaliar a resistência de 12 cultivares de arroz a essas doenças, sob condições artificiais de inoculação, em casa de vegetação. Não houve correlação entre resistência das cultivares a R. oryzae e R. solani quanto ao comprimento da lesão na bainha infectada pelo método de palito de dentes. A relação entre tamanho da lesão na bainha e folha foi linear e significativamente negativa (r = -0,66, PIsolates of Rhizoctonia solani and Rhizoctonia oryzae, the causal agents of sheath blight and sheath rot diseases, respectively, were collected from irrigated rice fields in the State of Tocantins, Brazil. The main objective of the investigation was to assess the resistance of 12 genotypes to these diseases, under artificial inoculation tests in greenhouse condition. There was no correlation between the resistance of cultivars to R. oryzae and R. solani for lesion extension on sheath infection obtained by the toothpick method. The relationship between lesion size on sheath and leaf was linear and significantly negative (r = -0.66, P<=0.05, thereby indicating that there is no relationship between resistance of sheath and leaf to infection by R. solani in rice cultivars. Among the early maturing genotypes Labelle was highly susceptible in all methods of inoculation. The area under disease progress curve based on lesion height on the culm and the inoculation method with rice husk and grain were found more adequate for determining the differences in the degree of resistance among cultivars. Leaves exhibited resistance to infection by R. oryzae in inoculation tests with mycelial discs.

  10. Proteomic analysis of Rhizoctonia solani AG-1 sclerotia maturation.

    Science.gov (United States)

    Kwon, Young Sang; Kim, Sang Gon; Chung, Woo Sik; Bae, Hanhong; Jeong, Sung Woo; Shin, Sung Chul; Jeong, Mi-Jeong; Park, Soo-Chul; Kwak, Youn-Sig; Bae, Dong-Won; Lee, Yong Bok

    2014-01-01

    Rhizoctonia solani (R. solani), a soil-borne necrotrophic pathogen, causes various plant diseases. Rhizoctonia solani is a mitosporic fungus, the sclerotium of which is the primary inoculum and ensures survival of the fungus during the offseason of the host crop. Since the fungus does not produce any asexual or sexual spores, understanding the biology of sclerotia is important to examine pathogen ecology and develop more efficient methods for crop protection. Here, one- and two-dimensional gel electrophoresis (1-DE and 2-DE, respectively) were used to examine protein regulation during the maturation of fungal sclerotia. A total of 75 proteins (20 proteins from 1-DE using matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) and 55 proteins from 2-DE using MALDI-TOF MS or MALDI-TOF/TOF MS) were differentially expressed during sclerotial maturation. The identified proteins were classified into ten categories based on their biological functions, including genetic information processing, carbohydrate metabolism, cell defense, amino acid metabolism, nucleotide metabolism, cellular processes, pathogenicity and mycotoxin production, and hypothetical or unknown functions. Interestingly, two vacuole function-related proteins were highly up-regulated throughout sclerotial maturation, which was confirmed at the transcript level by reverse transcriptase polymerase chain reaction (RT-PCR) analysis. These findings contribute to our understanding of the biology of R. solani sclerotia. PMID:24863472

  11. Mycoparasitism of Rhizoctonia solani by Endophytic Chaetomium spirale ND35 : Ultrastructure and Cytochemistry of the Interaction

    OpenAIRE

    Gao, Kexiang; Liu, X.; Kang, Zhensheng; Mendgen, Kurt

    2005-01-01

    The interaction between endophytic biocontrol agent Chaetomium spirale ND35 and the soil-borne plant pathogen Rhizoctonia solani was studied by light microscopy and transmission electron microscopy (TEM), as well as further investigated by gold cytochemistry to assess the potential role of cell wall degrading enzymes (CWDEs) during the mycoparasitic process. Macroscopic observations of fungal growth in dual cultures revealed that pathogen growth inhibition occurred soon after contact with the...

  12. Interaction of sugar beet host resistance and rhizoctonia solani AG-2-2 IIIB strains

    Science.gov (United States)

    Rhizoctonia root rot caused by Rhizoctonia solani can cause serious economic losses in sugar beet fields. Preliminary evidence suggests there could be interactions between different strains and resistance sources. Thus, field studies were conducted to determine if nine R. solani AG-2-2 IIIB strain...

  13. A quitosana como fungistático no crescimento micelial de Rhizoctonia solani Kuhn / Chitosan as fungistatic mycelial growth of Rhizoctonia solani Kuhn

    Scientific Electronic Library Online (English)

    Álvaro Rodrigo, Freddo; Sérgio Miguel, Mazaro; Eleandro José, Brun; Américo, Wagner Júnior.

    2014-01-01

    Full Text Available Rhizoctonia solani é um fungo causador de tombamento de plântulas em várias espécies vegetais. A quitosana é um polímero derivado do processo de desacetilação da quitina, a qual é encontrada em grande quantidade na carapaça de crustáceos, insetos e parede celular de fungos. A quitosana tem sido test [...] ada para diversos usos, inclusive no controle de fitopatógenos em agricultura, já que apresenta atividade antimicrobiana, para controle de patógenos. O presente trabalho teve como objetivo avaliar o efeito fungistático de diferentes concentrações de quitosana (0; 0,25; 0,5; 1 e 2%) no crescimento micelial do fungo R. solani in vitro. Os resultados obtidos demonstraram efeito significativo de quitosana nas diferentes concentrações utilizadas, na redução do crescimento micelial de R. solani. Observou-se também aumento do efeito fungistático da quitosana conforme o aumento da dose. Abstract in english Rhizoctonia solani is a fungus that causes damping-off of seedlings in various plant species. Chitosan is a polymer derived from the process of desacetylation of chitin, which is found in large quantities in the exoskeleton of crustaceans, insects and fungal cell wall. Chitosan has been tested for v [...] arious uses, including the control of plant pathogens in agriculture, since it presents antimicrobial activity to control pathogens. This study aimed to evaluate the fungistatic effect of different chitosan concentrations (0; 0.25; 0.5; 1 and 2%) in mycelial growth in vitro of the fungus R. solani. The results showed a significant effect of different concentrations of chitosan, in reduccing the mycelial growth of R. solani. It was also observed increased fungistatic effect with increasing of the concentration.

  14. Pea seed treatment for Rhizoctonia solani control / Desempenho de sementes de ervilhas em função do controle químico de Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Patrícia Pereira da, Silva; Raquel Alves de, Freitas; Warley Marcos, Nascimento.

    Full Text Available Durante o estabelecimento das lavouras de ervilha, a ocorrência de Rhizoctonia solani causando tombamento de plântulas tem sido observada. O presente trabalho teve como objetivo verificar a eficiência do uso de fungicidas no tratamento de sementes de ervilha cultivar Mikado, visando o controle de Rh [...] izoctonia solani e seus efeitos na qualidade fisiológica dessas sementes. Sementes foram tratadas com os seguintes fungicidas: Carbendazim, Carbendazim + Thiram, Captan, Iprodione, Iprodione + Thiram, Metalaxil-M + Fludioxonil, Pencicurom, Procimidone e Tolifluanida. Como testemunha, foi utilizada sementes tratadas com água destilada. A avaliação da qualidade fisiológica das sementes após o tratamento foi realizada pelos seguintes testes: germinação, primeira contagem, envelhecimento acelerado, condutividade elétrica e emergência de plântulas. As sementes tratadas foram semeadas em solo não inoculado e inoculado com R. solani. A emergência de plântulas foi reduzida em solo inoculado, sendo que os tratamentos que apresentaram melhores resultados foram Carbendazim, Pencicurom, Iprodione e Carbendazim + Thiram. O fungicida Captan prejudicou a qualidade fisiológica das sementes tanto em laboratório como no campo. Com relação à germinação, os tratamentos que apresentaram melhores resultados foram Carbendazim, Pencicurom, Iprodione e Carbendazim + Thiram. Abstract in english The objectives of this study were to evaluate the efficiency of fungicides for pea seed treatment against damping-off caused by Rhizoctonia solani and to verify their effects on physiological seed quality. 'Mikado' pea seeds were treated with the following fungicides: Carbendazim, Carbendazim + Thir [...] am, Captan, Iprodione, Iprodione + Thiram, Metalaxyl-M + Fludioxonil, Pencycuron, Procymidone and Tolyfluanid. Control seeds were treated with deionized water. Physiological seed quality was evaluated with the following tests: germination, first count, accelerated aging and electrical conductivity. Seeds were sown in soil inoculated and no inoculated with R. solani. The experimental design was completely random with four replications. Seedling emergence was reduced in inoculated soil and the best treatments for R. solani control were Carbendazim, Pencycuron, Iprodione and Carbendazim + Thiram. Captan reduced seed physiological quality in both the laboratory and field.

  15. Incompatibilidade somática em Rhizoctonia solani AG-1 IA da soja / Somatic incompatibility in Rhizoctonia solani AG-1 IA of soybean

    Scientific Electronic Library Online (English)

    Ana Paula da Silva de, Campos; Paulo Cezar, Ceresini.

    2006-09-01

    Full Text Available O fungo Rhizoctonia solani AG-1 IA é um dos patógenos mais importantes que afeta a cultura da soja no Brasil, causando a mela ou queima foliar. A doença está associada com a fase teleomórfica de R. solani, o basidiomiceto Thanatephorus cucumeris. Neste estudo, baseando em conhecimento prévio sobre a [...] biologia de R. solani AG-1 IA, duas hipóteses foram testadas. Na primeira hipótese postulou-se a ocorrência de incompatibilidade somática em populações de R. solani AG-1 IA. A segunda hipótese testada foi de que esta população de R. solani AG-1 IA da soja apresenta indicações de estrutura sexual clonal. Duas amostras de isolados de R. solani AG-1 IA da soja obtidas no Maranhão e no Mato Grosso foram utilizadas. Na primeira amostra, foram selecionados isolados apresentando diferentes perfis de RAPD (Random Amplified Polymorphic DNA), procurando maximizar a diversidade dos isolados, e evitando a introdução de possíveis clones no teste. Os isolados foram pareados em todas as combinações possíveis em meio de BDA mais carvão ativado e examinados quanto às interações somáticas resultantes. Seis grupos de incompatibilidade somática (GCS) foram detectados entre 24 isolados do AG-1 IA. Entretanto, análises microscópicas dos pareamentos entre isolados indicaram maior freqüência de incompatibilidade somática, impossibilitando o grupamento em GCS. No geral, a metodologia de avaliação das interações somáticas macroscópicas em meio BDA + carvão ativado, não se mostrou totalmente apropriada para discriminação das categorias de reações de compatibilidade entre isolados de R. solani AG-1 IA. Com a segunda amostra procurou-se determinar a ocorrência de clones na população do patógeno, ou seja, isolados que compartilham o mesmo padrão fenotípico de RAPD e somaticamente compatíveis. No caso de R. solani AG 1 IA da soja, a gama de interações somáticas entre pareamentos de isolados e, principalmente, os desvios na associação estrita entre os GCS detectados neste trabalho, conjuntamente com os perfis de RAPD observados anteriormente por Fenille (11) e Meyer (20), são consistentes com recombinação. Entretanto, o patógeno ainda apresenta um componente clonal expressivo na população. De um total de 43 isolados, os exemplos de prováveis clones na população do patógeno totalizaram 16 isolados. Abstract in english Rhizoctonia solani anastomosis group 1 IA (AG-1 IA) is considered one of the most important pathogens affecting soybean in Brazil, causing the aerial or foliar blight. This disease is associated with the teleomorphase of R. solani AG-1 IA, the basidiomycete fungus Thanatephorus cucumeris. In this st [...] udy, based on previous knowledge of the biology of R. solani AG-1 IA, two hypotheses were tested. In the first we postulated the occurrence of somatic incompatibility in populations of R. solani AG-1 IA. The second was that the population of R. solani AG1 IA from soybean has a clonal structure. Two population samples of R. solani AG-1 IA from soybean, obtained in Maranhão and Mato Grosso were analyzed. In the first sample, isolates with distinct RAPD (Random Amplified Polymorphic DNA) profile were selected to maximize the genetic diversity of isolates and to avoid the introduction of clones in the assay. The isolates were paired in all possible combinations in PDA plus charcoal medium and examined according to the resulting somatic interactions. Six somatic compatibility groups (SCG) were detected among 24 isolates of AG-1 IA. However, microscopic analyzes of the pairings indicated higher frequency of somatic incompatibility, resulting in the impossibility of grouping any two isolates of R. solani AG-1 IA into SCG. In general, the methodology for evaluating the macroscopic somatic interactions in PDA plus charcoal medium seemed not totally appropriate for discriminating between categories of somatic compatibility amongst isolates of R. solani AG-1 IA. With the second sample of isolates we aimed to determine the occurrence of clones in the population

  16. Some Properties of Inulinase from Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Figen Ertan

    2005-01-01

    Full Text Available The preparation and some biochemical properties of inulinase from R. solani which isolated from soil in Tekirdag - Turkey, was carried out by dialysis and concentrated with silica gel-60 then, further proceeded with Sephadex G-150 and DEAE-Cellulose chromatographies. The specific activity of the enzyme was enhanced from 0.256-5.43 U mg -1. The enzyme showed maximum activity at 35?C and pH 5.0, it was stable in the pH range of 5.0-6.5 and up to 40?C. The activity of enzyme was inhibited strongly by Hg2+ and Ag2+ and KCN and DTNB. The action mode of enzyme for inulin was determined as endohydrolitic-action by TLC.

  17. REAÇÃO DE CULTIVARES DO FEIJOEIRO COMUM ÀS PODRIDÕES RADICULARES CAUSADAS POR Rhizoctonia solani E Fusarium solani f. sp. phaseoli

    Directory of Open Access Journals (Sweden)

    Braycia Afonso de Miranda

    2007-12-01

    Full Text Available REACTION OF COMMON BEAN CULTIVARS TOROOT ROT CAUSED BY Rhizoctonia solaniAND Fusarium solani f. sp. phaseoliRhizoctonia solani Kuhn is a necrotrophic fungus andsoil inhabitant that attacks great number of vegetable species. Inbean plants, R. solani can induce different symptoms includingtoppling, root and colon plant rottenness. Fusarium solani (MartSacc. f. sp. phaseoli (Burcholder occurs in practically all beanproducing areas in Brazil and can cause root rots and death tobean plants. This study evaluated the reaction of commercialcommon bean cultivars growing in R. solani or F. solani f. sp.phaseoli infested soil, under green house conditions. Theexperimental design was entirely randomized, with 24 treatmentsand four replications. A Oxisol was infested with trituratedsorghum grains that were previously colonized by R. solani (1.0g/1.4 L of soil or F. solani f. sp phaseoli (8.0 g/1.4 L of soil. Thedisease evaluations were accomplished 21 days after planting.All plants were carefully removed, their root systems werewashed in running water and the disease severity was evaluatedaccording to Abawi & Pastor-Corrales (1990 scale for diseaseseverity. The cultivar behavior ranged according to the inoculatedpathogen, all cultivars were susceptible with different degrees ofsusceptibility. Among evaluated common bean cultivars Pérolawas less susceptible to R. solani, and Radiante was lesssusceptible to F. solani f. sp. phaseoli.

  18. TEMPERATURE EFFECT ON RHIZOCTONIA SOLANI ANALYZED BY MICROCALORIMETRY

    Directory of Open Access Journals (Sweden)

    Antonio Orozco-Avitia

    2013-01-01

    Full Text Available Temperature is one of the factors playing an important role in fungi growth and spread. The aim of this study was to determine the effect of temperature on the growth of ten Rhizoctonia solani isolates. Colony Growth Rate (GR was measured in potato-agar-dextrose cultures and Metabolic Efficiency (ME by isothermal microcalorimetry in R. solani isolates growing in a temperature range of 10 to 40°C at 5°C intervals. The apparent activation Energy (Ea was determined in the range of 15 to 30°C. Different values of Ea were found for each of the strains analyzed. GR increased as temperature increased up to 30°C, showing the highest values between 25°C. ME decreased as temperature increased in nine out of ten isolates, reaching an optimum for the different isolates between 15 and 25°C. Both GR and ME analyses showed different behaviors for each isolate. R. solani AG4 isolates showed a variable response to the same temperature of exposure and it appears that microcalorimetry is more sensitive in detecting early effects of heat stress.

  19. SCREENING AND CHARACTERIZATION OF STREPTOMYCES ISOLATES FOR BIOCONTROL OF RHIZOCTONIA SOLANI AND OTHER PLANT PATHOGENS

    Science.gov (United States)

    Rhizoctonia solani, a ubiquitous soilborne fungal plant pathogen, is responsible for economic losses of agricultural, forestry, horticultural and ornamental crops worldwide. Soil actinomycetes are known to enhance fertility and possess antimicrobial properties against various plant pathogens. One hu...

  20. Transgenic expression of Lactoferrin imparts resistance to a soilborne fungal pathogen Rhizoctonia solani

    Science.gov (United States)

    Transgenic tobacco (Nicotiana tabacum var Xanthi) and Arabidopsis (A. thaliana) plants expressing an antimicrobial bovine lactoferrin (BLF) gene were developed and evaluated for resistance against an economically important fungal pathogen Rhizoctonia solani, the causal agent of damping off diseases....

  1. Identifikasi dan Kuantifikasi Metabolit Bakteri Pelarut Fosfat dan Pengaruhnya terhadap Aktivitas Rhizoctonia solani pada Tanaman Kedelai

    OpenAIRE

    Tri Candra Setiawati; Paniman Asna Mihardja

    2008-01-01

    Phosphate solubilizing bacteria (PSB) metabolites are organic acids, phosphomonoesterase enzyme (alkaline phosphatase) and antibiotic, which is able to dissolve insoluble phosphate. Phosphate solubilizing bacteria used in this study was expected to suppress Rhizoctonia solani attacks. This experiment was aimed at (1) identifiying and quantifying PSB metabolites, and (2) examining their capability as biocontrol agent for Rhizoctonia solani in vitro and hydroponics soybean. This study was con...

  2. Some characteristics of isolates of Rhizoctonia solani from patch of wheat and barley

    OpenAIRE

    Helena Furga?-W?gorzycka; Jan Adamiak; Ewa Adamiak

    1998-01-01

    Rhizoctonia-like fungi were isolated from the roots of discased wheat and barley plants sampled from the centre and periphery of bare patches and from apparently healthy plants from outside of the patches. Of the isolates recovered. 89% were multinucleate and belonged to R. solani anastomosis groups: AG-8, AG-2-2 and AG-4. The remaining isolates were binucleate Rhizoctonia spp. The multinucleate isolates of R. solani were all pathogenic. All the binucleate isolates were non-pathogenic. The AG...

  3. Caracterização morfológica de fontes de resistência de meloeiro a Rhizoctonia solani / Reaction of melon accessions to Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Rui, Sales Júnior; Glauber HS, Nunes; Katchen JP, Silva; Gabriel G, Costa; Izabel M, Guimarães; Sami J, Michereff.

    2015-06-01

    Full Text Available A rizoctoniose, ocasionada pelo fungo Rhizoctonia solani, é uma doença frequente em áreas cultivadas, intensivamente com melão (Cucumis melo) no nordeste brasileiro. O objetivo do presente trabalho foi identificar e caracterizar morfologicamente fontes de resistência de meloeiro a R. solani. No prim [...] eiro ensaio foi avaliado o nível de resistência de 22 acessos de meloeiro coletados no nordeste brasileiro, frente ao isolado RS-21. Os acessos resistentes do primeiro experimento juntamente com 13 linhagens do cruzamento ACP x AF-646 foram avaliados para reação aos isolados RS-22 e RS-23 em um segundo ensaio. Utilizou-se o delineamento inteiramente casualizado com cinco repetições. Foram identificados como fontes de resistência os acessos T-A-08, T-A-09, T-A-19 e a linhagem ACP-AF-06. Nos dois ensaios de inoculação, as sementes foram plantadas em solo infestado com o patógeno pela incorporação de 50 mg de substrato (grãos de arroz) colonizado/kg de solo. A avaliação dos acessos foi realizada após 45 dias, com o auxílio de escala de notas de 0 a 4, para agrupamento de cada genótipo em cinco classes. As fontes de resistência foram caracterizadas morfologicamente em um ensaio em blocos casualizados com três repetições. A caracterização identificou os acessos T-A-08 e T-A-19 como sendo pertencentes à variedade botânica momordica e o acesso T-A-09 e a linhagem ACP-AF-06, pertencentes às variedades acidulus e inodorus, respectivamente. As fontes de resistência poderão ser utilizadas em futuros programas de melhoramento genético visando obter genótipos (linhagens e híbridos simples) resistentes a R. solani. Abstract in english ABSTRACT Rhizoctonia root rot, caused by Rhizoctonia solani, is a common disease in areas intensively cultivated with melon (Cucumis melo) in the Northeastern Brazil. The objective of this study was to identify and characterize morphologically resistance sources of melon to R. solani. In the first [...] trial, twenty-two melon accessions collected in the Northeastern Brazil were evaluated for their reaction to the isolate RS-21, in an experiment with the completely randomized design and five replications. The resistant accessions of the first experiment and 13 inbred lines of the ACP x AF -646 cross were evaluated for their reaction to the RS-22 and RS-23 isolates on a second trial carried out in a randomized design with five replications. The accessions T-A-08, T-A-09, T-A-19 and the line ACP-AF-06 were identified as sources of resistance. In both inoculation trials, seeds were planted in infested soil (50 mg of colonized rice grains/1.0 kg of soil). The evaluation of accessions was performed after 45 days, with a score scale from 0.0 to 4.0 to cluster genotypes in five classes. Resistance sources were characterized morphologically in an essay carried out in randomized block design with three replications. The characterization identified the T-A-08 and T-A-19 accessions as belonging to the botanical variety momordica and the T-A-09 accession and the ACP-AF-06 inbred line as belonging to the varieties acidulus and inodorus, respectively. Resistance sources may be used in future breeding programs aiming to obtain genotypes (inbred lines and hybrids) resistant to R. solani.

  4. Metodologias de inoculação de Rhizoctonia solani na cultura da cenoura / Inoculation methodology of Rhizoctonia solani in carrot

    Scientific Electronic Library Online (English)

    Amanda Cabral Corrêa de, Oliveira; Paulo Estevão de, Souza; Edson Ampélio, Pozza; Felipe de Carvalho, Manerba; Maurício Ferreira, Lopes.

    2008-06-01

    Full Text Available Rhizoctonia solani pode causar diferentes tipos de doenças em cenoura (Daucus carota L.). Para a avaliação de métodos de controle geralmente se utiliza inoculação artificial. Objetivou-se neste trabalho, ajustar uma concentração de inóculo de R. solani (AG-4) no cultivo de cenoura. Utilizou-se delin [...] eamento experimental em blocos ao acaso, com 5 repetições sendo a unidade experimental um vaso de 3L com 40 sementes. Como substrato, utilizou-se solo/areia (3:1). Os tratamentos em esquema fatorial 4 x 3 sendo, 4 densidades de inóculo (9; 18; 36; 72; mg de inóculo·kg-1 de solo) e 3 métodos de infestação artificial (incorporados a todo o solo; incorporados na superfície; contato direto com as sementes) e uma testemunha adicional. O experimento foi conduzido em câmara de crescimento a 20(0)C, com fotoperíodo de 12 h. As avaliações foram realizadas diariamente do 8º ao 30º dia após a semeadura, registrando-se o estande e o número de plântulas com tombamento. Analisou-se o índice de velocidade de emergência, porcentagem média de tombamento pré e pós emergência. A densidade de 72 mg de inóculo·kg-1 de solo incorporado na superfície foi o método mais eficiente. Abstract in english Rhizoctonia solani may cause different diseases in carrot (Daucus carota L.). To test control methods, artificial inoculation is generally employed. This work aimed to adjust a methodology to inoculate R. solani (AG-4) in carrot. A randomized block outline with five replicates was used, with an expe [...] rimental unit of a 3L-pot with 40 seeds and a substact composed by a mixture of soil/sand (3:1 v/v). Treatments were those in a factorial experiment 4 x 3, with 4 inoculum densities (9; 18; 36; 72 mg of inoculum.kg-1 of soil) and three forms of artificial infestation (incorporated to the substract as a whole; incorporated on the surface; with direct contact with seeds) and an additional control. The experiment was carried out in a growth chamber at 20(0)C and a 12h photoperiod. The evaluations were daily performed from the 8th to the 30th day after sowing, recording plant stand and number of seedlings with damping-off. The emergence index, averge percentage of pre and post emergence. Were analyzed the density of 72 mg of inoculum·kg-1 of soil, incorporated on the surface of the susbtract was the most efficient inoculation method.

  5. Reaction of faba bean genotypes to Rhizoctonia solani and resistance stability Reação de genótipos de fava a Rhizoctonia solani e estabilidade da resistência

    OpenAIRE

    Assunc?a?o, Iraildes P.; Nascimento, Liliane D.; Ferreira, Me?rcia F.; Oliveira, Francisco J.; Michereff, Sami J.; Sa, Gaus Lima

    2011-01-01

    The production of faba bean (Phaseolus lunatus) is limited due to the occurrence of Rhizoctonia canker, caused by the fungus Rhizoctonia solani. In order to select materials with potential for use in faba beans breeding programs and/or disease integrated management, 72 genotypes were evaluated and also stability of the disease resistance in relation to different pathogen isolates, inoculum densities and soil type. The seeds were sown in soil infested with the pathogen by the addition of colon...

  6. Relação entre coberturas vegetais e supressividade de solos a Rhizoctonia solani / Relationship between vegetation and soil suppressiveness to Rhizoctonia solani

    Scientific Electronic Library Online (English)

    RAQUEL, GHINI; MARGARIDA M. H., ZARONI.

    2001-03-01

    Full Text Available Áreas de uma microbacia sem a incidência de doenças causadas por Rhizoctonia solani GA 4 foram agrupadas estatisticamente, pelo método de Ward, com relação à supressividade dos solos ao patógeno, avaliada pela taxa de crescimento micelial. Entre os grupos formados, foi definido um gradiente de supre [...] ssividade. A relação entre gradientes de supressividade e tipos de cobertura vegetal foi descrita com auxílio da análise de correspondências múltiplas, sendo que, de modo geral, o pasto e o pousio, seguidos da mata, tornaram os solos mais supressivos, ao passo que a cana-de-açúcar (Saccharum officinarum), o milho (Zea mays ), o café (Coffea arabica) e o solo arado tornaram os solos mais conducentes. Porém, os resultados mostraram que outros fatores, além da cobertura vegetal, podem estar afetando a supressividade. Um tratamento biocida (fumigação) dos solos mais supressivos promoveu um maior incremento da taxa de crescimento do patógeno do que o observado com solos mais conducentes. Abstract in english Areas from a microbasin without the incidence of plant diseases caused by Rhizoctonia solani GA 4 were statistically grouped by Ward's method, in relation to soil suppressiveness, described by the mycelial growth rate. A gradient of suppressiveness was defined between the groups. The relationship be [...] tween suppressiveness and types of vegetation was described by a multiple correspondence analysis. In general, soils from pasture, fallow ground and forest were classified as suppressive soils, while sugar cane (Saccharum officinarum), maize (Zea mays ), coffee (Coffea arabica) and ploughed soils, as conducive soils. However, results showed that other factors affect suppressiveness besides vegetation. A biocide treatment (fumigation) promoted a greater increase in the growth rate of the pathogen on suppressive soils than on conducive ones

  7. Relação entre coberturas vegetais e supressividade de solos a Rhizoctonia solani Relationship between vegetation and soil suppressiveness to Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    RAQUEL GHINI

    2001-03-01

    Full Text Available Áreas de uma microbacia sem a incidência de doenças causadas por Rhizoctonia solani GA 4 foram agrupadas estatisticamente, pelo método de Ward, com relação à supressividade dos solos ao patógeno, avaliada pela taxa de crescimento micelial. Entre os grupos formados, foi definido um gradiente de supressividade. A relação entre gradientes de supressividade e tipos de cobertura vegetal foi descrita com auxílio da análise de correspondências múltiplas, sendo que, de modo geral, o pasto e o pousio, seguidos da mata, tornaram os solos mais supressivos, ao passo que a cana-de-açúcar (Saccharum officinarum, o milho (Zea mays , o café (Coffea arabica e o solo arado tornaram os solos mais conducentes. Porém, os resultados mostraram que outros fatores, além da cobertura vegetal, podem estar afetando a supressividade. Um tratamento biocida (fumigação dos solos mais supressivos promoveu um maior incremento da taxa de crescimento do patógeno do que o observado com solos mais conducentes.Areas from a microbasin without the incidence of plant diseases caused by Rhizoctonia solani GA 4 were statistically grouped by Ward's method, in relation to soil suppressiveness, described by the mycelial growth rate. A gradient of suppressiveness was defined between the groups. The relationship between suppressiveness and types of vegetation was described by a multiple correspondence analysis. In general, soils from pasture, fallow ground and forest were classified as suppressive soils, while sugar cane (Saccharum officinarum, maize (Zea mays , coffee (Coffea arabica and ploughed soils, as conducive soils. However, results showed that other factors affect suppressiveness besides vegetation. A biocide treatment (fumigation promoted a greater increase in the growth rate of the pathogen on suppressive soils than on conducive ones

  8. Influence of Rhizoctonia solani on Egg Hatching and Infectivity of Rotylenchulus reniformis

    OpenAIRE

    Sankaralingam, A.; Mcgawley, E. C.

    1994-01-01

    The effects of culture filtrates of Rhizoctonia solani and root exudates of R. solani-infected cotton (Gossypium hirsutum) seedlings on hatching of eggs and infectivity of females of Rotylenchulus reniformis were evaluated in an attempt to account for the enhanced nematode reproduction observed in the presence of this fungus. Crude filtrates of R. solani cultures growing over sterile, deionized distilled water did not affect egg hatching. Exudates from roots of cotton seedlings increased hatc...

  9. Crop Residue Affects Rhizoctonia solani Population Dynamics and Seedling Blight of Canola

    OpenAIRE

    Ahmed, H. U.; Hwang, S. F.; Turnbull, G. D.; Strelkov, S. E.; Gossen, B. D.

    2014-01-01

    Seedling blight caused by Rhizoctonia solani Kühn substantially reduces stand establishment and seed yield of canola (Brassica napus L.) in western Canada. The effect of crop residue on soil populations of R. solani and canola seedling blight was examined under field, greenhouse and laboratory conditions. Field plots were established with inoculation or noninoculation with R. solani as the main plot and barley, canola, oat and field pea residues as the sub...

  10. In vitro antagonistic activity of fungi isolated from sclerotia on potato tubers against Rhizoctonia solani

    OpenAIRE

    Demi?rci?, Erkol; Dane, Elif; Eken, Cafer

    2011-01-01

    Forty-five fungal isolates were obtained from sclerotia of Rhizoctonia solani on potato tubers in Erzurum, Turkey. The interaction between fungal isolates and R. solani was studied in dual culture technique. Some fungal isolates affected R. solani by antibiosis and/or parasitism. Results of the antagonism tests showed that Acremonium sp., Gliocladium viride, Paecilomyces marquandii, Paecilomyces sulphurellus, Penicillium camemberti, Penicillium expansum, Penicillium frequentans (ME-50), Penic...

  11. Real-time pcr (qpcr) assay for rhizoctonia solani anastomoses group ag2-2 iiib

    International Nuclear Information System (INIS)

    Rhizoctonia solani anastomosis group AG2-2 IIIB is a severe sugar beet and maize pathogen. It causes crown and root rot disease which leads to yield losses world-wide. The soil-borne pathogen is difficult to detect and quantify by conventional methods. We developed a real-time PCR (qPCR) assay for the quantification of genomic DNA of Rhizoctonia solani AG2-2 IIIB based on the ITS region of rDNA genes. The limit of quantification of the assay is 1.8 pg genomic DNA. The amplification efficiency was 96.4. The assay will be helpful in the diagnoses of Rhizoctonia solani infection of sugar beet and maize roots and in the quantification of R. solani AG2-2 IIIB inoculum in plant debris and soil. (author)

  12. Susceptibility of leguminous green manure species to Rhizoctonia solani and Sclerotium rolfsii Suscetibilidade de espécies de leguminosas usadas como adubo verde a Rhizoctonia solani e Sclerotium rolfsii

    Directory of Open Access Journals (Sweden)

    Trazilbo José de Paula Júnior

    2011-12-01

    Full Text Available We studied the susceptibility of species used as green manure in common bean fields to root rot (Rhizoctonia solani and southern blight (Sclerotium rolfsii. Seeds of Crotalaria breviflora, Canavalia ensiformis, Cajanus cajan, Dolichos lablab, Stizolobium cinereum, S. aterrimum, and the bean cvs. "Pérola", "Valente" and "Carnaval" were sown in soil infested by either R. solani AG-4 or S. rolfsii in greenhouse. The emergence of D. lablab seedlings in soil infested by R. solani dropped to 62%. C. breviflora, C. ensiformis and cv. "Valente" presented the lowest root rot severity. The pathogen S. rolfsii drastically reduced seedling emergence in all species; no C. cajan and S. cinereum seedling emerged. All plant species presented high southern blight severity. We conclude that leguminous crops are not suitable as green manure for areas of bean cultivation with high R. solani and S. rolfsii populations.Estudou-se a suscetibilidade de leguminosas utilizadas como adubos verdes em campos cultivados com feijão à podridão-radicular (Rhizoctonia solani e à podridão-do-colo (Sclerotium rolfsii. Crotalaria breviflora, Canavalia ensiformis, Cajanus cajan, Dolichos lablab, Stizolobium cinereum, S. aterrimum, e as cultivares de feijão Pérola, Valente e Carnaval foram semeadas em solo infestado por R. solani AG-4 ou S. rolfsii em casa de vegetação. A emergência de D. lablab em solo infestado por R. solani foi reduzida a 62%. C. breviflora, C. ensiformis e Valente apresentaram a menor severidade de podridão-radicular. O fungo S. rolfsii reduziu drasticamente a emergência de todas as espécies; nenhuma plântula de C. cajan e S. cinereum emergiu. Todas as espécies apresentaram alta severidade de podridão-do-colo. As espécies de leguminosas testadas não são apropriadas para serem utilizadas como adubo verde em áreas de cultivo de feijão com alta população de R. solani e S. rolfsii.

  13. Susceptibility of leguminous green manure species to Rhizoctonia solani and Sclerotium rolfsii / Suscetibilidade de espécies de leguminosas usadas como adubo verde a Rhizoctonia solani e Sclerotium rolfsii

    Scientific Electronic Library Online (English)

    Trazilbo José de, Paula Júnior; Hudson, Teixeira; Rogério Faria, Vieira; Miller da Silva, Lehner; Renan Cardoso de, Lima; Telma Fallieri Nascimento, Queiroz.

    2011-12-01

    Full Text Available Estudou-se a suscetibilidade de leguminosas utilizadas como adubos verdes em campos cultivados com feijão à podridão-radicular (Rhizoctonia solani) e à podridão-do-colo (Sclerotium rolfsii). Crotalaria breviflora, Canavalia ensiformis, Cajanus cajan, Dolichos lablab, Stizolobium cinereum, S. aterrim [...] um, e as cultivares de feijão Pérola, Valente e Carnaval foram semeadas em solo infestado por R. solani AG-4 ou S. rolfsii em casa de vegetação. A emergência de D. lablab em solo infestado por R. solani foi reduzida a 62%. C. breviflora, C. ensiformis e Valente apresentaram a menor severidade de podridão-radicular. O fungo S. rolfsii reduziu drasticamente a emergência de todas as espécies; nenhuma plântula de C. cajan e S. cinereum emergiu. Todas as espécies apresentaram alta severidade de podridão-do-colo. As espécies de leguminosas testadas não são apropriadas para serem utilizadas como adubo verde em áreas de cultivo de feijão com alta população de R. solani e S. rolfsii. Abstract in english We studied the susceptibility of species used as green manure in common bean fields to root rot (Rhizoctonia solani) and southern blight (Sclerotium rolfsii). Seeds of Crotalaria breviflora, Canavalia ensiformis, Cajanus cajan, Dolichos lablab, Stizolobium cinereum, S. aterrimum, and the bean cvs. " [...] Pérola", "Valente" and "Carnaval" were sown in soil infested by either R. solani AG-4 or S. rolfsii in greenhouse. The emergence of D. lablab seedlings in soil infested by R. solani dropped to 62%. C. breviflora, C. ensiformis and cv. "Valente" presented the lowest root rot severity. The pathogen S. rolfsii drastically reduced seedling emergence in all species; no C. cajan and S. cinereum seedling emerged. All plant species presented high southern blight severity. We conclude that leguminous crops are not suitable as green manure for areas of bean cultivation with high R. solani and S. rolfsii populations.

  14. Draft Genome Sequence of the Plant-Pathogenic Soil Fungus Rhizoctonia solani Anastomosis Group 3 Strain Rhs1AP.

    Science.gov (United States)

    Cubeta, Marc A; Thomas, Elizabeth; Dean, Ralph A; Jabaji, Suha; Neate, Stephen M; Tavantzis, Stellos; Toda, Takeshi; Vilgalys, Rytas; Bharathan, Narayanaswamy; Fedorova-Abrams, Natalie; Pakala, Suman B; Pakala, Suchitra M; Zafar, Nikhat; Joardar, Vinita; Losada, Liliana; Nierman, William C

    2014-01-01

    The soil fungus Rhizoctonia solani is a pathogen of agricultural crops. Here, we report on the 51,705,945 bp draft consensus genome sequence of R. solani strain Rhs1AP. A comprehensive understanding of the heterokaryotic genome complexity and organization of R. solani may provide insight into the plant disease ecology and adaptive behavior of the fungus. PMID:25359908

  15. Draft Genome Sequence of the Plant-Pathogenic Soil Fungus Rhizoctonia solani Anastomosis Group 3 Strain Rhs1AP

    OpenAIRE

    Cubeta, Marc A.; Thomas, Elizabeth; Dean, Ralph A.; Jabaji, Suha; Neate, Stephen M.; Tavantzis, Stellos; Toda, Takeshi; Vilgalys, Rytas; Bharathan, Narayanaswamy; Fedorova-abrams, Natalie; Pakala, Suman B.; Pakala, Suchitra M.; Zafar, Nikhat; Joardar, Vinita; Losada, Liliana

    2014-01-01

    The soil fungus Rhizoctonia solani is a pathogen of agricultural crops. Here, we report on the 51,705,945 bp draft consensus genome sequence of R. solani strain Rhs1AP. A comprehensive understanding of the heterokaryotic genome complexity and organization of R. solani may provide insight into the plant disease ecology and adaptive behavior of the fungus.

  16. Effects of Meloidogyne spp. and Rhizoctonia solani on the Growth of Grapevine Rootings

    OpenAIRE

    Walker, G. E.

    1997-01-01

    A disease complex involving Meloidogyne incognita and Rhizoctonia solani was associated with stunting of grapevines in a field nursery. Nematode reproduction was occurring on both susceptible and resistant cultivars, and pot experiments were conducted to determine the virulence of this M. incognita population, and of M. javanica and M. hapla populations, to V. vinifera cv. Colombard (susceptible) and to V. champinii cv. Ramsey (regarded locally as highly resistant). The virulence of R. solani...

  17. A greenhouse test for screening sugar beet (Beta vulgaris) for resistance to Rhizoctonia solani

    OpenAIRE

    Scholten, O. E.; Panella, L.; Bock, T. S. M.; Lange, W.

    2001-01-01

    Rhizoctonia solani Kühn is a serious plant pathogenic fungus, causing various types of damage to sugar beet (Beta vulgaris L.). In Europe, the disease is spreading and becoming a threat for the growing of this crop. Plant resistance seems to be the most practical and economical way to control the disease. Experiments were carried out to optimise a greenhouse procedure to screen plants of sugar beet for resistance to R. solani. In the first experiment, two susceptible accessions were evaluate...

  18. Randomly Amplified Polymorphic DNA of Trichoderma isolates and antagonism against Rhizoctonia solani

    OpenAIRE

    Larissa Brandão Góes; Ana Bolena Lima da Costa; Laurineide Lopes de Carvalho Freire; Neiva Tinti de Oliveira

    2002-01-01

    Random Amplified Polymorphic DNA (RAPD) procedure was used to examine the genetic variability among fourteen isolates of Trichoderma and their ability to antagonize Rhizoctonia solani using a dual-culture assay for correlation among RAPD products and their hardness to R. solani. Seven oligodeoxynucleotide primers were selected for the RAPD assays which resulted in 197 bands for 14 isolates of Trichoderma. The data were entered into a binary matrix and a similarity matrix was constructed using...

  19. Effects of granular nematicides on the infection of potatoes by Rhizoctonia solani.

    OpenAIRE

    Hofman, T. W.

    1988-01-01

    The granular nematicides aldicarb, oxamyl and ethoprophos often are applied to control plant parasitic nematodes. However, the use of these pesticides may have some disadvantages. In field trials, they increased stem infection of potatoes caused by Rhizoctonia solani Kühn and incidence of black scurf (sclerotia of R. solani ) on tubers. This thesis, reports about possible mechanisms involved in the increased infection in nematicide treated fields. The effects of granular nematicides were stu...

  20. Induction of systemic resistance by a hypovirulent Rhizoctonia solani isolate in tomato

    OpenAIRE

    Valentino, Danila; Tamietti, Giacomo; Cardinale, Francesca; Ferraris, Lucia

    2006-01-01

    A polynucleate Rhizoctonia isolate (R3) was analysed for virulence, growth characteristics, enzyme production and presence of dsRNAs. Taxonomic position was assessed morphologically and by anastomosis group (AG) testing and ITS sequence analysis. Results indicated that R3 is a hypovirulent R. solani AG 4. Mechanisms underlying biocontrol towards virulent R. solani and Botrytis cinerea were investigated and plant-mediated resistance was followed using biochemical markers of defence (PR1, lamin...

  1. Determination of Mycorrhizae Interactions and Pathogenicity of Rhizoctonia solani Kühn Isolated from Strawberry and Xanthium strumarium

    OpenAIRE

    Bayo?zen, Ays?enur; Yildiz, Ayhan

    2009-01-01

    The effects of mycorrhizal fungi on the disease severity of Rhizoctonia solani Kühn., and the role of mycorrhizal fungi on strawberry (Fragaria vesca L.) growth were investigated. Strawberry seedlings were inoculated with BioOrganics as a mycorrhizal preparation against 2 R. solani isolates, which were isolated from strawberry (RsFv) and Xanthium strumarium (RsXs). The highest disease severity in strawberry roots was observed after inoculation with RsFv at a rate of 67%. On the other hand, t...

  2. Identification and quantification of Rhizoctonia solani and R. oryzae using real-time polymerase chain reaction.

    Science.gov (United States)

    Okubara, P A; Schroeder, K L; Paulitz, T C

    2008-07-01

    Rhizoctonia solani and R. oryzae are the principal causal agents of Rhizoctonia root rot in dryland cereal production systems of the Pacific Northwest. To facilitate the identification and quantification of these pathogens in agricultural samples, we developed SYBR Green I-based real-time quantitative-polymerase chain reaction (Q-PCR) assays specific to internal transcribed spacers ITS1 and ITS2 of the nuclear ribosomal DNA of R. solani and R. oryzae. The assays were diagnostic for R. solani AG-2-1, AG-8, and AG-10, three genotypes of R. oryzae, and an AG-I-like binucleate Rhizoctonia species. Quantification was reproducible at or below a cycle threshold (Ct) of 33, or 2 to 10 fg of mycelial DNA from cultured fungi, 200 to 500 fg of pathogen DNA from root extracts, and 20 to 50 fg of pathogen DNA from soil extracts. However, pathogen DNA could be specifically detected in all types of extracts at about 100-fold below the quantification levels. Soils from Ritzville, WA, showing acute Rhizoctonia bare patch harbored 9.4 to 780 pg of R. solani AG-8 DNA per gram of soil.. Blastn, primer-template duplex stability, and phylogenetic analyses predicted that the Q-PCR assays will be diagnostic for isolates from Australia, Israel, Japan, and other countries. PMID:18943261

  3. Reaction of faba bean genotypes to Rhizoctonia solani and resistance stability Reação de genótipos de fava a Rhizoctonia solani e estabilidade da resistência

    Directory of Open Access Journals (Sweden)

    Iraildes P Assunção

    2011-12-01

    Full Text Available The production of faba bean (Phaseolus lunatus is limited due to the occurrence of Rhizoctonia canker, caused by the fungus Rhizoctonia solani. In order to select materials with potential for use in faba beans breeding programs and/or disease integrated management, 72 genotypes were evaluated and also stability of the disease resistance in relation to different pathogen isolates, inoculum densities and soil type. The seeds were sown in soil infested with the pathogen by the addition of colonized substrate (rice grains. The evaluation of genotypes was done after 15 days, using a note scale to discriminate the genotypes into five reaction classes. None of the 72 genotypes showed immunity to R. solani and only four genotypes (F-42, F-49, F-53 and F-58 behaved as highly resistant. The reactions presented by these genotypes varied according to the R. solani isolate, inoculum density and soil used. The genotype F-58 showed more stable resistance to pathogen isolates and inoculum densities. The genotype F-53 showed resistance stability in soils collected in different locations, remaining highly resistant in all situations. The genotype F-58 did not show high resistance to only one tested soil. Therefore, the genotypes F-58 and F-53 are promising sources of resistance to R. solani and should be indicated in areas infested by the pathogen.A produção de fava (Phaseolus lunatus é limitada pela ocorrência da rizoctoniose, causada pelo fungo Rhizoctonia solani. Visando selecionar materiais com potencial de utilização nos programas de melhoramento e/ou no manejo integrado da doença, foram avaliados 72 genótipos de fava e verificada a estabilidade da resistência em relação a diferentes isolados do patógeno, densidades de inóculo e tipos de solo. As sementes foram plantadas em solo infestado com o patógeno pela incorporação de substrato (grãos de arroz colonizado. A avaliação dos genótipos foi realizada após 15 dias, com o auxílio de escala de notas, discriminando-os em cinco classes de reação. Nenhum dos 72 genótipos apresentou reação de imunidade a R. solani e apenas quatro genótipos (F-42, F-49, F-53 e F-58 comportaram-se como altamente resistentes. As reações apresentadas por esses genótipos variaram conforme o isolado de R. solani, a densidade de inóculo e o solo utilizado. O genótipo F-58 evidenciou maior estabilidade na resistência aos isolados do patógeno e densidades de inóculo. O genótipo F-53 demonstrou estabilidade da resistência em solos coletados em diferentes locais, mantendo alta resistência em todas as situações. O genótipo F-58 não demonstrou alta resistência em somente um solo. Portanto, os genótipos F-58 e F-53 constituem fontes promissoras de resistência a R. solani e devem ser preferidas em campos infestados pelo patógeno.

  4. Molecular characterisation of an endornavirus from Rhizoctonia solani AG-3PT infecting potato.

    Science.gov (United States)

    Das, Subha; Falloon, Richard E; Stewart, Alison; Pitman, Andrew R

    2014-11-01

    Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a soil-borne plant pathogenic fungus that has a broad host range, including potato. In this study, the double-stranded RNA (dsRNA) profiles were defined for 39 Rhizoctonia solani isolates representative of two different anastomosis groups (AGs) associated with black scurf of potato in New Zealand. A large dsRNA of c. 12 kb-18 kb was detected in each of the isolates, regardless of AG or virulence on potato. Characterisation of the large dsRNA from R. solani AG-3PT isolate RS002, using random amplification of total dsRNA and analyses of overlapping cDNA sequences, resulted in the assembly of a consensus sequence of 14?694 nt. A single, large open reading frame was identified on the positive strand of the assembled sequence encoding a putative polypeptide of at least 4893 amino acids, with a predicted molecular mass of 555.6 kDa. Conserved domains within this polypeptide included those for a viral methyltransferase, a viral RNA helicase 1 and an RNA-dependent RNA polymerase. The domains and their sequential organisation revealed the polyprotein was very similar to those encoded by dsRNA viruses of the genus Endornavirus, in the family Endornaviridae. This is the first report of an endornavirus in R. solani, and thus the putative virus is herein named Rhizoctonia solani endornavirus - RS002 (RsEV-RS002). Partial characterisation of the large dsRNAs in five additional AG-3PT isolates of R. solani also identified them as probable endornaviruses, suggesting this family of viruses is widespread in R. solani infecting potato. The ubiquitous nature of endornaviruses in this plant pathogen implies they may have an important, but yet uncharacterised, role in R. solani. PMID:25442295

  5. Actividad fungicida del hongo liquenizado Loxospora pustulata sobre Rhizoctonia solani / Fungicide activity of lichen-forming fungi Loxospora pustulata above Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Daymara I, Vaillant Flores; Carlos R, Romeu Carballo; Marlene, Gómez Peralta; Rebeca, Ramírez Ochoa.

    2014-06-01

    Full Text Available Los líquenes son hongos que establecen una relación de simbiosis con uno o varios organismos fotosintéticos (algas o cianobacterias). En esta relación el hongo (micobionte) produce un determinado número de metabolitos secundarios con actividad antibiótica. De acuerdo a esta afirmación se propone: co [...] mprobar el efecto fungicida de los metabolitos secundarios producidos en medio de cultivo por el micobionte del liquen Loxospora pustulata, sobre Rhizoctonia solani aislado de papa. El micobionte se cultivó en medio agar papa dextrosa (PDA), posteriormente se fermentó en caldo de papa por cultivo agitado y los metabolitos se extrajeron con acetato de etilo. Se prepararon concentraciones de 0,01; 0,03; 0,07% p/v del extracto liquénico en PDA donde se sembraron discos de R. solani y se determinó el porcentaje de inhibición del crecimiento micelial. El extracto liquénico mostró 100% de inhibición del desarrollo de R. solani a las tres concentraciones. Abstract in english The lichens are fungi that establish a symbiotic relation with one or various photosynthetic organisms (algae or cyanobacterium). In this relation the fungi (mycobiont) produce secondary metabolites with antibiotic activity. For this reason the fungicide effect of metabolites produced in culture med [...] ia by the lichen's mycobiont Loxospora pustulata, above Rhizoctonia solani isolated from potato was verified. The mycobiont was cultivated in media potato dextrose agar (PDA) and it was fermented in potato broth by shaken culture. The metabolites were extracted with ethyl acetate. A solution in PDA at 0,01: 0.03: 0,07% w/v concentrations was prepared from the lichens extracts. R. solani discs were placed in the solution and the mycelial growth inhibition percentage was measured. The lichen extract showed 100% of inhibition of the R. solani mycelial growth to all concentrations.

  6. Ultrastructural analysis of anastomosis group 9 of Rhizoctonia solani

    International Nuclear Information System (INIS)

    The ultrastructure of R. solani AG-9 (S-21, ATCC 62804) was investigated with transmission electron microscopy (TEM). The most important characteristics were those related with cell wall thickness, cytoplasmic matrix composition, number of nuclei and nucleoli and secretory material production. The majority of examined hyphae showed lateral cell walls thinner than those recorded before. The cytoplasmic matrix consistently appeared differentiated into two classes, one formed by a highly electron dense granular fine material and the other one showing a coloidal substance of very low density which give these cells a 'tiger-like' aspect. The granular dense matrix always had abundant free ribosomes and usually surrounded the cytoplasmic organelles and the septal pore apparatus. The somatic cells showed up to 5 nuclei, some of which with three nucleoli. Masses of secretory material surrounded by membrane were regularly seen in the cytoplasm, with sizes similar to those of nuclei

  7. Reação de resistência de genótipos de tomateiro (Lycopersicum spp. à infecção por Rhizoctonia solani Kuhn Resistance reaction of tomato genotypes (Lycopersicum spp. to Rhizoctonia solani Kuhn

    Directory of Open Access Journals (Sweden)

    A.M. Rodrigues Cassiolato

    1994-12-01

    Full Text Available Dada a importância da tomaticultura no Brasil e das enfermidades que atacam esta cultura, da mesma forma que visando futuros estados em programas de melhoramento vegetal para resistência à patógenos, este trabalho teve por objetivos: avaliar o grau de patogenicidade de quatro isolados de Rhizoctonia solani obtidos de plantas doentes de tomateiro (RT, berinjelas (RB1 e RB2 e pimentão (RP, em viveiros, frente a 9 genótipos de tomateiros e avaliar a reação de resistência de 73 genótipos de tomateiros ao R. solani. Nos experimentos utilizou-se solo esterilizado, em condições de casa de vegetação. Para o experimento I, os isolados de R. solani, oriundos das plantas de tomateiro (RT e berinjela (RB, foram igualmente mais patogênicos que os isolados de berinjela (RB, e pimentão (RP, com relação aos 9 genótipos de tomateiro testados. Pode-se dizer que os isolados variaram em graus de agressividade. Quanto às reações de resistência a R. solani, observou-se que os diferentes genótipos não diferiram estatisticamente entre si. Com relação ao experimento II, entre os 73 genótipos de tomateiro (incluindo espécies selvagens, variedades nacionais e introduções, pode-se observar que houve grande variabilidade quanto a reação de resistência a R. solani (isolado do tomateiro - RT, com percentuais de sobrevivência de plantas variando de 91%, para a cultivar Quinck Pick, até 0% de sobrevivência para o genótipo LA-462. Não foi verificada imunidade em nenhum material avaliado e sim níveis de resistência, onde esta, expressa em percentagem de sobrevivência, ocorreu de uma maneira contínua, desde uma reação de suscetibilidade até altos níveis de resistência.The present study was undertaken with the following objectives: 1 to evaluate the level of pathogenicity of four Rhizoctonia solani isolates obtained from diseased tomato plants (RT, from eggplant (RB1 and RB2, and pepper (RP and tested on 9 tomato genotypes grown in experimental plots; and 2 evaluate the resistance reaction of 73 tomato genotypes to the pathogen. Experiments were performed in greenhouse using sterilized soil. In experiment I, R. solani isolates from RT and RB2 plants were identically more pathogenic RB1 and RP. In experiment II, wide variability in the resistance reaction to R. solani (isolated from a tomato plant - RT was observed among the 73 tomato genotypes (which included wild species, Brazilian varieties and introduced material, with percentage of plant survival ranging from 91% for the cultivar Quick Pick to 0% for the genotype LA-462. None of the materials tested showed immunity, but different levels of resistance were observed, ranging from susceptibility to high resistance, as expressed by the survival percentages.

  8. TEMPERATURE EFFECT ON RHIZOCTONIA SOLANI ANALYZED BY MICROCALORIMETRY

    OpenAIRE

    Antonio Orozco-Avitia; Martin Esqueda; Amparo Meza; Martin Tiznado; Aldo Gutierrez; Alfonso Gardea

    2013-01-01

    Temperature is one of the factors playing an important role in fungi growth and spread. The aim of this study was to determine the effect of temperature on the growth of ten Rhizoctonia solani isolates. Colony Growth Rate (GR) was measured in potato-agar-dextrose cultures and Metabolic Efficiency (ME) by isothermal microcalorimetry in R. solani isolates growing in a temperature range of 10 to 40°C at 5°C intervals. The apparent activation Energy (Ea) was determined in the range of 15 to...

  9. NATURAL SUPPRESSIVENESS TO Rhizoctonia solani OF DIFFERENT SOILS ON CERRADOS FROM THE STATE OF GOIÁS SUPRESSIVIDADE DE DIFERENTES SOLOS A Rhizoctonia solani, NOS CERRADOS DO ESTADO DE GOIÁS

    Directory of Open Access Journals (Sweden)

    Gilmarcos de Carvalho Corrêa

    2007-09-01

    Full Text Available

    This study was carried out at greenhouse in order to evaluate the occurrence of natural suppressiveness to Rhizoctonia solani of soils on cerrados. A complete randomized experimental design was used with ten soils and three replications for treatment, evaluating final stand, sick plantets percentage and disease severity in common beans (Phaseolus vulgaris L.. Results indicated suppressiveness to R. solani in soils from Goianésia growed with sugar cane and two soils from Orizona with natural vegetation and pasture respectively.

    KEY-WORDS: Supressive soils; Phaseolus vulgaris.

    O presente trabalho foi conduzido nas instalações da Embrapa Arroz e Feijão, no município de Santo Antônio de Goiás (GO, com o objetivo de se comparar solos provenientes de diferentes localidades quanto à supressividade a um isolado de Rhizoctonia solani. O delineamento experimental adotado foi inteiramente casualizado, com dez tratamentos (solos de diferentes origens e três repetições. O experimento foi conduzido em casa de vegetação e foram avaliados stand final, porcentagem de plântulas doentes e severidade da doença. Os resultados indicam que os solos provenientes de Goianésia (GO, cultivados com cana-de-açúcar, e dois dos solos provenientes de Orizona (GO, sendo um de cerrado natural e outro cultivado com pastagem, apresentaram características de supressividade à R. solani, agente causal da podridão radicular do feijoeiro.

    PALAVRAS-CHAVE: Cerrados; solos supressivos; feijoeiro.

  10. Stem Rot on Adzuki Bean (Vigna angularis) Caused by Rhizoctonia solani AG 4 HGI in China

    Science.gov (United States)

    Sun, Suli; Xia, Changjian; Zhang, Jiqing; Duan, Canxing; Wang, Xiaoming; Wu, Xiaofei; Lee, Suk-Ha; Zhu, Zhendong

    2015-01-01

    During late August and early September 2011, stem rot symptoms were observed on adzuki bean plants (Vigna angularis) growing in fields located in Beijing and Hebei Province, China, respectively. In this study, four isolates were obtained from infected stems of adzuki bean plants. Based on their morphology, and sequence and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the ribosomal DNA internal transcribed spacers (rDNA-ITS) region, the four isolates were identified as Rhizoctonia solani in anastomosis group (AG) 4 HGI. Pathogenicity tests showed that all isolates were strongly pathogenic to adzuki bean and resulted in serious wilt symptoms which was similar to observations in the fields. Additionally, the isolates infected several other crops and induced related rot on the roots and basal stems. To our knowledge, this is the first report of Rhizoctonia solani AG 4 HGI causing stem rot on adzuki bean. PMID:25774112

  11. Genetic Diversity among Nile Delta Isolates of Rhizoctonia solani Kühn Based on Pathogenicity, Compatibility, Isozyme Analysis and Total Protein Pattern

    OpenAIRE

    Mahmoud, Yehia A. -g; Gaafar, Reda M.; Mubarak, H. M.

    2007-01-01

    The present study obtained 12 isolates from Rhizoctonia solani Kühn isolated from Cotton L., Trifolium L. and Vicia faba L. from different localities in the Nile Delta of Egypt. All strains were pathogenic and caused seed rot, wilt, stunting, and pre-emergence and post-emergence damping-off. The isolated strains produced different forms of infection cushions that ensure the pathogenicity of these strains. SDS-PAGE of the 12 R. solani isolates showed that although the R. solani isolates were ...

  12. Over-expression of a protein kinase gene enhances the defense of tobacco against Rhizoctonia solani

    OpenAIRE

    Chaco?n, Osmany; Gonza?lez, Marleny; Lo?pez, Yunior; Portieles, Roxana; Pujol, Merardo; Gonza?lez, Ernesto; Schoonbeek, Henk-jan; Me?traux, Jean-pierre; Borra?s-hidalgo, Orlando

    2010-01-01

    To identify Nicotiana tabacum genes involved in resistance and susceptibility to Rhizoctonia solani, suppression subtractive hybridization was used to generate a cDNA library from transcripts that are differentially expressed during a compatible and incompatible interaction. This allowed the isolation of a protein kinase cDNA that was down-regulated during a compatible and up-regulated during an incompatible interaction. Quantitative RT–PCR analysis of this gene confirmed the differential e...

  13. Rhizoctonia solani as a component in the bottom rot complex of glasshouse lettuce

    OpenAIRE

    Kooistra, T.

    1983-01-01

    The basal parts of maturing glasshouse lettuce can be attacked by several soil fungi, which cause bottom rot. Until recently quintozene was generally applied against this disease complex. The study of the causal fungi - especially Rhizoctonia solani - and their control was undertaken in view of the need for quintozene replacing fungicides.A survey revealed that Botrytis cinerea was the most frequently observed pathogen, especially in winter crops. The incidence of Sclerotinia minor, Sclerotin...

  14. Identification of Rhizoctonia solani isolates from sugar beet roots by analyzing the ITS region of ribosomal DNA

    OpenAIRE

    Stojšin Vera B.; Budakov Dragana; Jacobsen Barry; Grimme Eva; Bagi Ferenc F.; Jasni? Stevan

    2007-01-01

    Rhizoctonia solani (Kühn) is one of the most important sugar beet pathogens Rhizoctonia solani anastomosis groups (AGs) 2-2 and 4 are proven to be the most common pathogenic strains on sugar beet. AG 2-2 (intraspecific groups IIIB and IV) can cause root and crown rot while damping-off of seedlings is most frequently attributed to AG 4. Four isolates of R. solani from sugar beet roots showing characteristic crown and root rot symptoms, collected from different localities in Vojvodina Province...

  15. Reaction of faba bean genotypes to Rhizoctonia solani and resistance stability / Reação de genótipos de fava a Rhizoctonia solani e estabilidade da resistência

    Scientific Electronic Library Online (English)

    Iraildes P, Assunção; Liliane D, Nascimento; Mércia F, Ferreira; Francisco J, Oliveira; Sami J, Michereff; Gaus SA, Lima.

    2011-12-01

    Full Text Available A produção de fava (Phaseolus lunatus) é limitada pela ocorrência da rizoctoniose, causada pelo fungo Rhizoctonia solani. Visando selecionar materiais com potencial de utilização nos programas de melhoramento e/ou no manejo integrado da doença, foram avaliados 72 genótipos de fava e verificada a est [...] abilidade da resistência em relação a diferentes isolados do patógeno, densidades de inóculo e tipos de solo. As sementes foram plantadas em solo infestado com o patógeno pela incorporação de substrato (grãos de arroz) colonizado. A avaliação dos genótipos foi realizada após 15 dias, com o auxílio de escala de notas, discriminando-os em cinco classes de reação. Nenhum dos 72 genótipos apresentou reação de imunidade a R. solani e apenas quatro genótipos (F-42, F-49, F-53 e F-58) comportaram-se como altamente resistentes. As reações apresentadas por esses genótipos variaram conforme o isolado de R. solani, a densidade de inóculo e o solo utilizado. O genótipo F-58 evidenciou maior estabilidade na resistência aos isolados do patógeno e densidades de inóculo. O genótipo F-53 demonstrou estabilidade da resistência em solos coletados em diferentes locais, mantendo alta resistência em todas as situações. O genótipo F-58 não demonstrou alta resistência em somente um solo. Portanto, os genótipos F-58 e F-53 constituem fontes promissoras de resistência a R. solani e devem ser preferidas em campos infestados pelo patógeno. Abstract in english The production of faba bean (Phaseolus lunatus) is limited due to the occurrence of Rhizoctonia canker, caused by the fungus Rhizoctonia solani. In order to select materials with potential for use in faba beans breeding programs and/or disease integrated management, 72 genotypes were evaluated and a [...] lso stability of the disease resistance in relation to different pathogen isolates, inoculum densities and soil type. The seeds were sown in soil infested with the pathogen by the addition of colonized substrate (rice grains). The evaluation of genotypes was done after 15 days, using a note scale to discriminate the genotypes into five reaction classes. None of the 72 genotypes showed immunity to R. solani and only four genotypes (F-42, F-49, F-53 and F-58) behaved as highly resistant. The reactions presented by these genotypes varied according to the R. solani isolate, inoculum density and soil used. The genotype F-58 showed more stable resistance to pathogen isolates and inoculum densities. The genotype F-53 showed resistance stability in soils collected in different locations, remaining highly resistant in all situations. The genotype F-58 did not show high resistance to only one tested soil. Therefore, the genotypes F-58 and F-53 are promising sources of resistance to R. solani and should be indicated in areas infested by the pathogen.

  16. Biocontrol efficacy of different isolates of Trichoderma against soil borne pathogen Rhizoctonia solani.

    Science.gov (United States)

    Asad, Saeed Ahmad; Ali, Naeem; Hameed, Abdul; Khan, Sabaz Ali; Ahmad, Rafiq; Bilal, Muhammad; Shahzad, Muhammad; Tabassum, Ayesha

    2014-01-01

    In this study, the biocontrol abilities of water-soluble and volatile metabolites of three different isolates of Trichoderma (T. asperellum, T. harzianum and Trichoderma spp.) against soil borne plant pathogen Rhizoctonia solani were investigated both in vitro and in vivo. The results showed for the first time that mycelial growth inhibition of the pathogen was 74.4-67.8% with water-soluble metabolites as compared to 15.3-10.6% with volatile metabolites in vitro. In vivo antagonistic activity of Trichoderma isolates against R. solani was evaluated on bean plants under laboratory and greenhouse conditions. We observed that T. asperellum was more effective and consistent, lowering disease incidence up to 19.3% in laboratory and 30.5% in green house conditions. These results showed that three isolates of Trichoderma could be used as effective biocontrol agents against R. solani. PMID:25033669

  17. A novel postharvest rot of okra pods caused by Rhizoctonia solani in Brazil / Uma nova podridão pós-colheita de frutos de quiabo causada por Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Gilmar P., Henz; Carlos A., Lopes; Ailton, Reis.

    2007-06-01

    Full Text Available Frutos de quiabo apresentando podridão e lesões marrons foram coletados em um supermercado de Brasília DF. O objetivo deste trabalho foi identificar o agente causal e comprovar o envolvimento do fungo como causador da doença (Postulados de Koch) e determinar algumas condições favoráveis à ocorrência [...] da doença em frutos de quiabo após a colheita. O patógeno foi identificado como Rhizoctonia solani baseado nas suas características morfológicas, como hifas marrons a ocre, com ramificações laterais em ângulos quase retos com constrições na base, células da hifa com 6-10 µm de largura com um septo perto da base. Cinco isolados foram obtidos dos frutos infectados e identificados como sendo do grupo de anastomose AG 1-IB. Frutos de quiabo cv. Santa Cruz 47 inoculados com discos de micélio de R. solani com e sem ferimentos e mantidos em câmaras úmidas, a 25 ºC, por sete dias ficaram completamente apodrecidos pelo patógeno, com cor marrom, enquanto somente os frutos com ferimentos mantidos a 12 ºC apresentaram lesões pequenas, variando de 0,6 a 1,0 mm de diâmetro. Em outro experimento, foi demonstrado que o patógeno foi capaz de crescer na superfície de diferentes materiais usados na confecção de embalagens de produtos hortícolas, como madeira de pinus, papelão corrugado, plástico, isopor e folhas de jornal mantidos em câmara úmida (24 ºC, 96 % UR). A ocorrência da doença está relacionada com manuseio pós-colheita inadequado, e a transmissão de propágulos do fungo junto com restos culturais ou partículas de solo. Este é o primeiro relato de R. solani causando podridão pós-colheita em frutos de quiabo no Brasil. Abstract in english Okra pods with unusual brown lesions and rot were collected in a local supermarket in Brasília DF. The objective of this paper was to characterize the causal agent, to fulfill Koch's postulates and to determine some conditions conducive to disease. The pathogen was identified as Rhizoctonia solani b [...] ased on morphological characteristics which fitted the fungus description, such as pale to brown hyphae, with nearly right-angled side branches constricted at the base, hyphal cells 6-10 µm wide with a septum near the base. Five isolates were obtained from infected pods and identified as AG 1-IB anastomosis group. Wounded or unwounded okra pods cv. Santa Cruz 47 were inoculated with mycelium disks of R. solani and kept in humid chambers at 12 ºC or 25 ºC. After seven days at 25 ºC, both wounded and unwounded pods were completely rotted and brown, while those kept at 12 ºC showed small lesions ranging from 0.6 to 1.0 mm only in wounded pods. The pathogen was able to grow in different materials used for assembling crates and packs of horticultural products, such as pinewood, corrugated carton, plastic, Styrofoam and newspaper sheets when kept in humid chambers (24 ºC, 96 % RH). The disease occurrence can be related to careless handling practices and to the transmission of R. solani propagules by infected plant debris or soil particles. This is the first report of Rhizoctonia solani causing postharvest rot in okra pods in Brazil.

  18. A novel postharvest rot of okra pods caused by Rhizoctonia solani in Brazil Uma nova podridão pós-colheita de frutos de quiabo causada por Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Gilmar P. Henz

    2007-06-01

    Full Text Available Okra pods with unusual brown lesions and rot were collected in a local supermarket in Brasília DF. The objective of this paper was to characterize the causal agent, to fulfill Koch's postulates and to determine some conditions conducive to disease. The pathogen was identified as Rhizoctonia solani based on morphological characteristics which fitted the fungus description, such as pale to brown hyphae, with nearly right-angled side branches constricted at the base, hyphal cells 6-10 µm wide with a septum near the base. Five isolates were obtained from infected pods and identified as AG 1-IB anastomosis group. Wounded or unwounded okra pods cv. Santa Cruz 47 were inoculated with mycelium disks of R. solani and kept in humid chambers at 12 ºC or 25 ºC. After seven days at 25 ºC, both wounded and unwounded pods were completely rotted and brown, while those kept at 12 ºC showed small lesions ranging from 0.6 to 1.0 mm only in wounded pods. The pathogen was able to grow in different materials used for assembling crates and packs of horticultural products, such as pinewood, corrugated carton, plastic, Styrofoam and newspaper sheets when kept in humid chambers (24 ºC, 96 % RH. The disease occurrence can be related to careless handling practices and to the transmission of R. solani propagules by infected plant debris or soil particles. This is the first report of Rhizoctonia solani causing postharvest rot in okra pods in Brazil.Frutos de quiabo apresentando podridão e lesões marrons foram coletados em um supermercado de Brasília DF. O objetivo deste trabalho foi identificar o agente causal e comprovar o envolvimento do fungo como causador da doença (Postulados de Koch e determinar algumas condições favoráveis à ocorrência da doença em frutos de quiabo após a colheita. O patógeno foi identificado como Rhizoctonia solani baseado nas suas características morfológicas, como hifas marrons a ocre, com ramificações laterais em ângulos quase retos com constrições na base, células da hifa com 6-10 µm de largura com um septo perto da base. Cinco isolados foram obtidos dos frutos infectados e identificados como sendo do grupo de anastomose AG 1-IB. Frutos de quiabo cv. Santa Cruz 47 inoculados com discos de micélio de R. solani com e sem ferimentos e mantidos em câmaras úmidas, a 25 ºC, por sete dias ficaram completamente apodrecidos pelo patógeno, com cor marrom, enquanto somente os frutos com ferimentos mantidos a 12 ºC apresentaram lesões pequenas, variando de 0,6 a 1,0 mm de diâmetro. Em outro experimento, foi demonstrado que o patógeno foi capaz de crescer na superfície de diferentes materiais usados na confecção de embalagens de produtos hortícolas, como madeira de pinus, papelão corrugado, plástico, isopor e folhas de jornal mantidos em câmara úmida (24 ºC, 96 % UR. A ocorrência da doença está relacionada com manuseio pós-colheita inadequado, e a transmissão de propágulos do fungo junto com restos culturais ou partículas de solo. Este é o primeiro relato de R. solani causando podridão pós-colheita em frutos de quiabo no Brasil.

  19. The influence of soil moisture and Rhizoctonia solani anastomosis and intraspecific group on the incidence of damping-off and the incidence and severity of Rhizoctonia crown and root rot in sugar beet

    Science.gov (United States)

    Rhizoctonia crown and root rot (Rhizoctonia solani) reduces plant stands, sugar quality and yield in sugar beet. To evaluate the influence of R. solani anastomosis (AG) and intraspecific groups and soil moisture on disease incidence and severity, a field trial was established in Ridgetown, Ontario, ...

  20. Genetic and Genomic Analysis of Rhizoctonia solani Interactions with Arabidopsis; Evidence of Resistance Mediated through NADPH Oxidases

    OpenAIRE

    Foley, Rhonda C.; Gleason, Cynthia A.; Anderson, Jonathan P.; Hamann, Thorsten; Singh, Karam B.

    2013-01-01

    Rhizoctonia solani is an important soil-borne necrotrophic fungal pathogen, with a broad host range and little effective resistance in crop plants. Arabidopsis is resistant to R. solani AG8 but susceptible to R. solani AG2-1. A screen of 36 Arabidopsis ecotypes and mutants affected in the auxin, camalexin, salicylic acid, abscisic acid and ethylene/jasmonic acid pathways did not reveal any variation in response to R. solani and demonstrated that resistance to AG8 was independent of these defe...

  1. Diversity of Rhizoctonia solani associated with pulse crops in different agro-ecological regions of India.

    Science.gov (United States)

    Dubey, Sunil C; Tripathi, Aradhika; Upadhyay, Balendu K; Deka, Utpal K

    2014-06-01

    Four hundred seventy Rhizoctonia solani isolates from different leguminous hosts originating from 16 agro-ecological regions of India covering 21 states and 72 districts were collected. The disease incidence caused by R. solani varied from 6.8 to 22.2 % in the areas surveyed. Deccan plateau and central highlands, hot sub-humid ecoregion followed by northern plain and central highlands and hot semi-arid ecoregion showed the highest disease incidence. R. solani isolates were highly variable in growth diameter, number, size and pattern of sclerotia formation as well as hyphal width. The isolates obtained from aerial part of the infected plants showing web blight symptoms produced sclerotia of 1-2 mm in size whereas, the isolates obtained from infected root of the plants showing wet root rot symptoms produced microsclerotia (R. solani isolates showed R. solani associated with the pulse crops. The frequency (25.6 %) of AG3 was the highest followed by AG2-3 (20.9 %) and AG5 (17.4 %). The cropping sequence of rice/sorghum/wheat-chickpea/mungbean/urdbean/cowpea/ricebean influenced the dominance of AG1 (16.3 %). Phylogenetic analysis utilizing ITS-5.8S rDNA gene sequences indicated high level of genetic similarity among isolates representing different AGs, crops and regions. ITS groups did not correspond to the morphological characters. The sequence data from this article has been deposited with NCBI data libraries with JF701707 to JF701795 accession numbers. PMID:24399024

  2. Factors affecting antifungal activity of Streptomyces philanthi RM-1-138 against Rhizoctonia solani.

    Science.gov (United States)

    Boukaew, Sawai; Prasertsan, Poonsuk

    2014-01-01

    Sheath blight disease of rice caused by Rhizoctonia solani Kühn is economically important disease in most of the world's rice growing areas. The disease causes severe yield losses of >20% of rice in Thailand. Our previous investigation reported the antifungal activity of Streptomyces philanthi RM-1-138 against R. solani PTRRC-9. In this study, glucose yeast-malt extract medium, initial pH of 7.5 and a temperature of 30 °C were found to be optimum for both cell growth and antifungal activity of S. philanthi RM-1-138. The inhibition of 94 and 100% on the growth of R. solani PTRRC-9 were achieved from the antifungal metabolites of the 6 and 9-days-old culture filtrates of S. philanthi RM-1-138, respectively. Heat treatment on the culture filtrate had slight effect on its antifungal activity. The culture broth demonstrated higher antifungal activity on growth of R. solani PTRRC-9 (90.4%) than the culture filtrate (31.5%) and its effective dose was at 0.1% (v/v). The present results indicated the possibilities of using either the culture broth or culture filtrate of S. philanthi RM-1-138 to inhibit growth of R. solani PTRRC-9. PMID:23839715

  3. Crop Residue Affects Rhizoctonia solani Population Dynamics and Seedling Blight of Canola

    Directory of Open Access Journals (Sweden)

    H.U. Ahmed

    2014-01-01

    Full Text Available Seedling blight caused by Rhizoctonia solani Kühn substantially reduces stand establishment and seed yield of canola (Brassica napus L. in western Canada. The effect of crop residue on soil populations of R. solani and canola seedling blight was examined under field, greenhouse and laboratory conditions. Field plots were established with inoculation or noninoculation with R. solani as the main plot and barley, canola, oat and field pea residues as the sub-plots. Soil samples were collected from each subplot for analysis in a greenhouse bioassay and laboratory assay of R. solani population before seeding canola. The crop residue effect was not significant. Under inoculation with R. solani, the yield was consistently greater when canola was grown on barley residue compared to the canola residue over two-year trials, although oat and pea residue contributed to greater yield. Without inoculation, canola yield was greatest when grown on barley residue, intermediate on oat and pea and the least on canola in the first trial and in the second trial greater yield was obtained on barley and oat residues compared to other residues. In the greenhouse bioassay, canola seedling emergence was greater, while damping off and root rot were less severe, following barley or oat compared to canola or field pea in both inoculated and non-inoculated treatments. Populations of Rhizoctonia were lower following barley or oat relative to canola or field pea. Crop rotation and incorporation of barley or oat residue between canola crops may be a useful strategy to reduce seedling blight of canola.

  4. SUPRESSIVIDADE NATURAL DE SOLOS DA REGIÃO CENTRO-OESTE A Rhizoctonia solani KÜHN NATURAL SUPPRESSIVENESS OF SOILS FROM WEST CENTRAL BRAZIL TO Rhizoctonia solani Kühn

    Directory of Open Access Journals (Sweden)

    Sheila Andrade Botelho

    2007-09-01

    Full Text Available

    Rhizoctonia solani é um fungo cosmopolita que habita o solo, com vasto número de hospedeiros, e causa importantes doenças na maioria das plantas cultivadas em todo o mundo. É uma espécie complexa, com muitos biotipos que diferem quanto à patogenicidade, aos hospedeiros, à distribuição na natureza e à aparência em meio de cultura. O feijoeiro comum é suscetível a este patógeno e a sua suscetibilidade é inversamente proporcional ao desenvolvimento da planta. A atividade microbiana de alguns solos pode prevenir o estabelecimento de fungos fitopatogênicos. Solos com esta propriedade são denominados antagônicos, de longa vida, resistentes ou supressivos. O objetivo deste trabalho foi avaliar os níveis de supressividade natural a R. solani de alguns solos classificados como latossolo roxo, latossolo vermelho-escuro, areia quartzoza e latossolo roxo, respectivamente, coletados nos municípios de Itumbiara, Silvânia, Jussara e Santa Helena de Goiás, no Estado de Goiás, em três áreas contíguas com os seguintes históricos de uso: a solo cultivado com feijão irrigado via pivô central por mais de quatro anos consecutivos; b solo sob vegetação nativa; e c solo sob pastagem de Brachiaria decubens. Os solos foram coletados na camada de 0-20 cm e armazenados em casa de vegetação. Para a inoculação dos solos foram utilizados grãos de sorgo, inoculados com Rhizoctonia solani, em seis densidades – 0, 100, 500, 1.000, 5.000 e 10.000 propágulos/g de solo – e triturados. O experimento foi conduzido sob condições de casa de vegetação, em um delineamento de blocos completos casualizados e esquema fatorial 6 x 4 x 3. A unidade experimental foi constituída de bandejas plásticas com 4 kg de solo e 40 plantas. Quinze dias após a emergência, as plantas foram arrancadas e avaliadas. Posteriormente, foi calculado o índice de McKinney. A análise de variância apresentou interação tripla significativa, e os graus de liberdade foram desdobrados em análises de regressão entre as doses de inóculo e o índice de doença em porcentagem, numa equação exponencial do tipo: ID = A x e (-B/dose do inóculo + 1. Nas regiões de Itumbiara e Silvânia, o índice de doença progrediu como aumento do número de propágulos por grama de solo, atingindo valores superiores a 70%. Porém, para ambas as regiões, não houve diferenças significativas entre os solos de mata, pastagem e feijão com relação ao índice de doença. Por outro lado, nos solos de Jussara e Santa Helena, foi observado um incremento do índice da doença com o aumento da dose de inóculo para todos os históricos, e os solos de mata e de pastagem apresentaram índice de doença semelhante em todas as doses de inóculo utilizadas. Em solos provenientes de área de feijão irrigado, da região de Santa Helena, os incrementos no índice de doença foram menores, não ultrapassando a 60%.

    PALAVRAS-CHAVE: Podridão radicular de Rhizoctonia; controle biológico; população microbiana do solo.

    Rhizoctonia solani is a highly destructive world wide soil fungus, with a large host-range, that causes important diseases in a great number of the crops. It is a complex specie whichpossesses many biotypes, differing in their pathogenicity, hosts,distribution in the nature and cultural appearance in solid media.Dry beans are susceptible to this pathogen and the susceptibility is inversely proportional to the host development. The microbial activity of some soils can prevent the establishment of phytopathogenic fungi. Soils with this property are named antagonistic, long life, resistant or supressive. The objective of this work was to evalu

  5. Real-time PCR (qPCR) assay for Rhizoctonia solani anastomoses group AG2-2IIIb

    OpenAIRE

    Abbas, S. J.; Ahmad, B.; Karlovsky, P.

    2014-01-01

    Rhizoctonia solani anastomosis group AG2-2 IIIB is a severe sugar beet and maize pathogen. It causes crown and root rot disease which leads to yield losses world-wide. The soil-borne pathogen is difficult to detect and quantify by conventional methods. We developed a real-time PCR (qPCR) assay for the quantification of genomic DNA of Rhizoctonia solani AG2-2 IIIB based on the ITS region of rDNA genes. The limit of quantification of the assay is 1.8 pg genomic DNA. The amplif...

  6. Seed disinfection effect of atmospheric pressure plasma and low pressure plasma on Rhizoctonia solani.

    Science.gov (United States)

    Nishioka, Terumi; Takai, Yuichiro; Kawaradani, Mitsuo; Okada, Kiyotsugu; Tanimoto, Hideo; Misawa, Tatsuya; Kusakari, Shinichi

    2014-01-01

    Gas plasma generated and applied under two different systems, atmospheric pressure plasma and low pressure plasma, was used to investigate the inactivation efficacy on the seedborne pathogenic fungus, Rhizoctonia solani, which had been artificially introduced to brassicaceous seeds. Treatment with atmospheric plasma for 10 min markedly reduced the R. solani survival rate from 100% to 3% but delayed seed germination. The low pressure plasma treatment reduced the fungal survival rate from 83% to 1.7% after 10 min and the inactivation effect was dependent on the treatment time. The seed germination rate after treatment with the low pressure plasma was not significantly different from that of untreated seeds. The air temperature around the seeds in the low pressure system was lower than that of the atmospheric system. These results suggested that gas plasma treatment under low pressure could be effective in disinfecting the seeds without damaging them. PMID:24975415

  7. Expression of Dm-AMP1 in rice confers resistance to Magnaporthe oryzae and Rhizoctonia solani.

    Science.gov (United States)

    Jha, Sanjay; Tank, Harsukh G; Prasad, Bishun Deo; Chattoo, Bharat B

    2009-02-01

    Magnaporthe oryzae and Rhizoctonia solani, are among the most important pathogens of rice, severely limiting its productivity. Dm-AMP1, an antifungal plant defensin from Dahlia merckii, was expressed in rice (Oryza sativa L. sp. indica cv. Pusa basmati 1) using Agrobacterium tumefaciens-mediated transformation. Expression levels of Dm-AMP1 ranged from 0.43% to 0.57% of total soluble protein in transgenic plants. It was observed that constitutive expression of Dm-AMP1 suppresses the growth of M. oryzae and R. solani by 84% and 72%, respectively. Transgenic expression of Dm-AMP1 was not accompanied by an induction of pathogenesis-related (PR) gene expression, indicating that the expression of DmAMP1 directly inhibits the pathogen. The results of in vitro, in planta and microscopic analyses suggest that Dm-AMP1 expression has the potential to provide broad-spectrum disease resistance in rice. PMID:18618285

  8. Induction of Laccase Activity in Rhizoctonia solani by Antagonistic Pseudomonas fluorescens Strains and a Range of Chemical Treatments

    OpenAIRE

    Crowe, Jonathan D.; Olsson, Stefan

    2001-01-01

    Fungi often produce the phenoloxidase enzyme laccase during interactions with other organisms, an observation relevant to the development of biocontrols. By incorporating the laccase substrate 2,2?-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) into agar, we analyzed laccase induction in the plant-pathogenic fungus Rhizoctonia solani when paired against isolates of the soil bacterium Pseudomonas fluorescens. Substantial induction of R. solani laccase was seen only in pairings with ...

  9. Identification of Spanish isolates of Rhizoctonia solani from potato by anastomosis grouping, ITS-RFLP and RAMS-fingerprinting

    OpenAIRE

    Marti?n Esteban, Mª Paz; El Bakali, Abdessamad M.; Lilja, Arja; Hantula, Jarkko

    2003-01-01

    Anastomosis grouping, restriction fragment length polymorphism (RFLP) of the ITS regions including the 5.85 rDNA, and random amplified microsatellites (RAMS) were used to characterize isolates of Rhizoctonia solani collected from Spain and Finland. There was a high similarity between the results obtained with the three techniques. RAMS markers revealed more genetic variation among isolates of R. solani than RFLP. The anastomosis group (AG)-3 isolates were clearly separated from isolates belon...

  10. Randomly Amplified Polymorphic DNA of Trichoderma isolates and antagonism against Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Larissa Brandão Góes

    2002-06-01

    Full Text Available Random Amplified Polymorphic DNA (RAPD procedure was used to examine the genetic variability among fourteen isolates of Trichoderma and their ability to antagonize Rhizoctonia solani using a dual-culture assay for correlation among RAPD products and their hardness to R. solani. Seven oligodeoxynucleotide primers were selected for the RAPD assays which resulted in 197 bands for 14 isolates of Trichoderma. The data were entered into a binary matrix and a similarity matrix was constructed using DICE similarity (SD index. A UPGMA cluster based on SD values was generated using NTSYS (Numerical Taxonomy System, Applied Biostatistics computer program. A mean coefficient of similarity obtained for pairwise comparisons among the most antagonics isolates was around 40%. The results presented here showed that the variability among the isolates of Trichoderma was very high. No relationship was found between the polymorphism showed by the isolates and their hardness, origin and substrata.A técnica de RAPD (Random Amplified Polymorphic DNA foi utilizada para examinar a variabilidade genética em quatorze isolados de Trichoderma além de sua capacidade de antagonizar o fungo fitopatogênico Rhizoctonia solani usando pareamento in vitro, e a possível relação entre perfís de RAPD e agressividade dos isolados de Trichoderma a R. solani. Foram selecionados sete primers para os ensaios de RAPD, os quais produziram 197 bandas. Os dados foram introduzidos no programa de computador NTSYS (Numerical Taxonomy System, Applied Biostatisticsna forma de uma matrix binária, sendo construída uma matriz de similaridade utilizando-se o coeficiente de similaridade de DICE (SD e baseado nos valores SD, pelo método de agrupamento UPGMA um dendrograma. Observou-se que o grau de similaridade das amostras que apresentaram melhor desempenho antagônico foi bastante baixo, em torno de 40%. Os resultados demonstraram que a variabilidade entre os isolados de Trichoderma é muito alta. Aparentemente não foi demonstrada nenhuma relação entre o perfil de RAPD obtido e o nível de antagonismo dos isolados de Trichoderma nem agrupamento em função da origem dos isolados ou substrato.

  11. Effect of Population Dynamics of Pseudomonas cepacia and Paecilomyces lilacinus on Colonization of Polyfoam Rooting Cubes by Rhizoctonia solani

    OpenAIRE

    Cartwright, D. Kelly; Benson, D. M.

    1994-01-01

    Suspensions of Pseudomonas cepacia (strain 5.5B) and Paecilomyces lilacinus (isolate 6.2F) were applied to polyfoam rooting cubes for control of stem rot of poinsettia caused by Rhizoctonia solani. The populations of antagonists and colonization of rooting cubes by R. solani were monitored during a 3-week period. Colonization of cubes by R. solani was reduced in cubes treated with P. cepacia, but the population of P. cepacia decreased by as much as 97% during the test period. Increased coloni...

  12. Diversidade genética de isolados de Rhizoctonia solani coletados em feijão-caupi no Estado de Roraima Genetic diversity of Rhizoctonia solani isolates collected from Cowpea in the State of Roraima

    Directory of Open Access Journals (Sweden)

    Aloísio Sartorato

    2006-06-01

    Full Text Available O feijão-caupi (Vigna unguiculata é uma das principais fontes de proteína para a população de baixa renda, principalmente nas Regiões Norte e Nordeste do Brasil. Esta leguminosa é suscetível a várias doenças incluindo a mela ou murcha-da-teia-micélica, cujo agente causal é o fungo Rhizoctonia solani (teleomorfo: Thanatephorus cucumeris. Embora Rhizoctonia solani seja um agente causal de doença muito importante, no Brasil inexiste qualquer informação sobre as características de seus isolados associados ao feijão-caupi. O objetivo do presente estudo foi avaliar, utilizando-se das técnicas Random Amplified Polymorphic DNA (RAPD e RFLP-ITS (Internal Transcribed Spacer, a diversidade genética de isolados de R. solani coletados de plantas de feijão-caupi oriundas da região de cerrado e de mata do Estado de Roraima. Pelos resultados obtidos pode-se concluir que existe diversidade genética em R.. solani coletada de feijão-caupi e que os dois métodos moleculares utilizados foram eficientes em avaliar a divergência genética deste patógeno.Cowpea (Vigna unguiculata is one of the most important sources of protein for people with low incomes in Northern and Northeastern Brazil. Cowpea is susceptible to several diseases, including web blight caused by the fungus Rhizoctonia solani (teleomorph Thanatephorus cucumeris. Although R. solani is a very important disease agent, in Brazil there is no information on isolate characteristics when this fungus is associated with cowpea. The objective of this study was to evaluate, using Random Amplified Polymorphic DNA (RAPD and RFLP-ITS (Internal Transcribed Spacer techniques, the genetic diversity of R. solani isolates collected in the State of Roraima from cowpea cultivated under 'savannah' and 'forest' ecosystems. From the results it was possible to demonstrate genetic diversity among R. solani isolates and to prove that both molecular techniques used were efficient in evaluating it.

  13. Integrated options for the management of black root rot of strawberry caused by Rhizoctonia solani Kuhn.

    Science.gov (United States)

    Asad-Uz-Zaman, Md; Bhuiyan, Mohammad Rejwan; Khan, Mohammad Ashik Iqbal; Alam Bhuiyan, Md Khurshed; Latif, Mohammad Abdul

    2015-02-01

    An investigation was made to manage strawberry black root rot caused by Rhizoctonia solani (R. solani) through the integration of Trichoderma harzianum (T. harzianum) isolate STA7, mustard oil cake and Provax 200. A series of preliminary experiments were conducted to select a virulent isolate of R. solani, an effective isolate of T. harzianum, a suitable organic amendment, and a suitable fungicide before setting the experiment for integration. The pathogenicity of the selected four isolates of R. solani was evaluated against strawberry and isolate SR1 was selected as the test pathogen due to its highest virulent (95.47% mortality) characteristics. Among the 20 isolates of T. harzianum, isolate STA7 showed maximum inhibition (71.97%) against the test pathogen (R. solani). Among the fungicides, Provax-200 was found to be more effective at lowest concentration (100 ppm) and highly compatible with Trichoderma isolates STA7. In the case of organic amendments, maximum inhibition (59.66%) of R. solani was obtained through mustard oil cake at the highest concentration (3%), which was significantly superior to other amendments. Minimum percentages of diseased roots were obtained with pathogen (R. solani)+Trichoderma+mustard oil cake+Provax-200 treatment, while the highest was observed with healthy seedlings with a pathogen-inoculated soil. In the case of leaf and fruit rot diseases, significantly lowest infected leaves as well as fruit rot were observed with a pathogen+Trichoderma+mustard oil cake+Provax-200 treatment in comparison with the control. A similar trend of high effectiveness was observed by the integration of Trichoderma, fungicide and organic amendments in controlling root rot and fruit diseases of strawberry. Single application of Trichoderma isolate STA7, Provax 200 or mustard oil cake did not show satisfactory performance in terms of disease-free plants, but when they were applied in combination, the number of healthy plants increased significantly. The result of the current study suggests the superiority of our integrated approach to control the sclerotia forming pathogen R. solani compared to the individual treatment either by an antagonist or by a fungicide or by mustard oil cake. PMID:25595298

  14. Biological control of Rhizoctonia solani in tomatoes with Trichoderma harzianum mutants

    Scientific Electronic Library Online (English)

    Jaime, Montealegre; Luis, Valderrama; Soledad, Sánchez; Rodrigo, Herrera; Ximena, Besoain; Luz María, Pérez.

    2010-03-15

    Full Text Available Biocontrol of Rhizoctonia solani in tomatoes cultivated under greenhouse and field conditions was analyzed using the Trichoderma harzianum mutants Th650-NG7, Th11A80.1, Th12A40.1, Th12C40.1 and Th12A10.1 and ThF2-1, respectively. Their innocuousness on tomato cultivars 92.95 and Gondola (greenhouse [...] assays), and on cultivar Fortaleza (field assays) was established. Alginate pellets (1.7 g pellets/L soil) containing c.a1 x 10(5) colony forming units (cfu)/g pellet were applied to a soil previously inoculated with R. solani at transplant (greenhouse) or to a naturally infected soil (field). Controls considered parental wild strains, a chemical fungicide and no additions. Th11A 80.1, Th12A10.1 and Th650-NG7 prevented the 100% mortality of tomato plants cv. 92.95 caused by R. solani, and the 40% mortality in tomato plants cv. Gondola (greenhouse assays). Mortality reduction was reflected in canker level lessening and in plant parameters increases (development, fresh and dry weights). A different degree of susceptibility of tomato plants was observed, being Gondola cv. more resistant than 92.95 cv. to infection in a soil previously inoculated with R. solani. Tomato plants of cv. Fortaleza did not show mortality in naturally infected soils (field assays), where the mutant ThF2-1 reduced significantly the canker level caused by R. solani.

  15. Diversidad genética de aislados de Rhizoctonia solani (Kuhn) de chile en México / Genetic diversity of Rhizoctonia solani isolates (Kuhn) from pepper in Mexico

    Scientific Electronic Library Online (English)

    Víctor, Montero-Tavera; Brenda Zulema, Guerrero-Aguilar; José Luis, Anaya-López; Talina Olivia, Martínez-Martínez; Lorenzo, Guevara-Olvera; Mario Martín, González-Chavira.

    1043-10-01

    Full Text Available Una de las principales limitantes para la producción de chile son los hongos patógenos causantes de la enfermedad conocida como "marchitez del chile" o "secadera". Esta enfermedad puede ser devastadora cuando las condiciones climáticas son favorables para el patógeno. A pesar de que se han intentado [...] diferentes medios de control (químicos y culturales) ninguno ha tenido éxito. Una alternativa para su control es producir germoplasma resistente, sin embargo para poder establecer un programa de mejoramiento efectivo es necesario conocer la distribución y diversidad genética de los patógenos involucrados, particularmente de Rhizoctonia solani, que por su ubicuidad representa un peligro potencial en todas las zonas productoras. Por ello el objetivo fue caracterizar a R. solani en las zona Centro Norte de México y determinar su diversidad genética. Para cumplir con este objetivo se consideraron los estados de Chihuahua, Durango, Zacatecas, San Luis Potosí, Colima, Querétaro y Guanajuato donde en 2009 se colectaron plantas adultas de Chile con síntomas de marchitez, se aisló al hongo y se encontró una incidencia del 33%, encontrándose tanto en tallo como en raíz. Las células miceliales fueron multinucleadas, características de las cepas patogénicas. Las pruebas de anastomosis demostaron la presencia en México de los grupos GA4, GA-2.1, GA-IIB, GA-2IV, GA7, GA11, GA12 y GA13. La diversidad genética de este hongo fue muy alta, de tal manera que las relaciones demostradas por la construcción de dendrogramas no muestran tendencias homogéneas pues los principales grupos formados contienen elementos de todos los estados. Abstract in english One of the major constraints for the production of pepper are pathogenic fungi causing diseases known as "pepper blight" or "damping off". This disease can be devastating when weather conditions are favorable for the pathogen. Although different means of control (chemical and cultural) have benn use [...] d but none has been successful. An alternative to control is to produce resistant germplasm, however in order to establish an effective breeding program is necessary to know the distribution and genetic diversity of the pathogens involved, particularly Rhizoctonia solani, which by its ubiquity represents a potential danger in all producing areas. Thus, the objective was to characterize R. solani in North Central area from Mexico and determine its genetic diversity. To achieve with this goal are considered the states of Chihuahua, Durango, Zacatecas, San Luis Potosi, Colima, Queretaro and Guanajuato where in 2009 were collected adult plants of pepper with pepper blight symptoms, the fungus was isolated and found an incidence of 33%, finding it in both stem and root. Mycelial cells were multinucleated, a characteristic from pathogenic strains. The anastomosis testing showed that in Mexico are present the groups GA4, GA-2. 1, GA-IIB, GA-2IV, GA7, GA11, GA12 and GA13. The genetic diversity of this fungus was very high, so that the relationships demonstrated by the construction of dendrogram show no homogeneous trends so as the main groups formed contain elements of all states.

  16. Genetic Variability in Rhizoctonia solani Isolated from Vitis vinifera Based on Amplified Fragment Length Polymorphism

    Directory of Open Access Journals (Sweden)

    Amparo Meza-Moller

    2011-01-01

    Full Text Available Problem statement: Rhizoctonia solani is a potential grapevine pathogen. In order to develop effective methods of control, it is necessary to document its genetic diversity. Approach: The objective of this study was to analyze the genetic variability of R. solani isolated from the rhizosphere of ungrafted V. vinifera var. perlette seedless planted in Sonora, Mexico using Amplified Fragment Length Polymorphism (AFLP. Results: In the selective amplification using eight primer combinations we obtained a total of 446 AFLP markers with a 100% polymorphism. Out of 41 isolates, 36 different AFLP patterns were observed and five were replicates of the same pattern. The dendrogram shows inter- and intrapopulation similarity indexes of 0.26, 0.98 and 0.31, 0.98, respectively. Six groups emerged from the principal components analysis, five of which were clearly defined, while the other one was spread out. Conclusion: We conclude that R. solani growing in Sonoran vineyards shows a high degree of genetic variability, even under similar environmental conditions.

  17. Transcriptional responses of the bacterial antagonist Serratia plymuthica to the fungal phytopathogen Rhizoctonia solani.

    Science.gov (United States)

    Neupane, Saraswoti; Finlay, Roger D; Alström, Sadhna; Elfstrand, Malin; Högberg, Nils

    2015-02-01

    Rhizobacteria with biocontrol ability exploit a range of mechanisms to compete successfully with other microorganisms and to ensure their growth and survival in the rhizosphere, ultimately promoting plant growth. The rhizobacterium Serratia plymuthica?AS13 is able to promote oilseed rape growth and improve seedling survival in the presence of the fungal pathogen, Rhizoctonia solani?AG 2-1; however, our understanding of the mechanisms underlying the antagonism of Serratia is limited. To elucidate possible mechanisms, genome-wide gene expression profiling of S.?plymuthica?AS13 was carried out in the presence or absence of R.?solani. We used RNA sequencing methodology to obtain a comprehensive overview of Serratia gene expression in response to R.?solani. The differential gene expression profiles of S.?plymuthica?AS13 revealed significantly increased expression of genes related to the biosynthesis of the antibiotic pyrrolnitrin (prnABCD), protease production and transporters. The results presented here provide evidence that antibiosis is a major functional mechanism underlying the antagonistic behaviour of S.?plymuthica?AS13. PMID:25139310

  18. Identification of Rhizoctonia solani associated with soybean in Brazil by rDNA-ITS sequences

    Directory of Open Access Journals (Sweden)

    Fenille Roseli C.

    2003-01-01

    Full Text Available The aim of this study was to identify isolates of Rhizoctonia solani causing hypocotyl rot and foliar blight in soybean (Glycine max in Brazil by the nucleotide sequences of ITS-5.8S regions of rDNA. The 5.8S rDNA gene sequence (155 bp was highly conserved among all isolates but differences in length and nucleotide sequence of the ITS1 and ITS2 regions were observed between soybean isolates and AG testers. The similarity of the nucleotide sequence among AG-1 IA isolates, causing foliar blight, was 95.1-100% and 98.5-100% in the ITS1 and ITS2 regions, respectively. The nucleotide sequence similarity among subgroups IA, IB and IC ranged from 84.3 to 89% in ITS1 and from 93.3 to 95.6% in ITS2. Nucleotide sequence similarity of 99.1% and 99.3-100% for ITS1 and ITS2, respectively, was observed between AG-4 soybean isolates causing hypocotyl rots and the AG-4 HGI tester. The similarity of the nucleotide sequence of the ITS-5.8S rDNA region confirmed that the R. solani Brazilian isolates causing foliar blight are AG-1 IA and isolates causing hypocotyl rot symptoms are AG-4 HGI. The ITS-5.8S rDNA sequence was not determinant for the identification of the AG-2-2 IIIB R. solani soybean isolate.

  19. Chitosan-cinnamon beads enhance suppressive activity against Rhizoctonia solani and Meloidogyne incognita in vitro.

    Science.gov (United States)

    Seo, Dong-Jun; Nguyen, Dang-Minh-Chanh; Park, Ro-Dong; Jung, Woo-Jin

    2014-01-01

    A novel chitosan-cinnamon bead carrier was prepared in this study. Chitosan was mixed with cinnamon powder (CP) and cinnamon extract (CE) to obtain chitosan-cinnamon powder (CCP) beads and chitosan-cinnamon extracted (CCE) beads, respectively. The potential antifungal and nematicidal activities of CCP and CCE were investigated against Rhizoctonia solani and Meloidogyne incognita in vitro. Relative antifungal activity of the CCP (5% CP) bead-treated R. solani was 30.9 and 23.9% after 1 and 2 day incubations, respectively. Relative antifungal activity of the CCE (0.5% CE) bead-treated R. solani was 4.3, 3.0 and 4.2% after 1, 2 and 3 days of incubation. Inhibition of hatch by CCP beads with CP of 5% was 78.8%. Inhibition of hatch by CCE beads with CE of 0.5% was 82.0%. J2 mortality following the CCP (5% CP) and CCE (0.5% CE) bead treatments was 85.0 and 95.8%, respectively against M. incognita after 48 h incubations. PMID:24417978

  20. Investigating the roles of MicroRNAs in biotic stress response induced by Rhizoctonia solani in rice

    Energy Technology Data Exchange (ETDEWEB)

    Syuhada, O. Nurfarahana; Kalaivani, N. [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2014-09-03

    Sheath blight disease, caused by Rhizoctonia solani 1802/KB was screened on two rice varieties, Oryza sativaindica cultivar MR219 and Oryza sativa indica cultivar UKMRC9. The disease symptom was severe in MR219 compared to UKMRC9. Total RNA from R. solani 1802/KB, infected rice leaves of MR219 and infected rice leaves of UKMRC9 were extracted using TRIzol reagent, purified and sent for small RNA sequencing. Three miRNA libraries were generated and analyzed. The libraries generated 65 805, 78 512 and 81 325 known miRNAs respectively. The structure of miRNA of these samples was predicted. The up-regulated and down-regulated of miRNAs target gene prediction and its target functions were discovered and were mainly related to the growth and development of metabolism, protein transport, transcriptional regulation, stress response, and hormone signaling and electron transfer. Sheath blight-induced differential expression of known miRNAs tends to targetMYB transcription factor, F-box proteins, NBS-LRR, leucine-rich repeat receptor protein kinases and zinc finger proteins. Detecting new miRNAs and measuring the expression profiles of known miRNAs is an important tasks required for a better understanding of various biological conditions. Therefore, further analysis using Gene Ontology Slim will be conducted to deduce some biological information from the datasets obtained.

  1. Investigating the roles of MicroRNAs in biotic stress response induced by Rhizoctonia solani in rice

    International Nuclear Information System (INIS)

    Sheath blight disease, caused by Rhizoctonia solani 1802/KB was screened on two rice varieties, Oryza sativaindica cultivar MR219 and Oryza sativa indica cultivar UKMRC9. The disease symptom was severe in MR219 compared to UKMRC9. Total RNA from R. solani 1802/KB, infected rice leaves of MR219 and infected rice leaves of UKMRC9 were extracted using TRIzol reagent, purified and sent for small RNA sequencing. Three miRNA libraries were generated and analyzed. The libraries generated 65 805, 78 512 and 81 325 known miRNAs respectively. The structure of miRNA of these samples was predicted. The up-regulated and down-regulated of miRNAs target gene prediction and its target functions were discovered and were mainly related to the growth and development of metabolism, protein transport, transcriptional regulation, stress response, and hormone signaling and electron transfer. Sheath blight-induced differential expression of known miRNAs tends to targetMYB transcription factor, F-box proteins, NBS-LRR, leucine-rich repeat receptor protein kinases and zinc finger proteins. Detecting new miRNAs and measuring the expression profiles of known miRNAs is an important tasks required for a better understanding of various biological conditions. Therefore, further analysis using Gene Ontology Slim will be conducted to deduce some biological information from the datasets obtained

  2. Investigating the roles of MicroRNAs in biotic stress response induced by Rhizoctonia solani in rice

    Science.gov (United States)

    Syuhada, O. Nurfarahana; Kalaivani, N.

    2014-09-01

    Sheath blight disease, caused by Rhizoctonia solani 1802/KB was screened on two rice varieties, Oryza sativaindica cultivar MR219 and Oryza sativa indica cultivar UKMRC9. The disease symptom was severe in MR219 compared to UKMRC9. Total RNA from R. solani 1802/KB, infected rice leaves of MR219 and infected rice leaves of UKMRC9 were extracted using TRIzol reagent, purified and sent for small RNA sequencing. Three miRNA libraries were generated and analyzed. The libraries generated 65 805, 78 512 and 81 325 known miRNAs respectively. The structure of miRNA of these samples was predicted. The up-regulated and down-regulated of miRNAs target gene prediction and its target functions were discovered and were mainly related to the growth and development of metabolism, protein transport, transcriptional regulation, stress response, and hormone signaling and electron transfer. Sheath blight-induced differential expression of known miRNAs tends to targetMYB transcription factor, F-box proteins, NBS-LRR, leucine-rich repeat receptor protein kinases and zinc finger proteins. Detecting new miRNAs and measuring the expression profiles of known miRNAs is an important tasks required for a better understanding of various biological conditions. Therefore, further analysis using Gene Ontology Slim will be conducted to deduce some biological information from the datasets obtained.

  3. Randomly Amplified Polymorphic DNA of Trichoderma isolates and antagonism against Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Larissa Brandão, Góes; Ana Bolena Lima da, Costa; Laurineide Lopes de Carvalho, Freire; Neiva Tinti de, Oliveira.

    2002-06-01

    Full Text Available A técnica de RAPD (Random Amplified Polymorphic DNA) foi utilizada para examinar a variabilidade genética em quatorze isolados de Trichoderma além de sua capacidade de antagonizar o fungo fitopatogênico Rhizoctonia solani usando pareamento in vitro, e a possível relação entre perfís de RAPD e agress [...] ividade dos isolados de Trichoderma a R. solani. Foram selecionados sete primers para os ensaios de RAPD, os quais produziram 197 bandas. Os dados foram introduzidos no programa de computador NTSYS (Numerical Taxonomy System, Applied Biostatistics)na forma de uma matrix binária, sendo construída uma matriz de similaridade utilizando-se o coeficiente de similaridade de DICE (SD) e baseado nos valores SD, pelo método de agrupamento UPGMA um dendrograma. Observou-se que o grau de similaridade das amostras que apresentaram melhor desempenho antagônico foi bastante baixo, em torno de 40%. Os resultados demonstraram que a variabilidade entre os isolados de Trichoderma é muito alta. Aparentemente não foi demonstrada nenhuma relação entre o perfil de RAPD obtido e o nível de antagonismo dos isolados de Trichoderma nem agrupamento em função da origem dos isolados ou substrato. Abstract in english Random Amplified Polymorphic DNA (RAPD) procedure was used to examine the genetic variability among fourteen isolates of Trichoderma and their ability to antagonize Rhizoctonia solani using a dual-culture assay for correlation among RAPD products and their hardness to R. solani. Seven oligodeoxynucl [...] eotide primers were selected for the RAPD assays which resulted in 197 bands for 14 isolates of Trichoderma. The data were entered into a binary matrix and a similarity matrix was constructed using DICE similarity (SD) index. A UPGMA cluster based on SD values was generated using NTSYS (Numerical Taxonomy System, Applied Biostatistics) computer program. A mean coefficient of similarity obtained for pairwise comparisons among the most antagonics isolates was around 40%. The results presented here showed that the variability among the isolates of Trichoderma was very high. No relationship was found between the polymorphism showed by the isolates and their hardness, origin and substrata.

  4. Identifikasi dan Kuantifikasi Metabolit Bakteri Pelarut Fosfat dan Pengaruhnya terhadap Aktivitas Rhizoctonia solani pada Tanaman Kedelai

    Directory of Open Access Journals (Sweden)

    Tri Candra Setiawati

    2008-09-01

    Full Text Available Phosphate solubilizing bacteria (PSB metabolites are organic acids, phosphomonoesterase enzyme (alkaline phosphatase and antibiotic, which is able to dissolve insoluble phosphate. Phosphate solubilizing bacteria used in this study was expected to suppress Rhizoctonia solani attacks. This experiment was aimed at (1 identifiying and quantifying PSB metabolites, and (2 examining their capability as biocontrol agent for Rhizoctonia solani in vitro and hydroponics soybean. This study was conducted in three stages. The first stage of this study was culturing two PSB isolates (Pseudomonas putida 27.4B and Pseudomonas diminuta in the Pikovskaya medium to analyze their metabolites. The second and third stage of this study was testing the antagonist of two bacteria to suppressed R. solani activity, which was conducted in vitro, and in hydroponics medium soybean as indicator plant. The results showed that P. putida 27.4B and P. diminuta produced organic acids i.e.: citrate, formic, succinic, acetic, propionate, butyrate, and oxalate. The totals of organic acids from each bacterium were 70,3 mg.kg-1 and 61,9 mg.kg-1. Production of alkaline phosphatase enzyme in Pikovskaya medium of P. Putida 27.4B was 11,71 ìg pNP .mL-1.h-1 and P. diminuta was 24,04 ìg pNP.mL-1.h-1. Concentration of this enzyme in soil medium was higher than that in Pikovskaya medium with 26,27 ìg pNP.g-1.h-1 and 39,03 ìg pNP.g-1.h-1 respectively. This study also showed that total concentration of antibiotics (tetracycline, oxitetracycline and penicillin produced by the PSB, were 3,2 ìg.mL-1 (P. putida 27.4B and 10,96 ìg.m1-1 (P. diminuta, respectively. The results from second stage of this study showed that by using in vitro, the reduced growth of R. solani was observed 58,35% with P. putida 27.4B and 41,96% with P. diminuta. In addition, inoculations of PSB in hydroponics medium reduced the fungal pathogenesis from 10,71% to 21,42% of pre and post emergence damping-off. Visually, the symptom of pathogen attack appeared within the period of 2 untill 14 days after infection.

  5. High protection of protein kinase NtPK against the phytopatogenic fungus Rhizoctonia solani / La proteína quinasa NtPK confiere alto nivel de protección contra el hongo fitopatógeno Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Orlando, Borrás; Osmani, Chacón; Marleny, González; Roxana, Portieles; Ernesto, González; Merardo, Pujol.

    2012-12-01

    Full Text Available Con el objetivo de identificar los genes involucrados en la resistencia y susceptibilidad de la Nicotiana tabacum al hongo fitopatógeno Rhizoctonia solani, se generaron (a través de librerías substractivas) transcriptos que se expresan diferentemente en cada interacción. Ello permitió el aislamiento [...] de un gen que codifica para una proteína quinasa que se silencia durante la interacción de susceptibilidad y se activa durante la resistencia. La expresión de este gen en plantas de tabaco incrementó significativamente su resistencia frente a un aislado agresivo de R. solani. Sin embargo, el silenciamiento del gen redujo drásticamente la resistencia a una cepa no agresiva de R. solani. Además se evaluaron genes como superóxido dismutasa, hsr203j, quitinasas y fenilalanina amonio-liasa relacionados con la resistencia a enfermedades en plantas de tabaco en las que se sobrexpresa o silencia el gen que codifica para la proteína quinasa. Este gen se puede utilizar para el diseño de una estrategia de resistencia a R. solani en cultivos de tabaco u otras plantas de la familia Solanácea, susceptibles a este fitopatógeno. Abstract in english To identify Nicotiana tabacum genes involved in resistance and susceptibility to the phytopathogenic fungus Rhizoctonia solani, transcripts were generated (by subtractive libraries), which were differentially expressed in each interaction. This enabled isolation of a gene coding for a protein kinase [...] that becomes silent during the susceptibility interaction and is activated during resistance. The expression of this gene in tobacco plants significantly increased resistance against an aggressive isolate of R. solani. However, silencing the gene drastically reduced resistance to a non-aggressive isolate of R. solani. Besides, genes such as: superoxide dismutase, hsr203j, chitinases and phenylalanine ammonia lyase, related with resistance to tobacco plant diseases, in which the gene coding for the protein kinase is overexpressed or silenced, were evaluated. This gene can be used to design a strategy of resistance to R. solani in tobacco cultures or other plants of the Solanaceae family, susceptible to this phytopathogen.

  6. Population Dynamics of Sugar Beets, Rhizoctonia solani, and Laetisaria arvalis: Responses of a Host, Plant Pathogen, and Hyperparasite to Perturbation in the Field †

    OpenAIRE

    Allen, Michael F.; Boosalis, Michael G.; Kerr, Eric D.; Muldoon, Anne E.; Larsen, Harold J.

    1985-01-01

    Rhizoctonia solani causes crown rot of sugar beets, a severe disease that has destroyed up to 60% of the plants in a test field in western Nebraska. Laetisaria arvalis, a natural hyperparasite of Rhizoctonia spp., was isolated from fields in western Nebraska. To test for the potential for biological control of R. solani, in November 1980 (following harvest) we applied various combinations of a nematicide (Telone II; Dow Chemical Co.), a nutrition source (sugar beet pulp), and an inoculum of L...

  7. Efectividad in vitro de Bacillus y polifenoles de plantas nativas de México sobre Rhizoctonia-Solani / In vitro effectiveness of Bacillus and polyphenols of native plants from Mexico on Rhizoctonia-Solani

    Scientific Electronic Library Online (English)

    Francisco, Castillo-Reyes; Francisco Daniel, Hernández-Castillo; Gabriel, Gallegos-Morales; Alberto, Flores-Olivas; Raúl, Rodríguez-Herrera; Cristóbal N., Aguilar.

    2015-05-01

    Full Text Available Con el objetivo de encontrar alternativas para el manejo de patógenos que provocan enfermedades en el sistema radical de las plantas se evaluó el efecto in vitro de bacterias antagonista del género Bacillus aisladas de la rizosfera y de extractos etanolicos de plantas de las especies Larrea tridenta [...] ta, Flourensia cernua, Opuntia ficus-indica, Agave lechuguilla y Yucca filifera endémicas del desierto Chihuahuense contra el fitopatógeno Rhizoctonia solani. Las bacterias se obtuvieron de la forma esporulada, una suspensión de suelo se calentó 15 min 80 °C para eliminar formas no esporuladas. Los extractos vegetales se obtuvieron por infusión. Como resultado se encontró que las cepas de Bacillus aislados presentan un efecto antagonista in vitro sobre la inhibición micelial de Rhizoctonia solani desde 40 a 67%. La caracterización por secuenciación del gen 16S del ADNr se determinó que los aislamientos pertenecen a las especies de B. subtilis, B. pumilus y a B. atrophaeus, quienes están reportadas con efecto antagónico sobre organismos fitopatógenos. Para el caso de los extractos se encontró un efecto en la inhibición micelial hasta 100% en su mayoría todos los extractos inhibieron el crecimiento del micelio de R. solani al 100% excepto el extracto de Y. filifera que solo tuvo 46% con la dosis más alta evaluada (3 000 ppm). Los extractos de F. cernua muestran que a 160 ppm de polifenoles totales se inhibe completamente a R. solani. Abstract in english In order to find alternatives for pathogen management causing diseases in the root system of plants, was evaluated the in vitro effect of antagonistic bacteria of the genus Bacillus isolated from rhizosphere and from ethanolic extracts of plants species Larrea tridentata, Flourensia cernua, Opuntia [...] ficus-indica, Agave lechuguilla and Yucca filifera, that are endemic from the Chihuahua desert against plant pathogen Rhizoctonia solani. Bacteria were obtained as spore form; a soil suspension was heated for 15 min at 80 °C to remove non-sporulating forms. Plant extracts were obtained by infusion. As a result it was found that strains of Bacillus isolates have an in vitro antagonistic effect on mycelia inhibition of Rhizoctonia solani from 40 to 67%. The characterization 16S rDNA gene sequencing determined that the isolates belong to the species of B. subtilis, B. pumilus and B. atrophaeus, that are reported with antagonistic effect on plant pathogenic organisms. In the case of extracts, an effect on mycelial inhibition of up to 100% was found; most extracts inhibited micelial growth of R. solani at 100% except for Y. filifera extract that only obtained 46% with the highest dose evaluated (3 000 ppm). F. cernua extracts show that at 160 ppm of total polyphenols completely inhibited R. solani.

  8. Identification and functional analysis of AG1-IA specific genes of Rhizoctonia solani.

    Science.gov (United States)

    Ghosh, Srayan; Gupta, Santosh Kumar; Jha, Gopaljee

    2014-11-01

    Rhizoctonia solani is an important necrotrophic fungal pathogen which causes disease on diverse plant species. It has been classified into 14 genetically distinct anastomosis groups (AGs), however, very little is known about their genomic diversity. AG1-IA causes sheath blight disease in rice and controlling this disease remains a challenge for sustainable rice cultivation. Recently the draft genome sequences of AG1-IA (rice isolate) and AG1-IB (lettuce isolate) had become publicly available. In this study, using comparative genomics, we report identification of 3,942 R. solani genes that are uniquely present in AG1-IA. Many of these genes encode important biological, molecular functions and exhibit dynamic expression during in-planta growth of the pathogen in rice. Based upon sequence similarity with genes that are required for plant and human/zoonotic diseases, we identified several putative virulence/pathogenicity determinants amongst AG1-IA specific genes. While studying the expression of 19 randomly selected genes, we identified three genes highly up-regulated during in-planta growth. The detailed in silico characterization of these genes and extent of their up-regulation in different rice genotypes, having variable degree of disease susceptibility, suggests their importance in rice-Rhizoctonia interactions. In summary, the present study reports identification, functional characterization of AG1-IA specific genes and predicts important virulence determinants that might enable the pathogen to grow inside hostile plant environment. Further characterization of these genes would shed useful insights about the pathogenicity mechanism of AG1-IA on rice. PMID:25070039

  9. Identification of signatory secondary metabolites during mycoparasitism of Rhizoctonia solani by Stachybotrys elegans.

    Science.gov (United States)

    Chamoun, Rony; Aliferis, Konstantinos A; Jabaji, Suha

    2015-01-01

    Stachybotrys elegans is able to parasitize the fungal plant pathogen Rhizoctonia solani AG-3 following a complex and intimate interaction, which, among others, includes the production of cell wall-degrading enzymes, intracellular colonization, and expression of pathogenic process encoding genes. However, information on the metabolome level is non-existent during mycoparasitism. Here, we performed a direct-infusion mass spectrometry (DIMS) metabolomics analysis using an LTQ Orbitrap analyzer in order to detect changes in the profiles of induced secondary metabolites of both partners during this mycoparasitic interaction 4 and 5 days following its establishment. The diketopiperazine(s) (DKPs) cyclo(S-Pro-S-Leu)/cyclo(S-Pro-S-Ile), ethyl 2-phenylacetate, and 3-nitro-4-hydroxybenzoic acid were detected as the primary response of Rhizoctonia 4 days following dual-culturing with Stachybotrys, whereas only the latter metabolite was up-regulated 1 day later. On the other hand, trichothecenes and atranones were mycoparasite-derived metabolites identified during mycoparasitism 4 and 5 days following dual-culturing. All the above secondary metabolites are known to exhibit bioactivity, including fungitoxicity, and represent key elements that determine the outcome of the interaction being studied. Results could be further exploited in programs for the evaluation of the bioactivity of these metabolites per se or their chemical analogs, and/or genetic engineering programs to obtain more efficient mycoparasite strains with improved efficacy and toxicological profiles. PMID:25972848

  10. ISOLATION AND MOLECULAR CHARACTERIZATION OF EGYPTIAN TRICHODERMA AND ASSESSMENT OF THEIR ANTAGONISTIC POTENTIAL AGAINST RHIZOCTONIA SOLANI

    Directory of Open Access Journals (Sweden)

    Gamal Mohamedin Hassan

    2015-06-01

    Full Text Available Morphological and molecular characterization of antagonistic ability of Trichoderma species was studied. Soil dilution plate method was used to isolate trichoderma from rhizosphere of bean, cowpea, cucumber, wheat and faba bean plants. Based on morphological and cultural characteristics, the Trichoderma isolates were identified as T. harzianum (10 isolates, T. koningii (8 isolates, and T. viride (2 isolates. A portion of rDNA, 560-600 bp was amplified from six biocontrol isolates using ITS1 and ITS 4 primers, and was sequenced and aligned against ex-type strain sequences from TrichoBlast and established Trichoderma taxonomy. Molecular phylogenetic analysis were performed based on nucleotide sequences in order to examine these isolates among 15 accession numbers of Trichoderma spp. found in GenBank. The results indicate that the FUE3, FUE5, FUE6, FUE9 and FUE18 Trichoderma isolates are closely related to Trichoderma koningii, while FUE15 isolate is closely related to Trichoderma harzianim .This result was in accordance with the result obtained from morphological and cultural characteristics. Production of volatile inhibitors and mycoparasitism were investigated using in vitro and in vivo tests in dual culture PDA medium and infected soils. The percent inhibitory effect against growth of Rhizoctonia solani was calculated, T. koningii FUE3 showed the greatest antagonistic effect to the pathogen (57.77% in vitro experiment whereas T. koningii FUE6 and FUE18 were gave the highest reduction 96% of disease incidence caused by R. solani in greenhouse conditions.

  11. Application of Fluorescent Pseudomonads in Biological Control of Rhizoctonia solani , Causal Agent of Colza

    Directory of Open Access Journals (Sweden)

    M. Javan Nikkhah

    2008-01-01

    Full Text Available   Two hundred fifty seven bacterial isolates were collected from colza root and rhizosphere in Golestan, Mazandaran, Guilan and Tehran provinces. Antagonistic effect of bacterial isolates on Rhizoctonia solani, the causal agent of colza damping off, was studied using dual culture method. The results showed that, 60 isolates had the ability to inhibit the growth of R. solani on PDA medium. On the basis of the biochemical, physiological and morphological tests, isolates P1, P2 and P3 were identified as Pseudomonas fluorescens. Biocontrol mechanism studies showed that isolates produced antibiotics and volatile metabolites prevented the mycelial growth of the fungus. The isolates produced some of antimicrobial metabolites including hydrogen cyanide, protease and siderophore. Isolate P3 was more effective to inhibit the growth of the fungus in-vitro. The effect of isolates on disease reduction in comparison with control was significantly different. None of the isolates were able to prevent disease occurrence completely. Isolates applied as soil treatment had a significantly higher disease control as compared to seed treatment method. Isolate P3 had considerable effect on reduction disease in the greenhouse conditions. All isolates were capable of colonizing canola roots and so increased canola growth in free-causal agent conditions.

  12. Virulence and molecular characterization of Costa Rican isolates of Rhizoctonia solani from common bean

    Scientific Electronic Library Online (English)

    Floribeth, Mora-Umaña; Natalia, Barboza; Ricardo, Alvarado; Marcela, Vásquez; Graciela, Godoy-Lutz; James R., Steadman; Pilar, Ramírez.

    2013-12-01

    Full Text Available Web blight is one of the main diseases that affects bean (Phaseolus vulgaris) cultivation. It infects diverse organs at any growth stage of the plant and can be present at different altitudes in a humid tropical climate. The causal agent of this disease is Thanatephorus cucumeris in its sexual stage [...] and Rhizoctonia solani in the anamorph. The objective of this investigation was to characterize molecular isolates of R. solani obtained from bean plants from diverse production regions in Costa Rica and determine their virulence. Fifty-one samples of symptomatic bean plants were collected using a global positioning system. Virulence was evaluated using the detached leaf technique. Isolates were identified using AG 1-IA, AG 1-IB, AG 1-IC, AG 1-ID, AG 2-2, AG 2-2IIIB, AG 2-2IV and AG 4 molecular markers. ITS sequences were obtained and analyzed with BLAST, aligned, and a phylogenetic tree was constructed. A high degree of virulence and genetic variability between isolates was identified and the anastomosis subgroups of isolates were independent of their geographical origin.

  13. Molecular characterization and screening for sheath blight resistance using Malaysian isolates of Rhizoctonia solani.

    Science.gov (United States)

    Nadarajah, Kalaivani; Omar, Nurfarahana Syuhada; Rosli, Marhamah Md; Shin Tze, Ong

    2014-01-01

    Two field isolates of Rhizoctonia solani were isolated from infected paddy plants in Malaysia. These isolates were verified via ITS-rDNA analysis that yielded ~720?bp products of the ITS1-5.8S-ITS4 region, respectively. The sequenced products showed insertion and substitution incidences which may result in strain diversity and possible variation in disease severity. These strains showed some regional and host-specific relatedness via Maximum Likelihood and further phylogenetic analysis via Maximum Parsimony showed that these strains were closely related to R. solani AG1-1A (with 99-100% identity). Subsequent to strain verification and analysis, these isolates were used in the screening of twenty rice varieties for tolerance or resistance to sheath blight via mycelial plug method where both isolates (1801 and 1802) showed resistance or moderate resistance to Teqing, TETEP, and Jasmine 85. Isolate 1802 was more virulent based on the disease severity index values. This study also showed that the mycelial plug techniques were efficient in providing uniform inoculum and humidity for screening. In addition this study shows that the disease severity index is a better mode of scoring for resistance compared to lesion length. These findings will provide a solid basis for our future breeding and screening activities at the institution. PMID:25258710

  14. Proteomic response of Rhizoctonia solani GD118 suppressed by Paenibacillus kribbensis PS04.

    Science.gov (United States)

    Wang, Liuqing; Liu, Mei; Liao, Meide

    2014-12-01

    Rice sheath blight, caused by Rhizoctonia solani, is considered a worldwide destructive rice disease and leads to considerable yield losses. A bio-control agent, Paenibacillus kribbensis PS04, was screened to resist against the pathogen. The inhibitory effects were investigated (>80 %) by the growth of the hyphae. Microscopic observation of the hypha structure manifested that the morphology of the pathogenic mycelium was strongly affected by P. kribbensis PS04. To explore essentially inhibitory mechanisms, proteomic approach was adopted to identify differentially expressed proteins from R. solani GD118 in response to P. kribbensis PS04 using two-dimensional gel electrophoresis. Protein profiling was used to identify 13 differential proteins: 10 proteins were found to be down-regulated while 3 proteins were up-regulated. These proteins were involved in material and energy metabolism, antioxidant activity, protein folding and degradation, and cytoskeleton regulation. Among them, material and energy metabolism was differentially regulated by P. kribbensis PS04. Protein expression was separately inhibited by the bio-control agent in oxidation resistance, protein folding and degradation, and cytoskeleton regulation. Proteome changes of the mycelium assist in understanding how the pathogen was directly suppressed by P. kribbensis PS04. PMID:25164959

  15. Isolation and characterization of siderophore producing antagonistic rhizobacteria against Rhizoctonia solani.

    Science.gov (United States)

    Solanki, Manoj Kumar; Singh, Rajesh Kumar; Srivastava, Supriya; Kumar, Sudheer; Kashyap, Prem Lal; Srivastava, Alok K; Arora, Dilip K

    2014-06-01

    Plant protection through siderophore producing rhizobacteria (SPR) has emerged as a sustainable approach for crop health management. In present study, 220 bacteria isolated from tomato rhizosphere were screened for in vitro antagonistic activity against Rhizoctonia solani AG-4. Nine potent antagonistic strains viz., Alcaligenes sp. (MUN1, MB21, and MPF37), Enterobacter sp. (MPM1), Pseudomonas sp. (M10A and MB65), P. aeruginosa (MPF14 and MB123) and P. fluorescens (MPF47) were identified on the basis of physiological characters and 16S rDNA sequencing. These strains were able to produce hydrolytic enzymes, hydrogen cyanide, indole acetic acid, although, only few strains were able to solubilize phosphate. Two strains (MB123 and MPF47) showed significant disease reduction in glasshouse conditions were further evaluated under field conditions using three different application methods. Application of P. fluorescens (MPF47) in nursery as soil mix?+?seedling root treatments prior to transplantation resulted in significant disease reduction compared to control. Total chlorophyll and available iron were significantly higher in the MPF47 treated plants in contrast to infected control. In conclusion, siderophore producing bacteria MPF47 have strong biocontrol abilities and its application as soil mix?+?seedling root treatments provided strong shield to plant roots against R. solani and could be used for effective bio-management of pathogen. PMID:23686438

  16. Mechanism for mercury tolerance in fungi. [Aspergillus niger; Rhizoctonia solani; Pythium ultimum

    Energy Technology Data Exchange (ETDEWEB)

    Ashworth, L.J. Jr.; Amin, J.V.

    1964-01-01

    Aspergillus niger was protected from mercury (Hg) poisoning by sulfhydryl (SH) compounds (glutathione and cysteine) in culture experiments, whereas Rhizoctonia solani and Pythium ultimum were not protected. Two- to 30-day-old mycelium of A. niger was found to be more tolerant to Hg than either younger or older mycelia. Mycelia of the other fungi were sensitive regardless of age. Mercury tolerance of A. niger mycelium was altered when sulfur nutrition was modified; it was greater after growth on a substrate containing reduced sulfur than after growth on one containing sulfate. The Hg tolerance of A. niger mycelium appears to be due to a pool of intracellular SH that is free of protein and that protects enzyme systems by forming complexes with Hg as it is taken up by the thallus. Potato-dextrose broth-grown mats of A. niger contained about 100 ..mu..g of SH/g of dry mycelia after 36 hr and after 5 days. R.. solani had about 9 ..mu..g of SH/g of mycelia after 5 days; a measurable amount was not recovered from P. ultimum. 20 references, 1 figure, 2 tables.

  17. Antifungal activity of volatile compounds-producing Pseudomonas P2 strain against Rhizoctonia solani.

    Science.gov (United States)

    Elkahoui, Salem; Djébali, Naceur; Yaich, Najeh; Azaiez, Sana; Hammami, Majdi; Essid, Rym; Limam, Ferid

    2015-01-01

    Several volatile organic compounds (VOCs) producing endophyte bacteria were isolated from the leaves of olive trees and tested for their antifungal activity against several pathogenic fungi. An antagonistic strain called P2 showed 97 % of homology with Pseudomonas sp. strains on the basis of its 16S rDNA sequence and biochemical properties. P2 strain drastically inhibited the growth of Rhizoctonia solani mycelia (86 %) at 5 day-post-confrontation (dpc) and strongly reduced fungi infection on potato slices at 10(7) bacteria ml(-1) for 3 and 7 dpc. P2 strain was also positive for protease activity as well as siderophore production. Light microscopy analysis showed that treatment of R. solani mycelia with P2 strain induced thickening of the cell-wall, vesiculation of protoplasm and blockage of fungal hyphae branching. VOCs analysis using GC-MS allowed the detection of two major products with m/z of 93.9910 and 125.9630 corresponding to dimethyl disulfide and dimethyl trisulfide respectively. VOCs-producing P2 strain could be a promising agent in the protection of tuber crops against fungal diseases. PMID:25384611

  18. Effect of Potassium Damping-off (Pythium sp and Rhizoctonia solani) and Cold Tolerance on Tobacco Seedlings

    OpenAIRE

    Gu?ngo?r, O?zlem

    1998-01-01

    Effect of Potassium on damping off tobacco caused by Pythium sp and Rhizoctonia solani were investigated by giving 10, 20, 30 kg/da (5, 10, 15 ppm) K2SO4 as K2O base and pathogen inoculum at the same time at green house experiments. Potassium application did not present disease development at all three rates, but at the rate of 20 kg/da K2O there were a slight seedling cover of 13,75% and 3,75% for Pythium sp. and R.solani especially. Potassium at the rate of 10 kg/da prevented cold shock of...

  19. Molecular characterization of Rhizoctonia solani AG4 using PCR-RFLP of the rDNA-ITS region

    OpenAIRE

    Kilic?og?lu, Melike C?ebi?; O?zkoc?, I?brahim

    2010-01-01

    Rhizoctonia solani isolates obtained from common beans (Phaseolus vulgaris L.) were included in an AG4 anastomosis group in accordance with hyphal anastomosis. In the subgrouping of AG4 isolates, PCR-RFLP patterns in the rDNA-ITS were used. After obtaining the genomic DNA belonging to R. solani AG4, an approximately 700 bp amplification product of the ITS1-5.8S-ITS2 region was obtained with PCR, using ITS1 and ITS4 universal primers. The PCR products were digested with MseI, HincII, AvaII, an...

  20. High-resolution mapping of Rsn1, a locus controlling sensitivity of rice to a necrosis-inducing phytotoxin from Rhizoctonia solani AG1-IA

    Science.gov (United States)

    Rhizoctonia solani is a necrotrophic fungal pathogen that causes disease on all major crop-plant species. Anastomosis group 1-IA is the causal agent of sheath blight of rice (Oryza sativa), one of the most important rice diseases worldwide. R. solani AG-IA produces a necrosis-inducing phytotoxin a...

  1. Silício alterando compostos derivados da pirólise de bainhas foliares de plantas de arroz infectadas por Rhizoctonia solani Silicon altering compounds derived from the pyrolyses of leaf sheaths of rice plants infected with Rhizoctonia solani

    OpenAIRE

    Daniel Augusto Schurt; Fabrício de Ávila Rodrigues; Vivian Carré-Missio; Nilda de Fátima Ferreira Soares

    2013-01-01

    Este trabalho teve como objetivo elucidar, por meio da pirólise analítica acoplada à cromatografia gasosa e espectrometria de massa, alterações na composição química da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou não com silício (Si) e infectadas por Rhizoctonia solani. A concentração de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg-1) em comparação com as plantas não supridas (0,45 da...

  2. Comparison of different methods for total RNA extraction from sclerotia of Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Canwei, Shu; Si, Sun; Jieling, Chen; Jianyi, Chen; Erxun, Zhou.

    2014-01-15

    Full Text Available Background Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is one of the most important pathogens of rice (Oryza sativa L.) that causes severe yield losses in all rice-growing regions. Sclerotia, formed from the aggregation of hyphae, are important structures in the life cycles of R. solani [...] and contain a large quantity of polysaccharides, lipids, proteins and pigments. In order to extract high-quality total RNA from the sclerotia of R. solani, five methods, including E.Z.N.A.™ Fungal RNA Kit, sodium dodecyl sulfate (SDS)-sodium borate, SDS-polyvinylpyrrolidone (PVP), guanidinium thiocyanate (GTC) and modified Trizol, were compared in this study. Results The electrophoresis results showed that it failed to extract total RNA from the sclerotia using modified Trizol method, whereas it could extract total RNA from the sclerotia using other four methods. Further experiments confirmed that the total RNA extracted using SDS-sodium borate, SDS-PVP and E.Z.N.A.™ Fungal RNA Kit methods could be used for RT-PCR of the specific amplification of GAPDH gene fragments, and that extracted using GTC method did not fulfill the requirement for above-mentioned RT-PCR experiment. Conclusion It is concluded that SDS-sodium borate and SDS-PVP methods were the better ones for the extraction of high-quality total RNA that could be used for future gene cloning and expression studies, whereas E.Z.N.A.™ Fungal RNA Kit was not taken into consideration when deal with a large quantity of samples because it is expensive and relatively low yield.

  3. Phylogeography of the Solanaceae-infecting Basidiomycota fungus Rhizoctonia solani AG-3 based on sequence analysis of two nuclear DNA loci

    OpenAIRE

    Vilgalys Rytas J; James Timothy Y; David, Shew H.; Ceresini Paulo C; Cubeta Marc A

    2007-01-01

    Abstract Background The soil fungus Rhizoctonia solani anastomosis group 3 (AG-3) is an important pathogen of cultivated plants in the family Solanaceae. Isolates of R. solani AG-3 are taxonomically related based on the composition of cellular fatty acids, phylogenetic analysis of nuclear ribosomal DNA (rDNA) and beta-tubulin gene sequences, and somatic hyphal interactions. Despite the close genetic relationship among isolates of R. solani AG-3, field populations from potato and tobacco exhib...

  4. DNA Microsatellite Analysis of Kenyan Isolates of Rhizoctonia solani from Common Bean (Phaseolus vulgaris L.)

    OpenAIRE

    Mwang Ombe, A. W.; G. Thiong`O; Olubayo, F. M.; Kiprop, E. K.

    2007-01-01

    Seven hundred and fifty bean plant samples with root rot symptoms were collected from farmers' fields during two surreys carried out in Embu district, Kenya. Various fungal pathogens were isolated in the laboratory from these samples; among them were 50 isolates of Rhizoctonia solani, which were subjected to pathogenicity tests in a glasshouse. Thirty-six isolates of R. solani obtained from beans with root rots were subjected to DNA microsatellite analysis. Five isolates of R. solani that cau...

  5. Molecular detection of antibiotic related genes from Pseudomonas aeruginosa FP6, an antagonist towards Rhizoctonia solani and Colletotrichum gloeosporioides

    OpenAIRE

    Bakthavatchalu, Sasirekha; Shivakumar, Srividya; Sullia, Shankar Bhat

    2013-01-01

    Despite the importance of antibiosis in biological control, little is known about the genes involved in antifungal activity. Therefore, the present study was aimed at identifying the location of the antagonistic gene(s) in Pseudomonas aeruginosa FP6 towards Rhizoctonia solani and Colletotrichum gloeosporioides using a PCR-based approach. A new bacterial strain, designated as FP6, was isolated from rhizospheric soil and identified as a member of Pseudomonas aeruginosa based on 16S rRNA analysi...

  6. FT-ICR/MS and GC-EI/MS Metabolomics Networking Unravels Global Potato Sprout's Responses to Rhizoctonia solani Infection

    OpenAIRE

    Aliferis, Konstantinos A.; Jabaji, Suha

    2012-01-01

    The complexity of plant-pathogen interactions makes their dissection a challenging task for metabolomics studies. Here we are reporting on an integrated metabolomics networking approach combining gas chromatography/mass spectrometry (GC/MS) with Fourier transform ion cyclotron resonance/mass spectrometry (FT-ICR/MS) and bioinformatics analyses for the study of interactions in the potato sprout-Rhizoctonia solani pathosystem and the fluctuations in the global metabolome of sprouts. The develop...

  7. The effect of chemical haulm destruction and haulm pulling on potato black scurf caused by Rhizoctonia solani AG-3.

    OpenAIRE

    Dijst, G.

    1989-01-01

    Factors influencing black scurf formation in untreated crops and after haulm destruction were investigated. As potato tubers mature they may gradually become covered with black scurf, the sclerotia of the fungus Rhizoctonia solani AG-3. After haulm destruction, black scurf formation is stimulated by changes at the tuber surface due to accelerated tuber maturation. These changes probably start within 3 to 6 days.The final amount of black scurf at harvesting depended on the method of haulm dest...

  8. Induction of systemic resistance in rice by leaf extracts of Zizyphus jujuba and Ipomoea carnea against Rhizoctonia solani

    OpenAIRE

    Kagale, Sateesh; Marimuthu, Thambiayya; Kagale, Jayashree; Thayumanavan, Balsamy; Samiyappan, Ramasamy

    2011-01-01

    Plants accumulate a great diversity of natural products, many of which confer protective effects against phytopathogenic attack. Earlier we had demonstrated that the leaf extracts of Zizyphus jujuba and Ipomoea carnea inhibit the in vitro mycelial growth of Rhizoctonia solani, and effectively reduce the incidence of sheath blight disease in rice.7 Here we demonstrate that foliar application of the aqueous leaf extracts of Z. jujuba and I. carnea followed by challenge inoculation with R. solan...

  9. The impact of the pathogen Rhizoctonia solani and its beneficial counterpart Bacillus amyloliquefaciens on the indigenous lettuce microbiome

    OpenAIRE

    GabrieleBerg; ArminErlacher; RitaGrosch

    2014-01-01

    Lettuce belongs to the most commonly raw eaten food worldwide and its microbiome plays an important role for both human and plant health. Yet, little is known about the impact of potentially occurring pathogens and beneficial inoculants of the indigenous microorganisms associated with lettuce. To address this question we studied the impact of the phytopathogenic fungus Rhizoctonia solani and the biological control agent Bacillus amyloliquefaciens FZB42 on the indigenous rhizosphere and phyllo...

  10. Resistência física de bainhas de plantas de arroz supridas com silício e infectadas por Rhizoctonia solani / Physical resistance of leaf sheaths of rice plants supplied with silicon and infected by Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Daniel Augusto, Schurt; Fabrício Ávila, Rodrigues; Ricardo Dutra, Reis; Wiler Ribas, Moreira; Naiara Fernandes Abreu, Souza; Washington Azevedo, Silva.

    2012-08-01

    Full Text Available Este trabalho objetivou associar a deposição de silício (Si) nas bainhas de plantas de arroz ao aumento da resistência física à infecção por Rhizoctonia solani. Plantas das cultivares suscetíveis BR-Irga 409 e Labelle foram cultivadas em solução nutritiva contendo (+Si) ou não (-Si) Si. A concentraç [...] ão de Si nas bainhas das plantas supridas com Si e inoculadas com R. solani aumentou significativamente em relação às plantas não supridas com Si reduzindo o comprimento relativo da lesão às 96 horas após inoculação (hai). Houve diferença significativa entre os tratamentos -Si e +Si quanto à força necessária para uma agulha metálica atravessar as bainhas às 48 e 72 hai. A maior resistência física às 24 hai deve-se ao fato de que R. solani estava crescendo sobre o tecido sem destruí-lo, o que pôde ser comprovado pela ausência de sintomas. Após esse período, a resistência diminuiu devido ao rápido crescimento de R. solani. Entretanto, nas bainhas de plantas supridas com Si, a força necessária para a agulha penetrar foi maior às 48 e 72 hai. A resistência das bainhas de plantas supridas com Si à infecção por R. solani pode ser explicada, em parte, pela maior resistência física decorrente da deposição desse elemento. Abstract in english This study aimed to associate the silicon (Si) deposition on sheaths of rice plants with an increase in physical resistance against infection by Rhizoctonia solani. Plants from the susceptible cultivars BR-Irga 409 and Labelle were grown in nutrient solution containing (+Si) or not (-Si) Si. Si conc [...] entration on sheaths of plants supplied with Si and inoculated with R. solani significantly increased compared to plants non-supplied with Si, reducing the relative lesion length at 96 hours after inoculation (hai). There were significant differences between -Si and +Si treatments for the force required of a metal needle to pass through the sheaths at 48 and 72 hai. The greater physical resistance at 24 hai was due to the fact that R. solani was growing on sheath tissue without destroying it, which could be proved by the absence of symptoms. After this period, the resistance decreased due to the rapid R. solani growth. However, on sheaths of plants supplied with Si, the force required for the needle to penetrate was higher at 48 and 72 hai. The sheath resistance of plants supplied with Si to infection by R. solani can be explained partly by the greater physical resistance due to Si deposition.

  11. Genome sequencing and comparative genomics of the broad host-range pathogen Rhizoctonia solani AG8.

    Science.gov (United States)

    Hane, James K; Anderson, Jonathan P; Williams, Angela H; Sperschneider, Jana; Singh, Karam B

    2014-05-01

    Rhizoctonia solani is a soil-borne basidiomycete fungus with a necrotrophic lifestyle which is classified into fourteen reproductively incompatible anastomosis groups (AGs). One of these, AG8, is a devastating pathogen causing bare patch of cereals, brassicas and legumes. R. solani is a multinucleate heterokaryon containing significant heterozygosity within a single cell. This complexity posed significant challenges for the assembly of its genome. We present a high quality genome assembly of R. solani AG8 and a manually curated set of 13,964 genes supported by RNA-seq. The AG8 genome assembly used novel methods to produce a haploid representation of its heterokaryotic state. The whole-genomes of AG8, the rice pathogen AG1-IA and the potato pathogen AG3 were observed to be syntenic and co-linear. Genes and functions putatively relevant to pathogenicity were highlighted by comparing AG8 to known pathogenicity genes, orthology databases spanning 197 phytopathogenic taxa and AG1-IA. We also observed SNP-level "hypermutation" of CpG dinucleotides to TpG between AG8 nuclei, with similarities to repeat-induced point mutation (RIP). Interestingly, gene-coding regions were widely affected along with repetitive DNA, which has not been previously observed for RIP in mononuclear fungi of the Pezizomycotina. The rate of heterozygous SNP mutations within this single isolate of AG8 was observed to be higher than SNP mutation rates observed across populations of most fungal species compared. Comparative analyses were combined to predict biological processes relevant to AG8 and 308 proteins with effector-like characteristics, forming a valuable resource for further study of this pathosystem. Predicted effector-like proteins had elevated levels of non-synonymous point mutations relative to synonymous mutations (dN/dS), suggesting that they may be under diversifying selection pressures. In addition, the distant relationship to sequenced necrotrophs of the Ascomycota suggests the R. solani genome sequence may prove to be a useful resource in future comparative analysis of plant pathogens. PMID:24810276

  12. A One-Step, Immunochromatographic Lateral Flow Device Specific to Rhizoctonia solani and Certain Related Species, and Its Use to Detect and Quantify R. solani in Soil.

    Science.gov (United States)

    Thornton, Christopher R; Groenhof, Andrew C; Forrest, Robert; Lamotte, Richard

    2004-03-01

    ABSTRACT A murine hybridoma cell line GD2 secreting an immunoglobulin (Ig)M monoclonal antibody (MAb) was produced against surface antigens from an anastomosis group (AG) 4 isolate of Rhizoctonia solani (teleomorph: Thanatephorus cucumeris). Ascites were produced in mice using GD2 hybridoma cells and used to develop a rapid immunochromatographic lateral flow device (LFD) for the detection of antigens from R. solani and certain related Rhizoctonia spp. The LFD was tested for specificity against surface antigens from related and unrelated soil fungi. Antigens from representative isolates of R. solani AGs 1, 2-1, 2-3, 2-t, 3, 4, 5, 6, 7, 8, 9, 10, 11, and BI gave a positive response in LFD tests, as did antigens from Thanatephorus orchidicola, T. praticola, R. fragariae (teleomorph: Ceratorhiza fragariae), Ceratorhiza goodyerae-repentis, Ceratobasidium cornigerum, and binucleate AGE. Antigens from R. solani AGs 2-2, 2-2IIIB, and 2-2IV and from the related fungi R. carotae, R. cerealis (teleomorph: Ceratobasium cereale), R. crocorum (teleomorph: Helicobasidium brebissonii), R. oryzae (teleomorph Waitea circinata), and R. zeae gave negative responses, as did antigens from a range of unrelated fungi and oomycetes including Fusarium, Gliocladium, Trichoderma, Pythium, and Phytophthora spp. The usefulness of the LFD to detect R. solani was demonstrated in soils naturally infested with R. solani AG3. There was close agreement between results of LFD tests and conventional plate enrichment tests employing selective medium. The specificity of the technique was confirmed by polymerase chain reaction PCR using R. solani AG3-specific primers and by analyses based on sequences of the internal transcribed spacer (ITS)1-5.8S-ITS2 rRNA-encoding regions of unrelated fungi recovered from soil samples. The LFD was used to quantify R. solani AG4 in artificially infested soil samples (chopped potato soil inoculum). Estimates of CFU per gram of soil were derived using a most-probable number technique, which was based on the presence or absence of a detectable signal in the LFD. Estimates of CFU obtained in LFD tests and those obtained in a plate-trapped antigen enzyme-linked immunosorbent assay incorporating MAb GD2 were identical (449 CFU g(-1) of soil). PMID:18943976

  13. Identification of Rhizoctonia solani isolates from sugar beet roots by analyzing the ITS region of ribosomal DNA

    Directory of Open Access Journals (Sweden)

    Stojšin Vera B.

    2007-01-01

    Full Text Available Rhizoctonia solani (Kühn is one of the most important sugar beet pathogens Rhizoctonia solani anastomosis groups (AGs 2-2 and 4 are proven to be the most common pathogenic strains on sugar beet. AG 2-2 (intraspecific groups IIIB and IV can cause root and crown rot while damping-off of seedlings is most frequently attributed to AG 4. Four isolates of R. solani from sugar beet roots showing characteristic crown and root rot symptoms, collected from different localities in Vojvodina Province, were chosen and compared to the well-characterized R. solani isolate R9, AG 2-2 IV, from the USA. All Vojvodinian isolates showed medium level of pathogenicity and were able to cause crown and root rot symptoms on inoculated sugar beet roots. Based on anastomosis reaction, isolates from Vojvodina did not belong to the AG 2-2 group. Sequencing of the ITS (internal transcribed spacer region of ribosomal DNA was performed on the Vojvodinian isolates from R9 in order to determine their relatedness. Sequence analysis showed that these isolates were different than R9 and were closely related (99-100% sequence homology to anastomosis group 4, subgroup HG II.

  14. Mobile elements and mitochondrial genome expansion in the soil fungus and potato pathogen Rhizoctonia solani AG-3.

    Science.gov (United States)

    Losada, Liliana; Pakala, Suman B; Fedorova, Natalie D; Joardar, Vinita; Shabalina, Svetlana A; Hostetler, Jessica; Pakala, Suchitra M; Zafar, Nikhat; Thomas, Elizabeth; Rodriguez-Carres, Marianela; Dean, Ralph; Vilgalys, Rytas; Nierman, William C; Cubeta, Marc A

    2014-03-01

    The soil fungus Rhizoctonia solani is an economically important pathogen of agricultural and forestry crops. Here, we present the complete sequence and analysis of the mitochondrial genome of R. solani, field isolate Rhs1AP. The genome (235 849 bp) is the largest mitochondrial genome of a filamentous fungus sequenced to date and exhibits a rich accumulation of introns, novel repeat sequences, homing endonuclease genes, and hypothetical genes. Stable secondary structures exhibited by repeat sequences suggest that they comprise functional, possibly catalytic RNA elements. RNA-Seq expression profiling confirmed that the majority of homing endonuclease genes and hypothetical genes are transcriptionally active. Comparative analysis suggests that the mitochondrial genome of R. solani is an example of a dynamic history of expansion in filamentous fungi. PMID:24461055

  15. In vitro and glasshouse biocontrol of Rhizoctonia solani with improved strains of Trichoderma spp. / Biocontrol de Rhizoctonia solani in vivo y en invernadero, con cepas mejoradas de Trichoderma spp.

    Scientific Electronic Library Online (English)

    Jaime R, Montealegre; Fabián, Ochoa; Ximena, Besoain; Rodrigo, Herrera; Luz M, Pérez.

    Full Text Available J.R. Montealegre, F. Ochoa, X. Besoain, R. Herrera y L.M. Pérez. 2014. Biocontrol de Rhizoctonia solani in vivo y en invernadero, con cepas mejoradas de Trichoderma spp. Cien. Inv. Agr. 41(2):197-206. Se comparó la capacidad de cepas de Trichoderma spp., obtenidas previamente por fusión de protoplas [...] tos, con la de sus correspondientes cepas parentales, para biocontrolar a Rhizoctonia solani. El efecto biocontrolador se analizó sobre dos cepas de R. solani: 509 (GA 2-1) y 618 (GA 4). Las cepas producto de fusión de protoplastos de Trichoderma spp. fueron más efectivas que al menos una de las correspondientes cepas parentales. La inhibición más alta en experimentos de cultivos duales, se observó con las cepas ThF2-1 (89,79%), ThF3-3 (90,55%), ThF4-15 (91,75%) y ThF5-8 (77,67%) sobre R. solani 509; mientras que el efecto biocontrolador sobre R. solani 618, sólo logró un 60,19% de inhibición con la cepa ThF2-1. El efecto inhibidor del desarrollo se debió principalmente a la secreción de metabolitos difusibles. El porcentaje de mortalidad y nivel de cancro en plantas de tomate se evaluó en experimentos de invernadero, en los que todas las cepas producto de la fusión de protoplastos de Trichoderma spp. suprimieron la mortalidad de plantas de tomate, y solamente ThF2-1 y ThF5-8 disminuyeron significativamente el nivel de cancro. Abstract in english J.R. Montealegre, F. Ochoa, X. Besoain, R. Herrera, and L.M. Pérez. 2014. In vitro and glasshouse biocontrol of Rhizoctonia solani with improved strains of Trichoderma spp. Cien. Inv. Agr. 41(2):197-206. The potential of Trichoderma spp. fusants for the biocontrol of Rhizoctonia solani was compared [...] with the ability of their corresponding parental strains. Their effect was tested in vitro using two R. solani strains, 509 (AG 2-1) and 618 (AG 4). The highest inhibitions in growth in dual cultures were obtained with the ThF2-1 (89.79%), ThF3-3 (90.55%), ThF4-15 (91.75%) and ThF5-8 (77.67%) fusants on R. solani 509; only ThF2-1 was able to inhibit the growth of R. solani 618 (60.19%). The inhibitory effect on growth was mainly due to diffusible metabolites. Percent mortality and canker level in tomato plants were evaluated in glasshouse experiments where all of the evaluated fusants suppressed plant mortality, but only ThF2-1 and ThF5-8 significantly decreased the canker level.

  16. Preparation and characterization of nano-sized calcium carbonate as controlled release pesticide carrier for validamycin against Rhizoctonia solani

    International Nuclear Information System (INIS)

    Nano-sized calcium carbonate (nano-CC) was studied in terms of acting as a carrier for a pesticide. Nano-CC was prepared by reaction of calcium chloride and sodium carbonate by the reversed-phase microemulsion method and then loaded with the pesticide validamycin. The resulting material was characterized by X-ray diffraction analysis and scanning electron microscopy. The loading efficiency, sustained-release performance, germicidal efficacy, and stability also were investigated. The size of the loaded nano-CC can be adjusted to between 50 to 200 nm by varying the water/surfactant molar ratio from 30/1 to 10/1, and the loading efficiency can be increased to about 20% by increasing the size of the nano-CC. The material displayed better germicidal efficacy against Rhizoctonia solani compared to conventional technical validamycin after about 7 days, and the time of the release of validamycin was extended to 2 weeks. Given the loading efficiency, stability, sustained-release performance and good environmental compatibility of the material, the method for its preparation may be extended to other hydrophilic pesticide. (author)

  17. Development of a difenoconazole/propiconazole microemulsion and its antifungal activities against Rhizoctonia solani AG1-IA.

    Science.gov (United States)

    Leng, Pengfei; Zhang, Zhiming; Li, Qian; Zhang, Yunsong; Zhao, Maojun; Pan, Guangtang

    2012-06-01

    According to its physical and chemical properties, the composition of difenoconazole/propiconazole microemulsion was as follows: xylene as solvent, emulsifier HSH as surfactant and methanol as cosurfactant. The optimal formulation of difenoconazole/propiconazole microemulsion was oil/SAA/water = 1/2/5 (w/w), in which the SAA consisted of emulsifier HSH and methanol with ratio of 3/2 (w/w). The cloud point of difenoconazole/propiconazole microemulsion was 70 degrees C and its effective ingredient content was 2.5% measured by High Performance Liquid Chromatography (HPLC). Its heat storage stability was studied according to the standards. The decomposition rates of the difenoconazole/propiconazole microemulsion were merely 2.45%, 2.63% respectively and met the Food and Agriculture Organization (FAO) standards of pesticide microemulsion. Investigated by Transmission Electron Microscopy (TEM) the particle size of difenoconazole/propiconazole microemulsion was 90-140 nm and its antifungal activities against Rhizoctonia solani AG1-IA were tested and compared with that of Meiyu. We found that the inhibition rates in the difenoconazole/propiconazole microemulsion treatment group were significantly higher than that of the emulsion group with the same content of effective ingredients and the study also revealed that its inhibiting ability on the formation and germination of sclerotia was significant. PMID:22822543

  18. Do fungicides used to control Rhizoctonia solani impact the non-target arbuscular mycorrhizal fungus Rhizophagus irregularis?

    Science.gov (United States)

    Buysens, Catherine; Dupré de Boulois, Hervé; Declerck, Stéphane

    2015-05-01

    There is growing evidence that the application of biocontrol organisms (e.g., Pseudomonas and Bacillus spp., arbuscular mycorrhizal fungi-AMF) is a feasible option to reduce incidence of plant pathogens in an integrated control strategy. However, the utilization of these microorganisms, in particular AMF, may be threatened by the application of fungicides, a widely-used measure to control Rhizoctonia solani in various crops among which potato. Prior to their application, it is thus important to determine the impact of fungicides on AMF. The present study investigated, under in vitro controlled conditions, the impact of azoxystrobin (a systemic broad-spectrum fungicide), flutolanil (a systemic Basidiomycota-specific fungicide), and pencycuron (a contact Rhizoctonia-specific fungicide) and their respective formulations (Amistar, Monarch, and Monceren) on the growth and development of the AMF Rhizophagus irregularis MUCL 41833 (spore germination, root colonization, extraradical mycelium development, and spore production) at doses used to control R. solani. Results demonstrated that azoxystrobin and its formulation Amistar, at threshold values for R. solani control (estimated by the half maximal inhibitory concentration, IC50, on a dry weight basis), did not affect spore germination and potato root colonization by R. irregularis, while the development of extra-radical mycelium and spore production was reduced at 10 times the threshold value. Flutolanil and its formulation Monarch at threshold value did not affect spore germination or extra-radical development but decreased root colonization and arbuscule formation. At threshold value, pencycuron and its formulation Monceren, did not affect spore germination and intra- or extraradical development of R. irregularis. These results suggest that azoxystrobin and pencycuron do not affect the AMF at threshold concentrations to control R. solani in vitro, while flutolanil (as formulation) impacts the intraradical phase of the fungus. These fungicides and R. irregularis thus have the potential to be used in parallel against Rhizoctonia disease in potato. PMID:25312740

  19. Phylogenetic analysis of Rhizoctonia solani AG-4 isolates from common beans in Black Sea coastal region, Turkey, based on ITS-5.8S rDNA

    OpenAIRE

    Kilic?og?lu, Melike C?ebi?; O?zkoc?, I?brahim

    2013-01-01

    In this study, 114 Rhizoctonia solani isolates were obtained from diseased common bean (Phaseolus vulgaris L.) plants from the Black Sea coastal region of Turkey. Genetic variation was determined among R. solani anastomosis group 4 (AG-4) subgroups (AG-4 HG-I and AG-4 HG-II). ITS-5.8 rDNA sequences of these isolates were aligned with other known R. solani sequences from GenBank, and distance and parsimony analysis were used to determine phylogenetic relationships. The R. solani AG-4 isolates ...

  20. Control biológico de Rhizoctonia solani en plantas de papa criollaSolanum phureja usando cepas nativas de Pseudomonas fluorescens / BIOCONTROL OF Rhizoctonia solani IN NATIVE POTATO (Solanum phureja) PLANTS USING NATIVE Pseudomonas fluorescens

    Scientific Electronic Library Online (English)

    GLORIA, BAUTISTA; HENRY, MENDOZA; DANIEL, URIBE.

    2007-06-01

    Full Text Available Rhizoctonia solani es un hongo fitopatógeno del suelo, el cual produce una reducción significativa del vigor de las plantas y de la producción de tubérculos en cultivos de papa. Es de gran interés la búsqueda de alternativas de manejo de esta enfermedad, especialmente desde la perspectiva de control [...] biológico ya que los cultivos de papa son los mayores consumidores de plaguicidas de origen químicos en Colombia. Con el objeto de obtener una cepa del grupo de las Pseudomonas fluorescentes con la capacidad para reducir los síntomas de la enfermedad producidos por R. solani, se realizó en un estudio previo el aislamiento y caracterización de una colección de aislamientos de Pseudomonas fluorescentes provenientes de diferentes cultivos de la región papera más productiva del país. Seis cepas nativas de P. fluorescens con buena, moderada o ninguna capacidad para inhibir el crecimiento fúngico in vitro fueron seleccionadas. A pesar de las diferencias encontradas en términos de la dinámica y capacidad de colonización, todas las cepas evaluadas indujeron el crecimiento en las plantas de S. phureja y redujeron los síntomas de la enfermedad producidos por R. solani a nivel de invernadero. Nuestros resultados sustentan la conclusión que la asociación de cepas de P. fluorescens con la rizosfera de S. phureja es una alternativa para el manejo de R. solani en papa. Abstract in english Rhizoctonia solani is a soil borne phytopathogen associated with reduced plant vigor and tuber production in potato crops. There is a huge interest to search alternatives of biological control management of this disease, because the potato crops in Colombia are the highest consumers of chemical pest [...] icides in Colombia. In order to obtain a fluorescent Pseudomonas strain with the capacity to reduce the disease symptoms produced by R. solani, determination and isolation of the predominant fluorescent Pseudomonas in several potato crops of the main Colombian producing region was done in a previous study. Six different P. fluorescens strains with none, moderate and high fungal growth inhibition capacity in vitro, were used in this study. Despite of the differences found in the dynamics of colonization and colonization capacity, all evaluated strains induced S. phureja growth and reduced disease symptoms produced by R. solani. Our results support the conclusion that association of P. fluorescens strains with S. phureja rhizosphere is a feasible alternative for the management of R. solani symptoms.

  1. Control biológico de Rhizoctonia solani en plantas de papa criollaSolanum phureja usando cepas nativas de Pseudomonas fluorescens BIOCONTROL OF Rhizoctonia solani IN NATIVE POTATO (Solanum phureja PLANTS USING NATIVE Pseudomonas fluorescens

    Directory of Open Access Journals (Sweden)

    GLORIA BAUTISTA

    2007-06-01

    Full Text Available Rhizoctonia solani es un hongo fitopatógeno del suelo, el cual produce una reducción significativa del vigor de las plantas y de la producción de tubérculos en cultivos de papa. Es de gran interés la búsqueda de alternativas de manejo de esta enfermedad, especialmente desde la perspectiva de control biológico ya que los cultivos de papa son los mayores consumidores de plaguicidas de origen químicos en Colombia. Con el objeto de obtener una cepa del grupo de las Pseudomonas fluorescentes con la capacidad para reducir los síntomas de la enfermedad producidos por R. solani, se realizó en un estudio previo el aislamiento y caracterización de una colección de aislamientos de Pseudomonas fluorescentes provenientes de diferentes cultivos de la región papera más productiva del país. Seis cepas nativas de P. fluorescens con buena, moderada o ninguna capacidad para inhibir el crecimiento fúngico in vitro fueron seleccionadas. A pesar de las diferencias encontradas en términos de la dinámica y capacidad de colonización, todas las cepas evaluadas indujeron el crecimiento en las plantas de S. phureja y redujeron los síntomas de la enfermedad producidos por R. solani a nivel de invernadero. Nuestros resultados sustentan la conclusión que la asociación de cepas de P. fluorescens con la rizosfera de S. phureja es una alternativa para el manejo de R. solani en papa.Rhizoctonia solani is a soil borne phytopathogen associated with reduced plant vigor and tuber production in potato crops. There is a huge interest to search alternatives of biological control management of this disease, because the potato crops in Colombia are the highest consumers of chemical pesticides in Colombia. In order to obtain a fluorescent Pseudomonas strain with the capacity to reduce the disease symptoms produced by R. solani, determination and isolation of the predominant fluorescent Pseudomonas in several potato crops of the main Colombian producing region was done in a previous study. Six different P. fluorescens strains with none, moderate and high fungal growth inhibition capacity in vitro, were used in this study. Despite of the differences found in the dynamics of colonization and colonization capacity, all evaluated strains induced S. phureja growth and reduced disease symptoms produced by R. solani. Our results support the conclusion that association of P. fluorescens strains with S. phureja rhizosphere is a feasible alternative for the management of R. solani symptoms.

  2. Role of bacterial communities in the natural suppression of Rhizoctonia solani bare patch disease of wheat (Triticum aestivum L.).

    Science.gov (United States)

    Yin, Chuntao; Hulbert, Scot H; Schroeder, Kurtis L; Mavrodi, Olga; Mavrodi, Dmitri; Dhingra, Amit; Schillinger, William F; Paulitz, Timothy C

    2013-12-01

    Rhizoctonia bare patch and root rot disease of wheat, caused by Rhizoctonia solani AG-8, develops as distinct patches of stunted plants and limits the yield of direct-seeded (no-till) wheat in the Pacific Northwest of the United States. At the site of a long-term cropping systems study near Ritzville, WA, a decline in Rhizoctonia patch disease was observed over an 11-year period. Bacterial communities from bulk and rhizosphere soil of plants from inside the patches, outside the patches, and recovered patches were analyzed by using pyrosequencing with primers designed for 16S rRNA. Taxa in the class Acidobacteria and the genus Gemmatimonas were found at higher frequencies in the rhizosphere of healthy plants outside the patches than in that of diseased plants from inside the patches. Dyella and Acidobacteria subgroup Gp7 were found at higher frequencies in recovered patches. Chitinophaga, Pedobacter, Oxalobacteriaceae (Duganella and Massilia), and Chyseobacterium were found at higher frequencies in the rhizosphere of diseased plants from inside the patches. For selected taxa, trends were validated by quantitative PCR (qPCR), and observed shifts of frequencies in the rhizosphere over time were duplicated in cycling experiments in the greenhouse that involved successive plantings of wheat in Rhizoctonia-inoculated soil. Chryseobacterium soldanellicola was isolated from the rhizosphere inside the patches and exhibited significant antagonism against R. solani AG-8 in vitro and in greenhouse tests. In conclusion, we identified novel bacterial taxa that respond to conditions affecting bare patch disease symptoms and that may be involved in suppression of Rhizoctonia root rot and bare batch disease. PMID:24056471

  3. Queima foliar e tombamento de mudas em plantas medicinais causadas por Rhizoctonia solani AG1 - 1B Leaf blight and seedling damping-off of medicinal plants caused by Rhizoctonia solani AG1 - 1B

    Directory of Open Access Journals (Sweden)

    Reginaldo G. Mafia

    2005-06-01

    Full Text Available Recentemente, em plantas medicinais da família Labiatae (Rosmarinus officinalis, Lavandula sp., Salvia officinalis e Thymus vulgaris, constatou-se tombamento de mudas em pós-emergência e queima foliar ascendente. Em isolamentos efetuados a partir de tecidos doentes, observou-se o desenvolvimento de um fungo com hifas ramificadas em ângulo de aproximadamente 90º, constrição na base da ramificação, septo próximo à inserção da hifa lateral e outras características típicas do gênero Rhizoctonia. Inoculou-se o fungo em plantas sadias cultivadas em vasos plásticos. Naquelas inoculadas por pincelamento de inóculo, ocorreu queima foliar de forma generalizada aos quatro dias da inoculação, enquanto nas inoculadas pela deposição de inóculo na superfície dos vasos, houve queima foliar ascendente, como observado em condições naturais, aos dez dias da inoculação. Com base na morfologia da colônia, crescimento micelial, número de núcleos, identificação do grupo e subgrupo de anastomose e da fase teleomórfica, o patógeno foi caracterizado como Rhizoctonia solani (fase anamórfica de Thanatephorus cucumeris. Com a reprodução dos sintomas da doença por inoculação artificial nas mudas e o reisolamento, em meio de batata dextrose ágar (BDA, do mesmo fungo a partir de tecidos doentes confirmou-se R. solani como o agente etiológico da doença.Recently, seedling damping off and blight progressing from old to young leaves were found on medicinal plants of the family Labiatae (Rosmarinus officinalis, Lavandula sp., Salvia officinalis and Thymus vulgaris. A fungus was isolated from diseased tissues, in which the hyphae had diameter, ramification angle of about 90º, basal constriction, a septum next to the lateral hyphae, and other typical characteristics of the genus Rhizoctonia. The fungus was inoculated on healthy plants cultivated in plastic pots by brushing inoculum suspension on leaves (brushing or by pouring the inoculum suspension on the surface of pots (soil infestation. On plants inoculated by brushing, disease symptoms occurred on all leaves four days after inoculation. On plants inoculated by soil infestation, leaf blight continued to ascent for ten days after inoculation under natural conditions. Based on colony morphology, mycelial growth, number of nuclei, identification of anastomosys group and subgroup, and on the teleomorph, the pathogen was considered to be Rhizoctonia solani (anamorph of Thanatephorus cucumeris. As disease symptoms were reproduced by artificial inoculation on plants and the fungus was reisolated on potato dextrose agar (PDA from diseased tissues, R. solani was confirmed to be the causal agent of the disease.

  4. Queima foliar e tombamento de mudas em plantas medicinais causadas por Rhizoctonia solani AG1 - 1B / Leaf blight and seedling damping-off of medicinal plants caused by Rhizoctonia solani AG1 - 1B

    Scientific Electronic Library Online (English)

    Reginaldo G., Mafia; Acelino C., Alfenas; Luiz A., Maffia; Gizella M., Ventura; Eraclides M., Ferreira; Irislei F., Neves; Cláudia A., Vanetti; Clarice, Silva.

    2005-06-01

    Full Text Available Recentemente, em plantas medicinais da família Labiatae (Rosmarinus officinalis, Lavandula sp., Salvia officinalis e Thymus vulgaris), constatou-se tombamento de mudas em pós-emergência e queima foliar ascendente. Em isolamentos efetuados a partir de tecidos doentes, observou-se o desenvolvimento de [...] um fungo com hifas ramificadas em ângulo de aproximadamente 90º, constrição na base da ramificação, septo próximo à inserção da hifa lateral e outras características típicas do gênero Rhizoctonia. Inoculou-se o fungo em plantas sadias cultivadas em vasos plásticos. Naquelas inoculadas por pincelamento de inóculo, ocorreu queima foliar de forma generalizada aos quatro dias da inoculação, enquanto nas inoculadas pela deposição de inóculo na superfície dos vasos, houve queima foliar ascendente, como observado em condições naturais, aos dez dias da inoculação. Com base na morfologia da colônia, crescimento micelial, número de núcleos, identificação do grupo e subgrupo de anastomose e da fase teleomórfica, o patógeno foi caracterizado como Rhizoctonia solani (fase anamórfica de Thanatephorus cucumeris). Com a reprodução dos sintomas da doença por inoculação artificial nas mudas e o reisolamento, em meio de batata dextrose ágar (BDA), do mesmo fungo a partir de tecidos doentes confirmou-se R. solani como o agente etiológico da doença. Abstract in english Recently, seedling damping off and blight progressing from old to young leaves were found on medicinal plants of the family Labiatae (Rosmarinus officinalis, Lavandula sp., Salvia officinalis and Thymus vulgaris). A fungus was isolated from diseased tissues, in which the hyphae had diameter, ramific [...] ation angle of about 90º, basal constriction, a septum next to the lateral hyphae, and other typical characteristics of the genus Rhizoctonia. The fungus was inoculated on healthy plants cultivated in plastic pots by brushing inoculum suspension on leaves (brushing) or by pouring the inoculum suspension on the surface of pots (soil infestation). On plants inoculated by brushing, disease symptoms occurred on all leaves four days after inoculation. On plants inoculated by soil infestation, leaf blight continued to ascent for ten days after inoculation under natural conditions. Based on colony morphology, mycelial growth, number of nuclei, identification of anastomosys group and subgroup, and on the teleomorph, the pathogen was considered to be Rhizoctonia solani (anamorph of Thanatephorus cucumeris). As disease symptoms were reproduced by artificial inoculation on plants and the fungus was reisolated on potato dextrose agar (PDA) from diseased tissues, R. solani was confirmed to be the causal agent of the disease.

  5. Genetic analyses of Rhizoctonia solani isolates from Phaseolus vulgaris grown in the Atlantic Rainforest Region of São Paulo, Brazil / Análise genética de isolados de Rhizoctonia solani de Phaseolus vulgaris da região da Mata Atlântica de São Paulo, Brasil

    Scientific Electronic Library Online (English)

    LYNDEL W., MEINHARDT; NELSON A., WULFF; CLÁUDIA M., BELLATO; SIU M., TSAI.

    2002-06-01

    Full Text Available A diversidade genética de 18 isolados de Rhizoctonia solani de feijoeiro (Phaseolus vulgaris) cultivado na Mata Atlântica de São Paulo, Brasil foi avaliada através da análise do espaçadores transcritos internos (ITS), microssatélites e iniciadores ("primers") específicos para sequências teloméricas. [...] A análise de restrição da região ribossomal ITS1/5,8S/ITS2 produziu um padrão de bandas específico para o grupo de anastomose 4 (GA 4) e seus subgrupos. O padrão obtido com ITS/RFLP, microsatélites e os iniciadores teloméricos permitiram identificar cinco a 11 genótipos entre os isolados de R. solani. Enquanto todos os isolados foram patogênicos em feijoeiro, não houve correlação entre patogenicidade e diferenças genotípicas. Os diferentes iniciadores para PCR revelaram que muitos isolados são geneticamente similares, análise esta que pode ser confirmada por mais de um conjunto de iniciadores, fortalecendo a relação deste agrupamento. Abstract in english Rhizoctonia solani isolates obtained from common beans (Phaseolus vulgaris) grown in the mountainous Atlantic Rainforest (Mata Atlântica) region of São Paulo, Brazil, were analyzed to determine their genetic diversity using internal transcribed spacer (ITS), microsatellite and telomere sequence-base [...] d PCR primers. Restriction digestion of the ITS1/5.8S/ITS2 ribosomal regions yielded unique banding patterns specific for AG4 and its subgroups. The ITS restriction digestion (ITS/RFLP), telomere and microsatellite primers identified five to 11 genotypes within the isolates of R. solani. While all isolates were pathogenic on beans, there was no correlation found between genotypic differences and pathogenicity. The different PCR primers revealed a number of isolates that were genetically similar. Some of these genetic groups were supported by more than one of the primers utilized in this study, thus confirming their relationship.

  6. Genetic analyses of Rhizoctonia solani isolates from Phaseolus vulgaris grown in the Atlantic Rainforest Region of São Paulo, Brazil Análise genética de isolados de Rhizoctonia solani de Phaseolus vulgaris da região da Mata Atlântica de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    LYNDEL W. MEINHARDT

    2002-06-01

    Full Text Available Rhizoctonia solani isolates obtained from common beans (Phaseolus vulgaris grown in the mountainous Atlantic Rainforest (Mata Atlântica region of São Paulo, Brazil, were analyzed to determine their genetic diversity using internal transcribed spacer (ITS, microsatellite and telomere sequence-based PCR primers. Restriction digestion of the ITS1/5.8S/ITS2 ribosomal regions yielded unique banding patterns specific for AG4 and its subgroups. The ITS restriction digestion (ITS/RFLP, telomere and microsatellite primers identified five to 11 genotypes within the isolates of R. solani. While all isolates were pathogenic on beans, there was no correlation found between genotypic differences and pathogenicity. The different PCR primers revealed a number of isolates that were genetically similar. Some of these genetic groups were supported by more than one of the primers utilized in this study, thus confirming their relationship.A diversidade genética de 18 isolados de Rhizoctonia solani de feijoeiro (Phaseolus vulgaris cultivado na Mata Atlântica de São Paulo, Brasil foi avaliada através da análise do espaçadores transcritos internos (ITS, microssatélites e iniciadores ("primers" específicos para sequências teloméricas. A análise de restrição da região ribossomal ITS1/5,8S/ITS2 produziu um padrão de bandas específico para o grupo de anastomose 4 (GA 4 e seus subgrupos. O padrão obtido com ITS/RFLP, microsatélites e os iniciadores teloméricos permitiram identificar cinco a 11 genótipos entre os isolados de R. solani. Enquanto todos os isolados foram patogênicos em feijoeiro, não houve correlação entre patogenicidade e diferenças genotípicas. Os diferentes iniciadores para PCR revelaram que muitos isolados são geneticamente similares, análise esta que pode ser confirmada por mais de um conjunto de iniciadores, fortalecendo a relação deste agrupamento.

  7. Silicon potentiates the activities of defense enzymes in the leaf sheaths of rice plants infected by Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Daniel A., Schurt; Maria F. A., Cruz; Kelly J. T., Nascimento; Marta C. C., Filippi; Fabrício A., Rodrigues.

    2014-12-01

    Full Text Available This study aimed to assess the ability of silicon (Si) to potentiate defense enzyme activities in rice leaf sheaths and thus reduce sheath blight, caused by Rhizoctonia solani, development. Rice plants of BR-Irga 409 and Labelle cultivars were grown in a hydroponic solution containing 0 (-Si) or 2 m [...] M (+Si) Si and inoculated with R. solani. Silicon concentration in the leaf sheaths was significantly higher in the +Si plants than the -Si plants by 727% for BR-Irga 409 and 714% for Labelle. The area under relative lesion expansion progress curve was significantly lower for +Si plants than -Si plants, by 34.2% for BR-Irga 409 and 30.59% for Labelle. Increases in the activities of phenylalanine ammonia-lyases, peroxidases, polyphenoloxidases and chitinases in the leaf sheaths of plants supplied with Si, especially of those from BR-Irga 409, led to reduced progress of sheath blight lesions.

  8. Biological Control of Potato Isolate of Rhizoctonia solani by Streptomyces olivaceus Strain 115

    OpenAIRE

    Shahrokhi, S.; Shahidi Bonjar, G. H.; Saadoun, I.

    2005-01-01

    This is the first report of antifungal activity of Iranian actinomycete isolates against Rhizoctonia solani Kuhn AG-3 (Teleomorph: Thanatephorus cucumeris [(Frank) Donk]). Biological control offers an environmentally friendly alternative to the use of antimicrobials for controlling plant diseases. A collection of about 200 actinomycete strains was screened for the ability to produce metabolites that inhibit R. solani growth in vitro. The Streptomyces olivaceus strain 115 showed strong in vi...

  9. Occurrence of Banded Leaf and Sheath Blight of Maize in Jharkhand with Reference to Diversity in Rhizoctonia solani

    OpenAIRE

    Akhtar, J.

    2009-01-01

    Survey during kharif, 2005 and 2006 were carried out to record occurrence of disease and diversity in R. solani among the naturally occurring populations and revealed that banded leaf and sheathblight incited by Rhizoctonia solani, is show ing wide spread w ith the disease severity ranging from 30.30 to80.46 per cent and gaining the economic importance in the state of Jharkhand. Five isolates from five differentlocations showed variation in their morphological characters such as abundance of ...

  10. A gene for plant protection: expression of a bean polygalacturonase inhibitor in tobacco confers a strong resistance against Rhizoctonia solani and two oomycetes.

    OpenAIRE

    Orlando Borras-Hidalgo; Claudio Caprari; Ingrid Hernandez-Estevez; Giulia De Lorenzo; Felice Cervone

    2012-01-01

    We have tested whether a gene encoding a polygalacturonase-inhibiting protein (PGIP) protects tobacco against a fungal pathogen (Rhizoctonia solani) and two oomycetes (Phytophthora parasitica var. nicotianae and Peronospora hyoscyami f. sp. tabacina). The trials were performed in greenhouse conditions for R. solani and P. parasitica and in the field for P. hyoscyami. Our results show that expression of PGIP is a powerful way of engineering a broad-spectrum disease resistance.

  11. Genetic Variability in Rhizoctonia solani Isolated from Vitis vinifera Based on Amplified Fragment Length Polymorphism

    OpenAIRE

    Amparo Meza-Moller; Martin Esqueda; Felipe Sanchez-Teyer; Georgina Vargas-Rosales; Gardea, Alfonso A.; Martin Tiznado-Hernandez

    2011-01-01

    Problem statement: Rhizoctonia solani is a potential grapevine pathogen. In order to develop effective methods of control, it is necessary to document its genetic diversity. Approach: The objective of this study was to analyze the genetic variability of R. solani isolated from the rhizosphere of ungrafted V. vinifera var. perlette seedless planted in Sonora, Mexico using Amplified Fragment Length Polymorphism (AFLP). Results: In the selective amplification using eight primer combinations we o...

  12. The Mechanism of Antifungal Action of a New Polyene Macrolide Antibiotic Antifungalmycin 702 from Streptomyces padanus JAU4234 on the Rice Sheath Blight Pathogen Rhizoctonia solani

    OpenAIRE

    Xiong, Zhi-qiang; Tu, Xiao-rong; Wei, Sai-jin; Huang, Lin; Li, Xun-hang; Lu, Hui; Tu, Guo-quan

    2013-01-01

    Antifungalmycin 702, a new polyene macrolide antibiotic produced by Streptomycespadanus JAU4234, has a broad antifungal activity and may have potential future agricultural and/or clinical applications. However, the mechanism of antifungal action of antifungalmycin 702 remains unknown. Antifungalmycin 702 strongly inhibited mycelial growth and sclerotia formation/germination of Rhizoctonia solani. When treated with antifungalmycin 702, the hyphae morphology of R. solani became more irregular. ...

  13. Induction of systemic resistance in rice by leaf extracts of Zizyphus jujuba and Ipomoea carnea against Rhizoctonia solani.

    Science.gov (United States)

    Kagale, Sateesh; Marimuthu, Thambiayya; Kagale, Jayashree; Thayumanavan, Balsamy; Samiyappan, Ramasamy

    2011-07-01

    Plants accumulate a great diversity of natural products, many of which confer protective effects against phytopathogenic attack. Earlier we had demonstrated that the leaf extracts of Zizyphus jujuba and Ipomoea carnea inhibit the in vitro mycelial growth of Rhizoctonia solani, and effectively reduce the incidence of sheath blight disease in rice. Here we demonstrate that foliar application of the aqueous leaf extracts of Z. jujuba and I. carnea followed by challenge inoculation with R. solani induces systemic resistance in rice as evident from significantly increased accumulation of pathogenesis-related proteins such as chitinase, ?-1,3-glucanase and peroxidase, as well as defense-related compounds such as phenylalanine ammonia-lyase and phenolic substances. Thin layer chromatographic separation of secondary metabolites revealed presence of alkaloid and terpenoid compounds in the leaf extracts of Z. jujuba that exhibited toxicity against R. solani under in vitro condition. Thus, the enhanced sheath blight resistance in rice seedlings treated with leaf extracts of Z. jujuba or I. carnea can be attributed to the direct inhibitory effects of these leaf extracts as well as their ability to elicit systemic resistance against R. solani. PMID:21593600

  14. A novel mycovirus closely related to viruses in the genus Alphapartitivirus confers hypovirulence in the phytopathogenic fungus Rhizoctonia solani.

    Science.gov (United States)

    Zheng, Li; Zhang, Meiling; Chen, Qiguang; Zhu, Minghai; Zhou, Erxun

    2014-05-01

    We report here the biological and molecular attributes of a novel dsRNA mycovirus designated Rhizoctonia solani partitivirus 2 (RsPV2) from strain GD-11 of R. solani AG-1 IA, the causal agent of rice sheath blight. The RsPV2 genome comprises two dsRNAs, each possessing a single ORF. Phylogenetic analyses indicated that this novel virus species RsPV2 showed a high sequence identity with the members of genus Alphapartitivirus in the family Partitiviridae, and formed a distinct clade distantly related to the other genera of Partitiviridae. Introduction of purified RsPV2 virus particles into protoplasts of a virus-free virulent strain GD-118 of R. solani AG-1 IA resulted in a derivative isogenic strain GD-118T with reduced mycelial growth and hypovirulence to rice leaves. Taken together, it is concluded that RsPV2 is a novel dsRNA virus belonging to Alphapartitivirus, with potential role in biological control of R. solani. PMID:24889241

  15. Mass spectrometry identification of antifungal lipopeptides from Bacillus sp. BCLRB2 against Rhizoctonia solani and Sclerotinia sclerotiorum.

    Science.gov (United States)

    Elkahoui, S; Djébali, N; Karkouch, I; Ibrahim, A Hadj; Kalai, L; Bachkovel, S; Tabbene, O; Limam, F

    2014-01-01

    This work aims to characterize the bioactive molecules produced by an antagonistic Bacillus sp. strain BCLRB2 isolated from healthy leaves of olive tree against Rhizoctonia solani and Sclerotinia sclerotiorum. The bacterial strain isolated showed a high and persistent antifungal activity against the two pathogens. The free-cell supernatant showed also a high antifungal activity against R. solani and at a lower extent against S. sclerotiorum. The partial purification of the antifungal substances with methanol gradient applied to C18 column binding the Bacillus BCLRB2 culture supernatant showed that the 20% and 60% methanol fractions had a high and specific activity against S. sclerotiorum and R. solani, respectively. The mass spectrometry identification of the compounds in the fraction specifically active against S. sclerotiorum revealed the presence of bacillomycin D C16 as a major lipopeptide. The fraction specifically active against R. solani contained bacillomycin D C15 and 2 unknown lipopeptides. The 80% methanol fraction had a moderate and a broad spectrum activity against the two pathogens and consisted from two iturin D (C13 and C14) as a major lipopeptides. PMID:25272736

  16. Dried powders of velvetbean and pine bark added to soil reduce Rhizoctonia solani-induced disease on soybean Pós secos de mucuna e casca de pinus adicionados ao solo reduzem a doença causada por Rhizoctonia solani em soja

    Directory of Open Access Journals (Sweden)

    Luiz E. B. Blum

    2006-06-01

    Full Text Available Diseases induced by Rhizoctonia solani, like damping-off and root and stem rot on soybean (Glycine max, are a serious problem around the world. The addition of some organic material to soil is an alternative control for these diseases. In this study, benzaldehyde and dried powders of kudzu (Pueraria lobata, velvetbean or mucuna (Mucuna deeringiana, and pine bark (Pinus spp. were used in an attempt to improve soybean plant growth and to reduce the disease R. solani (AG-4 causes on soybean. Benzaldehyde (0.1-0.4 mL/kg of soil and velvetbean (25-100 g/kg significantly (P As doenças em soja (Glycine max causadas por Rhizoctonia solani são um sério problema ao redor do mundo. A incorporação ao solo de resíduos orgânicos é uma alternativa para o controle destas doenças. Neste estudo, benzaldeido e pós-secos de kudzu (Pueraria lobata, mucuna (Mucuna deeringiana e casca de pinus (Pinus spp. foram usados com o objetivo de melhorar o crescimento de plantas de soja e de diminuir a doença causada por R. solani (AG-4. Benzaldehyde (0,1-0,4 mL/kg de solo e mucuna (25-100 g/kg reduziram significativamente (P < 0.05 o crescimento micelial de R. solani em experimentos de laboratório. Em experimentos conduzidos em casa de vegetação a porcentagem de plantas sobreviventes foi maior em solo com casca de pinus e mucuna (50-100 g/kg. Em solo tratado com kudzu (r²=0,91 ou mucuna (r²=0,94, houve tendência significativa em aumentar a massa fresca das plantas de soja. Em microparcelas de campo solos com mucuna (r²=0,85 ou com casca de pinus (r²=0,61 reduziram significativamente a quantidade de doença. A quantidade de Bacillus megaterium (r²=0,87 e Trichoderma hamatum (r²=0,92 e a hidrólise de diacetato fluoresceina (r²=0,91 foram maiores em solo com doses crescentes de mucuna, indicando uma maior atividade microbiana. Neste estudo conclui-se que pós-secos de mucuna e casca de pinus, incorporados ao solo, podem reduzir a doença causada por R. solani em soja.

  17. Rhizoctonia solani Kühn aislado de papa (Solanum tuberosum L.): En los estados Táchira, Mérida, Trujillo y Lara. I. Caracterización cultural / Rhizoctonia solani Kühn isolated from potato (Solanum tuberosum L.): in Táchira, Mérida, Trujillo and Lara States, Venezuela. I. Cultural characterization

    Scientific Electronic Library Online (English)

    Yoleidy, Escalona; Dorian, Rodríguez; Alexander, Hernández.

    2011-12-01

    Full Text Available La papa es uno de los rubros más importantes en la economía de Venezuela. Este cultivo se ve afectado por diferentes patógenos, uno de ellos es el hongo Rhizoctonia solani, que ocasiona la rizoctoniosis, enfermedad que está ampliamente distribuida en el país y es la causa de pérdidas económicas cons [...] iderables. Con la finalidad de comparar las poblaciones del hongo en Venezuela, se llevó a cabo el trabajo; para ello se colectaron muestras en diferentes zonas productoras de papa de los estados Táchira, Mérida, Trujillo, y Lara. El patógeno fue caracterizado culturalmente mediante el estudio de su condición nuclear y determinación del grupo de anastomosis (AG), así como la evaluación del desarrollo micelial, número y diámetro de esclerocios, a 10, 20 y 30 °C. Se encontraron diferencias significativas (P?0,01) en cuanto a las características culturales de las cepas evaluadas, las cuales mostraron mejor comportamiento en su desarrollo a 20 °C; se determinó que 97,5 % de las cepas fueron AG-3 y 2,5 % AG-2.1. Los resultados indicaron diferencias culturales entre las poblaciones de R. solani analizadas lo que puede estar asociado con el comportamiento de la enfermedad en las diferentes localidades. Abstract in english Potato is one of the most important crops in Venezuelan economy. This crop is affected by different pathogens, one of which is the fungus Rhizoctonia solani, the inducer of rhizoctonia disease; which is widely distributed and is the cause of considerable economic losses. In order to know phenotypic [...] variation among fungus populations, this research was carried out with samples collected at different potato producing areas of Táchira, Merida, Trujillo, and Lara States. The pathogen was culturally characterized by the study and determination of its nuclear condition, anastomosis group (AG), as well as colony growth, and number and diameter of sclerotia at 10, 20 and 30 °C. Significant differences (P?0.01) were found among strains with regard to the cultural characteristics; in general, strains showed better behavior of their development at 20 °C; 97.5 % of the strains were found to be AG-3 and the other 2.5 %, AG-2.1. Results indicated differences in cultural characteristics among the R. solani populations, which may be associated with disease behavior at the different localities.

  18. Estudio de Rhizoctonia solani Kühn aislado de papa (Solanum tuberosum L.) en los estados Táchira, Mérida, Trujillo y Lara: II. virulencia y caracterización molecular / Rhizoctonia solani Kühn isolated from potato in various Venezuelan states: II. Virulence and molecular characterization

    Scientific Electronic Library Online (English)

    Yoleidy, Escalona; Dorian, Rodríguez; Alexander, Hernández.

    2012-04-01

    Full Text Available Rhizoctonia solani ocasiona la enfermedad conocida como rizoctoniosis en el cultivo de la papa y constituye un serio problema en Venezuela. En el país se han identificado los grupos anastomósicos presentes y se ha realizado la caracterización cultural del hongo pero no la molecular ni la de virulenc [...] ia, por lo que estos objetivos fueron planteados en el presente trabajo. Se utilizaron cuarenta aislamientos obtenidos de los estados Táchira, Mérida, Trujillo y Lara. Se utilizaron las técnicas de RAPD, UPR e ITS para la caracterización molecular, y pruebas de patogenicidad en papa ‘Kennebec’ para determinar la virulencia. Con las tres técnicas moleculares se observaron variaciones genéticas entre las cepas del hongo y se confirmó la presencia de AG-3 y AG-2.1 de R. solani. Las cepas mostraron diferencias significativas en la virulencia, la cual estuvo influenciada por la temperatura. Abstract in english Rhizoctonia solani causes the disease known as rizoctoniosis in potato and it is a serious problem in Venezuela. Anastomosis groups and cultural characterization have been determined in the country, but neither molecular nor virulence characterization. Therefore, the research focused on those two ob [...] jectives. Forty isolates from Táchira, Merida, Trujillo and Lara States were used on which RAPD, UPR and ITS techniques were performed; also, pathogenicity tests were run on ‘Kennebec’ potato plants. Genetic variability among isolates was observed with all three molecular techniques and presence of AG-3 and AG-2.1 was confirmed. Isolates showed significant difference with regard to virulence, which was influenced by temperature.

  19. Solarização do solo em casa-de-vegetação e campo para o controle de Rhizoctonia solani AG-4 / Soil solarization under greenhouse and field conditions to the control of Rhizoctonia solani AG-4

    Scientific Electronic Library Online (English)

    Flávia Rodrigues Alves, Patrício; Hiroshi, Kimati; João, Tessarioli Neto; Ademir, Petenatti; Benedito Camargo, Barros.

    2007-09-01

    Full Text Available Os cultivos em ambientes protegidos apresentaram uma grande expansão na década de 1990 no Brasil. O solo desses locais pode, por ser intensa e sucessivamente cultivado, se tornar infestado por patógenos como Rhizoctonia solani, responsável por tombamento e podridão de raízes em muitas espécies de pl [...] antas. O presente trabalho avaliou o emprego da solarização, dentro e fora de uma casa-de-vegetação vedada com plástico transparente, para o controle de R. solani. Quatro experimentos foram realizados, dois no verão de 1997/1998 e outros dois no verão seguinte, 1998/1999, em Piracicaba, SP (latitude 22º 42' e longitude 47º 38'). Bolsas de náilon contendo solo autoclavado misturado a grãos de trigo colonizados com R. solani AG-4 foram enterradas a 10 e a 20 cm de profundidade em parcelas solarizadas e não solarizadas, dentro e fora da casa-de-vegetação, sendo coletadas após 20, 30 e 40 dias para os dois primeiros experimentos e 15, 30 e 45 dias para o terceiro e quarto. Avaliou-se a viabilidade do patógeno após a recuperação dos grãos dos solos, por meio do plaqueamento destes em ágar-água, contando-se, dois dias depois, sob microscópio estereoscópio, os que apresentaram crescimento micelial característico de R. solani. Foi obtida a erradicação do patógeno após 20 e 30 dias de solarização na casa de vegetação e após 30 a 45 dias no campo, provavelmente porque houve menor perda de calor durante a noite no ambiente protegido, pois as temperaturas médias (40 a 45 º C, dependendo do experimento) e máxima (49º C) dos solos solarizados às 15:00 horas, a 10 cm de profundidade, foram semelhantes nos dois ambientes. Nas parcelas não solarizadas da casa-de-vegetação o patógeno também perdeu a viabilidade, porém mais lentamente (40 dias de tratamento para sua erradicação) que nas parcelas solarizadas. Abstract in english Crops grown under protected environment have had a great expansion in Brazil in the decade of 1990. In such environments soil is intensively and successively used and it may become infested with soilborne plant pathogens, such as Rhizoctonia solani, responsible for seedling damping-off and root rots [...] of several plant species. In the present work soil solarization was used to the control of R. solani under greenhouse and field conditions. Four experiments were carried out, two in the summer of 1997/1998 and the other two in 1998/1999 in Piracicaba city, São Paulo state, Brazil (latitude 22º 42' and longitude 47º 38'). Nylon bags containing disinfested soil with propagules of R. solani AG4 (wheat grains previously colonized with the pathogen) were buried at 10 and 20 cm soil depth in solarized and non-solarized plots. After 20, 30, and 40 days in the two first experiments and 15, 30, and 45 days in the third and fourth experiments, the bags were removed from the soil. The grains were collected from the soil of each bag and placed in water-agar Petri dishes. After two days of incubation, grains showing typical growth of R. solani mycelium were assessed. Eradication of R. solani was accomplished after 20 to 30 days of soil solarization inside the greenhouse and after 30 to 45 days in the field, probably because in the protected environment the heat loss was smaller at night, since at 15:00 h the soil temperatures were similar in the solarized soils of both environments; with maximum of 49º C and medium temperatures between 40 and 45 º C, at 10 cm soil depth. In the non-solarized soil of the greenhouse the pathogen also lost its viability, although more slowly (40 days of treatment) than in the solarized plots.

  20. Efeito do silicato de cálcio e da autoclavagem na supressividade e na conducividade de dois solos à Rhizoctonia solani / Influence of calcium silicate and sterilization on the natural suppressiveness and on the conduciveness of two soils to Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Fabrício de Ávila, Rodrigues; Gilberto Fernandes, Corrêa; Gaspar Henrique, Korndörfer; Maria Amelia dos, Santos; Lawrence Elliot, Datnoff.

    1367-13-01

    Full Text Available Objetivou-se verificar o efeito da aplicação de silicato de cálcio e da esterilização na supressividade natural de um Latossolo Vermelho-Escuro (LEa) álico textura muito argilosa e na conducividade natural de uma Terra Roxa Estruturada eutrófica (TRe) ao fungo Rhizoctonia solani, em condições de cas [...] a de vegetação. Utilizou-se o delineamento inteiramente casualizado em esquema fatorial 2 x 3 x 2. Os fatores foram: duas classes de solo (LEa e TRe - 0-20 cm); três tratamentos (esterilização ou não por autoclavagem, aplicação de silicato e testemunha) e infestação ou não com R. solani, com três repetições e 16 plântulas de feijoeiro por parcela. A aplicação de silicato foi feita incorporando 0,63 g do produto em 1 kg de cada material de solo, seguido de incubação por 30 dias. Para promover a infestação artificial, foram colocados 800 mg de inóculo em 1 kg de cada material de solo. O silicato de cálcio aumentou os teores de Ca trocável e a soma de bases nos dois solos. Um decréscimo na saturação por Al de 70 para 19% e um aumento na saturação por bases de 9 para 21% alteraram significativamente a supressividade natural do LEa à R. solani. Com relação à TRe, a aplicação de silicato não teve nenhum efeito na sua conducividade, dado ao seu natural caráter eutrófico, o qual já é favorável ao desenvolvimento deste fungo. A esterilização não influiu no desenvolvimento de R. solani, o que sugere que os fatores abióticos foram os responsáveis pela supressividade ou conducividade desses solos. Abstract in english The effect of calcium silicate slag and soil sterilization on the natural suppressiveness of a Typic Acrustox (clay Dark Red Latosol -- LEa) and the natural conduciveness of an Oxic Haplustoll (TRe) to Rhizoctonia solani were studied under greenhouse conditions. The experimental design was a three-r [...] eplicate completely randomized one, with 2 x 3 x 2 factorial combination of the following treatments: two soil kinds (LEa and TRe, collected at 0-20 cm layer); three treatments with and without soil sterilization, calcium silicate slag and nontreated control; and uninfested and infested with R. solani. Each soil material was infested previously with 800 mg of the inoculum per kg soil. Application of silicate was done mixing 0,63 g of this product with 1 kg each soil material and incubated for 30 days. The application ofsilicate increased the exchangeable Ca2+ and bases amount in both soils. The decrease in the aluminum saturation level from 70 to 19% and the increase in base saturation from 9 to 21% altered significantly the natural suppressiveness of LEa to R. solani. Application of silicate to the TRe had no effect on its conduciveness, for its natural eutrophic character, which is benefic to R. solani development. Sterilization by autoclavation did not influence disease development on bean by R. solani. This suggests that possibly other abiotic factors were responsible for either suppressiveness or conduciveness of these soils.

  1. Influence of glyphosate on Rhizoctonia crown and root rot (Rhizoctonia solani) in glyphosate-resistant sugarbeet (Beta vulgaris L.)

    Science.gov (United States)

    Previous greenhouse studies with a non-commercial glyphosate-resistant sugarbeet variety indicated that susceptibility to Rhizoctonia crown and root rot could increase after glyphosate was applied. Greenhouse and field experiments were conducted in 2008 and 2009 to determine if glyphosate influenced...

  2. Effects of fescue Festuca arundinacea and/or clover Trifolium repens debris and fescue leaf leachate on clover as modified by ozone and Rhizoctonia solani

    Energy Technology Data Exchange (ETDEWEB)

    Kochhar, M.; Reinert, R.A.; Blum, U.

    1982-08-01

    Clover Trifolium repens and tall fescue Festuca arundinacea plants were exposed to ozone and inoculated with Rhizoctonia solani separately and in combination to investigate ozone/R. solani interactions on clover and tall fescue biomass, in the presence of clover and/or tall fescue debris or fescue leaf leachate. Ozone reduced biomass in clover. Rhizoctonia solani alone reduced clover biomass but the amount of this reduction was significantly greater in the presence of a single acute O/sub 3/ exposure. In the presence of multiple O/sub 3/ exposures the synergistic effect on clover biomass disappeared and the stress from R. solani was lost. The effects of O/sub 3/ and R. solani were not as pronounced on fescue as they were on clover. The debris treatments increased biomass of both clover and fescue, but the magnitude of change depended on the debris type. Leachate from fescue modified the effects of R. solani and O/sub 3/, but debris from clover and/or fescue did not. Clover plants treated with R. solani and O/sub 3/ had less biomass than control plants when stressed by leachate from fescue, but significantly greater biomass in the presence of leachate from O/sub 3/-treated fescue leaves.

  3. Micoflora asociada a dos sustratos orgánicos y su efecto en el control de Rhizoctonia solani Kühn / Mycoflora of two organic substrates and its effect on the control of Rhizoctonia solani Kühn

    Scientific Electronic Library Online (English)

    Clemencia, Guédez; Luis Miguel, Cañizalez; Carmen, Castillo; Rafael, Olivar.

    2009-12-01

    Full Text Available Los abonos orgánicos se vienen utilizando como ente supresor de enfermedades de la raíz de la planta, debido a la gran cantidad de microorganismos que interactúan en ellos, lo que ha llevado a considerarlos como parte de las estrategias de control biológico. En este contexto, se evaluó la diversidad [...] de la micoflora de dos sustratos orgánicos (suelo orgánico y lombricompuesto) y su efecto sobre el control del hongo Rhizoctonia solani. La diversidad de la micoflora de los sustratos se determinó a través del método de dilución de placas de Warcup, que permitió contar el número de colonias e identificar los hongos. Los aislamientos más abundantes de cada sustrato fueron seleccionados para realizar cultivos duales con Rhizoctonia solani. Se encontraron 16 aislamientos de hongos pertenecientes a tres ordenes y ocho géneros, incluyendo (Penicillium sp., Aspergillus sp., Fusarium sp. y Trichoderma harzianum Rifai). En el lombricompuesto se encontró una micoflora significativamente más abundante (P?0,05) que en el suelo orgánico. En los cultivos duales, T. harzianum presentó un porcentaje de inhibición de R. solani significativamente superior (P?0,05) al del resto de los hongos. Con la incorporación del lombricompuesto no se introdujeron nuevos hongos, pero sí se incrementaron las poblaciones existentes en la micoflora nativa. T. harzianum resultó ser el hongo de mayor crecimiento y mayor porcentaje de inhibición, lo que sugiere que es un controlador biológico de R. solani, y que es factible incorporarlo al suelo durante la preparación del mismo. Abstract in english The use of organic manures for root disease control, which results from the remarkable diversity of microorganisms that interact there, has led to consider them as part of biological control strategies. In this context, we evaluated the mycological diversity of two organic substrates, (organic soil [...] and vermicompost) and their effect on the control of the fungus Rhizoctonia solani. The mycoflora of the two organic substrates was assessed through Warcup's soil plate method, which allowed identifying the fungi and counting the number of colonies. The most abundant isolates were grown against R. solani in dual cultures. The results allowed identifying 16 isolates belonging to three orders and eight genera of fungi, including Penicillium sp., Aspergillus sp., Fusarium sp. and Trichoderma harzianum Rifai. A significantly more abundant mycoflora (P?0.05) was found in the vermicompost substrate. In the dual cultures, T. harzianum attained a higher pathogen inhibition percentage (P?0.05) than the other fungi. The vermicompost substrate did not determine the growth of new fungi, but enhanced the development of the pre-existing native ones. Not only having shown the best results in controlling R. solani, but also the most vigorous growth among the identified fungi, T. harzianum comes up as a promissory biological controller of the pathogen, that can be incorporated to the soil during its preparation.

  4. Essential oil of mustard to control Rhizoctonia solani causing seedling damping off and seedling blight in nursery Utilização de óleo essencial de mostarda no controle de tombamento e requeima causadas por Rhizoctonia solani em viveiro

    Directory of Open Access Journals (Sweden)

    Onkar D. Dhingra

    2004-12-01

    Full Text Available The essential oil extracted from mustard (Brassica rapa seeds was evaluated for its effect on suppression of Rhizoctonia solani growth in vitro, and in field soils, for reducing saprophytic substrate colonization and seedling damping off and blight using snap beans as indicator plant, the in vitro growth was completely inhibited at a concentration of 50 mul/l. The saprophytic substrate colonization in soils 24 h after treatment was drastically reduced to 45% at 150 mul/kg soil concentration, in contrast to 100% colonization at concentrations of 0, 50, or 75 mul/kg. This recovery rate gradually declined to 6% and 60%, respectively, in nine days. A control of pre and post-emergence seedling damping off and blight in common beans (Phaseolus vulgaris, without any apparent phytotoxic effect was achieved by irrigating R. solani infested soils with water containing the emulsified essential oil to provide 150 mul/l soil volume ten days prior to planting, gave over 95%. The effect of the mustard essential oil was not influenced by the physical soil texture, and it appears to be a good substitute for methyl bromide fumigation in nurseries for seedling production.Foi avaliado o efeito do óleo essencial extraído de sementes de mostarda (Brassica rapa na supressão do crescimento in vitro de Rhizoctonia solani, na redução da colonização saprofítica no solo, e no tombamento e requeima de plântulas, utilizando feijão-vagem (Phaseolus vulgaris como planta indicadora. O crescimento in vitro de R. solani foi completamente inibido na concentração de 50 mil/l. A colonização saprofítica do substrato foi drasticamente reduzida para 45% na concentração de 150 mil/kg, 24 h após o tratamento. Nas concentrações de 0, 50 e 75 mil/kg de solo houve 100% de colonização do substrato. Esta taxa de recuperação diminuiu gradualmente para 6% e 60%, respectivamente, em nove dias. A irrigação de solos infestados por R. solani com água contendo o óleo essencial emulsificado para fornecer 150 mil/l de solo, dez dias antes do plantio, resultou em 95% de controle do tombamento e requeima em mudas de feijão-vagem, sem qualquer efeito aparente de fitotoxidez. O efeito do óleo essencial não foi influenciado pela textura do solo e parece ser um bom substituto para o fumigante brometo de metila em viveiros.

  5. Caracterización y evaluacion de virulencia en aislamientos de rhizoctonia solani kühn, causante de la mancha bandeada en maíz / Characterization and evaluation of virulence in rhizoctonia solani kühn isolates, causal agent of leaf banded spot on maize / Caracterização e avaliação de virulência em isolamentos de rhizoctonia solani kühn, causante da mancha bandeada no milho

    Scientific Electronic Library Online (English)

    Rosaura, Perdomo; Alexander, Hernández; Alex, González; Juan, Pineda; Jesús, Alezones.

    2007-01-01

    Full Text Available Na Venezuela a mancha bandeada do milho, causada por Rhizoctonia solani Kühn, tem uma alta incidência e distribuição nas principais áreas de plantio de milho, causando diminuição do rendimento. Em 2004 foram conduzidos ensaios com o objetivo de caracterizar e avaliar a virulência de 25 isolamentos d [...] e R. solani. Para a caracterização se realizaram avaliações culturais, microscópicas e moleculares, estas últimas utilizando uma seqüência de amplificação específica da região espaçadora transcrita interna do DNA ribossomal (rDNA-ITS). Para a avaliação da virulência se realizaram provas de inoculação nas línhas de milho CML-254 e L-82201-22-1-1, tanto em laboratório, usando uma solução de cinetina (6- furfuril-amino-purina), como em estufa, inoculando plântulas. As provas de caracterização demonstraram que os isolamentos efetivamente correspondiam a R. solani, ainda quando houve diferenças na cor das colônias, crescimento micelial e tamanho de esclerócios, entre outras. A análise molecular demonstrou que os isolamentos pertencem ao grupo de anastomosis AG1-IA. Na prova de inoculação em laboratório os isolamentos G1SOM1 e P2TUR3 tiveram maior índice de virulência. Em estufa, os isolamentos mais virulentos foram B1TOR1, P2TUR6 e B2SAB1. A linha CML-254 mostrou o maior nível de resistência à enfermidade em ambas provas de virulência. Os resultados permitiram identificar e caracterizar isolamentos que podem ser utilizados em programas de melhoramento genético para a identificação de possíveis fontes de resistência e na avaliação do germoplasma melhorado. Abstract in spanish En Venezuela la mancha bandeada del maíz, causada por Rhizoctonia solani Kühn, tiene una alta incidencia y distribución en las principales zonas maiceras, causando disminución de los rendimientos. En 2004 se condujeron ensayos con el objetivo de caracterizar y evaluar la virulencia de 25 aislamiento [...] s de R. solani. Para la caracterización se realizaron evaluaciones culturales, microscópicas y moleculares, estas últimas utilizando una secuencia de amplificación específica de la transcrita región espaciadora interna del ADN ribosomal (rADN-ITS). Para la evaluación de la virulencia se realizaron pruebas de inoculación en las líneas de maíz CML-254 y L-82201-22-1-1, tanto en laboratorio, usando una solución de cinetina (6- furfuril-amino-purina), como en invernadero, inoculando plántulas. Las pruebas de caracterización demostraron que los aislamientos efectivamente correspondían a R. solani, aun cuando hubo diferencias en el color de las colonias, crecimiento micelial y tamaño de esclerocios, entre otras. El análisis molecular demostró que los aislamientos pertenecen al grupo de anastomosis AG1-IA. En la prueba de inoculación en laboratorio los aislamientos G1SOM1 y P2TUR3 tuvieron mayor índice de virulencia. En invernadero los aislamientos más virulentos fueron B1TOR1, P2TUR6 y B2SAB1. La línea CML-254 mostró el mayor nivel de resistencia a la enfermedad en ambas pruebas de virulencia. Los resultados permitieron identificar y caracterizar aislamientos que pueden ser utilizados en programas de mejoramiento genético para la identificación de posibles fuentes de resistencia y en la evaluación del germoplasma mejorado. Abstract in english In Venezuela, banded leaf spot caused by Rhizoctonia solani Kühn is a widely distributed disease in the most important maize growing areas, causing important yield losses. In 2004, experiments were conducted with the purpose of characterizing and evaluating the virulence of 25 isolates of R. solani. [...] Characterization tests were performed throughout cultural, microscopic, and molecular evaluations, the latter using a specific ribosomal internal transcribed spacer region (rADN-ITS). Virulence tests were performed on the maize inbred lines CML-254 y L-82201-22-1-1, both in the laboratory using KIN solution (6-furfurilaminopurine), and in a greenhouse inoculating seedlings. Characterization tests demonstrated that all

  6. Efeito do silício nas concentrações de lignina e de açúcares em bainhas de folhas de arroz infectadas por Rhizoctonia solani / Effect of silicon on lignin and sugar concentrations of leaf sheaths in rice plants infected by Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Daniel Augusto, Schurt; Fabrício Ávila, Rodrigues; Jorge Luiz, Colodette; Vivian, Carré-Missio.

    Full Text Available A queima das bainhas, causada pelo fungo Rhizoctonia solani Kühn, é uma das mais importantes doenças que afetam a produção de arroz no mundo. Este trabalho teve como objetivo verificar o efeito do silício (Si) nas concentrações de lignina solúvel e insolúvel e de açúcares totais em bainhas de folhas [...] de arroz infectadas por R. solani. Plantas de arroz dos cultivares BR-Irga-409 e Labelle foram cultivadas em solução nutritiva sem (0 mM) ou com (2 mM) Si. A concentração de Si nas bainhas das folhas das plantas dos cultivares BR-Irga-409 e Labelle supridas com Si aumentou em 77% e 84%, respectivamente, em relação às plantas não supridas com Si. O comprimento relativo da lesão de queima das bainhas foi significativamente menor nas bainhas das plantas supridas com Si em relação às bainhas das plantas não supridas com esse elemento. Não houve efeito do Si e nem da inoculação com R. solani nas concentrações de mananas, galactanas, arabinanas, xilanas, glucanas e de açúcares totais nas bainhas das plantas dos dois cultivares. Para as plantas dos dois cultivares supridas com Si, a concentração de açúcares totais foi menor quando comparada com a dos dois cultivares na ausência de Si. Não houve variação na concentração de lignina insolúvel, solúvel e total entre os cultivares. As concentrações de lignina insolúvel e total foram maiores nas plantas supridas com Si, independentemente da inoculação com R. solani. Em conclusão, plantas de arroz supridas com Si foram mais resistentes à queima das bainhas devido a uma maior lignificação dos tecidos das bainhas e menor concentração de açúcares totais. Abstract in english Sheath blight, caused by the fungus Rhizoctonia solani Kühn, is the major disease affecting rice production worldwide. This study aimed to verify the effect of silicon (Si) on the concentrations of soluble and insoluble lignin and sugars in the leaf sheaths of rice plants infected by R. solani. Rice [...] plants from cultivars BR-Irga-409 and Labelle were grown in nutrient solution without or with Si (2 mM). As compared to plants non-supplied with Si, the Si concentration in leaf sheaths in cultivars BR-Irga-409 and Labelle supplied with Si increased by 77% and 84%, respectively. The relative lesion length of sheath blight was significantly lower in plants supplied with Si compared to non-supplied plants. There was no effect of Si or inoculation with R. solani on the concentrations of mannans, galactans, arabinans, xylans, glucans and sugars in the sheaths of plants from both cultivars. There was no variation in the concentrations of insoluble, soluble and total lignin between the cultivars. The concentrations of total and insoluble lignin were higher on plants supplied with Si regardless of inoculation with R. solani. In conclusion, the rice plants supplied with Si were more resistant to sheath blight due to an increase in the lignifications of the leaf sheath tissues and the lower concentration of total sugars.

  7. Screening, identification and evaluation of potential biocontrol fungal endophytes against Rhizoctonia solani AG3 on potato plants.

    Science.gov (United States)

    Lahlali, Rachid; Hijri, Mohamed

    2010-10-01

    Rhizoctonia solani is an important soilborne pathogen of potato plants whose control typically depends on chemicals. Here, we screened six fungal endophytes for the suppression of R. solani growth both in vitro and in a greenhouse. These isolates were identified using morphology and internal transcribed spacer regions of rDNA as Alternaria longipes, Epicoccum nigrum, Phomopsis sp., and Trichoderma atroviride. Both T. atroviride and E. nigrum showed significant in vitro inhibition of mycelial growth of R. solani, with the greatest inhibition zone observed for E. nigrum species in dual cultures. The highest inhibition was observed for T. atroviride. The inhibition rate was also significantly correlated with the culture filtrates of these isolates. Confocal microscopy showed that T. atroviride acts as a mycoparasite and competitor. However, E. nigrum and A. longipes produce secondary metabolites, while Phomospsis sp. competes for nutrients and space. Greenhouse experiments confirmed that T. atroviride and E. nigrum improved potato yield significantly and decreased the stem disease severity index of sensitive potato. PMID:20738401

  8. Analysis of Phaseolus vulgaris response to its association with Trichoderma harzianum (ALL-42) in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani.

    Science.gov (United States)

    Pereira, Jackeline L; Queiroz, Rayner M L; Charneau, Sébastien O; Felix, Carlos R; Ricart, Carlos A O; da Silva, Francilene Lopes; Steindorff, Andrei Stecca; Ulhoa, Cirano J; Noronha, Eliane F

    2014-01-01

    The present study was carried out to evaluate the ability of Trichoderma harzianum (ALL 42-isolated from Brazilian Cerrado soil) to promote common bean growth and to modulate its metabolism and defense response in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani using a proteomic approach. T. harzianum was able to promote common bean plants growth as shown by the increase in root/foliar areas and by size in comparison to plants grown in its absence. The interaction was shown to modulate the expression of defense-related genes (Glu1, pod3 and lox1) in roots of P. vulgaris. Proteomic maps constructed using roots and leaves of plants challenged or unchallenged by T. harzianum and phytopathogenic fungi showed differences. Reference gels presented differences in spot distribution (absence/presence) and relative volumes of common spots (up or down-regulation). Differential spots were identified by peptide fingerprinting MALDI-TOF mass spectrometry. A total of 48 identified spots (19 for leaves and 29 for roots) were grouped into protein functional classes. For leaves, 33%, 22% and 11% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. For roots, 17.2%, 24.1% and 10.3% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. PMID:24878929

  9. Biotic and abiotic factors associated with soil suppressiveness to Rhizoctonia solani Fatores bióticos e abióticos associados à supressividade de solos a Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Raquel Ghini

    2006-04-01

    Full Text Available Crop management may modify soil characteristics, and as a consequence, alter incidence of diseases caused by soilborne pathogens. This study evaluated the suppressiveness to R. solani in 59 soil samples from a microbasin. Soil sampling areas included undisturbed forest, pasture and fallow ground areas, annual crops, perennial crops, and ploughed soil. The soil samples were characterized according to abiotic variables (pH; electrical conductivity; organic matter content; N total; P; K; Ca; Mg; Al; H; S; Na; Fe; Mn; Cu; Zn; B; cation exchange capacity; sum of bases and base saturation and biotic variables (total microbial activity evaluated by the CO2 evolution and fluorescein diacetate hydrolysis; culturable bacterial, fungal, actinomycetes, protozoa, fluorescent Pseudomonas and Fusarium spp. communities. The contribution and relationships of these variables to suppression to R. solani were assessed by path analysis. When all samples were analyzed together, only abiotic variables correlated with suppression of R. solani, but the entire set of variables explained only 51% of the total variation. However, when samples were grouped and analyzed by vegetation cover, the set of evaluated variables in all cases accounted for more than 90% of the variation in suppression of the pathogen. In highly suppressive soils of forest and pasture/fallow ground areas, several abiotic variables and fluorescein diacetate hydrolysis correlated with suppression of R. solani and the set of variables explained more than 98% of suppressiveness.As atividades agrícolas podem modificar as características do solo e, como conseqüência, alterar a incidência de patógenos veiculados pelo solo. Este trabalho avaliou a supressividade a R. solani em 59 amostras de solos de uma microbacia. As áreas amostradas foram selecionadas quanto à vegetação, incluindo mata, pasto/pousio, culturas anuais, culturas perenes e solo arado. As amostras de solo foram caracterizadas quanto às propriedades abióticas (pH, condutividade elétrica, teor de matéria orgânica, N total, P, K, Ca, Mg, Al, H, S, Na, Fe, Mn, Cu, Zn, B, capacidade de troca catiônica, soma de bases e saturação de bases e bióticas (atividade microbiana do solo, avaliada pelo desprendimento de CO2 e hidrólise de diacetato de fluoresceína; comunidades de bactérias, fungos, actinomicetos, protozoários, Pseudomonas fluorescentes e Fusarium spp.. A contribuição e relação dessas variáveis para a supressividade a R. solani foram quantificadas por análise de coeficientes de trilha. Quando se avaliaram todas as amostras em conjunto, somente variáveis abióticas apresentaram correlação com a supressão a R. solani, mas o conjunto das variáveis explicou somente 51% da variação total. Entretanto, quando as amostras foram agrupadas e analisadas considerando o tipo de cobertura vegetal, o conjunto de variáveis explicou mais de 90% da variação da supressividade. Para as áreas de floresta e pasto/pousio, as quais foram classificadas como as mais supressivas, algumas variáveis abióticas e a hidrólise de diacetato de fluoresceína apresentaram correlação com a supressão de R. solani e o conjunto de variáveis explicou mais de 98% da supressividade nesses solos.

  10. Biotic and abiotic factors associated with soil suppressiveness to Rhizoctonia solani / Fatores bióticos e abióticos associados à supressividade de solos a Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Raquel, Ghini; Marcelo Augusto Boechat, Morandi.

    2006-04-01

    Full Text Available As atividades agrícolas podem modificar as características do solo e, como conseqüência, alterar a incidência de patógenos veiculados pelo solo. Este trabalho avaliou a supressividade a R. solani em 59 amostras de solos de uma microbacia. As áreas amostradas foram selecionadas quanto à vegetação, in [...] cluindo mata, pasto/pousio, culturas anuais, culturas perenes e solo arado. As amostras de solo foram caracterizadas quanto às propriedades abióticas (pH, condutividade elétrica, teor de matéria orgânica, N total, P, K, Ca, Mg, Al, H, S, Na, Fe, Mn, Cu, Zn, B, capacidade de troca catiônica, soma de bases e saturação de bases) e bióticas (atividade microbiana do solo, avaliada pelo desprendimento de CO2 e hidrólise de diacetato de fluoresceína; comunidades de bactérias, fungos, actinomicetos, protozoários, Pseudomonas fluorescentes e Fusarium spp.). A contribuição e relação dessas variáveis para a supressividade a R. solani foram quantificadas por análise de coeficientes de trilha. Quando se avaliaram todas as amostras em conjunto, somente variáveis abióticas apresentaram correlação com a supressão a R. solani, mas o conjunto das variáveis explicou somente 51% da variação total. Entretanto, quando as amostras foram agrupadas e analisadas considerando o tipo de cobertura vegetal, o conjunto de variáveis explicou mais de 90% da variação da supressividade. Para as áreas de floresta e pasto/pousio, as quais foram classificadas como as mais supressivas, algumas variáveis abióticas e a hidrólise de diacetato de fluoresceína apresentaram correlação com a supressão de R. solani e o conjunto de variáveis explicou mais de 98% da supressividade nesses solos. Abstract in english Crop management may modify soil characteristics, and as a consequence, alter incidence of diseases caused by soilborne pathogens. This study evaluated the suppressiveness to R. solani in 59 soil samples from a microbasin. Soil sampling areas included undisturbed forest, pasture and fallow ground are [...] as, annual crops, perennial crops, and ploughed soil. The soil samples were characterized according to abiotic variables (pH; electrical conductivity; organic matter content; N total; P; K; Ca; Mg; Al; H; S; Na; Fe; Mn; Cu; Zn; B; cation exchange capacity; sum of bases and base saturation) and biotic variables (total microbial activity evaluated by the CO2 evolution and fluorescein diacetate hydrolysis; culturable bacterial, fungal, actinomycetes, protozoa, fluorescent Pseudomonas and Fusarium spp. communities). The contribution and relationships of these variables to suppression to R. solani were assessed by path analysis. When all samples were analyzed together, only abiotic variables correlated with suppression of R. solani, but the entire set of variables explained only 51% of the total variation. However, when samples were grouped and analyzed by vegetation cover, the set of evaluated variables in all cases accounted for more than 90% of the variation in suppression of the pathogen. In highly suppressive soils of forest and pasture/fallow ground areas, several abiotic variables and fluorescein diacetate hydrolysis correlated with suppression of R. solani and the set of variables explained more than 98% of suppressiveness.

  11. Evaluación de aislamientos de Trichoderma spp. contra Rhizoctonia solani y Sclerotium rolfsii bajo condiciones in vitro y de invernadero / Evaluation of Trichoderma spp. isolates against Rhizoctonia solani and Sclerotium rolfsii under in vitro and greenhouse conditions

    Scientific Electronic Library Online (English)

    Liliana, Hoyos-Carvajal; Paola, Chaparro; Miriam, Abramsky; Ilan, Chet; Sergio, Orduz.

    2008-12-01

    Full Text Available Se evaluó la eficacia biológica de ocho aislamientos de Trichoderma spp. provenientes de suelos de Colombia para el control de los agentes causales de volcamiento, Sclerotium rolfsii y Rhizoctonia solani, bajo condiciones in vitro y de invernadero. Los análisis in vitro mostraron la capacidad antagó [...] nica de todos los aislamientos evaluados. En condiciones de invernadero, cuatro aislamientos fueron altamente eficaces contra S. rolfsii en plantas de fríjol en semillero (>90% de reducción de la enfermedad) y dos aislamientos fueron eficaces contra R. solani en plantas de algodón en semillero (58 y 61% de reducción de la enfermedad). El análisis UP-PCR y DS-PCR permitió determinar tres grupos de aislamientos; dentro de estas asociaciones formadas no se encontró ninguna relación evidente entre la posición en el dendrograma y la actividad antagónica, pero sí permitió separar las especies de Trichoderma por grupos, e incluso encontrar diferencias dentro de aislamientos de una misma especie. Los resultados muestran que el comportamiento micoparasítico de los aislamientos de Trichoderma spp. varía según el hongo fitopatógeno, evidenciando una amplia especificidad del antagonista por su sustrato, es decir por el hongo atacado; por lo tanto es necesario realizar cuidadosas selecciones del aislamiento de Trichoderma que se utilice en programas de control de fitopatógenos. Abstract in english The biological effectiveness of eight isolates of Trichoderma spp. coming from Colombian soils was evaluated under in vitro and greenhouse conditions for the controlled causal agents of damping-off, Sclerotium rolfsii and Rhizoctonia solani. In vitro analysis showed the antagonistic capacity of all [...] evaluated isolates. Under greenhouse conditions, four isolates were highly effective against S. rolfsii in bean nursery plants (>90% of disease reduction) and two isolates were effective against R. solani in cotton nursery plants (58 and 61% of disease reduction). The analysis UP-PCR and DS-PCR permitted the determination of three groups of isolates. Within these associations no clear link between the position in the dendrogram and antagonistic activity was found, but it allowed separation of species of Trichoderma by groups and even within isolates of the same species. The results indicate that the mycoparasitic capacity of Trichoderma spp. varies according to the phytopathogen fungi, showing a broad specificity of the antagonist for its substrate that is attacked by the fungus. Therefore it is necessary to make careful selections of the isolates of Trichoderma to be used in pathogens control programs.

  12. Efeito do tratamento de sementes de algodão com fungicidas no controle do tombamento de plântulas causado por Rhizoctonia solani / Effect of cotton seed dressing with fungicides for the control of seedling damping-off caused by Rhizoctonia solani

    Scientific Electronic Library Online (English)

    AUGUSTO C. P., GOULART.

    2002-07-01

    Full Text Available Este trabalho foi desenvolvido na Embrapa Agropecuária Oeste, em Dourados, MS, e teve por objetivo avaliar a eficiência de alguns fungicidas, aplicados no tratamento de sementes de algodão (Gossypium hirsutum), no controle do tombamento de plântulas causado por Rhizoctonia solani. Foi realizado test [...] e em casa de vegetação, utilizando a cultivar DeltaOpal. Sementes tratadas e não tratadas com fungicidas foram semeadas em areia contida em bandejas plásticas, dispostas em orifícios individuais, eqüidistantes e a 3 cm de profundidade. A inoculação com R. solani foi feita pela distribuição homogênea do inóculo do fungo na superfície do substrato. O fungo foi cultivado por 35 dias em sementes de aveia autoclavadas e trituradas em moinho (1 mm). Foram utilizados 9 g de inóculo por bandeja de areia. Foi observado efeito do tratamento fungicida na emergência inicial e final de plântulas, com destaque para triadimenol + pencycuron + tolylfluanid e triadimenol + tolylfluanid, seguidos de carboxin + thiram, triadimenol e carboxin + thiram + carbendazim. Os tratamentos mais eficientes no controle do tombamento de pós-emergência do algodoeiro foi obtido com a mistura triadimenol + pencycuron + tolylfluanid, seguida de triadimenol, triadimenol + tolylfluanid e carboxin+thiram. Nenhum dos fungicidas testados foi fitotóxico ao algodão. Abstract in english This work was carried out at Embrapa Agropecuaria Oeste, Dourados, MS in order to evaluate the efficiency of several fungicides, applied as seed dressing, in the control of damping-off caused by Rhizoctonia solani. Greenhouse testing was performed, using the cotton (Gossypium hirsutum) cv. DeltaOpal [...] . Treated and untreated seeds with the fungicides were sowed in sand contained in plastic flats, placed in individual and equidistant wells, 3 cm deep. Inoculation with R. solani was done by the homogeneous distribution of the fungus inoculum onto the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill (1 mm). Nine grams of the fungus inoculum were put into each plastic flat. The effect of the fungicide treatment on initial and final seedling emergence was observed, with distinction to triadimenol + pencycuron + tolylfluanid and triadimenol + tolylfluanid, followed by carboxin + thiram, triadimenol and carboxin + thiram + carbendazim. The most efficient treatments in the control of cotton seedling pos-emergence damping-off were triadimenol + pencycuron + tolylfluanid, followed by triadimenol, triadimenol + tolylfluanid and carboxin + thiram. No phytotoxic effects were observed on cotton.

  13. Encapsulamento de Trichoderma inhamatum para o controle biológico de Rhizoctonia solani na propagaç??o clonal de Eucalyptus

    Directory of Open Access Journals (Sweden)

    Mafia Reginaldo G.

    2003-01-01

    Full Text Available Testou-se um novo sistema para o encapsulamento de Trichoderma inhamatum em grânulos de alginato de sódio, visando o controle biológico de Rhizoctonia solani, agente etiológico da mela de estacas/miniestacas de Eucalyptus spp. para enraizamento. No novo sistema idealizado, foi utilizado um aparato simples capaz de substituir eficientemente o equipamento (Bomba Peristáltica anteriormente utilizado, sendo possível aumentar a produção de 594 grânulos/min para aproximadamente 6.734 grânulos/min. Com este novo sistema, um isolado de T. inhamatum (UFV - 03 foi encapsulado em grânulos contendo as fontes alimentares: farelo de trigo, palha de arroz, farelo de aveia, folhas de eucalipto ou farelo de milho na concentração de 50 g/l. Na segunda etapa, a melhor fonte alimentar foi testada nas concentrações de 0 a 60 g/l. Os grânulos foram veiculados em substrato de enraizamento de eucalipto na concentração de 2% (p/p inoculado com micélio triturado de R. solani (2 mg/g de substrato e a atividade saprofítica do patógeno foi quantificada por meio do método de iscas. Posteriormente, os grânulos produzidos com a fonte alimentar e concentração que promoveram maior inibição do desenvolvimento de R. solani foram utilizados para determinar o tempo mínimo de pré-incubação e competição para supressão do patógeno, com a mesma metodologia. Observou-se aumento da supressão da atividade saprofítica de R. solani ao acréscimo de uma fonte alimentar. Daquelas testadas, farelo de trigo foi a melhor. Além disso, houve interação significativa e positiva ao aumento de sua concentração na formulação.

  14. Scarlet-Rz1, an EMS-generated hexaploid wheat with tolerance to the soilborne necrotrophic pathogens Rhizoctonia solani AG-8 and R. oryzae.

    Science.gov (United States)

    Okubara, Patricia Ann; Steber, Camille M; Demacon, Victor L; Walter, Nathalie L; Paulitz, Timothy C; Kidwell, Kimberlee K

    2009-07-01

    The necrotrophic root pathogens Rhizoctonia solani AG-8 and R. oryzae cause Rhizoctonia root rot and damping-off, yield-limiting diseases that pose barriers to the adoption of conservation tillage in wheat production systems. Existing control practices are only partially effective, and natural genetic resistance to Rhizoctonia has not been identified in wheat or its close relatives. We report the first genetic resistance/tolerance to R. solani AG-8 and R. oryzae in wheat (Triticum aestivum L. em Thell) germplasm 'Scarlet-Rz1'. Scarlet-Rz1 was derived from the allohexaploid spring wheat cultivar Scarlet using EMS mutagenesis. Tolerant seedlings displayed substantial root and shoot growth after 14 days in the presence of 100-400 propagules per gram soil of R. solani AG-8 and R. oryzae in greenhouse assays. BC(2)F(4) individuals of Scarlet-Rz1 showed a high and consistent degree of tolerance. Seedling tolerance was transmissible and appeared to be dominant or co-dominant. Scarlet-Rz1 is a promising genetic resource for developing Rhizoctonia-tolerant wheat cultivars because the tolerance trait immediately can be deployed into wheat breeding germplasm through cross-hybridization, thereby avoiding difficulties with transfer from secondary or tertiary relatives as well as constraints associated with genetically modified plants. Our findings also demonstrate the utility of chemical mutagenesis for generating tolerance to necrotrophic pathogens in allohexaploid wheat. PMID:19407984

  15. EFECTO DE DIFERENTES DERIVADOS DE LA QUITINA SOBRE EL CRECIMIENTO In Vitro DEL HONGO Rhizoctonia solani Kuhn

    Directory of Open Access Journals (Sweden)

    Yanet Parra

    2002-01-01

    Full Text Available En la Estación Experimental del Arroz "Los Palacios", se estudió el efecto in vitro de diferentes derivados de la quitina (QC, HMK-70, Q-63, HQ-63, D-glucosamina y N-acetil-glucosamina sobre el crecimiento del hongo Rhizoctonia solani Kuhn. Para ello se evaluó el diámetro de la colonia a los dos, cuatro y seis días, determinándose el porcentaje de inhibición del crecimiento del hongo. Los resultados mostraron un marcado efecto inhibitorio de la cepa evaluada en presencia de las quitosanas HMK-70, Q-63 y su correspondiente hidrolizado enzimático HQ-63; dicho efecto aumentó con la concentración de los productos, destacándose los dos últimos, con una inhibición del 100 % a la concentración de 1 mg.mL-1. Por su parte, la D-glucosamina y la N-Acetil-Glucosamina no mostraron inhibición del crecimiento micelial, mientras que la quitina coloidal (QC presentó un ligero efecto inhibitorio sobre el hongo en estudio.

  16. Molecular identification of thirteen isolates of Trichoderma spp. and evaluation of their pathogenicity towards Rhizoctonia solani Kühn / Identificación molecular y evaluación patogénica de trece aislamientos de Trichoderma spp. frente a Rhizoctonia solani Kühn

    Scientific Electronic Library Online (English)

    Danay, Infante; Benedicto, Martínez; Belkis, Peteira; Yusimy, Reyes; Alfredo, Herrera.

    2013-03-01

    Full Text Available La incidencia de las enfermedades causadas por Rhizoctonia solani Kühn en las plantas aumenta cada año. Su control es fundamentalmente con productos químicos, en su mayoría muy tóxicos. Por tal razón, se investigan alternativas bioplaguicidas. Trichoderma spp. es uno de los hongos más utilizados par [...] a el control biológico de plagas, por sus propiedades y mecanismos de acción: competencia por el sustrato, antibiosis y micoparasitismo. Este trabajo tuvo como objetivos la identifi cación molecular y evaluación patogénica de 13 aislamientos del género Trichoderma frente a aislamientos de R. solani. Se evaluó su efecto antibiótico sobre aislamientos de 3 grupos de anastomosis de R. solani (AG-2.1, AG-5, AG-8) por el método de celofán. La identificación molecular partió de la secuenciación del espaciador interno del transcrito de la región del ADN ribosomal y del factor de elongación de la traducción EF1A. Más del 70 % de los aislamientos evaluados ejerció un efecto fungistático; mientras que el resto actuó como fungicida. La evaluación de la eficacia técnica en condiciones de campo corroboró estos resultados. A partir de la secuenciación y comparación de los datos de las secuencias depositadas en TrichoBLAST/GenBank, se comprobó que todos los aislamientos tenían el 100 % de identidad con la especie Trichoderma asperellum Samuels. Se seleccionaron los aislamientos 3, 13, 17, 75, 78, 85 y 90 como promisorios agentes de control biológico, por su alto potencial antibiótico y eficacia técnica en condiciones de campo. Abstract in english Disease caused by Rhizoctonia solani Kühn infestations has become a growing problem for commercially important crops. Although this fungus is usually controlled through the application of chemicals, the heavy ecological and financial toll of the latter has prompted for research on biopesticides as a [...] viable alternative. Trichoderma spp. is a well-known fungus often used for the biological control of crop pests, whose anti-fungal mechanisms include competition for the substrate, antibiosis and/or mycoparasitism. In the present work, we have used molecular techniques (sequencing of amplicons from the internal transcribed spacer of ribosomal DNA and the EF1A translation elongation factor) for the taxonomic identification of 13 Trichoderma spp. isolates in our collection, also evaluating their antibiotic effect on strains from three anastomosis groups of R. solani (AG-2.1, AG-5, AG-8) by the cellophane method. The sequences obtained from all isolates exhibited 100 % identity with deposited T. asperellum Samuels sequences in TrichoBLAST/GenBank, enabling their taxonomic assignment to this species. When analyzed by in vitro tests, over 70 % of the isolates exhibited a fungistatic effect towards R. solani, with the remaining strains exhibiting fungicidal activity; these results were later corroborated by technical efficacy tests under field conditions. Isolates 3, 13, 17, 75, 78, 85 and 90 were selected as potential biocontrol agents due to their high antibiotic activity and technical efficacy under field conditions.

  17. Controle de Rhizoctonia solani e Fusarium oxysporum f.sp. phaseoli por biopreparados de isolados de Trichoderma spp. / Rhizoctonia solani and Fusarium oxysporum f.sp. phaseoli control by biopreparation with Trichoderma spp. isolates

    Scientific Electronic Library Online (English)

    Pedro Paulo, Dias; Ricardo Luis Louro, Berbara; Maria do Carmo de Araújo, Fernandes.

    2013-12-01

    Full Text Available Os experimentos objetivaram avaliar em condições de casa de vegetação o biocontrole dos fitopatógenos Rhizoctonia solani (RS) e Fusarium oxysporum f.sp. phaseoli (FOP) em alface (Lactuca sativa L.) cultivar Regina, e feijão-vagem (Phaseolus vulgaris L.) cultivar Alessa, respectivamente, utilizando c [...] omo agentes antagonistas, 10 isolados de Trichoderma spp. selecionados em testes in vitro. Foram feitos biopreparados à base de arroz previamente colonizado por isolados de Trichoderma spp. e posteriormente triturados. Para a realização dos testes, os biopreparados foram inoculados previamente na proporção de 10(9) conídios.mL-1, em substrato comercial para produção de mudas. Após sete dias, os patógenos foram introduzidos separadamente em duas concentrações distintas: R. solani na proporção de 144 mg de meio de arroz por kg de substrato e F. oxysporum f.sp. phaseoli inoculado na forma de suspensão contendo 4,75 x 10(6) conídios.mL-1. Avaliou-se a influência dos biopreparados na % de damping-off de pós-emergência em plantas de alface e a severidade de murcha em plantas de feijão-vagem. O biopreparado referente ao isolado T-03 foi o mais eficiente no controle de R. solani em plantas de alface cultivar Regina, por ter reduzido a incidência de damping-off de pós-emergência nessa cultura. Por outro lado, nenhum dos biopreparados apresentou efeito antagonista satisfatório à F. oxysporum f.sp. phaseoli em plantas de feijão-vagem. Abstract in english The experiments aimed to evaluate under greenhouse conditions the biocontrol of plant pathogens Rhizoctonia solani (RS) and Fusarium oxysporum f.sp. phaseoli (FOP) in lettuce (Lactuca sativa L.) cultivar Regina and in common bean (Phaseolus vulgaris L.) cultivar Alessa, respectively, using as antago [...] nistic agents 10 Trichoderma spp. isolates selected from in vitro tests. Inoculants were prepared with rice previously colonized by Trichoderma spp. and subsequently ground. For the tests, the antagonists were previously inoculated at a ratio of 10(9) conidia mL-1 on commercial substrate for seedling production. Following seven days, the pathogens were separately introduced at two different concentrations: R. solani at a ratio of 144 mg rice medium per kg of substrate and F oxysporum f.sp. phaseoli inoculated as a suspension containing 4.75 x 10(6) conidia mL-1. The influence of antagonists on % post-emergence damping-off in lettuce and the severity of wilt in common beans were evaluated. The biopreparation with T-03 isolate was most effective in controlling R. solani in lettuce cultivar Regina, for having reduced the incidence of post-emergence damping-off in this culture. On the other hand, none of the biopreparations showed satisfactory antagonistic effect on F. oxysporum f.sp. phaseoli in common bean plants.

  18. Efecto diferencial de seis aislamientos de trichoderma sobre la severidad de Rhizoctonia solani, desarrollo radical y crecimiento de plantas de maíz Differential effect of six Trichoderma isolates on root development, plant growth and severity of Rhizoctonia solani on mayze

    Directory of Open Access Journals (Sweden)

    Yuleidy López

    2010-04-01

    Full Text Available La mancha bandeada de la hoja en maíz, Rhizoctonia solani Kuhn, ha incrementado su incidencia en Venezuela y ocasiona considerables pérdidas en la producción. En muchos casos la microbiota del suelo sirve para proteger a la planta del ataque de patógenos y contribuye a su mayor desarrollo. Para estudiar medidas de biocontrol de R. solani se seleccionaron seis aislamientos de Trichoderma provenientes de la rizósfera de plantas de maíz colectadas en varias localidades de los estados Portuguesa y Yaracuy, las cuales fueron utilizadas en pruebas de antagonismo en vivero con un sustrato esterilizado. En el sustrato se hicieron dos hoyos y en ellos se colocaron dos granos de arroz esterilizados y 2 mL de solución de esporas del antagonista a 3-7x10(6 conidios·mL-1. Luego se colocó una semilla de maíz híbrido D2000 en cada hoyo y dos esclerocios de R. solani, se adicionaron 3 mL de la solución del antagonista y se cubrió con suelo esterilizado. Con relación a la sobrevivencia de plantas, hubo un efecto positivo en los tratamientos donde se utilizaron las cepas de Trichoderma, obteniéndose valores entre 70 y 90 %. En cuanto a la severidad de la enfermedad en la planta hasta los 60 días, se obtuvieron valores de 82,5 % en el testigo y 16,2 % en el mejor tratamiento con Trichoderma. Para un aislamiento proveniente de Píritu-estado Portuguesa se produjo el avance de la enfermedad fue el menor. Este aislamiento, seguido por el procedente de Yaritagua-estado Yaracuy, propiciaron un mayor crecimiento de la planta y mayor desarrollo radical.The banded leaf spot disease on maize, Rhizoctonia solani Kuhn, has increased its incidence in Venezuela, causing considerable damages and yield reduction. In many cases, soil microbiota can protect the plant from the pathogen attack and contributes to better plant development. In order to study forms of biocontrol of R. solani, six isolations of Trichoderma obtained from maize plant rizosphere were collected in several localities of Portuguesa and Yaracuy States; the isolations were used in antagonism tests on a sterilized substrate in nursery. Two orifices were made in the substrate and sterilized grains of rice were placed on them, covering with 2 mL of spore solution of the antagonist (3-7x10(6 conidia mL-1. Later, one maize of seed hybrid D2000 and two esclerotia of R. solani was placed in each hole and added 3 mL of the solution of the antagonist, covering with sterilized soil. In relation to plant survival, there was a positive effect of the treatments where Trichoderma was used, obtaining values between 70 and 90 %. As far as plant disease severity up to 60 days, it was obtained a value of 82.5 % in the control and 16.2 % in the best treatment with Trichoderma. For the isolation coming from Píritu-Portuguesa State, the advance of the disease was the smallest. This isolation, followed by the one coming from Yaritagua-Yaracuy State, promoted a greater plant growth and better root development.

  19. Efecto diferencial de seis aislamientos de trichoderma sobre la severidad de Rhizoctonia solani, desarrollo radical y crecimiento de plantas de maíz / Differential effect of six Trichoderma isolates on root development, plant growth and severity of Rhizoctonia solani on mayze

    Scientific Electronic Library Online (English)

    Yuleidy, López; Juan B, Pineda; Alexander, Hernández; Dilcia, Ulacio.

    2010-04-01

    Full Text Available La mancha bandeada de la hoja en maíz, Rhizoctonia solani Kuhn, ha incrementado su incidencia en Venezuela y ocasiona considerables pérdidas en la producción. En muchos casos la microbiota del suelo sirve para proteger a la planta del ataque de patógenos y contribuye a su mayor desarrollo. Para estu [...] diar medidas de biocontrol de R. solani se seleccionaron seis aislamientos de Trichoderma provenientes de la rizósfera de plantas de maíz colectadas en varias localidades de los estados Portuguesa y Yaracuy, las cuales fueron utilizadas en pruebas de antagonismo en vivero con un sustrato esterilizado. En el sustrato se hicieron dos hoyos y en ellos se colocaron dos granos de arroz esterilizados y 2 mL de solución de esporas del antagonista a 3-7x10(6) conidios·mL-1. Luego se colocó una semilla de maíz híbrido D2000 en cada hoyo y dos esclerocios de R. solani, se adicionaron 3 mL de la solución del antagonista y se cubrió con suelo esterilizado. Con relación a la sobrevivencia de plantas, hubo un efecto positivo en los tratamientos donde se utilizaron las cepas de Trichoderma, obteniéndose valores entre 70 y 90 %. En cuanto a la severidad de la enfermedad en la planta hasta los 60 días, se obtuvieron valores de 82,5 % en el testigo y 16,2 % en el mejor tratamiento con Trichoderma. Para un aislamiento proveniente de Píritu-estado Portuguesa se produjo el avance de la enfermedad fue el menor. Este aislamiento, seguido por el procedente de Yaritagua-estado Yaracuy, propiciaron un mayor crecimiento de la planta y mayor desarrollo radical. Abstract in english The banded leaf spot disease on maize, Rhizoctonia solani Kuhn, has increased its incidence in Venezuela, causing considerable damages and yield reduction. In many cases, soil microbiota can protect the plant from the pathogen attack and contributes to better plant development. In order to study for [...] ms of biocontrol of R. solani, six isolations of Trichoderma obtained from maize plant rizosphere were collected in several localities of Portuguesa and Yaracuy States; the isolations were used in antagonism tests on a sterilized substrate in nursery. Two orifices were made in the substrate and sterilized grains of rice were placed on them, covering with 2 mL of spore solution of the antagonist (3-7x10(6) conidia mL-1). Later, one maize of seed hybrid D2000 and two esclerotia of R. solani was placed in each hole and added 3 mL of the solution of the antagonist, covering with sterilized soil. In relation to plant survival, there was a positive effect of the treatments where Trichoderma was used, obtaining values between 70 and 90 %. As far as plant disease severity up to 60 days, it was obtained a value of 82.5 % in the control and 16.2 % in the best treatment with Trichoderma. For the isolation coming from Píritu-Portuguesa State, the advance of the disease was the smallest. This isolation, followed by the one coming from Yaritagua-Yaracuy State, promoted a greater plant growth and better root development.

  20. Relato de Rhizoctonia solani AG-4 HG I em crisântemo (Papiro Branco e Amarelo) e R. solani AG-4 HG III em gipsófila no estado de São Paulo, Brasil, e sua patogenicidade cruzada / Report of Rhizoctonia solani AG-4 HG I on chrysanthemum (White and Yellow Papyrus) and R. solani AG-4 HG III on gypsophila in the São Paulo State, Brazil, and their cross pathogenicity

    Scientific Electronic Library Online (English)

    César Júnior, Bueno; Wagner, Bettiol; Edisson Chavarro, Mesa; Paulo Cézar, Ceresini.

    2013-12-01

    Full Text Available Atualmente, grupamento de anastomose (AG) de Rhizoctonia sp. em crisântemo e ocorrência deste fungo em gipsófila ainda não foram relatados no Brasil. Assim, realizou-se teste de patogenicidade normal e cruzada e sequenciamento da região ITS-5.8S rDNA para identificar o AG de isolado obtido de planta [...] s de crisântemo (Papiro Branco) e de gipsófila, ambas originárias de Holambra / São Paulo, Brasil. Após os testes, relata-se pela primeira vez a ocorrência de R. solani AG-4 HG I em crisântemo (Papiro Branco e Amarelo) e R. solani AG-4 HG III em gipsófila, no estado de São Paulo, Brasil, e, também, a sua patogenicidade cruzada. Abstract in english Currently, anastomosis groups (AG) of Rhizoctonia sp. on chrysanthemum and occurrence of this fungus on gypsophila have not been reported in Brazil. However, in the present study, normal and cross pathogenicity and sequencing of ITS-5.8S rDNA regions were used to confirm the AG of isolate of Rhizoct [...] onia sp. obtained from chrysanthemum (White Papyrus) and from gypsophila plants cultivated in Holambra / São Paulo, Brazil. After these tests, it was confirmed the report of Rhizoctonia solani AG-4 HG I on chrysanthemum (White and Yellow Papyrus) and R. solani AG-4 HG III on gypsophila in the São Paulo state, Brazil, and also their cross pathogenicity.

  1. A PCR-based method to distinguish fungi of the rice sheath-blight complex, Rhizoctonia solani, R. oryzae and R. oryzae-sativae.

    Science.gov (United States)

    Johanson, A; Turner, H C; McKay, G J; Brown, A E

    1998-05-15

    Identification of Rhizoctonia solani, R. oryzae and R. oryzae-sativae, components of the rice sheath disease complex, is extremely difficult and often inaccurate and as a result may hinder the success of extensive breeding programmes throughout Asia. In this study, primers designed from unique regions within the rDNA internal transcribed spacers have been used to develop a rapid PCR-based diagnostic test to provide an accurate identification of the species on rice. Tests on the specificity of the primers concerned showed that they provide the means for accurate identification of the Rhizoctonia species responsible for sheath diseases in rice. PMID:9627963

  2. Comparison of the growth and some morphological and anatomical features of Rhizoctonia cerealis and R. solani

    Directory of Open Access Journals (Sweden)

    Zbigniew Weber

    1989-12-01

    Full Text Available In laboratory experiments were observed diameter of hyphae as well as the influence of temperature and kind of medium on mycelium growth, colour of colony and forming of sclerotia by R. cerealis and R. solani.

  3. Comparison of the growth and some morphological and anatomical features of Rhizoctonia cerealis and R. solani

    OpenAIRE

    Zbigniew Weber; Tomasz Zdziebkowski

    1989-01-01

    In laboratory experiments were observed diameter of hyphae as well as the influence of temperature and kind of medium on mycelium growth, colour of colony and forming of sclerotia by R. cerealis and R. solani.

  4. The impact of the pathogen Rhizoctonia solani and its beneficial counterpart Bacillus amyloliquefaciens on the indigenous lettuce microbiome

    Directory of Open Access Journals (Sweden)

    GabrieleBerg

    2014-04-01

    Full Text Available Lettuce belongs to the most commonly raw eaten food worldwide and its microbiome plays an important role for both human and plant health. Yet, little is known about the impact of potentially occurring pathogens and beneficial inoculants of the indigenous microorganisms associated with lettuce. To address this question we studied the impact of the phytopathogenic fungus Rhizoctonia solani and the biological control agent Bacillus amyloliquefaciens FZB42 on the indigenous rhizosphere and phyllosphere community of greenhouse-grown lettuce at two plant stages. The rhizosphere and phyllosphere gammaproteobacterial microbiomes of lettuce plants showed clear differences in their overall and core microbiome composition as well as in corresponding diversity indices. The rhizosphere was dominated by Xanthomonadaceae (48% and Pseudomonadaceae (37% with Rhodanobacter, Pseudoxanthomonas, Dokdonella, Luteimonas, Steroidobacter, Thermomonas as core inhabitants, while the dominating taxa associated to phyllosphere were Pseudomonadaceae (54%, Moraxellaceae (16% and Enterobacteriaceae (25% with Alkanindiges, Pantoea and a group of Enterobacteriaceae unclassified at genus level. The preferential occurrence of enterics in the phyllosphere was the most significant difference between both habitats. Additional enhancement of enterics on the phyllosphere was observed in bottom rot diseased lettuce plants, while Acinetobacter and Alkanindiges were identified as indicators of healthy plants. Interestingly, the microbial diversity was enhanced by treatment with both the pathogen, and the co-inoculated biological control agent. The highest impact and bacterial diversity was found by Rhizoctonia inoculation, but FZB42 lowered the impact of Rhizoctonia on the microbiome. This study shows that the indigenous microbiome shifts as a consequence to pathogen attack but FZB42 can compensate these effects, which supports their role as biocontrol agent and suggests a novel mode of action.

  5. Studies on Biological Control of Sugarbeet Pathogen Rhizoctonia solani Kuhn

    OpenAIRE

    Moussa, Tarek A. A.

    2002-01-01

    A field experiment was carried out to investigate the biological control of R. solani by different organisms including bacteria and fungi. Three methods of application were used during the study. Control results differed with the method of application used. The present study indicated that all the antagonists tested inhibited infection by R. solani and that the efficacy of prevention depended on the application method used. Coating sugarbeet seeds with antagonists was produced results for ap...

  6. Potential for the integration of biological and chemical control of sheath blight disease caused by Rhizoctonia solani on rice.

    Science.gov (United States)

    Boukaew, Sawai; Klinmanee, Chanasirin; Prasertsan, Poonsuk

    2013-10-01

    Biological control using antagonistic microbes to minimize the use of chemical pesticides has recently become more prevalent. In an attempt to find an integrated control system for sheath blight, caused by Rhizoctonia solani in rice, Streptomyces philanthi RM-1-138, commercial formulations of Bacillus subtilis as Larminar® and B. subtilis strain NSRS 89-24+MK-007 as Biobest® and chemical fungicides including carbendazim®, validamycin®, propiconazole® and mancozeb® were applied alone and in combination with S. philanthi RM-1-138. In vitro experiments showed that all treatments tested did provide some control against mycelial growth and sclerotia production by R. solani PTRRS-9. In addition, the four chemical fungicides had no detrimental effects on S. philanthi RM-1-138 even at high concentrations (up to 100 ?g/ml). The efficacy of S. philanthi RM-1-138, the commercial formulations of B. subtilis, chemical fungicides alone or in combination with S. philanthi RM-1-138 was also tested in a greenhouse experiment against sheath blight disease on rice plants. All treatments showed some protection of rice for sheath blight by 47-60 % when carbendazim® was applied alone and up to 74 % when combined with S. philanthi RM-1-138. PMID:23653261

  7. Biological Control Potential of Two Streptomyces Isolates on Rhizoctonia solani, the Causal Agent of Damping-off of Sugar Beet

    Directory of Open Access Journals (Sweden)

    Sadeghi, A.

    2006-01-01

    Full Text Available Biological control of sugar beet damping-off of Rhizoctonia solani by two Streptomyces isolates (S2 and C was evaluated in this study. The in vitro antagonism assays showed that active isolates had inhibitory effects on mycelium growth of the three R. solani AG-4 isolates (Rs1, Rs2 and Rs3. Soil treatment either with isolate S2 or C formulation inhibited the disease completely and increased seedling stand in infected and uninfected treatments significantly (p<0.05. Compared to controls, all treatments containing bacteria had enhanced shoot and root dry weight and root density. Both bacterial isolates maintained normal growth in pH ranges of 5.6, 7.2 and 8.0 at 29°C. Isolate C grew in pH ranges 5.6, 7.2 and 8.0 at 23-37°C, isolate S2 grew at 18-37°C in pH 5.6-8.0 but did not grow in acidic medium at 37°C. When pH decreased to 5.0, growth of C decreased and S2 inhibited. To elucidate the mode of antagonism, chitinase activity and siderophore production were evaluated. Both isolates showed chitinase activity on medium containing colloidal chitin. Biosynthesis of siderophore was detectable in isolate C but not in S2. The results of this study showed that these isolates had antifungal activities by production of siderophore and chitinase.

  8. Effect of Certain Fungicides and Isolates of Antagonistic Fungi on Rhizoctonia solani, the Causal Agent of Rice Sheath Blight

    Directory of Open Access Journals (Sweden)

    S. A. Elahinia

    2003-01-01

    Full Text Available Antagonistic fungi Trichoderma harzianum (T1, from bean fields in Ahwaz, T2, from rice fields in Rasht, T. viride (T3 from bean fields in Shahriar, T4 from the collection in Plant Pest and Disease Institute, Tehran, Gliocladium virens (from bean fields in Kamal Abad, Karaj and some fungicides (Benomyl, Carbendazim, Carboxin-Thiram, edifenphos and Zineb were used to control sheath blight of rice incited by Rhizoctonia solani in vitro and under greenhouse conditions. The experiment was carried out in a completely randomized design with 12 treatments and four replications on Khazar rice cultivar in a soil infected by R. solani under greenhouse conditions. The results showed that the antagonistic fungi reduce sheath blight by 19.8 (T1, 21.5 (T2, 27.5 (T3, 19.6 (T4 and 18.5 (G1 percent. The antagonistic fungi in order of efficacy were T2>T3>T1>T4>G1. Benomyl, Carbendazim, Carboxin-thiram, Edifenphos and Zineb reduced disease by 32.5, 21.5, 12.8, 9.5 and 0 percent, respectively. Statistical analysis of data indicated that there existed no significant differences between T1, T3, T4, and G1 and Carbendazim fungicide to control disease; however, the isolate T2 was as effective as Benomyl but Zineb had no effect on sheath blight.

  9. Efecto de algunos fungicidas sobre la interacción Rhizoctonia solani Kuhn-Micorriza vesículo arbuscular en soya, Glycine max Merril

    Directory of Open Access Journals (Sweden)

    Sánchez de Prager Marina

    1987-09-01

    Full Text Available En el campo se dispuso de dos preparaciones de suelo: natural y desinfectado químicamente (Ditrapex-CE y en el invernadero de suelo esterilizado con vapor. Se utilizaron los fungicidas Propamocarb, SN-84364, PCNB y Vitavax-300. Se contó con la flora micorrizógena natural y una cepa introducida, Glomus manihotis. R. solani disminuyó en un 50 % la emergencia de la soya, comportándose más agresivo en suelo desinfectado. En los primeros 15 días su ataque se incrementó y redujo el desarrollo de MVA en suelo natural. Al avanzar la edad de la planta decreció su infección. Con relación a la MVA la tendencia es contraria. La presencia de la MVA, incluyendo G. manihotis no incrementó significativamente la materia seca y el rendimiento de la soya. Al desinfectar el suelo los fungicidas afectaron negativamente la infección micorrizógena, mientras que en suelo natural no sucedió este fenómeno, al contrario SN-84364 incrementó su presencia. Este producto es el que menos afecta la simbiosis en el suelo desinfectado. Los fungicidas SN-84364 y PCNB mostraron gran especificidad contra R. solani y Vitavax-300 mayor espectro de acción.With the object to evaluate in the soybeans crop behavior in the interaction of Rhizoctonia solani, vesicular-arbuscular mycorrhizae (VAM and fungicides used to treatment of seed, two different soil preparations were used in the field trials: natural and chemically disinfected (Ditrapex-CE and under greenhouse: using vapor- sterilized. Was utilized the fungicides Propamocarb, SN-84364, PCNB y Vitavax- 300. Be had into account the natural mycorrhizal flora and a source of Glomus manihotis introduced. R. solani reduced the emergence of soybean by 50%, the above-metioned pathogen was more agressive in disinfected soil. In the 15 days first the attack increased and reduced the VAM development in the natural soil. With the age of the plant the pathogen infection decreased. With relation by VAM is contrary the tendency. The presence of VAM, G. manihotis including, not increased significantly the dry mass and yield of the soybean. The fungicides diminished the VAM infection in both chemically and physically disinfected soil, whereas this does not ocurr in natural soil,SN-84364, on the other hand, increased the VAM infection. This product affected least the simbiosis in the disinfected soil. SN-84364 and PCNB exhibitited their great especifity against R. solani and Vitavax-300 a greater spectrum of action.

  10. The interaction pattern between a homology model of 40S ribosomal S9 protein of Rhizoctonia solani and 1-hydroxyphenaize by docking study.

    Science.gov (United States)

    Dharni, Seema; Sanchita; Samad, Abdul; Sharma, Ashok; Patra, Dharani Dhar

    2014-01-01

    1-Hydroxyphenazine (1-OH-PHZ), a natural product from Pseudomonas aeruginosa strain SD12, was earlier reported to have potent antifungal activity against Rhizoctonia solani. In the present work, the antifungal activity of 1-OH-PHZ on 40S ribosomal S9 protein was validated by molecular docking approach. 1-OH-PHZ showed interaction with two polar contacts with residues, Arg69 and Phe19, which inhibits the synthesis of fungal protein. Our study reveals that 1-OH-PHZ can be a potent inhibitor of 40S ribosomal S9 protein of R. solani that may be a promising approach for the management of fungal diseases. PMID:24864254

  11. Biological Control Potential of Two Streptomyces Isolates on Rhizoctonia solani, the Causal Agent of Damping-off of Sugar Beet

    OpenAIRE

    Sadeghi, A.; A.R. Hessan; H. ASKARI; S. Aghighi; G.H. Shahidi Bonjar

    2006-01-01

    Biological control of sugar beet damping-off of Rhizoctonia solani by two Streptomyces isolates (S2 and C) was evaluated in this study. The in vitro antagonism assays showed that active isolates had inhibitory effects on mycelium growth of the three R. solani AG-4 isolates (Rs1, Rs2 and Rs3). Soil treatment either with isolate S2 or C formulation inhibited the disease completely and increased seedling stand in infected and uninfected treatments significantly (p<0.05). Compared to controls,...

  12. Identification of potential marker genes for Trichoderma harzianum strains with high antagonistic potential against Rhizoctonia solani by a rapid subtraction hybridization approach

    OpenAIRE

    Scherm, Barbara; Schmoll, Monika; Balmas, Virgilio; Kubicek, Christian P.; Migheli, Quirico

    2009-01-01

    A rapid subtraction hybridization approach was used to isolate genes differentially expressed during mycelial contact between Trichoderma harzianum (Hypocrea lixii) and Rhizoctonia solani, and could serve as marker genes for selection of superior biocontrol strains. Putatively positive clones were evaluated by transcription analysis during mycelial contact with R. solani versus growth on glucose, and for their differential transcription between two strains with either ...

  13. Integrated effect of microbial antagonist, organic amendment and fungicide in controlling seedling mortality (Rhizoctonia solani) and improving yield in pea (Pisum sativum L.).

    Science.gov (United States)

    Akhter, Wasira; Bhuiyan, Mohamed Khurshed Alam; Sultana, Farjana; Hossain, Mohamed Motaher

    2015-01-01

    The study evaluated the comparative performance of a few microbial antagonists, organic amendments and fungicides and their integration for the management of seedling mortality (Rhizoctonia solani Kühn) and yield improvement in pea (Pisum sativum L.). Before setting the experiment in field microplots, a series of in vitro and in vivo experiments were conducted to select a virulent isolate of R. solani, an effective antagonistic isolate of Trichoderma harzianum, a fungitoxic organic amendment and an appropriate fungicide. A greenhouse pathogenicity test compared differences in seedling mortality in pea inoculated by four isolates of R. solani and identified the isolate RS10 as the most virulent one. Among the 20 isolates screened in dual culture assay on PDA, T. harzianum isolate T-3 was found to show the highest (77.22%) inhibition of the radial growth of R. solani. A complete inhibition (100.00%) of colony growth of R. solani was observed when fungicide Bavistin 50 WP and Provax-200 at the rate of 100 and 250 ppm, respectively, were used, while Provax-200 was found to be highly compatible with T. harzianum. Mustard oilcake gave maximum inhibition (60.28%) of the radial growth of R. solani at all ratios, followed by sesame oilcake and tea waste. Integration of soil treatment with T. harzianum isolate T-3 and mustard oilcake and seed treatment with Provax-200 appeared to be significantly superior in reducing seedling mortality and improving seed yield in pea in comparison to any single or dual application of them in the experimental field. The research results will help growers develop integrated disease management strategies for the control of Rhizoctonia disease in pea. The research results show the need for an integrating selective microbial antagonist, organic amendment and fungicide to achieve appropriate management of seedling mortality (R. solani) and increase of seed yield in pea. PMID:25528673

  14. Polymorphism of genes coding for nuclear 18S rRNA indicates genetic distinctiveness of anastomosis group 10 from other groups in the Rhizoctonia solani species complex.

    OpenAIRE

    Liu, Z. L.; Domier, L. L.; Sinclair, J. B.

    1995-01-01

    DNA polymorphism in the 18S nuclear rRNA gene region was investigated by using 11 restriction endonucleases for 161 isolates of 25 intraspecific groups (ISGs) representing 11 reported anastomosis groups (AGs) of Rhizoctonia solani. A PCR-based restriction mapping method in which enzymatically amplified DNA fragments and subfragments were digested with one or two restriction enzymes was employed. Four types of DNA restriction maps of this region were constructed for these 25 ISGs. Map type I o...

  15. Biological Control of Rhizoctonia solani, the Causal Agent of Rice Sheath Blight by Antagonistics Bacteria in Greenhouse and Field Conditions

    OpenAIRE

    Mostapha Niknejad Kazempour

    2004-01-01

    Pseudomonas fluorescens isolates that inhibited growth of Rhizoctonia solani Kühn, the rice sheath blight pathogen were collected the rhizosplane and surrounding soil of healthy and rice sheath blight disease in farming of the Guilan province, Iran. Two hundred eighty eight isolates tested and among them only antagonistic ability of 8 isolates were demonstrated by using the dual culture method. According to the results of biochemical and morphological trials all isolates were identified as P...

  16. Distinctively variable sequence-based nuclear DNA markers for multilocus phylogeography of the soybean- and rice-infecting fungal pathogen Rhizoctonia solani AG-1 IA

    OpenAIRE

    Ciampi, Maisa B.; Liane Rosewich Gale; Macedo Lemos, Eliana G.; Ceresini, Paulo C.

    2009-01-01

    A series of multilocus sequence-based nuclear DNA markers was developed to infer the phylogeographical history of the Basidiomycetous fungal pathogen Rhizoctonia solani AG-1 IA infecting rice and soybean worldwide. The strategy was based on sequencing of cloned genomic DNA fragments (previously used as RFLP probes) and subsequent screening of fungal isolates to detect single nucleotide polymorphisms (SNPs). Ten primer pairs were designed based on these sequences, which resulted in PCR amplifi...

  17. Role of Biological Control on Some Physiological Aspects of Zea mays Infected by Rhizoctonia solani

    OpenAIRE

    El-daly, Faten A.; Nahed Haikal

    2006-01-01

    The results revealed that treatment with either Trichoderma harzianum or Bacillus subtilis by soil inoculation or grain coating significantly increased the percentage of healthy seedlings as well as the length, fresh and dry weight of seedlings. Photosynthetic pigments content of the leaves significantly increased in absence of Rhizoctonia solani alone. The same almost applied to soluble sugar content, amino acid content or total nitrogen of the seedlings, though less apparent or insignifican...

  18. Silício alterando compostos derivados da pirólise de bainhas foliares de plantas de arroz infectadas por Rhizoctonia solani Silicon altering compounds derived from the pyrolyses of leaf sheaths of rice plants infected with Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Daniel Augusto Schurt

    2013-03-01

    Full Text Available Este trabalho teve como objetivo elucidar, por meio da pirólise analítica acoplada à cromatografia gasosa e espectrometria de massa, alterações na composição química da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou não com silício (Si e infectadas por Rhizoctonia solani. A concentração de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg-1 em comparação com as plantas não supridas (0,45 dag kg-1. Na presença de Si, a área abaixo da curva do progresso da queima das bainhas foi significativamente reduzida em 19 e 25%, respectivamente, para as plantas das cultivares BR-Irga-409 e Labelle em relação à ausência desse elemento na solução nutritiva. Com base nos espectros de massas obtidos, foram identificados 33 compostos, dos quais 10 foram produtos da degradação de carboidratos e 23 derivados da lignina. Dentre os derivados da lignina, oito compostos eram do tipo p-hidroxifenila, 11 compostos do tipo guaiacila e quatro compostos do tipo siringila. Nas bainhas das plantas das duas cultivares de arroz, supridas ou não com Si, a concentração de lignina (p-hidroxifenila, siringila (S e guaiacila (G foi de, aproximadamente, 15%. Houve aumento na relação S/G apenas nas bainhas das plantas da cultivar BR-Irga 409 supridas com Si e infectadas por R. solani. A maior concentração de Si nas bainhas das plantas de arroz das duas cultivares, que por sua vez resultou em aumento na relação S/G, contribuiu para reduzir os sintomas da queima das bainhas.This study elucidated, through analytical pyrolysis coupled to gas chromatography and mass spectrometry, changes in the chemical composition of lignin on leaf sheaths of rice plants of cultivars BR-Irga 409 and Labelle supplied or non-supplied with silicon (Si and infected with Rhizoctonia solani. The Si concentration on leaf sheaths of plants supplied with this element was significatively higher (2.7 dag kg-1 as compared to non-supplied plants (0.45 dag kg-1. In the presence of Si, the area under leaf sheath blight progress curve was significantly reduced by 19 and 25% for plants from cultivars BR-Irga 409 and Labelle, respectively, in comparison to the absence of Si. Based on the mass spectra obtained, 33 compounds were identified, 10 of which were products from the degradation of carbohydrates and 23 derivate from lignin. From lignin derivatives, eight compounds were p-hydroxiphenil type, eleven compounds were guaiacyl type and four compounds were syringyl type. On leaf sheaths of both cultivars, the concentration of lignin (p-hydroxiphenil, syringyl (S and guaiacyl (G was around 15%, regardless of Si. There was no increase in the S/G ratio only for the leaf sheaths of BR-Irga 409 supplied with Si and infected with R. solani. High Si concentration on leaf sheaths of both cultivars, which in turn resulted in an increase in the S/G ratio, contributed to reduce leaf sheath blight symptoms.

  19. Silício alterando compostos derivados da pirólise de bainhas foliares de plantas de arroz infectadas por Rhizoctonia solani Silicon altering compounds derived from the pyrolyses of leaf sheaths of rice plants infected with Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Daniel Augusto Schurt

    2013-01-01

    Full Text Available Este trabalho teve como objetivo elucidar, por meio da pirólise analítica acoplada à cromatografia gasosa e espectrometria de massa, alterações na composição química da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou não com silício (Si e infectadas por Rhizoctonia solani. A concentração de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg-1 em comparação com as plantas não supridas (0,45 dag kg-1. Na presença de Si, a área abaixo da curva do progresso da queima das bainhas foi significativamente reduzida em 19 e 25%, respectivamente, para as plantas das cultivares BR-Irga-409 e Labelle em relação à ausência desse elemento na solução nutritiva. Com base nos espectros de massas obtidos, foram identificados 33 compostos, dos quais 10 foram produtos da degradação de carboidratos e 23 derivados da lignina. Dentre os derivados da lignina, oito compostos eram do tipo p-hidroxifenila, 11 compostos do tipo guaiacila e quatro compostos do tipo siringila. Nas bainhas das plantas das duas cultivares de arroz, supridas ou não com Si, a concentração de lignina (p-hidroxifenila, siringila (S e guaiacila (G foi de, aproximadamente, 15%. Houve aumento na relação S/G apenas nas bainhas das plantas da cultivar BR-Irga 409 supridas com Si e infectadas por R. solani. A maior concentração de Si nas bainhas das plantas de arroz das duas cultivares, que por sua vez resultou em aumento na relação S/G, contribuiu para reduzir os sintomas da queima das bainhas.This study elucidated, through analytical pyrolysis coupled to gas chromatography and mass spectrometry, changes in the chemical composition of lignin on leaf sheaths of rice plants of cultivars BR-Irga 409 and Labelle supplied or non-supplied with silicon (Si and infected with Rhizoctonia solani. The Si concentration on leaf sheaths of plants supplied with this element was significatively higher (2.7 dag kg-1 as compared to non-supplied plants (0.45 dag kg-1. In the presence of Si, the area under leaf sheath blight progress curve was significantly reduced by 19 and 25% for plants from cultivars BR-Irga 409 and Labelle, respectively, in comparison to the absence of Si. Based on the mass spectra obtained, 33 compounds were identified, 10 of which were products from the degradation of carbohydrates and 23 derivate from lignin. From lignin derivatives, eight compounds were p-hydroxiphenil type, eleven compounds were guaiacyl type and four compounds were syringyl type. On leaf sheaths of both cultivars, the concentration of lignin (p-hydroxiphenil, syringyl (S and guaiacyl (G was around 15%, regardless of Si. There was no increase in the S/G ratio only for the leaf sheaths of BR-Irga 409 supplied with Si and infected with R. solani. High Si concentration on leaf sheaths of both cultivars, which in turn resulted in an increase in the S/G ratio, contributed to reduce leaf sheath blight symptoms.

  20. Effect of Combined Use of Bacillus subtilis CA32 and Trichoderma harzianum RU01 on Biological Control of Rhizoctonia solani on Solanum melongena and Capsicum annuum

    Directory of Open Access Journals (Sweden)

    S. Abeysinghe

    2009-01-01

    Full Text Available A combination of two compatible biological control agents, Bacillus subtilis CA32 and Trichoderma harzianum RU01, both antagonistic to the pathogen Rhizoctonia solani, was used to control damping-off in Solanum melongena and Capsicum annuum. Radial growth of the mycelium of R. solani was inhibited by T. harzianum RU01 in dual Petri plate assay. T. harzianum RU01 was capable to invading the whole surface of the pathogen colony, sporulating on it and suppress the production of sclerotia of R. solani. Microscopic studies showed the hyphae of R. solani surrounded by the T. harzianum RU01 and subsequent disintegration. B. subtilis CA32 produced a zone of inhibition only with the pathogen and no sings of antagonism between the bacteria and T. harzianum RU01 on dual Petri plate assay. Significant plant protection was achieved when either B. subtilis added to the seeds or T. harzianum added to soil. However, when combine application of biocontrol agents, seed bacterization and T. harzianum application to soil, significantly enhanced the plant protection from R. solani. Soil application of B. subtilis and seed application of T. harzianum either singly or in combination did not protect from R. solani infection indicating that the importance of mode of application of biocontrol agents.

  1. Use of Pseudomonas aeruginosa in the control od root-knot disease complex in tomato: the effects of different inoculum levels of Meloidogyne javanica and Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    I. A. Siddiqui

    2001-06-01

    Full Text Available The potential impact of Pseudomons aeruginosa strain IE-6 as a biological control agent against Meloidogyne javanica at four inoculum densities (0, 250, 500 and 1000 eggs/plant and Rhizoctonia solani at three inoeulum levels (0, 1 and 3 ml culture suspension/kg of soil was examined on tomato in the greenhouse experiments. The biocontrol bacterium suppressed root infection caused by R. solani and M. javanica on tomato in both sterilized and non-sterilized soils. Root-rot infection increased with the increase in pathogen(s concentration. P. aeruginosa showed better biocontrol effects at low population levels of M.javanica and R. solani than at higher population densities of the pathogen(s. Root-rot disease severity was more pronounced in sterilized soil compared to the non-sterilized one. Soil infested with high population densities ofR. solani (3 ml /kg of soil and M. javanica (2000 eggs/pot resulted in complete mortality of tomato seedlings in sterilized soil, whereas some plants were found to survive in non-stenlized soil. There seems to be a correlation between population density of M. javanica and root colonization by R. solani. Root colonization by other three root-infecting fungi including Macrophomina phaseolina, Fusarium oxysporum and Fusarium solani was also lower in the presence of P. aeruginosa in non-sterilized soil. P. aeruginosa enhanced plant growth in both types of soil.

  2. Particle size affects Brassica seed meal-induced pathogen suppression of Rhizoctonia solani AG-5

    Science.gov (United States)

    R. solani AG-5 is a component of the pathogen complex that incites apple replant disease, and is suppressed via multiple mechanisms in response to B. juncea seed meal (SM) amendment. Allyl isothiocyanate (AITC) functions in suppression of this pathogen during the initial 24 h period post-seed meal a...

  3. Involvement of secondary metabolites and extracellular lytic enzymes produced by Pseudomonas fluorescens in inhibition of Rhizoctonia solani, the rice sheath blight pathogen.

    Science.gov (United States)

    Nagarajkumar, M; Bhaskaran, R; Velazhahan, R

    2004-01-01

    Fourteen strains of Pseudomonas fluorescens isolated from rhizosphere soil of rice were tested for their antagonistic effect towards Rhizoctonia solani, the rice sheath blight fungus. Among them, PfMDU2 was the most effective in inhibiting mycelial growth of R. solani in vitro. Production of chitinase, beta-1,3-glucanase, siderophores, salicylic acid (SA) and hydrogen cyanide (HCN) by P. fluorescens strains was evaluated. The highest beta-1,3-glucanase activity, siderophore production, SA production and HCN production were recorded with PfMDU2. A significant relationship between the antagonistic potential of P. fluorescens against R. solani and its level of beta-1,3-glucanase, SA and HCN was observed. PMID:15160609

  4. EFFICACY OF BIOCONTROL AGENTS IN CONTROLLING RHIZOCTONIA SOLANI ON NAGA KING CHILLI ( Capsicum chinense Jacq.)

    OpenAIRE

    Marinus Ngullie; Loli Daiho

    2013-01-01

    Available biocontrol agents were evaluated either alone or in various combinations for finding out their efficacy in suppressing Rhizoctonia seedling rot incidence and promoting plant growth of Naga king chilli (Capsicum chinense Jacq.) in green house as well field conditions. Among all tested combination, the treatment containing combination of T. viride +P. fluorescens was found most effective in reducing the incidence of seedling rot in both greenhouse and field condition. Highest pe...

  5. Characterization of antagonistic-potential of two Bacillus strains and their biocontrol activity against Rhizoctonia solani in tomato.

    Science.gov (United States)

    Solanki, Manoj Kumar; Singh, Rajesh Kumar; Srivastava, Supriya; Kumar, Sudheer; Kashyap, Prem Lal; Srivastava, Alok K

    2015-01-01

    To investigate the biocontrol mechanism of two antagonistic Bacillus strains (Bacillus subtilis MB14 and Bacillus amyloliquefaciens MB101), three in vitro antagonism assays were screened and the results were concluded that both strains inhibited Rhizoctonia solani growth in a similar manner by dual culture assay, but the maximum percent of inhibition only resulted with MB101 by volatile and diffusible metabolite assays. Moreover, cell free supernatant (CFS) of MB101 also showed significant (p?>?0.05) growth inhibition as compared to MB14, when 10 and 20% CFS mix with the growth medium of R. solani. After in vitro-validation, both strains were evaluated under greenhouse and the results concluded that strain MB101 had significant biocontrol potential as compared to MB14. Strain MB101 was enhanced the plant height, biomass and chlorophyll content of tomato plant through a higher degree of root colonization. In field trials, strain MB101 showed higher lessening in root rot symptoms with significant fruit yield as compare to strain MB14 and infected control. Next to the field study, the presence of four antibiotic genes (srfAA, fenD, ituC, and bmyB) also concluded the antifungal nature of both Bacillus strains. Phylogenetic analysis of protein sequences revealed a close relatedness of three genes (srfAA, fenD, and ituC) with earlier reported sequences of B. subtilis and B. amyloliquefaciens. However, bmyB showed heterogeneity in among both strains (MB14 and MB101) and it may be concluded that higher degree of antagonism, root colonization and different antibiotic producing genes may play an important role in biocontrol mechanism of strain MB101. PMID:24277414

  6. Suscetibilidade de cultivares de algodoeiro a Rhizoctonia solani e benefícios do tratamento de sementes com fungicidas / Susceptibility of cotton cultivars to Rhizoctonia solani and benefits of fungicide seed treatment

    Scientific Electronic Library Online (English)

    Augusto César Pereira, Goulart.

    2007-09-01

    Full Text Available Este trabalho teve por objetivo avaliar o comportamento de seis cultivares de algodoeiro (BRS-Ipê, BRS-Aroeira, BRS-Cedro, Fibermax 966, DeltaOpal e CNPA Ita 90-II) ao fungo Rhizoctonia solani AG-4 e os benefícios do tratamento de sementes de algodoeiro com fungicidas para cada cultivar em estudo, e [...] m relação à densidade de inóculo deste fungo. O ensaio foi conduzido na casa de vegetação da Embrapa Agropecuária Oeste, em Dourados, MS. Foram definidas quatro densidades populacionais do fungo (0; 1; 2 e 3g de inóculo do fungo/bandeja plástica de 56x35x10cm) para a realização do ensaio. As avaliações foram realizadas com base no desenvolvimento de sintomas e sobrevivência das plântulas, utilizando os dados de emergência inicial e final e de tombamento de pós-emergência. Sementes não tratadas e tratadas com a mistura fungicida tolylfluanid + pencycuron + triadimenol (30+50+50g do i.a./100kg de sementes) foram semeadas em areia contida em bandejas plásticas, dispostas em orifícios individuais, eqüidistantes e a 3cm de profundidade. A inoculação com R. solani foi feita pela distribuição homogênea do inóculo do fungo na superfície do substrato. O fungo foi cultivado por 35 dias em sementes de aveia preta autoclavadas e trituradas em moinho (1mm). Houve efeito significativo das interações cultivares x níveis de inóculo, cultivares x fungicidas e níveis de inóculo x fungicidas. O comportamento das cultivares foi significativamente influenciado pelas diferentes populações de R. solani, sendo que, a medida que se aumentou a densidade de inóculo do patógeno, menores índices de emergência e maiores índices de doença foram observados. Ficou claramente demonstrada também a importância do tratamento das sementes de algodoeiro com fungicidas, sendo que as melhores emergências e os menores índices de doença (tombamento e plântulas lesionadas), independente da cultivar testada, foram obtidos quando as sementes foram tratadas com a mistura tolylfluanid + pencycuron + triadimenol. Observou-se ainda que as populações do patógeno influenciaram significativamente nos benefícios do tratamento de sementes, demonstrando que a performance da mistura fungicida testada (tolylfluanid + pencycuron + triadimenol) foi melhor na presença dos níveis mais baixos de inóculo do fungo. Com relação as cultivares avaliadas e na ausência do tratamento da sementes com fungicidas, observou-se comportamento diferenciado de alguns materiais com relação ao ataque do fungo R. solani, merecendo destaque os genótipos CNPA ITA 90 II E BRS Aroeira, seguidas de BRS Cedro e BRS Ipê, demonstrando uma maior tolerância destas cultivares ao ataque de R. solani em comparação às demais. Abstract in english The objective of this work was to evaluate the behavior of six cotton cultivars (BRS-Ipê, BRS-Aroeira, BRS-Cedro, Fibermax 966, DeltaOpal and CNPA Ita 90-II) in relation to Rhizoctonia solani AG-4 and the benefits of cotton seed treatment with fungicides, for each tested cultivar, for the control of [...] damping-off in relation to inoculum densities of this fungus. This experiment was carried out at greenhouse conditions at Embrapa Agropecuária Oeste, in Dourados, MS. Four inoculum densities were tested (0; 1; 2 and 3g of fungus inoculum/plastic tray with dimensions of 56x35x10cm) in the trial. The evaluations were done based on symptoms development and seedling survival, using initial and final emergence and pre and pos damping-off data. Treated and untreated seeds with fungicides mixture tolylfluanid + pencycuron + triadimenol (30+50+50g a.i./100kg of seeds) were sowed in sand contained in plastic trays, by placing in equidistant 3-cm-deep wells. The inoculation with R. solani AG-4 was done by the homogeneous distribution of the fungus inoculum onto the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill (1mm). Significant effect of the interactions cultivars x inoculum densities, cultivars x fungicides and inoculum densities

  7. Suscetibilidade de cultivares de algodoeiro a Rhizoctonia solani e benefícios do tratamento de sementes com fungicidas Susceptibility of cotton cultivars to Rhizoctonia solani and benefits of fungicide seed treatment

    Directory of Open Access Journals (Sweden)

    Augusto César Pereira Goulart

    2007-09-01

    Full Text Available Este trabalho teve por objetivo avaliar o comportamento de seis cultivares de algodoeiro (BRS-Ipê, BRS-Aroeira, BRS-Cedro, Fibermax 966, DeltaOpal e CNPA Ita 90-II ao fungo Rhizoctonia solani AG-4 e os benefícios do tratamento de sementes de algodoeiro com fungicidas para cada cultivar em estudo, em relação à densidade de inóculo deste fungo. O ensaio foi conduzido na casa de vegetação da Embrapa Agropecuária Oeste, em Dourados, MS. Foram definidas quatro densidades populacionais do fungo (0; 1; 2 e 3g de inóculo do fungo/bandeja plástica de 56x35x10cm para a realização do ensaio. As avaliações foram realizadas com base no desenvolvimento de sintomas e sobrevivência das plântulas, utilizando os dados de emergência inicial e final e de tombamento de pós-emergência. Sementes não tratadas e tratadas com a mistura fungicida tolylfluanid + pencycuron + triadimenol (30+50+50g do i.a./100kg de sementes foram semeadas em areia contida em bandejas plásticas, dispostas em orifícios individuais, eqüidistantes e a 3cm de profundidade. A inoculação com R. solani foi feita pela distribuição homogênea do inóculo do fungo na superfície do substrato. O fungo foi cultivado por 35 dias em sementes de aveia preta autoclavadas e trituradas em moinho (1mm. Houve efeito significativo das interações cultivares x níveis de inóculo, cultivares x fungicidas e níveis de inóculo x fungicidas. O comportamento das cultivares foi significativamente influenciado pelas diferentes populações de R. solani, sendo que, a medida que se aumentou a densidade de inóculo do patógeno, menores índices de emergência e maiores índices de doença foram observados. Ficou claramente demonstrada também a importância do tratamento das sementes de algodoeiro com fungicidas, sendo que as melhores emergências e os menores índices de doença (tombamento e plântulas lesionadas, independente da cultivar testada, foram obtidos quando as sementes foram tratadas com a mistura tolylfluanid + pencycuron + triadimenol. Observou-se ainda que as populações do patógeno influenciaram significativamente nos benefícios do tratamento de sementes, demonstrando que a performance da mistura fungicida testada (tolylfluanid + pencycuron + triadimenol foi melhor na presença dos níveis mais baixos de inóculo do fungo. Com relação as cultivares avaliadas e na ausência do tratamento da sementes com fungicidas, observou-se comportamento diferenciado de alguns materiais com relação ao ataque do fungo R. solani, merecendo destaque os genótipos CNPA ITA 90 II E BRS Aroeira, seguidas de BRS Cedro e BRS Ipê, demonstrando uma maior tolerância destas cultivares ao ataque de R. solani em comparação às demais.The objective of this work was to evaluate the behavior of six cotton cultivars (BRS-Ipê, BRS-Aroeira, BRS-Cedro, Fibermax 966, DeltaOpal and CNPA Ita 90-II in relation to Rhizoctonia solani AG-4 and the benefits of cotton seed treatment with fungicides, for each tested cultivar, for the control of damping-off in relation to inoculum densities of this fungus. This experiment was carried out at greenhouse conditions at Embrapa Agropecuária Oeste, in Dourados, MS. Four inoculum densities were tested (0; 1; 2 and 3g of fungus inoculum/plastic tray with dimensions of 56x35x10cm in the trial. The evaluations were done based on symptoms development and seedling survival, using initial and final emergence and pre and pos damping-off data. Treated and untreated seeds with fungicides mixture tolylfluanid + pencycuron + triadimenol (30+50+50g a.i./100kg of seeds were sowed in sand contained in plastic trays, by placing in equidistant 3-cm-deep wells. The inoculation with R. solani AG-4 was done by the homogeneous distribution of the fungus inoculum onto the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill (1mm. Significant effect of the interactions cultivars x inoculum densities, cultivars x fungicides and inoculum densities x fungicides were oberved. The cultivars beh

  8. Caracterização citomorfológica, cultural, molecular e patogênica de Rhizoctonia solani Kühn associado ao arroz em Tocantins, Brasil / Citomorphological, cultural, molecular and pathogenical characterization of Rhizoctonia solani Kühn associated with rice in Tocantins, Brazil

    Scientific Electronic Library Online (English)

    Elaine Costa, Souza; Eiko Eurya, Kuramae; Andreia Kazumi, Nakatani; Marco Antonio, Basseto; Anne Sitarana, Prabhu; Paulo Cezar, Ceresini.

    2007-06-01

    Full Text Available No Estado do Tocantins, no Norte do Brasil, a incidência de rizoctoniose no arroz é importante, causando danos significativos em lavouras de arroz irrigado. O principal objetivo deste trabalho foi determinar o grupo de anastomose (AG) de isolados de R. solani associados ao arroz naquela região, test [...] ando a hipótese de que esses isolados pertencem ao grupo padrão de anastomose AG-1 IA, que também é o agente causal da mela em soja em áreas úmidas do Norte do Brasil. Todos os quatro isolados de arroz foram caracterizados, através de fusão de hifas, como AG-1 IA. A caracterização cultural, em função das temperaturas basais (mínimas, máximas e ótimas), evidenciou que os isolados de R. solani de arroz apresentaram perfis semelhantes aos padrões AG-1 IA, AG-1 IB e AG-1 IC. Os isolados de arroz foram caracterizados como autotróficos para tiamina assim como os isolados padrões AG-1 IA, IB, IC, AG-4 HGI e o isolado da mela da soja. O teste de patogenicidade em plantas de arroz cultivar IRGA-409 e de patogenicidade cruzada à cultivar IAC-18 de soja (suscetível à mela), indicou que além de causar a queima da bainha em arroz, esses isolados causam mela em soja. Da mesma forma, o isolado SJ-047 foi patogênico ao arroz. As seqüências de bases de DNA da região ITS-5.8S do rDNA dos isolados do arroz foram similares às seqüências do AG-1 IA, depositadas no GenBank® - NCBI. A filogenia do ITS-rDNA indicou um grupo filogenético comum formado pelos isolados do arroz, o isolado da soja e o isolado teste do AG-1 IA. Assim, com base em características citomorfológicas, culturais, filogenéticas e patogênicas, foi confirmada a hipótese de que os isolados de R. solani patógenos de arroz do Estado do Tocantins pertencem ao grupo de anastomose AG-1 IA, além da indicação de que esses isolados podem também causar a mela em soja. Abstract in english In Tocantins State, Northern Brazil, the incidence of Rhizoctonia sheath blight on rice is important, causing significant yield losses on rice crops under irrigation. The main objective of this research was to determine the anastomosis group (AG) of R. solani associated with rice in that area, testi [...] ng the hypothesis that these isolates are from the AG-1 IA, which is also associated with the soybean leaf blight occurring in wet areas of Northern Brazil. All the four rice isolates were characterized, by hyphal fusion, as AG-1 IA. By cultural characterization, based on basal temperatures for mycelial growth (minimum, optimum and maximum), the rice isolates had growth profile similar to the tester isolates AG-1 IA, AG-1 IB and AG-1 IC. The rice isolates were characterized as autotrophic for thiamine, as well as the AG testers AG-1 IA, IB, IC, AG-4 HGI and the soybean leaf blight isolate SJ-047. The pathogenicity test on rice IRGA-409 and the cross pathogenicity on soybean IAC-18 (susceptible to the leaf blight disease) indicated that, besides causing sheath blight, these rice isolates also cause leaf blight on soybean. Similarly, the soybean isolates SJ-047 was pathogenic to rice. The sequences from the ITS-5.8S region of rDNA from the rice isolates were similar to sequences of AG-1 IA deposited at GenBank® - NCBI. The ITS-rDNA phylogeny indicated a common phylogenetic group formed by these rice isolates, the isolate SJ-047 and the tester AG-1 IA. Thus, based on cytomorphological, cultural, phylogenetics and pathogenic attributes, the hypothesis that the rice isolates of R. solani from Tocantins all belong to the AG-1 IA was confirmed, besides the indication that these isolates can also cause soybean foliar blight.

  9. Lippia graveolens and Carya illinoensis Organic Extracts and there in vitro Effect Against Rhizoctonia Solani Kuhn

    Directory of Open Access Journals (Sweden)

    Francisco D. Hernandez-Castillo

    2010-01-01

    Full Text Available Problem statement: Plant extracts with polyphenolic compounds obtained with different solvents have been evaluated against plant pathogens. However, most of these extract have been obtained using solvents no allowed under an organic production context. Approach: In the present research was to evaluate the inhibitory effect of polyphenolic extracts from L. graveolens and C. illinoensis, obtained with alternative organic solvents (lanolin and cocoa butter, water and ethanol against R. solani in order to determine the Inhibitory Concentration (IC50 of each extract. Results: The results showed that extracts of both L. graveolens and C. illinoensis obtained with lanolin and ethanol (200 and 3000 ppm of total tannins, respectively inhibited at 100% growth of R. solani. The IC50 for each extract was highly variable, low IC50 values were obtained with L. graveolens (4.50×101 and C. illinoensis (4.33×102 extract using lanolin and ethanol respectively. Tannins extraction was strongly dependent on plant species and in the solvent used. Conclusion: The alternative organic solvents lanolin and cocoa butter allowed the recovery of polyphenols compounds with antifungal activity against R. solani.

  10. Interplay between parasitism and host ontogenic resistance in the epidemiology of the soil-borne plant pathogen Rhizoctonia solani.

    Science.gov (United States)

    Simon, Thomas E; Le Cointe, Ronan; Delarue, Patrick; Morlière, Stéphanie; Montfort, Françoise; Hervé, Maxime R; Poggi, Sylvain

    2014-01-01

    Spread of soil-borne fungal plant pathogens is mainly driven by the amount of resources the pathogen is able to capture and exploit should it behave either as a saprotroph or a parasite. Despite their importance in understanding the fungal spread in agricultural ecosystems, experimental data related to exploitation of infected host plants by the pathogen remain scarce. Using Rhizoctonia solani / Raphanus sativus as a model pathosystem, we have obtained evidence on the link between ontogenic resistance of a tuberizing host and (i) its susceptibility to the pathogen and (ii) after infection, the ability of the fungus to spread in soil. Based on a highly replicable experimental system, we first show that infection success strongly depends on the host phenological stage. The nature of the disease symptoms abruptly changes depending on whether infection occurred before or after host tuberization, switching from damping-off to necrosis respectively. Our investigations also demonstrate that fungal spread in soil still depends on the host phenological stage at the moment of infection. High, medium, or low spread occurred when infection was respectively before, during, or after the tuberization process. Implications for crop protection are discussed. PMID:25127238

  11. Phylogeography of the Solanaceae-infecting Basidiomycota fungus Rhizoctonia solani AG-3 based on sequence analysis of two nuclear DNA loci

    Directory of Open Access Journals (Sweden)

    Vilgalys Rytas J

    2007-09-01

    Full Text Available Abstract Background The soil fungus Rhizoctonia solani anastomosis group 3 (AG-3 is an important pathogen of cultivated plants in the family Solanaceae. Isolates of R. solani AG-3 are taxonomically related based on the composition of cellular fatty acids, phylogenetic analysis of nuclear ribosomal DNA (rDNA and beta-tubulin gene sequences, and somatic hyphal interactions. Despite the close genetic relationship among isolates of R. solani AG-3, field populations from potato and tobacco exhibit comparative differences in their disease biology, dispersal ecology, host specialization, genetic diversity and population structure. However, little information is available on how field populations of R. solani AG-3 on potato and tobacco are shaped by population genetic processes. In this study, two field populations of R. solani AG-3 from potato in North Carolina (NC and the Northern USA; and two field populations from tobacco in NC and Southern Brazil were examined using sequence analysis of two cloned regions of nuclear DNA (pP42F and pP89. Results Populations of R. solani AG-3 from potato were genetically diverse with a high frequency of heterozygosity, while limited or no genetic diversity was observed within the highly homozygous tobacco populations from NC and Brazil. Except for one isolate (TBR24, all NC and Brazilian isolates from tobacco shared the same alleles. No alleles were shared between potato and tobacco populations of R. solani AG-3, indicating no gene flow between them. To infer historical events that influenced current geographical patterns observed for populations of R. solani AG-3 from potato, we performed an analysis of molecular variance (AMOVA and a nested clade analysis (NCA. Population differentiation was detected for locus pP89 (?ST = 0.257, significant at P ST = 0.034, not significant. Results based on NCA of the pP89 locus suggest that historical restricted gene flow is a plausible explanation for the geographical association of clades. Coalescent-based simulations of genealogical relationships between populations of R. solani AG-3 from potato and tobacco were used to estimate the amount and directionality of historical migration patterns in time, and the ages of mutations of populations. Low rates of historical movement of genes were observed between the potato and tobacco populations of R. solani AG-3. Conclusion The two sisters populations of the basidiomycete fungus R. solani AG-3 from potato and tobacco represent two genetically distinct and historically divergent lineages that have probably evolved within the range of their particular related Solanaceae hosts as sympatric species.

  12. Silício alterando compostos derivados da pirólise de bainhas foliares de plantas de arroz infectadas por Rhizoctonia solani / Silicon altering compounds derived from the pyrolyses of leaf sheaths of rice plants infected with Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Daniel Augusto, Schurt; Fabrício Ávila, Rodrigues; Vivian, Carré-Missio; Nilda Fátima Ferreira, Soares.

    2013-03-01

    Full Text Available Este trabalho teve como objetivo elucidar, por meio da pirólise analítica acoplada à cromatografia gasosa e espectrometria de massa, alterações na composição química da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou não com silício (Si) e infectadas por Rhiz [...] octonia solani. A concentração de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg-1) em comparação com as plantas não supridas (0,45 dag kg-1). Na presença de Si, a área abaixo da curva do progresso da queima das bainhas foi significativamente reduzida em 19 e 25%, respectivamente, para as plantas das cultivares BR-Irga-409 e Labelle em relação à ausência desse elemento na solução nutritiva. Com base nos espectros de massas obtidos, foram identificados 33 compostos, dos quais 10 foram produtos da degradação de carboidratos e 23 derivados da lignina. Dentre os derivados da lignina, oito compostos eram do tipo p-hidroxifenila, 11 compostos do tipo guaiacila e quatro compostos do tipo siringila. Nas bainhas das plantas das duas cultivares de arroz, supridas ou não com Si, a concentração de lignina (p-hidroxifenila, siringila (S) e guaiacila (G)) foi de, aproximadamente, 15%. Houve aumento na relação S/G apenas nas bainhas das plantas da cultivar BR-Irga 409 supridas com Si e infectadas por R. solani. A maior concentração de Si nas bainhas das plantas de arroz das duas cultivares, que por sua vez resultou em aumento na relação S/G, contribuiu para reduzir os sintomas da queima das bainhas. Abstract in english This study elucidated, through analytical pyrolysis coupled to gas chromatography and mass spectrometry, changes in the chemical composition of lignin on leaf sheaths of rice plants of cultivars BR-Irga 409 and Labelle supplied or non-supplied with silicon (Si) and infected with Rhizoctonia solani. [...] The Si concentration on leaf sheaths of plants supplied with this element was significatively higher (2.7 dag kg-1) as compared to non-supplied plants (0.45 dag kg-1). In the presence of Si, the area under leaf sheath blight progress curve was significantly reduced by 19 and 25% for plants from cultivars BR-Irga 409 and Labelle, respectively, in comparison to the absence of Si. Based on the mass spectra obtained, 33 compounds were identified, 10 of which were products from the degradation of carbohydrates and 23 derivate from lignin. From lignin derivatives, eight compounds were p-hydroxiphenil type, eleven compounds were guaiacyl type and four compounds were syringyl type. On leaf sheaths of both cultivars, the concentration of lignin (p-hydroxiphenil, syringyl (S) and guaiacyl (G)) was around 15%, regardless of Si. There was no increase in the S/G ratio only for the leaf sheaths of BR-Irga 409 supplied with Si and infected with R. solani. High Si concentration on leaf sheaths of both cultivars, which in turn resulted in an increase in the S/G ratio, contributed to reduce leaf sheath blight symptoms.

  13. Biochemical changes in the mycelium of two Rhizoctonia solani isolates during autolysis

    Directory of Open Access Journals (Sweden)

    M. N. Reddy

    1988-12-01

    Full Text Available Some biochemical changes occurring in the mycelium of two isolates (one pathogenic FR and another non-pathogenic GD2 of R. solani during autolytic phase of their growth were studied, by growing the fungi for periods longer than 210 days. During autolysis a decrease of 76.4% and 78.5% in mycelial dry weight occurred in pathogenic and non-pathogenic isolates respectively, compared to that at the beginning of autolysis. The mycelium of non-pathogenic isolate was more affected during autolytic phase of growth than that of the pathogenic isolate.

  14. EFFICACY OF BIOCONTROL AGENTS IN CONTROLLING RHIZOCTONIA SOLANI ON NAGA KING CHILLI ( Capsicum chinense Jacq.

    Directory of Open Access Journals (Sweden)

    Marinus Ngullie

    2013-07-01

    Full Text Available Available biocontrol agents were evaluated either alone or in various combinations for finding out their efficacy in suppressing Rhizoctonia seedling rot incidence and promoting plant growth of Naga king chilli (Capsicum chinense Jacq. in green house as well field conditions. Among all tested combination, the treatment containing combination of T. viride +P. fluorescens was found most effective in reducing the incidence of seedling rot in both greenhouse and field condition. Highest per plant yield was also recorded from the same combination and it was followed by T. viride. However, the commercially available fungicide Copper oxychloride (0.1% showed 9.82 % and11.88% disease incidence in greenhouse and field condition respectively

  15. Bioprospecção de isolados de Trichoderma spp. para o controle de Rhizoctonia solani na produção de mudas de pepino / Bioprospection of Trichoderma spp. isolates to control Rhizoctonia solani on cucumber seedling production

    Scientific Electronic Library Online (English)

    Cleusa Maria Mantovanello, Lucon; Claudia Mitsue, Koike; Alice Ishida, Ishikawa; Flávia Rodrigues Alves, Patrício; Ricardo, Harakava.

    2009-03-01

    Full Text Available O objetivo deste trabalho foi selecionar e identificar isolados de Trichoderma spp. para o controle do tombamento causado por Rhizoctonia solani (AG-4) em plântulas de pepino (Cucumis sativus L.), além de avaliar o efeito de concentrações crescentes e de combinações dos isolados mais eficientes no c [...] ontrole da doença. Os experimentos foram conduzidos em casa de vegetação, com 490 isolados. O tombamento das mudas foi avaliado uma semana após a aplicação à base das plântulas de substrato infestado com antagonista (1%) e patógeno (1%). Os doze isolados que proporcionaram mais de 85% de redução da doença foram testados em concentrações crescentes para o controle do patógeno (1%): 0,5, 1, 2, 3 e 4%. Também foi avaliado o efeito das combinações dos cinco isolados mais promissores. Os isolados mais efetivos foram identificados pelo sequenciamento da região espaçadores internos transcritos (ITS) do DNA ribossômico. Dos 490 isolados testados 44 (9%) reduziram o tombamento. As concentrações de antagonistas superiores a 2% foram as mais efetivas no controle da doença. Apenas duas combinações resultaram no aumento do controle da doença. Os isolados mais efetivos foram identificados como T. hamatum (IB08, IB30, IB60), T. harzianum (IB34, IB35), T. atroviride (IB13), T. spirale (IB16, IB24) e T. asperellum (IB44). Não foi possível a identificação da espécie de três isolados. Abstract in english The objective of this work was to select and identify Trichoderma spp. isolates for the control of Rhizoctonia solani (AG-4) damping-off on cucumber (Cucumis sativus L.) seedlings, as well as to evaluate the effects of increasing concentrations and different combinations of the most efficient isolat [...] es in the disease control. The experiments were carried out in a greenhouse with 490 isolates. The disease on cucumber seedlings was evaluated one week after the application of a commercial substrate infested with both antagonist (1%) and pathogen (1%) to the seedlings' root collar. The twelve isolates that conferred more than 85% of disease reduction were further evaluated in pathogen control (1%) at the concentrations 0.5, 1, 2, 3 and 4%. The effect of combining five of the most promising isolates in disease control was also evaluated. The most effective isolates were identified through the sequencing of the ribosomal internal transcribed spacers (ITS) region. Out of the 490 isolates tested 44 (9%) caused reduction of damping-off. Antagonist concentrations higher than 2% conferred the most effective disease control. Only two combinations of isolates resulted in increased disease control. The most effective isolates were identified as T. hamatum (IB08, IB30, IB60), T. harzianum (IB34, IB35), T. atroviride (IB13), T. spirale (IB16, IB24) and T. asperellum (IB44). Three isolates could not be identified at species level.

  16. Bioprospecção de isolados de Trichoderma spp. para o controle de Rhizoctonia solani na produção de mudas de pepino Bioprospection of Trichoderma spp. isolates to control Rhizoctonia solani on cucumber seedling production

    Directory of Open Access Journals (Sweden)

    Cleusa Maria Mantovanello Lucon

    2009-03-01

    Full Text Available O objetivo deste trabalho foi selecionar e identificar isolados de Trichoderma spp. para o controle do tombamento causado por Rhizoctonia solani (AG-4 em plântulas de pepino (Cucumis sativus L., além de avaliar o efeito de concentrações crescentes e de combinações dos isolados mais eficientes no controle da doença. Os experimentos foram conduzidos em casa de vegetação, com 490 isolados. O tombamento das mudas foi avaliado uma semana após a aplicação à base das plântulas de substrato infestado com antagonista (1% e patógeno (1%. Os doze isolados que proporcionaram mais de 85% de redução da doença foram testados em concentrações crescentes para o controle do patógeno (1%: 0,5, 1, 2, 3 e 4%. Também foi avaliado o efeito das combinações dos cinco isolados mais promissores. Os isolados mais efetivos foram identificados pelo sequenciamento da região espaçadores internos transcritos (ITS do DNA ribossômico. Dos 490 isolados testados 44 (9% reduziram o tombamento. As concentrações de antagonistas superiores a 2% foram as mais efetivas no controle da doença. Apenas duas combinações resultaram no aumento do controle da doença. Os isolados mais efetivos foram identificados como T. hamatum (IB08, IB30, IB60, T. harzianum (IB34, IB35, T. atroviride (IB13, T. spirale (IB16, IB24 e T. asperellum (IB44. Não foi possível a identificação da espécie de três isolados.The objective of this work was to select and identify Trichoderma spp. isolates for the control of Rhizoctonia solani (AG-4 damping-off on cucumber (Cucumis sativus L. seedlings, as well as to evaluate the effects of increasing concentrations and different combinations of the most efficient isolates in the disease control. The experiments were carried out in a greenhouse with 490 isolates. The disease on cucumber seedlings was evaluated one week after the application of a commercial substrate infested with both antagonist (1% and pathogen (1% to the seedlings' root collar. The twelve isolates that conferred more than 85% of disease reduction were further evaluated in pathogen control (1% at the concentrations 0.5, 1, 2, 3 and 4%. The effect of combining five of the most promising isolates in disease control was also evaluated. The most effective isolates were identified through the sequencing of the ribosomal internal transcribed spacers (ITS region. Out of the 490 isolates tested 44 (9% caused reduction of damping-off. Antagonist concentrations higher than 2% conferred the most effective disease control. Only two combinations of isolates resulted in increased disease control. The most effective isolates were identified as T. hamatum (IB08, IB30, IB60, T. harzianum (IB34, IB35, T. atroviride (IB13, T. spirale (IB16, IB24 and T. asperellum (IB44. Three isolates could not be identified at species level.

  17. Control del mal de los almácigos causado por Rhizoctonia solani y Sclerotium rolfsii con caldos de cebolla / Control of seedling damping off caused by Rhizoctonia solani and Sclerotium rolfsii using onion broths

    Scientific Electronic Library Online (English)

    MC, Rivera; ER, Wright; MC, Fabrizio; G, Freixá; R, Cabalini; SE, Lopez.

    2013-12-01

    Full Text Available El mal de los almácigos causa muerte de plántulas. Los controles cultural y biológico constituyen las únicas herramientas orgánicas para su manejo. Acerca de la eficiencia de preparaciones vegetales, sólo se encuentra información de divulgación. Este trabajo evalúa el efecto de caldos fermentados de [...] cebolla sobre el crecimiento de Rhizoctonia solani y Sclerotium rolfsii y la incidencia de la enfermedad. Se obtuvieron caldo (B) y caldo esterilizado (SB), respectivamente, mediante hervido de trozos de cebollas y fermentación a temperatura ambiente, con o sin esterilización posterior. Se cultivaron los patógenos en APG suplementado con B y SB diluidos 1,7; 3,3; 8,3; 16,7 y 25%. Su crecimiento decreció con B al 8,3, 16,7 y 25%. La producción de esclerocios por S. rolfsii disminuyó con B, pero aumentó con SB. Penicillium purpurogenum, P. simplicissimum y Aspergillus niger aislados de B evidenciaron antibiosis, competencia e hiperparasitismo respecto de ambos patógenos. B y SB diluidos 10 y 50% fueron aplicados en almácigos de acelga (Beta vulgaris), tomate (Solanum lycopersicum), pimiento (Capsicum annuum) y berenjena (Solanum melongena) infestados. La pérdida de plántulas fue menor en el tratamiento con B al 50%, en relación al tratamiento con SB. Se concluye que la actividad antifúngica de B depende de su dilución y de su micota. La utilización de caldos de cebolla debería ser contemplada como alternativa para el manejo fitosanitario de bajo impacto ambiental. Se requiere continuar los estudios para completar el conocimiento acerca de los componentes químicos y microbiológicos de los caldos, y sus posibles cambios durante la fermentación. Abstract in english Damping off is a frequent disease that kills seedlings. Cultural and biological controls are the only tools in organic crops to manage this disease, and only empirical information is available on the eficiency of plant preparations. This work evaluates the effects of fermented onion decoctions on th [...] e growth of Rhizoctonia solani and Sclerotium rolfsii and disease incidence. Broth (B) and sterilized broth (SB) were respectively obtained by boiling chopped yellow onions in water, and incubating for 14 days at room temperature, with or without subsequent sterilization. The pathogens were grown on potato dextrose agar supplemented with B and SB, diluted at 1.7, 3.3, 8.3, 16.7 and 25% (v/v). Their growth was reduced by B at 8.3, 16.7 and 25%. Production of sclerotia by S. rolfsii was diminished by B, but stimulated by SB. Penicillium purpurogenum, P. simplicissimum and Aspergillus niger obtained from B behaved as antagonistic against both pathogens, showing antibiosis, competition and hyperparasitism in dual confrontations with them. Broth and SB at 10 and 50% dilutions were sprayed on chard (Beta vulgaris), tomato (Solanum lycopersicum), pepper (Capsicum annuum) and eggplant (Solanum melongena) seedlings cultivated in pathogen-colonized soil. Damping of incidence in the B treatment at 50% dilution was markedly lower than that in SB. It is concluded that B antifungal activity depends on its dilution and mycota. Broth sprays should be considered as a tool to control damping of in low-environment-impact crop production. Further studies are needed for a complete understanding of B chemical and microbiological components, as well as their changes during fermentation.

  18. The Interaction Pattern between a Homology Model of 40S Ribosomal S9 Protein of Rhizoctonia solani and 1-Hydroxyphenaize by Docking Study

    OpenAIRE

    Seema Dharni; Sanchita; Abdul Samad; Ashok Sharma; Dharani Dhar Patra

    2014-01-01

    1-Hydroxyphenazine (1-OH-PHZ), a natural product from Pseudomonas aeruginosa strain SD12, was earlier reported to have potent antifungal activity against Rhizoctonia solani. In the present work, the antifungal activity of 1-OH-PHZ on 40S ribosomal S9 protein was validated by molecular docking approach. 1-OH-PHZ showed interaction with two polar contacts with residues, Arg69 and Phe19, which inhibits the synthesis of fungal protein. Our study reveals that 1-OH-PHZ can be a potent inhibitor of ...

  19. Effect of successive cauliflower plantings and Rhizoctonia solani AG 2-1 inoculations on disease suppressiveness of a suppressive and a conducive soil

    OpenAIRE

    Postma, J.; Scheper, R. W. A.; Schilder, M. T.

    2010-01-01

    Disease suppressiveness against Rhizoctonia solani AG 2-1 in cauliflower was studied in two marine clay soils with a sandy loam texture. The soils had a different cropping history. One soil had a long-term (40 years) cauliflower history and was suppressive, the other soil was conducive and came from a pear orchard not having a cauliflower crop for at least 40 years. These two soils were subjected to five successive cropping cycles with cauliflower or remaining fallow in a greenhouse experimen...

  20. Transcriptome analysis of the phytopathogenic fungus Rhizoctonia solani AG1-IB 7/3/14 applying high-throughput sequencing of expressed sequence tags (ESTs).

    Science.gov (United States)

    Wibberg, Daniel; Jelonek, Lukas; Rupp, Oliver; Kröber, Magdalena; Goesmann, Alexander; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas

    2014-01-01

    Rhizoctonia solani is a soil-borne plant pathogenic fungus of the phylum Basidiomycota. It affects a wide range of agriculturally important crops and hence is responsible for economically relevant crop losses. Transcriptome analysis of the bottom rot pathogen R. solani AG1-1B (isolate 7/3/14) by applying high-throughput sequencing and bioinformatics methods addressing Expressed Sequence Tag (EST) data interpretation provided new insights in expressed genes of this fungus. Two normalized cDNA libraries representing different cultivation conditions of the fungus were sequenced on the 454 FLX (Roche) system. Subsequent to cDNA sequence assembly and quality control, ESTs were analysed applying advanced bioinformatics methods. More than 14?000 transcript isoforms originating from approximately 10?000 predictable R. solani AG1-IB 7/3/14 genes are represented in each dataset. Comparative analyses revealed several differentially expressed genes depending on the growth conditions applied. Determinants with predicted functions in recognition processes between the fungus and the host plant were identified. Moreover, many R. solani AG1-IB ESTs were predicted to encode putative cellulose, pectin, and lignin degrading enzymes. Furthermore, genes playing a possible role in mitogen-activated protein (MAP) kinase cascades, 4-aminobutyric acid (GABA) metabolism, melanin synthesis, plant defence antagonism, phytotoxin, and mycotoxin synthesis were detected. PMID:25209639

  1. Effect of Trichoderma harzianum biomass and Bradyrhizobium sp. strain NC 92 to control leaf blight disease of bambara groundnut (Vigna subterranea caused by Rhizoctonia solani in the field

    Directory of Open Access Journals (Sweden)

    Mana Kanjanamaneesathian

    2007-01-01

    Full Text Available Four hundred and sixty two strains of Trichoderma spp. were isolated from 23 soil samples in which groundnut (Arachis hypogaea L. and bambara groundnut (Vigna subterranea L. had been planted in Songkhla, Phattalung, Nakhon Si Thammarat, Narathiwat and Yala provinces. These fungi were tested against Rhizoctonia solani, a causal agent of leaf blight of bambara groundnut, using dual culture technique on PDA medium. Among 462 isolates tested, 226 isolates had an ability to overgrow R. solani completely. Further testing found 13 isolates having the ability to parasitize mycelia of R. solani. Among these isolates, ThB-1-54 produced a cellulolytic enzyme on congo-red agar. This isolate was later identified as T. harzianum Rifai. In the field test, applying biomass of the isolate ThB-1-54 cultured on ground mesocarp fiber of oil palm, the combination of the isolate ThB-1-54 on ground mesocarp fiber of oil palm and Bradyrhizobium sp. (strain NC 92, or fungicide (iprodione had no effect on disease severity, yield, or the amount of total nitrogen content in stems or seeds of bambara groundnut plant.

  2. Rice oxalate oxidase gene driven by green tissue-specific promoter increases tolerance to sheath blight pathogen (Rhizoctonia solani) in transgenic rice.

    Science.gov (United States)

    Molla, Kutubuddin A; Karmakar, Subhasis; Chanda, Palas K; Ghosh, Satabdi; Sarkar, Sailendra N; Datta, Swapan K; Datta, Karabi

    2013-12-01

    Rice sheath blight, caused by the necrotrophic fungus Rhizoctonia solani, is one of the most devastating and intractable diseases of rice, leading to a significant reduction in rice productivity worldwide. In this article, in order to examine sheath blight resistance, we report the generation of transgenic rice lines overexpressing the rice oxalate oxidase 4 (Osoxo4) gene in a green tissue-specific manner which breaks down oxalic acid (OA), the pathogenesis factor secreted by R.?solani. Transgenic plants showed higher enzyme activity of oxalate oxidase (OxO) than nontransgenic control plants, which was visualized by histochemical assays and sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Transgenic rice leaves were more tolerant than control rice leaves to exogenous OA. Transgenic plants showed a higher level of expression of other defence-related genes in response to pathogen infection. More importantly, transgenic plants exhibited significantly enhanced durable resistance to R.?solani. The overexpression of Osoxo4 in rice did not show any detrimental phenotypic or agronomic effect. Our findings indicate that rice OxO can be utilized effectively in plant genetic manipulation for sheath blight resistance, and possibly for resistance to other diseases caused by necrotrophic fungi, especially those that secrete OA. This is the first report of the expression of defence genes in rice in a green tissue-specific manner for sheath blight resistance. PMID:23809026

  3. Suppression subtractive hybridization and comparative expression of a pore-forming toxin and glycosyl hydrolase genes in Rhizoctonia solani during potato sprout infection.

    Science.gov (United States)

    Chamoun, Rony; Samsatly, Jamil; Pakala, Suman B; Cubeta, Marc A; Jabaji, Suha

    2015-06-01

    Rhizoctonia solani is a plant pathogenic fungus that causes black scurf on tubers and stem and stolon canker on underground parts of potato plant. Early in the season, the fungus attacks germinating sprouts underground before they emerge from the soil. Damage at this stage results in delayed emergence of weakened plants with poor and uneven stands. The mechanism underlying this phenomenon has been investigated in this study by coupling a cDNA-suppression subtractive hybridization (SSH) library to differential screening to identify transcripts of R. solani that are down-regulated during infection of potato sprouts. We report on the identification of 33 unique genes with functions related to carbohydrate binding, vitamin synthesis, pathogenicity, translation, ATP and nucleic acid binding and other categories. RACE-PCR was used to clone and characterize the first full-length cDNA clones, RSENDO1 and RSGLYC1 that encode for an eukaryotic delta-endotoxin CytB protein and an intracellular glycosyl hydrolase, respectively. Quantitative real-time PCR revealed the down-regulation of RSENDO1 during infection of potato sprouts and the up-regulation of RSGLYC1 when the fungus was grown on a cellulose-based nutrient medium. In contrast, additional experiments have highlighted the down-regulation of RSENDO1 when R. solani was co-cultured with the mycoparasite Stachybotrys elegans and the bacterial antagonist Bacillus subtilis B26. These results advance our understanding of R. solani-potato interaction in subterranean parts of the plant. Such approaches could be considered in building an efficient integrated potato disease management program. PMID:25472038

  4. Associação de Rhizoctonia solani Grupo de Anastomose 4 (AG-4 HGI e HGIII) à espécies de plantas invasoras de área de cultivo de batata / Rhizoctonia solani anastomosis group 4 (AG-4 HGI and HGIII) associated with weed species from a potato cropping area

    Scientific Electronic Library Online (English)

    Fátima Aparecida da, Silva-Barreto; Wagner Vicente, Pereira; Maisa Boff, Ciampi; Marcos Paz Saraiva, Câmara; Paulo Cezar, Ceresini.

    2010-06-01

    Full Text Available Os grupos 3 e 4 de anastomose (AG-3 e AG-4) do fungo Rhizoctonia solani são importantes grupos associados à batata no mundo. No Brasil, o AG-3 é relatado afetando principalmente batata e fumo. Já o AG-4 causa perdas consideráveis em culturas de importância econômica, como a soja, o feijão e o amendo [...] im, podendo ocorrer também em hortaliças como o espinafre, o pimentão, o brócolis, o tomate, a batata e frutíferas como o melão. Recentemente foi constatada, em Brasília-DF, a associação de R. solani a plantas invasoras em áreas de cultivo de batata. Entretanto, não há informação a respeito da etiologia do patógeno bem como do papel de espécies invasoras como outras hospedeiras no ciclo do patógeno. Objetivou-se com esse estudo caracterizar isolados de R. solani obtidos de batata e de outras três espécies de plantas invasoras associadas a áreas de cultivo da cultura: juá-de-capote [Nicandra physaloides (L.) Pers., Solanaceae], beldroega (Portulaca oleracea L., Portulacaceae), e caruru (Amaranthus deflexus L., Amaranthaceae). Foi confirmada a hipótese de que os isolados obtidos de R. solani de beldroega, caruru e juá-de-capote pertencem ao grupo 4 de anastomose e são patogênicos à batata, exceto o isolado de beldroega. Estes isolados apresentaram patogenicidade cruzada às três espécies e também patogênicos à maria-pretinha (Solanum americanum Mill.), uma outra espécie de Solanaceae invasora. A classificação dos isolados no grupo AG-4 HGI ou no grupo AG-4 HGIII (isolado de caruru) foi confirmada através de características culturais e moleculares (seqüenciamento da região ITS-5.8S do rDNA). Os resultados deste trabalho trazem implicações importantes para o manejo das podridões radiculares de Rhizoctonia em batata. Abstract in english The anastomosis groups 3 and 4 (AG-3 and AG-4) of the fungus Rhizoctonia solani are important groups associated with potatoes worldwide. In Brazil, the AG-3 is reported affecting mainly potatoes and tobacco. The AG-4 cause considerable losses in crops of economic importance, such as soybean, beans a [...] nd peanuts and may also occur in vegetables such as spinach, pepper, broccoli, tomatoes, potatoes and fruit such as melons. The association of R. solani with invasive plants was recently established in potato production areas from Brasília, DF. However, there is no information about the etiology of the pathogen as well as the role of invasive species as alternative hosts in the life cycle of the pathogen. The objective of this study was to characterize isolates of R. solani obtained from potatoes and three other invasive plant species associated with areas of potato production: Shoo-fly plant [Nicandra physaloides (L.) Pers., Solanaceae], pigweed (Portulaca oleracea L., Portulacaceae), and low-amaranth (Amaranthus deflexus L., Amaranthaceae). It was confirmed the hypothesis that the R. solani isolates obtained from pigweed, low-amaranth and Shoo-fly plant belong to the anastomosis group 4 and, except for the isolate from pigweed, are pathogenic to potatoes. These isolates were cross pathogencic to all the three weed species tested and also to American nightshade (Solanum americanum Mill.), another Solanaceae invasive of potato fields. The placement of the isolates in the group AG-4 HGI or in the group AG-4 HGIII (isolate from caruru) was confirmed by cultural and molecular characteristics (sequencing of the ITS-5.8S region of rDNA). The results of this study provide important implications for the management of the Rhizoctonia root rot in potatoes.

  5. Associação de Rhizoctonia solani Grupo de Anastomose 4 (AG-4 HGI e HGIII à espécies de plantas invasoras de área de cultivo de batata Rhizoctonia solani anastomosis group 4 (AG-4 HGI and HGIII associated with weed species from a potato cropping area

    Directory of Open Access Journals (Sweden)

    Fátima Aparecida da Silva-Barreto

    2010-06-01

    Full Text Available Os grupos 3 e 4 de anastomose (AG-3 e AG-4 do fungo Rhizoctonia solani são importantes grupos associados à batata no mundo. No Brasil, o AG-3 é relatado afetando principalmente batata e fumo. Já o AG-4 causa perdas consideráveis em culturas de importância econômica, como a soja, o feijão e o amendoim, podendo ocorrer também em hortaliças como o espinafre, o pimentão, o brócolis, o tomate, a batata e frutíferas como o melão. Recentemente foi constatada, em Brasília-DF, a associação de R. solani a plantas invasoras em áreas de cultivo de batata. Entretanto, não há informação a respeito da etiologia do patógeno bem como do papel de espécies invasoras como outras hospedeiras no ciclo do patógeno. Objetivou-se com esse estudo caracterizar isolados de R. solani obtidos de batata e de outras três espécies de plantas invasoras associadas a áreas de cultivo da cultura: juá-de-capote [Nicandra physaloides (L. Pers., Solanaceae], beldroega (Portulaca oleracea L., Portulacaceae, e caruru (Amaranthus deflexus L., Amaranthaceae. Foi confirmada a hipótese de que os isolados obtidos de R. solani de beldroega, caruru e juá-de-capote pertencem ao grupo 4 de anastomose e são patogênicos à batata, exceto o isolado de beldroega. Estes isolados apresentaram patogenicidade cruzada às três espécies e também patogênicos à maria-pretinha (Solanum americanum Mill., uma outra espécie de Solanaceae invasora. A classificação dos isolados no grupo AG-4 HGI ou no grupo AG-4 HGIII (isolado de caruru foi confirmada através de características culturais e moleculares (seqüenciamento da região ITS-5.8S do rDNA. Os resultados deste trabalho trazem implicações importantes para o manejo das podridões radiculares de Rhizoctonia em batata.The anastomosis groups 3 and 4 (AG-3 and AG-4 of the fungus Rhizoctonia solani are important groups associated with potatoes worldwide. In Brazil, the AG-3 is reported affecting mainly potatoes and tobacco. The AG-4 cause considerable losses in crops of economic importance, such as soybean, beans and peanuts and may also occur in vegetables such as spinach, pepper, broccoli, tomatoes, potatoes and fruit such as melons. The association of R. solani with invasive plants was recently established in potato production areas from Brasília, DF. However, there is no information about the etiology of the pathogen as well as the role of invasive species as alternative hosts in the life cycle of the pathogen. The objective of this study was to characterize isolates of R. solani obtained from potatoes and three other invasive plant species associated with areas of potato production: Shoo-fly plant [Nicandra physaloides (L. Pers., Solanaceae], pigweed (Portulaca oleracea L., Portulacaceae, and low-amaranth (Amaranthus deflexus L., Amaranthaceae. It was confirmed the hypothesis that the R. solani isolates obtained from pigweed, low-amaranth and Shoo-fly plant belong to the anastomosis group 4 and, except for the isolate from pigweed, are pathogenic to potatoes. These isolates were cross pathogencic to all the three weed species tested and also to American nightshade (Solanum americanum Mill., another Solanaceae invasive of potato fields. The placement of the isolates in the group AG-4 HGI or in the group AG-4 HGIII (isolate from caruru was confirmed by cultural and molecular characteristics (sequencing of the ITS-5.8S region of rDNA. The results of this study provide important implications for the management of the Rhizoctonia root rot in potatoes.

  6. Surface motility in Pseudomonas sp DSS73 is required for efficient biological containment of the root-pathogenic microfungi Rhizoctonia solani and Pythium ultimum

    DEFF Research Database (Denmark)

    Andersen, Jens Bo; Koch, Birgit

    2003-01-01

    Pseudomonas sp. DSS73 was isolated from the rhizoplane of sugar beet seedlings. This strain exhibits antagonism towards the root-pathogenic microfungi Pythium ultimum and Rhizoctonia solani. Production of the cyclic lipopeptide amphisin in combination with expression of flagella enables the growing bacterial culture to move readily over the surface of laboratory media. Amphisin is a new member of a group of dual-functioning compounds such as tensin, viscosin and viscosinamid that display both biosurfactant and antifungal properties. The ability of DSS73 to efficiently contain root-pathogenic microfungi is shown to arise from amphisin-dependent surface translocation and growth by which the bacterium can lay siege to the fungi. The synergistic effects of surface motility and synthesis of a battery of antifungal compounds efficiently contain and terminate growth of the microfungi.

  7. Efeitos de materiais orgânicos e da umidade do solo na patogenicidade de Rhizoctonia solani Kühn GA-4 HGI ao feijoeiro The role of the organic material amended and the soil moisture on the pathogenicity of Rhizoctonia solani Kühn AG-4 HGI in snap bean

    Directory of Open Access Journals (Sweden)

    Roseli Chela Fenille

    1999-10-01

    Full Text Available Foram avaliados, em casa de vegetação, os efeitos das seguintes variáveis sobre a patogenicidade de Rhizoctonia solani GA-4 HGI a plantas de feijão (Phaseolus vulgaris L., em solo artificialmente infestado: presença de materiais orgânicos com diferentes relações C:N (torta de mamona e bagaço de cana; níveis de decomposição da matéria orgânica, e condições de umidade do solo incorporado. A umidade do solo até o momento da semeadura foi mantida sob duas condições: 20% ou acima de 80% da capacidade de campo. Foram realizadas semeaduras aos 0, 7, 14, 21, 28 e 35 dias após inoculação e incorporação. As avaliações foram realizadas 14 dias após cada semeadura. O material com baixa relação C:N propiciou o aumento da incidência de R. solani no feijoeiro, enquanto o material com alta relação C:N não interferiu na incidência do patógeno. A incidência de R. solani no feijoeiro, em solo incorporado, foi independente da condição de umidade.The pathogenicity of Rhizoctonia solani AG-4 HGI on bean (Phaseolus vulgaris L. plants was evaluated, in artificially infested soil under greenhouse conditions, when submitted to the following treatments: amendments with different C:N ratios (castor-oil cake and sugar-cane bagasse; different organic matter decomposition levels; different moisture contents of the amended soil. Until the moment of sowing the soil moisture was maintained at 20% of the moisture-holding capacity or above 80%. The sowings were made at 0, 7, 14, 21, 28 and 35 days after the inoculation and amendments incorporation. Evaluations were carried out 14 days after each sowing date. The amendment with low C:N ratio increased the incidence of R. solani on bean plants, in any decomposition level, whereas the amendment with high C:N ratio did not interfere on the incidence of the pathogen. The incidence of R. solani on bean plants, in a soil amended with both castor-oil cake or sugar-cane bagasse, was independent of the soil moisture condition.

  8. Eficiência de diferentes moléculas na redução dos sintomas da queima das bainhas em arroz e no crescimento de Rhizoctonia solani in vitro Efficiency of different molecules on the reduction of sheath blight symptoms in rice and on Rhizoctonia solani growth in vitro

    Directory of Open Access Journals (Sweden)

    Daniel Augusto Schurt

    2013-04-01

    Full Text Available Este estudo verificou a eficiência da aplicação de diferentes moléculas em reduzir o comprimento relativo da lesão (CRL da queima das bainhas em arroz. Plantas dos cultivares BR-Irga 409 e Labelle foram cultivadas em solução nutritiva e inoculadas com Rhizoctonia solani, no estádio de máximo perfilhamento. Às 24 horas antes da inoculação, as bainhas das plantas foram pulverizadas com soluções de silicato de potássio (SP, silicato de potássio + fósforo (SP+F, Acibenzolar-S-Metil (ASM, fungicida Carbendazim, quitosana desacetilada (QD, etileno (ET e fosfito de potássio (FP. Plantas cujas bainhas foram pulverizadas com água destilada serviram como testemunhas. O efeito das moléculas contidas nesses produtos no crescimento micelial de R. solani foi testado in vitro. Para BR-Irga 409, o CRL foi menor com a aplicação do FP, em relação aos demais tratamentos, exceto o Carbendazim. A aplicação do Carbendazim reduziu em 86,1% o CRL, em relação à testemunha. O CRL foi significativamente menor no cultivar BR-Irga 409 do que no 'Labelle', com aplicação do FP. O crescimento micelial de R. solani foi reduzido apenas pelo FP e Carbendazim, em comparação com os demais tratamentos. Não houve diferença significativa entre os tratamentos testemunha, SP e SP+F para a concentração de Si nas bainhas das plantas dos dois cultivares.This study aimed to test the efficiency of different molecules on the reduction of the relative lesion extension (RLE of sheath blight in rice. Plants of cultivars BR-Irga 409 and Labelle were grown in nutrient solution and inoculated with Rhizoctonia solani at the maximum tillering stage. At 24 hours before inoculation, sheaths of plants were sprayed with solutions of potassium silicate (PS, potassium silicate + phosphorus (PS+P, Acibenzolar-S-Methyl (ASM, Carbendazim fungicide, deacetylated chitosan (DC, ethylene (ET and potassium phosphite (PP. Sheaths from plants sprayed with water served as the control treatment. The effect of these products on R. solani mycelia growth was also studied in vitro. For BR-Irga 409, the RLE was lower with the application of PP compared with the other treatments, except the Carbendazim. The application of Carbendazim reduced in 86.1% the RLE in comparison with the control. The RLE was lower for BR-Irga 409 than for Labell with the application of PP. Mycelia growth of R. solani was inhibited only by PP and Carbendazim in comparison with the other treatments. There was no significant difference among the treatments control, PS, and PS+P for silicon concentration on sheaths of plants of the two cultivars.

  9. Eficiência de diferentes moléculas na redução dos sintomas da queima das bainhas em arroz e no crescimento de Rhizoctonia solani in vitro / Efficiency of different molecules on the reduction of sheath blight symptoms in rice and on Rhizoctonia solani growth in vitro

    Scientific Electronic Library Online (English)

    Daniel Augusto, Schurt; Fabrício Ávila, Rodrigues; Naiara Fernandes Abreu, Souza; Ricardo Dutra, Reis.

    2013-04-01

    Full Text Available Este estudo verificou a eficiência da aplicação de diferentes moléculas em reduzir o comprimento relativo da lesão (CRL) da queima das bainhas em arroz. Plantas dos cultivares BR-Irga 409 e Labelle foram cultivadas em solução nutritiva e inoculadas com Rhizoctonia solani, no estádio de máximo perfil [...] hamento. Às 24 horas antes da inoculação, as bainhas das plantas foram pulverizadas com soluções de silicato de potássio (SP), silicato de potássio + fósforo (SP+F), Acibenzolar-S-Metil (ASM), fungicida Carbendazim, quitosana desacetilada (QD), etileno (ET) e fosfito de potássio (FP). Plantas cujas bainhas foram pulverizadas com água destilada serviram como testemunhas. O efeito das moléculas contidas nesses produtos no crescimento micelial de R. solani foi testado in vitro. Para BR-Irga 409, o CRL foi menor com a aplicação do FP, em relação aos demais tratamentos, exceto o Carbendazim. A aplicação do Carbendazim reduziu em 86,1% o CRL, em relação à testemunha. O CRL foi significativamente menor no cultivar BR-Irga 409 do que no 'Labelle', com aplicação do FP. O crescimento micelial de R. solani foi reduzido apenas pelo FP e Carbendazim, em comparação com os demais tratamentos. Não houve diferença significativa entre os tratamentos testemunha, SP e SP+F para a concentração de Si nas bainhas das plantas dos dois cultivares. Abstract in english This study aimed to test the efficiency of different molecules on the reduction of the relative lesion extension (RLE) of sheath blight in rice. Plants of cultivars BR-Irga 409 and Labelle were grown in nutrient solution and inoculated with Rhizoctonia solani at the maximum tillering stage. At 24 ho [...] urs before inoculation, sheaths of plants were sprayed with solutions of potassium silicate (PS), potassium silicate + phosphorus (PS+P), Acibenzolar-S-Methyl (ASM), Carbendazim fungicide, deacetylated chitosan (DC), ethylene (ET) and potassium phosphite (PP). Sheaths from plants sprayed with water served as the control treatment. The effect of these products on R. solani mycelia growth was also studied in vitro. For BR-Irga 409, the RLE was lower with the application of PP compared with the other treatments, except the Carbendazim. The application of Carbendazim reduced in 86.1% the RLE in comparison with the control. The RLE was lower for BR-Irga 409 than for Labell with the application of PP. Mycelia growth of R. solani was inhibited only by PP and Carbendazim in comparison with the other treatments. There was no significant difference among the treatments control, PS, and PS+P for silicon concentration on sheaths of plants of the two cultivars.

  10. Potencial antifúngico de cepas de Bacillusspp. y extracto de Larrea tridentatacontra Rhizoctonia solanien el cultivo de la papa (Solanum tuberosum L.) / Antifungal potential of Bacillus spp. strains and Larrea tridentata extract against Rhizoctonia solani on potato (Solanum tuberosum L.) crop

    Scientific Electronic Library Online (English)

    FD, Hernández-Castillo; RH, Lira-Saldivar; L, Cruz-Chávez; G, Gallegos-Morales; Me, Galindo-Cepeda; E, Padrón-Corral; M, Hernández-Suárez.

    2008-12-01

    Full Text Available El cultivo de papa en México es el que más funguicidas requiere para prevenir y controlar diversas enfermedades, estimándose que en este cultivo se aplican el 21,3% del total de los funguicidas disponibles. Los pesticidas sintéticos se destinan principalmente para combatir los hongos Phytophthora in [...] festans y Rhizoctonia solani. Esto trae como consecuencia severos daños a la salud y a los ecosistemas; es por eso que existe la necesidad de encontrar nuevas opciones para el manejo sustentable de los patógenos que atacan a este cultivo. Se realizaron investigaciones en condiciones de laboratorio, invernadero y campo con los siguientes objetivos (1) analizar el efecto antifúngico de tres cepas de bacterias del género Bacillus (B3, B9 y B15) contra R. solani, así como su efecto promotor del crecimiento en plantas de papa, (2) determinar el efecto de un extracto resinoso obtenido de hojas de Larrea tridentata contra el hongo R. solani, y (3) establecer si existe un efecto sinérgico al mezclar las cepas de Bacillus con el extracto de L. tridentata. Los resultados indicaron que las cepas bacterianas tuvieron una clara actividad antifúngica, al igual que el extracto de L. tridentata. Las cepas de Bacillus sobresalieron además por su efecto estimulador del crecimiento de las plantas y del rendimiento de papa, así como por el efecto sinérgico al mezclar las bacterias con el extracto de Larrea; un efecto potenciador similar se observó al aplicar la mezcla de las cepas. Los resultados obtenidos con las cepas de Bacillus, así como su mezcla con el extracto de L. tridentata son alentadores. Los mismos sugieren que podrían ser utilizados para apoyar programas de control biológico contra R. solani. Sin embargo, es necesario continuar con más trabajos in vivo para validar estos resultados. Abstract in english Potato crop requires more fungicides than any other crop in Mexico to prevent and control several diseases. More than 21,3% of the total available fungicides are required for cropping potato. High quantities of synthetic pesticides are intended to control Phytophthora infestans and Rhizoctonia solan [...] i fungi. As a result, this produces severe health problems and ecosystem disturbances. There is then an urgent need for finding new options for sustainable management of potato crop diseases. Several experiments were conducted under laboratory, greenhouse, and field conditions, to: (1) analyze the antifungal effect of bacteria strains of the genus Bacillus, and their effect on potato plant growth; (2) determine the effect of a resinous extract from Larrea tridentata leaves against the fungus R. solani, and (3) establish if there is a synergic effect when Bacillus spp. are mixed with L. tridentata extract. Results indicate an antifungal effect of bacterial strains and Larrea extract. Bacillus strains also stimulated plant growth and yield increase. A synergic effect was detected when Bacillus spp. were mixed with Larrea extract; a similar outcome occurred with the mixture of B3, B9 and B15 strains. Results obtained with Bacillus and Larrea, as well as with their mixture are encouraging since they could be used as an organic option for biological control programs against the fungus R. solani. However, more in vivo research is necessary to validate these results.

  11. Rhizoctonia solani AG-3PT is the major pathogen associated with potato stem canker and black scurf in Colombia / Rhizoctonia solani GA-3PT es el principal patógeno asociado con el chancro del tallo y la sarna negra de la papa en Colombia

    Scientific Electronic Library Online (English)

    Rosa Lilia, Ferrucho; Johan Manuel, Cifuentes; Paulo, Ceresini; Celsa, García-Domínguez.

    2012-08-01

    Full Text Available El chancro del tallo y la sarna negra de la papa son ocasionados por el hongo basidiomicete Thanatephorus cucumeris (especie anamórfica compleja Rhizoctonia solani). Estas dos enfermedades tienen una distribución global en los cultivos de papa, pero su etiología local es variable, dependiendo de la [...] predominancia de diferentes grupos de anastomosis (GA s) en una localidad dada. Al interior de esta especie compleja se han encontrado varios GA s asociados con el chancro del tallo y la sarna negra, como GA -1, GA -2-1, GA -2-2, GA -3, GA -4, GA -5 y GA -9. Este artículo presenta el estudio más exhaustivo a nivel poblacional realizado en Colombia sobre la distribución de los GA s de R. solani en lotes comerciales de papa. Se examinaron 433 aislamientos colectados entre 2005 y 2009 en las regiones paperas más importantes del país. Los aislamientos fueron asignados a los GA s por PCR usando cebadores específicos para el GA -3 y secuenciamiento del ITS -ADNr e interacciones hifales. El GA -3PT cubrió la mayoría de los aislamientos (88.45%), el GA -2-1 tuvo el 2.54% y los aislamientos restantes correspondieron a cepas binucleadas de R. solani (GA -A, -E, y -I). Las pruebas de patogenicidad sobre diferentes especies de plantas, incluida la papa, evidenciaron que el GA -3PT afecta los tallos de las plantas de la familia Solanácea; en otros hospedantes evaluados el daño fue severo en las raíces pero no en los tallos; el GA -2-1 ocasionó chancros en tallos de plántulas de Solanum tuberosum cv. Capiro y R. raphanistrumi and B. campestris subsp. Rapa, y pudrición de raíces en otras plantas. Los resultados de nuestro estudio indican que el GA -3PT de R. solani es el principal patógeno asociado con las enfermedades del chancro del tallo y la sarna negra de la papa en Colombia Abstract in english Stem canker and black scurf diseases of potatoes are caused by the basidiomycetous fungus Thanatephorus cucumeris (anamorphic species complex Rhizoctonia solani). These diseases have worldwide distribution wherever potato is grown but their etiology varies depending on the predominance of distinct R [...] . solani anastomosis groups (AG s) in a particular area. Within the species complex, several AG s have been associated with stem canker or black scurf diseases, including AG -1, AG -2-1, AG -2-2, AG -3, AG -4, AG -5 and AG -9. This article reports on the most comprehensive population-based study, providing evidence on the distribution of R. solani AG s in Colombian potato fields. A total of 433 isolates were sampled from the main potato cropping areas in Colombia from 2005 to 2009. Isolates were assigned to AG s by conventional PCR assays using specific primers for AG -3, sequencing of the ITS -rDNA and hyphal interactions. Most of the isolates evaluated were assigned to AG -3PT (88.45%), and a few to AG -2-1 (2.54%). The remaining isolates were binucleate Rhizoctonia (AG -A, E, and I). Pathogenicity tests on the stems and roots of different plant species, including the potato, showed that AG -3PT affects the stems of solanaceous plants. In other plant species, damage was severe in the roots, but not the stems. AG -2-1 caused stem canker of Solanum tuberosum cv. Capiro and in R. raphanistrumi and B.campestris subsp. Rapa plantlets and root rot in other plants. The results of our study indicated that R. solani AG -3PT was the principal pathogen associated with potato stem canker and black scurf diseases of potatoes in Colombia

  12. In vitro antifungal activities of extracts of fruits and other morphological parts of xanthium strumarium against the plant pathogen, rhizoctonia solani

    International Nuclear Information System (INIS)

    In vitro antifungal activity of different plant parts of Xanthium strumarium (Compositae) was investigated against Rhizoctonia solani to seek safe natural alternatives to the harmful synthetic fungicides. The most active plant parts of X. strumarium were seeds, extracted with n-hexane and the leaves, extracted with absolute ethanol. The two treatments resulted in growth inhibition diameters of 45 mm and 47 mm, respectively. The value of MIC lied between 350.0 and 175.0 mg of Xanthium oil/mL. Gas liquid chromatography of the seed oil of X. strumarium revealed the presence of the usual fatty acids, palmitoleic (7.6%), oleic (21.6%) and linoleic (70.4%). The oil was separated into free fatty acids fraction and unsaponifiable matter fraction. The unsaponifiable matter fraction was separated on TLC, out of six separated compounds, two were active against R. solani. The infrared spectra (FTIR) of these two purified compounds pointed to a long chain hydrocarbon back-bone for both, one of them possessing in addition, an alcoholic moiety. (author)

  13. Bacillomycin L and surfactin contribute synergistically to the phenotypic features of Bacillus subtilis 916 and the biocontrol of rice sheath blight induced by Rhizoctonia solani.

    Science.gov (United States)

    Luo, Chuping; Zhou, Huafei; Zou, Jincheng; Wang, Xiaoyu; Zhang, Rongsheng; Xiang, Yaping; Chen, Zhiyi

    2015-02-01

    The antagonistic activity of lipopeptides in Bacillus subtilis 916 has been well documented, yet relatively little is known about their mechanism in biofilm formation and environmental colonization. This study sought to examine the interaction of B. subtilis 916 on Rhizoctonia solani-infected rice sheath to elucidate the mechanism of colonization on plant leaves. Results showed that the mutants ?bac, ?srf, and ?srf?+?bac of B. subtilis 916, deficient in bacillomycin L and surfactin production, respectively, not only altered colony morphology but also changed swarming motility, reduced antagonistic activity, and decreased biofilm formation. In particular, biofilm formation in mutant ?bac, not ?srf or ?srf?+?bac, were restored with addition of surfactin and bacillomycin L at 10 and 50 ?g/mL, respectively. Moreover, surfactin and bacillomycin L were able to restore or enhance swarming motility in the corresponding mutants at 10 ?g/mL, respectively. With the aid of green fluorescent protein tagging, it was demonstrated that B. subtilis 916 formed a robust biofilm on the rice sheath blight lesion and colonized well on R. solani-infected rice sheath, while its corresponding mutants performed poorly. These observations also correlated with the rice cultivar pot experiments, in which B. subtilis 916 exhibited greater biocontrol than its mutants. Our results suggest that surfactin and bacillomycin L contribute differently but synergistically to the biocontrol of rice sheath blight in B. subtilis 916 through its antifungal activity, biofilm formation, and colonization. PMID:25398282

  14. Antagonistic Potentials of Rhizosphere-associated Bacterial Isolates Against Soil-borne Diseases of Tomato and Pepper Caused by Sclerotinia sclerotiorum and Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Soner Soylu

    2005-01-01

    Full Text Available By use of selective media, putative antagonist bacterial isolates were isolated from rhizosphere-associated soils from different parts of the Amik plain. Isolates to be tested were chosen in approximate proportion to their abundance on the plates. Selected 113 bacterial isolates were screened for in vitro antagonism towards two important soil-borne root infecting plant pathogens, Sclerotinia sclerotiorum and Rhizoctonia solani by using dual culture test. From this test, significant numbers of bacterial isolates, but not the yeast, were found to produce inhibition zones by inhibiting the hyphal growth of fungal pathogens to a varying degree. On the basis of the result obtained from the preliminary screening test, isolates belonging to Bacillus spp. and Pseudomonas spp. found to be highly efficient against fungal pathogens used in the experiment. Among the inhibitory isolates, bacterial isolates AKB50 and AFP104 significantly suppressed hyphal growth of S. sclerotiorum and R. solani by 75.3 and 83.3%, respectively. This study indicates that selected bacterial strain have potential for controlling of soil-borne disease agents.

  15. Distinctively variable sequence-based nuclear DNA markers for multilocus phylogeography of the soybean- and rice-infecting fungal pathogen Rhizoctonia solani AG-1 IA

    Scientific Electronic Library Online (English)

    Maisa B., Ciampi; Liane Rosewich, Gale; Eliana G. de Macedo, Lemos; Paulo C., Ceresini.

    Full Text Available A series of multilocus sequence-based nuclear DNA markers was developed to infer the phylogeographical history of the Basidiomycetous fungal pathogen Rhizoctonia solani AG-1 IA infecting rice and soybean worldwide. The strategy was based on sequencing of cloned genomic DNA fragments (previously used [...] as RFLP probes) and subsequent screening of fungal isolates to detect single nucleotide polymorphisms (SNPs). Ten primer pairs were designed based on these sequences, which resulted in PCR amplification of 200-320 bp size products and polymorphic sequences in all markers analyzed. By direct sequencing we identified both homokaryon and heterokaryon (i.e. dikaryon) isolates at each marker. Cloning the PCR products effectively estimated the allelic phase from heterokaryotic isolates. Information content varied among markers from 0.5 to 5.9 mutations per 100 bp. Thus, the former RFLP codominant probes were successfully converted into six distinctively variable sequence-based nuclear DNA markers. Rather than discarding low polymorphism loci, the combination of these distinctively variable anonymous nuclear markers would constitute an asset for the unbiased estimate of the phylogeographical parameters such as population sizes and divergent times, providing a more reliable species history that shaped the current population structure of R. solani AG-1 IA.

  16. Biocontrol of Rhizoctonia solani damping-off and promotion of tomato plant growth by endophytic actinomycetes isolated from native plants of Algerian Sahara.

    Science.gov (United States)

    Goudjal, Yacine; Toumatia, Omrane; Yekkour, Amine; Sabaou, Nasserdine; Mathieu, Florence; Zitouni, Abdelghani

    2014-01-20

    Thirty-four endophytic actinomycetes were isolated from the roots of native plants of the Algerian Sahara. Morphological and chemical studies showed that twenty-nine isolates belonged to the Streptomyces genus and five were non-Streptomyces. All isolates were screened for their in vitro antifungal activity against Rhizoctonia solani. The six that had the greatest pathogen inhibitory capacities were subsequently tested for their in vivo biocontrol potential on R. solani damping-off in sterilized and non-sterilized soils, and for their plant-growth promoting activities on tomato seedlings. In both soils, coating tomato seeds with antagonistic isolates significantly reduced (Pdiamide, tetramethylthiram (TMTD) and no significant differences (P<0.05) were observed. Furthermore, they resulted in a significant increase in the seedling fresh weight, the seedling length and the root length of the seed-treated seedlings compared to the control. The taxonomic position based on 16S rDNA sequence analysis and phylogenetic studies indicated that the strains CA-2 and AA-2 were related to Streptomyces mutabilis NBRC 12800(T) (100% of similarity) and Streptomyces cyaneofuscatus JCM 4364(T) (100% of similarity), respectively. PMID:23920229

  17. Compositional variability and antifungal potentials of ocimum basilicum, O. tenuiflorum, O. gratissimum and O. kilimandscharicum essential oils against Rhizoctonia solani and Choanephora cucurbitarum.

    Science.gov (United States)

    Padalia, Rajendra C; Verma, Ram S; Chauhan, Amit; Goswami, Prakash; Chanotiya, Chandan S; Saroj, Arvind; Samad, Abdul; Khaliq, Abdul

    2014-10-01

    The composition of hydrodistilled essential oils of Ocimum basilicum L. (four chemovariants), O. tenuiflorum L., O. gratissimum L., and O. kilimandscharicum Guerke were analyzed and compared by using capillary gas chromatography (GC/FID) and GC-mass spectrometry (GC/MS). Phenyl propanoids (upto 87.0%) and monoterpenoids (upto 83.3%) were prevalent constituents distributed in the studied Ocimum taxa. The major constituents of the four distinct chemovariants of O. basilicum were methyl chavicol (86.3%), methyl chavicol (61.5%)/linalool (28.6%), citral (65.9%); and linalool (36.1%)/citral (28.8%). Eugenol (66.5% and 78.0%) was the major constituent of O. tenuiflorum and O. gratissimum. Eugenol (34.0%), ?-bisabolene (15.4%), (E)-?-bisabolene (10.9%), methyl chavicol (10.2%) and 1,8-cineole (8.2%) were the major constituents of O. kilimandscharicum. In order to explore the potential for industrial use, the extracted essential oils were assessed for their antifungal potential through poison food technique against two phytopathogens, Rhizoctonia solani and Choanephora cucurbitarum, which cause root and wet rot diseases in various crops. O. tenuiflorum, O. gratissimum, and O. kilimandscharicum exhibited complete growth inhibition against R. solani and C. cucurbitarum after 24 and 48 h of treatment. O. basilicum chemotypes showed variable levels of growth inhibition (63.0%-100%) against these two phytopathogens. PMID:25522548

  18. Impact of Gamma Irradiation Stresses II. Control of Sugarbeet Pathogens Rhizoctonia solani Kuhn and Sclerotium rolfsii Sacc.

    Directory of Open Access Journals (Sweden)

    Tarek A. A. Moussa

    2003-01-01

    Full Text Available To control the fungal pathogens attacked sugarbeet plant, we subjected R. solani and S. rolfsii to different gamma irradiation doses (0.0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 and 7.0 kGy for R. solani and 0.0, 0.5, 1.0, 2.0, 3.0 and 4.0 kGy for S. rolfsii. The growth activities of R. solani were completely inhibited at dose 7.0 kGy, while S. rolfsii at 4.0 kGy. The infection percentage was inhibited with gamma irradiation doses increased for both R. solani and S. rolfsii. This was confirmed by the SDS-PAGE for cellular proteins of both R. solani and S. rolfsii, which showed a great variation in protein bands for the same fungus at different gamma irradiation doses. Finally, we can conclude that the gamma irradiation dose to control pathogenic fungi varies with different pathogenic fungi to control the pathogenicity of R. solani, we irradiate it at 7.0 kGy dose while at 4.0 kGy for S. rolfsii.

  19. Efeito da solarização do solo, seguida pela aplicação de Trichoderma spp: ou de fungicidas, sobre o controle de Pythium aphanidermatum e de Rhizoctonia solani AG-4 / Effect of soil solarization, followed or not by the application of Trichoderma spp: or fungicides for the control of Pythium aphanidermatum and Rhizoctonia solani AG-4

    Scientific Electronic Library Online (English)

    Flávia Rodrigues Alves, Patrício; Hiroshi, Kimati; João, Tessarioli Neto; Ademir, Petenatti; Benedito Camargo, Barros.

    2007-06-01

    Full Text Available O presente trabalho foi realizado com o objetivo de estudar alternativas para a desinfestação de solos, especialmente considerando a retirada do brometo de metila do mercado. Avaliou-se o efeito da solarização do solo, seguida ou não pela aplicação de isolados de Trichoderma spp. ou de fungicidas, s [...] obre o controle de Pythium aphanidermatum e de Rhizoctonia solani AG-4, responsáveis por tombamento e podridão de raízes em várias culturas. Dois experimentos foram realizados em Piracicaba, SP (latitude 22º 42' e longitude 47º38'), um em campo aberto e outro no interior de uma casa-de-vegetação vedada, em delineamento em blocos casualizados, em esquema fatorial (2x3), tendo como fatores a solarização (com e sem) e os tratamentos (com fungicida, um isolado de Trichoderma sp. e uma testemunha). Bolsas de náilon contendo solo naturalmente infestado com P. aphanidermatum ou solo contendo propágulos de R. solani AG-4 foram enterradas a 10 cm de profundidade, em parcelas solarizadas ou não, nos dois ambientes. Após 30 dias de solarização, as bolsas foram coletadas e o solo infestado com P. aphanidermatum recebeu os tratamentos: o isolado de Trichoderma sp. IB-26 ou o fungicida metalaxyl + mancozeb. O solo contendo propágulos de R. solani foi tratado com o isolado de Trichoderma sp. IB-17 ou o fungicida pencycuron. As soluções dos fungicidas foram aplicadas na forma de rega. Também foram mantidas testemunhas para ambos os patógenos. Avaliou-se a viabilidade de P. aphanidermatum pelo tombamento de pós-emergência de plântulas de pepino e de R. solani pelo número de plântulas de rabanete sobreviventes ao tombamento de pré e pós-emergência. A solarização, o controle biológico e a solarização seguida pelo controle biológico não promoveram o controle de P. aphanidermatum, obtido apenas com metalaxyl + mancozeb, nos solos solarizados ou não. A solarização aplicada nos dois ambientes controlou R. solani, assim como o fungicida pencycuron, mas não houve efeito sinérgico na associação entre as técnicas. A aplicação do isolado de Trichoderma sp. IB-17 não proporcionou o controle desse patógeno nos solos solarizados ou não. Abstract in english The development of alternative strategies for soil desinfestation with methyl bromide is necessary since the use of this compound faces increasing restrictions worldwide. Therefore the effect of soil solarization, followed by the application of isolates of Trichoderma spp. or fungicides, was evaluat [...] ed for the control of Pythium aphanidermatum and Rhizoctonia solani, both can cause damping-off and root rots of several crops. Two experiments were carried out, one under greenhouse conditions and the other one under field conditions, both in a randomized block design, in factorial scheme (2x3), involving the combination of soil solarization (solarized and non-solarized soils) and the application of chemical or biological treatments, plus controls. Nylon bags containing soil naturally infested with P. aphanidermatum or soil with propagules of R. solani AG-4 were buried at 10 cm soil depth in plots solarized or non-solarized. After 30 days of solarization the bags were collected and the soil infested with P. aphanidermatum was treated with Trichoderma sp. (isolate IB-26) or with the fungicide metalaxyl + mancozeb, whereas the soil containing propagules of R. solani received an isolate of Trichoderma sp. (isolate IB-17) or the fungicide pencycuron. Fungicide suspensions were irrigated over the soil. A control was maintained for the soils infested with both pathogens. Viability of P. aphanidermatum and R. solani was evaluated by post-emergence damping-off of cucumber seedlings and by pre and post-emergence damping-off of radish seedling, respectively. Soil solarization, the biological treatment and the association of both treatments had no effect on the control of P. aphanidermatum, which was achieved only by the treatment with metalaxyl + mancozeb in the solarized and non-solarized soil. Soil solarization applied in both en

  20. Respuesta al glifosato de un aislamiento de Rhizoctonia solani agente causal del anublo de la vaina del arroz, y de cuatro aislamientos de Trichoderma, bajo condiciones in vitro In vitro response of one isolate of Rhizoctonia solani, the pathogen of the rice sheath blight and four isolates of Trichoderma to glyphosate

    Directory of Open Access Journals (Sweden)

    Vargas de Álvarez Amparo

    2002-08-01

    Full Text Available El añublo de la vaina del arroz (Orysa saliva L., cuyo agente causal es Rhizoctonia solani Kuhn, es una de las enfermedades más importantes en el cultivo del arroz en Colombia. En los cultivos de arroz con frecuencia se aplica glifosato ((ácido N-(fosfonometil glicina para controlar las malezas, particularmente el arroz rojo (O. saliva, antes de la siembra del arroz. Observaciones de campo anteriores parecían indicar relación entre el uso intensivo del glifosato y el incremento en la incidencia del añublo de la vaina del arroz. Por tanto, se propuso el presente trabajo con el fin de dilucidar los posibles efectos del glifosato sobre R. solani y Trichoderma sp., conocido éste como antagonista de R. solani. Se determinó, bajo condiciones de laboratorio, el efecto del glifosato en el crecimiento, en medio líquido y sólido PDA, de R. solani y de Trichoderma. Se encontró que la dosis más alta de glifosato sin efecto detrimental sobre R. solani, fue de 300 mg/L y la dosis más baja del herbicida que
    causó la mayor inhibición del crecimiento del hongo fue
    de 2500 mg/L. Por otra parte, no se encontró que el glifosato
    estimulara el crecimiento de R. solani. En teoría, en una aplicación comercial de glifosato de 1,5 Kg ia/ha y asperjando directamente al suelo sin vegetación, el glifosato en el suelo estaría a una concentración de 0,75 mg/Kg de suelo (suponiendo que la capa arable de una hectárea de suelo pesa 2.000.000 de Kg; por tanto, la concentración de glifosato después de una aplicación comercial, está muy por debajo de la concentración a la cual se inicia la reducción del crecimiento de R. solani. Por su parte, la respuesta de Trichoderma al glifosato fue similar a la de R. solani; además, se encontró que el glifosato no afecta la capacidad antagonista de Trichoderma sobre R. sotaní. Estos resultados no apoyan la hipótesis que el glifosato, bajo las condiciones de uso en cultivos de arroz para el control de las malezas, estuviera afectando el crecimiento de R. solani o de su antagonista Trichoderma. Una posible relación entre el uso intensivo del herbicida y la incidencia del añublo de la vaina del arroz, debería investigarse en términos de supervivencia
    y germinación de esclerocios del patógeno.
    Rhizoctonia solani Kuhn is the causal agent ofthe sheath
    blight of rice (Orysa saliva L., one of the most important
    rice diseases in Colombia. G1yphosate (N-phosphonomethyl
    glicine acid is sprayed in rice fields as a preplant herbicide, specially aimed at red rice (O. saliva. Preliminary field observations in Tolima, Colombia suggested a relationship between intensive use of glyphosate and sheath blight incidence. Thus, the present study was undertaken to shed light on the effect of glyphosate on R. solani and Thrichoderma sp., a.putative antagonist, under laboratory conditions. The effect of the herbicide was assessed on the growth ofR. solani in summerged culture and solid media and of Thrichoderma on solid media. R. sotaní withstood up to 300 mg L-! without expressing reduction in growth, Increasing concentrations of the herbicide caused growth reduction, and the detrimental effect reached a plateau at 2500 mg L-1. Rhizoctonia growth was not enhanced at any herbicide concentration. The expected concentration of glyphosate in the soil after spraying at commercial dosages would be O, 75 mg Kg', which is well below the observed in vitro threshold. The response of Thrichoderma was similar to that of R. sotaní. Glyphosate did not affect the antagonistic ability of Thrichoderma against R. solani. These results do not support the view that glyphosate, as an herbicide treatment in rice
    field, may affect in any way the population densities of R.
    sotaní or its antagonist Thrichoderma sp. Therefore, the
    postulated connection between intensive herbicide use
    and increased sheath blight incidence is not substantiated
    on mycelial growth alone. T

  1. Reacción de genotipos de frijol a Fusarium spp. y Rhizoctonia solani bajo condiciones de campo e invernadero / Reaction of common bean genotypes to Fusarium spp. y Rhizoctonia solani under field and greenhose conditions

    Scientific Electronic Library Online (English)

    Rosa, Navarrete-Maya; Evangelina, Trejo-Albarrán; Jorge, Navarrete-Maya; José Manuel, Prudencio-Sains; Jorge Alberto, Acosta Gallegos.

    2009-12-01

    Full Text Available Las pudriciones de raíz inducidas por R. solani y Fusarium spp. afectan al cultivo de frijol (Phaseolus vulgaris L.) en el altiplano de México. Para identificar genotipos de frijol resistentes a ambos hongos bajo condiciones de invernadero y campo, se realizaron dos experimentos en 2001. En campo, b [...] ajo condiciones de temporal, se sembraron 15 genotipos el 24 de julio, en suelo naturalmente infestado con hongos inductores de pudriciones de raíz, en Texcoco, Estado de México. Durante el ciclo del cultivo se determinó la incidencia y severidad de la enfermedad en las etapas fenológicas V3, R5, R7 y R8; además, se registraron temperatura ambiente y precipitación pluvial diaria. Los mismos genotipos se sembraron en invernadero el 27 de julio de 2001 en macetas con suelo del mismo sitio, las determinaciones realizadas en ambos ensayos fueron similares. Se tomaron muestras de tejido vegetal para el aislamiento e identificación de los hongos causantes de pudriciones de raíz; ambos, R. solani y Fusarium spp. se recuperaron. En campo, se observaron pudriciones de raíz durante todo el ciclo, con la mayor severidad en las etapas R5 y R7, sin que se observaran genotipos inmunes. Negro Tacaná mostró resistencia intermedia a Fusarium spp. y G 12729 (genotipo silvestre) fue resistente en las primeras etapas fenológicas. En invernadero, ningún genotipo mostró un patrón de resistencia durante el ciclo. En campo, el ataque de R. solani fue menos severo que el de Fusarium spp., mientras que en invernadero el ataque de R. solani fue más alto. En campo, los genotipos Pinto Villa, Wisc RRR, PI 203958 y BAT 477 mostraron resistencia intermedia y fueron consistentes en su respuesta a ambos hongos, pero en invernadero mostraron susceptibilidad. La incidencia y la severidad de los patógenos mostraron diferencias relacionadas con las condiciones climáticas registradas durante el ciclo del cultivo. Abstract in english The root rot induced damage caused by R. solani and Fusarium spp. affects common bean (Phaseolus vulgaris L.) production at the highlands of Mexico. To identify bean genotypes resistant to both fungi, two experiments were conductedunderfieldand greenhouse conditions. In the field, under rainfed cond [...] itions, 15 bean genotypes were planted on July 24 2001, at Texcoco, state of Mexico. Incidence and attack severity were determined at the phenological stages V3, R5, R7 and R8; also, daily temperature and precipitation were recorded. The same genotypes were planted under greenhouse conditions on July 27th, 2001 in pots with soil from the same site. Plant samples were collected from all genotypes for isolation and identification of fungi causing root rots. Both,R. solani and Fusarium spp. were recovered. Under field conditions, root rots were observed throughout the cycle, with the greatest severity at the R5 and R7 stages, no immune genotypes were observed. Cultivar Negro Tacana showed intermediate resistance to Fusarium spp. and G 12729 (a wild genotype) was resistant during the early phenological stages. Under greenhouse conditions, any genotype showed a consistent resistance pattern during the cycle. Atthe field, the attack by R. solani was less severe than that of Fusarium spp., whereas in the greenhouse the attack R. solani was severe. Atthe field, cultivars Pinto Villa, Wisc RRR, PI 203,958 and BAT 477 were intermediate and consistent in its response to both fungi; however, were susceptible in the greenhouse. The disease incidence and severity on the genotypes showed differences related to climatic conditions registered during the growth cycle.

  2. Evaluación de la actividad quitinasa en procesos de control biológico de rhizoctonia solani y fusarium oxysporum f. sp. lycopersici en tomate, mediante fitoinvigorización de semillas en presencia de trichoderma koningii Evaluation of chitinase activity in biological control process of rhizoctonia solani y fusarium oxysporum f. sp. lycopersici in tomate, by using seed priming in the presence of trichoderma koningii

    Directory of Open Access Journals (Sweden)

    Cotes A. M.

    1998-12-01

    Full Text Available

    El propósito del presente trabajo fue el de establecer el posible papel de las quitinasas en un modelo de control, utilizando pregerminación controlada de semillas en presencia de Trichoderma koningii. Este método mostró ser eficiente para el control de Rhizoctonia solani y de Fusarium oxysporum en tomate. Al analizar los extractos y exudados de semillas y los extractos de suelo sembrado con semillas pregerminadas en presencia de T. koningii, se encontró que éstos presentaron niveles significativamente mayores de actividad endoquitinasa que los provenientes de semillas pregerminadas en ausencia del antagonista y que los provenientes de semillas no pregerminadas. Al evaluar in-vitro la actividad hidrolítica de dichos extractos y exudados, utilizando paredes celulares de R. solani y de Fusarium oxysporum, los provenientes de semillas pregerminadas en presencia de T. koningii también mostraron significativamente mayor actividad endoquitinasa que la presentada en los otros tratamientos. Se pudo concluir que la pregerminación controlada de semillas en presencia de T. koningii estimula la actividad endoquitinolítica de las semillas y que esta actividad quitinasa estuvo relacionada con la protección previamente obtenida. 

    The present work intended to establish in a control model, the possible role of chitinases by using seed priming in the presence of Trichoderma koningii. This method showed to be efficient to control Rhizoctonia solani and Fusarium oxysporum in tomato. The analysis of seed extracts and exudates, and soil extracts from soil seeded with seeds primed in the presence of T. koningii showed high endochitinase activity in the samples. This activity was higher than that exhibited by samples from primed seeds without antagonist and unprimed seeds.   In vitro evaluation of the hydrolytic activity of the extracts and exudates were performed using F. oxysporum and R. solani cell walls. The results also showed that the samples from seeds primed in the presence of T. koningii exhibited higher endochitinase activity than the others. These data allowed us to conclude that seed priming in the presence of T. koningii promotes endochinolytic activity in seeds. It was also concluded that this chitinase activity is related with the protection previously observed.

  3. Evaluación del método de conservación en papel de filtro en dos cepas de Bacillus subtilis Cohn mediante la actividad antagónica frente a Rhizoctonia solani Kühn / Evaluation of Filter Paper Disks Preserving Method in Two Bacillus subtilis Cohn. Strains by Antagonistic Activity on Rhizoctonia solani Kühn

    Scientific Electronic Library Online (English)

    Acenet I, Sosa López; Victoria, Pazos Álvarez-Rivera; Giovanni, Borges Marín; Marleny, González García; Enrique, Ponce Grijuela.

    2011-03-01

    Full Text Available Se evaluó la actividad antagónica de dos cepas de Bacillus subtilis conservadas en discos de papel de filtro a 4°C por un período de tres años. Se escogieron las cepas del género B. subtilis: Bs-21 y Bs-42, aisladas del suelo, autóctonas de Cuba, y antagónicas de la cepa Rs-10 de Rhizoctonia solani. [...] Se determinó la viabilidad, pureza y actividad antagónica de cinco colonias de Bs-42 y una de Bs-21, escogidas al azar y cultivadas en agar nutriente. Las colonias seleccionadas se evaluaron por el método de enfrentamiento dual en papa dextrosa agar, después de 96 h de incubación a 30°C. Ambas cepas presentaron una viabilidad de 108 UFC/mL. Los cultivos mantuvieron la pureza, las características morfológicas y respuesta positiva a la tinción de Gram, comparadas con la cepa de B. subtilis ATCC 6633. Todas las colonias seleccionadas inhibieron el crecimiento micelial de la cepa Rs-10 de R. solani, no así la de referencia. El análisis de varianza realizado mostró diferencias significativas en el porcentaje de inhibición de las colonias ensayadas. La cepa Bs-21 resultó ser la de menor inhibición con el 78%, y Bs-421 y Bs-422 las de mayor porcentaje con el 98%. Abstract in english Antagonistic activity of two Bacillus subtilis strains preserved in filter paper disks at 4°C for a period of three years was evaluated. Strains Bs-21 and Bs-42, isolated from Cuban soil and antagonists to Rhizoctonia solani Rs-10 were choiced. Five colonies from Bs-42 and one from Bs-21, randomly s [...] elected were growth in nutrient agar. The antagonism was compared by dual culture method in PDA after 96 h at 30°C. Viability of both strains was 108 CFU/mL. Selected colonies kept purity, morphological characteristics and positive response to Gram stain compared with B. subtilis ATCC 6633. All selected colonies inhibited mycelial growth of R. solani Rs-10, but not the reference strain. Strain Bs-21 had the lower inhibition (78%) while Bs-421 and Bs-422 had the higher percent (98%). Variance analysis showed significant differences in the percentage of inhibition exhibited by tested colonies.

  4. SENSIBILIDADE DE Rhizoctonia solani Kuhn, A FUNGICIDAS “IN VITRO” E EM PLÂNTULAS DE ALGODOEIRO (Gossypium hirsutum L., EM CONDIÇÕES DE CASA DE VEGETAÇÃO SENSIBILITY OF Rhizoctonia solani Kuhn TO FUNGICIDES “IN VITRO” AND IN COTTON PLANTULES (Gossypium hirsutum L AT GREENHOUSE CONDITIONS

    Directory of Open Access Journals (Sweden)

    Wilson Ferreira de Oliveira

    2007-09-01

    Full Text Available

    Foram instalados nas dependências do Departamento Fitossanitário da Escola de Agronomia - UFG, ensaio “in vitro”, em BDA2 e a nível de Casa de Vegetação, objetivando testar a eficiência de diferentes dosagens de Iprodione + Thiran (Rovrin em comparação com PCNB (Brassicol 75 BR, TMTD (Rhodiauran 70 e Captan + Pencycuron (Monceren para o controle de Rhizoctonia solani Kuhn, na cultura do algodoeiro, através do tratamento de sementes. Os resultados obtidos, nas condições de realização dos ensaios, permitem concluir que os fungicidas Rovrin - 320 g.i.a., Monceren - 210 g.i.a., Rovrin - 240 g.i.a., Rovrin - 200 g.i.a., PCNB - 450 g.i.a./100 litros de água ou 100 kg de sementes mostraram-se eficientes e não diferiram estatisticamente entre si no controle de R. solani, enquanto que o produto TMTD (Rhodiauran 70 na dosagem de 280 g.i.a./100 litros de água ou 100 kg de sementes de algodoeiro não se mostrou eficiente no controle deste agente causal.

    Aiming to test the efficiency of different dosages of Iprodione + Thiram (Rovrin in comparison with PCNB (Brassicol 75 BR, TMTD (Rhodiauran 70 and Captan + Pencycuron (Monceren for controlling Rhizoctonia solani Kuhn, in cotton plantation, through seeds treatment, was mounted essays “in vitro” at greenhouse level and BDA, in the Phytosanitary Department annexes of School of Agronomy-UFG. The results obtained, at essays conditions, permit to conclude that fungicides Rovrin - 320 g.i.a., Monceren - 210 g.i.a., Rovrin - 240 g.i.a., Rovrin - 200 g.i.a., PCNB - 450 g.i.a./l00 liters of water or 100kg of seeds, were efficient and statistically had no variation among them, in controlling R. solani, while chemical product TMTD (Rhodiauran 70, at dosage of 280 g.i.a./100 liters of water or 100 kg of cotton seeds, was not efficient in controlling this causal agent.

  5. Selección de aislamientos de Trichoderma spp. con potencial biocontrolador de Rhizoctonia solani Kühn en papa bajo condiciones de casa de malla

    Directory of Open Access Journals (Sweden)

    Garcés de Granada Emira

    2005-07-01

    Full Text Available El hongo fitopatógeno Rhizoctonia solani afecta raíces, tallos y tubérculos de papa, logrando reducir los rendimientos del cultivo hasta en un 50%. Con el propósito de ofrecer una alternativa biológica para el manejo de este problema, se evaluaron diez cepas nativas del hongo biocontrolador
    Trichoderma spp. Inicialmente se evaluó la actividad patogénica de dos aislamientos de R. solani (Rh005 y Rh006 inoculando suelo en proporciones del 2,5 y 10% peso a peso (p/p donde posteriormente fueron transplantadas plántulas de papa producidas in vitro, encontrando con ambos aislamientos 100% de incidencia de la enfermedad. Sin embargo, fue seleccionado el aislamiento Rh005 ya que presentó mayor porcentaje de daño expresado como volcamiento de las plantas. Como prueba preliminar de antagonismo, en recipientes con suelo se enterraron bolsas de muselina que contenían esclerocios de este último aislamiento y se trataron
    individualmente con suspensiones de los diferentes  aislamientos de Trichoderma spp.ajustadas a una concentración de 107conidios.ml-1, estableciéndose que los aislamientos de Trichoderma Th002, Th003, Th007, Th034 y Th181 parasitaron y degradaron más del 50% de los esclerocios. En el ensayo de protección al evaluar estos últimos aislamientos en casa de malla en donde se inoculó suelo con Rh005 (2% p/p se seleccionaron los aislamientos Th003 y Th034 por presentar diferencias con respecto a mayores pesos de biomasa fresca y seca en comparación con los restantes biocontroladores y los tratamientos químico, patógeno y testigo. Aunque no se logró disminuir la incidencia de la enfermedad, los aislamientos de Trichoderma seleccionados permitieron reducir el daño en las plantas observando mayor vigor, tallos normales con abundante follaje y mejor crecimiento radical.

  6. Influence of Weather and Soil Parameters on Development of Wet Root Rot in Pulse Crops and Virulence Analysis of Rhizoctonia solani Isolates

    Directory of Open Access Journals (Sweden)

    S. C. Dubey

    2012-10-01

    Full Text Available Wet root rot caused by Rhizoctonia solani Kühn in pulse crops was favored by wide range of soil parameters like temperature, humidity, pH, electric conductivity and soil texture. The areas surveyed for the collection of the isolates showing variable atmospheric temperature and relative humidity and low to medium levels of soil organic carbon and high level of available phosphorus influenced the development of the disease incidence from 2-48%. Seventy three cultivars of mungbean, twenty eight cultivars of urdbean and eight cultivars of cowpea were evaluated against virulent isolate of R. solani (RASC 30 to design a set of differential cultivars for virulence analysis. Two cultivars of urdbean, namely, NDU3-4 and IPU2-14, one cultivar of mungbean, namely, HUM 1 and three cultivars of cowpea, namely, V240, V585 and DCP7 showed resistant reactions. Four cultivars of urdbean, namely, TU94-2, KU323, KUG216 and B3-8-8, one cultivar of mungbean, namely, PDM54 and two cultivars of cowpea, namely, V578 and DCP13 were moderately resistant against the pathogen. The virulence analysis of 90 isolates of the pathogen representing 7 anastomosis groups (AGs isolated from pulse crops of 16 agro-ecological regions of India on a set of differential cultivars, namely, HUM 1, PDM 54 and Pusa Vishal of mungbean, NDU 3-4, KU 323, Uttara of urdbean and V 240, V 578 and Pusa Sukomal of cowpea grouped the isolates into five pathotypes. The differential cultivar for each pathotype was identified. The pathotypes were not corresponding to the AG type of the isolates. Except one pathotype (isolate RMPG28 belonging to AG2-3, each pathotype had the isolates from different AGs.

  7. Métodos de evaluación y reacción de cultivares para resistencia al añublo de la vaina del arroz causado por Rhizoctonia solani AG-1 IA / Evaluation methods and cultivars reaction for resistance to the rice sheath blight caused by Rhizoctonia solani AG-1 IA

    Scientific Electronic Library Online (English)

    Alex, González-Vera; Eduardo, Graterol; Brígida, Borges; Francis, Hernández.

    2011-04-01

    Full Text Available El arroz (Oryza sativa L.) en Venezuela, es afectado por el añublo de la vaina causado por Rhizoctonia solani (Teleomorfo = Thanatephorus cucumeris). No existe resistencia completa ante esta enfermedad. Por ello, los programas de mejoramiento genético deben evaluar un alto número de cultivares para [...] seleccionar aquellos cuantitativamente mejores en resistencia. Los objetivos fueron comparar métodos de evaluación de resistencia y la reacción de cultivares para resistencia al añublo de la vaina del arroz causado por R. solani AG-1 IA. Los métodos de evaluación usados fueron microcámaras y bola de micelio en umbráculo, la prueba de cinetina en laboratorio y la infestación con arroz colonizado bajo condiciones de campo. Se evaluaron 23 genotipos de arroz, incluyendo variedades testigo. Tres haplotipos de R. solani, previamente caracterizados, fueron utilizados para las inoculaciones. Los ensayos fueron de bloques completos al azar con tres repeticiones. La efectividad de los ensayos se determinó con base a la discriminación de los testigos de reacción conocida y a la mejor correlación de los métodos de laboratorio y umbráculo con los resultados de campo. El método de microcámaras, combinado con el aislado de R. solani A5B4 (64), presentó la mejor correlación con los resultados de campo (r = 0,50 en promedio), seguido por el método de bola de micelio (r = 0,49, promedio). Los cultivares testigo ‘Tetep’ (resistente) y ‘Lemont’ (susceptible) fueron consistentes en los ensayos. El análisis de componentes principales identificó los genotipos CT15150-M-11-4-3-2-M (derivado de un cruce con O. glaberrima), ‘SD20A’ y ‘D-Sativa’ con los mejores niveles de resistencia. Estos resultados indican la existencia de métodos confiables para evaluar el añublo de la vaina y de cultivares adaptados con resistencia a la enfermedad. Abstract in english The rice (Oryza sativa L.), in Venezuela, is affected by sheath blight caused by Rhizoctonia solani (teleomorph = Thanatephorus cucumeris). No complete resistance has been found in the world. In consequence, breeding programs should evaluate many cultivars for selecting those with the best quantitat [...] ive level of resistance. The objectives were to compare methods of evaluation and cultivars reaction for resistance to the sheath blight caused by R. solani AG-1 IA. The evaluation methods were microchamber and mycelium ball in greenhouse conditions, kinetin test in laboratory and colonized rice infestation under field conditions. The cultivars were 23 genotypes of rice, including control varieties. Three haplotypes of R. solani, previously characterized, were used for the inoculations. The experimental designs were randomized complete block with three replications. The effectiveness of the trials was determined based on the discrimination of controls with well-known reaction and the best correlation of the laboratory and greenhouse methods with the field results. The method of microchamber using the isolate A5B4 (64) had the best correlation with field results (r = 0.50 on average), followed by the method of ball mycelium (r = 0.49, on average). The control cultivars 'Tetep' (resistant) and 'Lemont' (susceptible) were consistent across the experiments. The principal component analysis identified the genotypes CT15150-M-11-4-3-2-M (derived from a cross with O. glaberrima), 'SD20A' and 'D-Sativa' with the best levels of resistance. These results indicate the existence of reliable methods to evaluate this disease and adapted cultivars with resistance to rice sheath blight.

  8. Evaluación in vitro de aislamientos de Trichoderma harzianum para el control de Rhizoctonia solani, Sclerotium rolfsii y Fusarium oxysporum en plantas de tomate / In vitro evaluation of Trichoderma harzianum for control of Rhizoctonia solani, Sclerotium rolfsii, and Fusarium oxysporum in tomato plants

    Scientific Electronic Library Online (English)

    Clemencia, Guédez; Luis, Cañizalez; Carmen, Castillo; Rafael, Olivar.

    2012-06-01

    Full Text Available En este estudio se determinó la capacidad antagónica de aislamientos de T. harzianum para el control de Rhizoctonia solani, Sclerotium rolfsii y Fusarium oxysporum en raíces de plantas de tomate. Se obtuvieron 6 aislamientos de T. harzianum de 6 municipios del estado Trujillo, empleando la técnica d [...] e siembra directa de raíces en agar agua acidificada. El antagonismo se realizó en cultivos duales utilizando agar papa dextrosa, incubados a 25 ºC, bajo un diseño al azar, con 18 tratamientos conformados por cada aislamiento de T. harzianum y cada patógeno, 3 tratamientos testigos correspondientes a cada patógeno y 3 repeticiones por tratamiento, evaluándose el modo de acción e inhibición del crecimiento radial al tercer día. Todos los aislamientos de T. harzianum mostraron un rápido crecimiento sin diferencias significativas entre ellos (p>0,05), aún cuando se observó que el T121 fue más eficaz como controlador. Al comparar el crecimiento de los aislamientos de T. harzianum con el de los hongos patógenos, se obtuvieron diferencias significativas (p Abstract in english This study determined the antagonistic capacity of T. harzianum isolates for control of Rhizoctonia solani, Sclerotium rolfsii, and Fusarium oxysporum in the roots of tomato plants. Six T. harzianum isolates were obtained from 6 municipalities of Trujillo State, using the direct inoculation of roots [...] in acidified water agar technique. The antagonism was carried out in dual cultures using potato dextrose agar, incubated at 25 ºC, under a random design, with 18 treatments conformed for each T. harzianum isolate and each pathogen, 3 control treatments corresponding to each pathogen, and 3 repetitions per treatment, evaluating the mode of action and inhibition of radial growth at the third day. All the T. harzianum isolates showed rapid growth without significant differences among them (p>0.05), even though it was observed that T121 was more efficient as controller. When comparing the growth of the T. harzianum isolates with that of the pathogenic fungi, there were significant differences (p

  9. Detection of trypsin inhibitor in seeds of Eucalyptus urophylla and its influence on the in vitro growth of the fungi Pisolithus tinctorius and Rhizoctonia solani Descoberta de inibidor de tripsina em sementes de Eucalyptus urophylla e sua influência sobre o crescimento in vitro dos fungos Pisolithus tinctorius e Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Célia Regina Tremacoldi

    2002-12-01

    Full Text Available Inhibitors of plant proteases can regulate the hydrolysis of proteins inside the cells and also participate in the mechanisms of plant defense against herbivore insects and pathogens. Here, we demonstrated that seeds of Eucalyptus urophylla exhibit activities of trypsin and papain inhibitors, two proteases commonly found in living cells. Low amounts of proteins of the crude protein extract of seeds and fractions partially purified by gel filtration, with inhibitory activity against trypsin, inhibited in vitro the mycelial growth of a compatible isolate of the ectomycorrhizal fungus Pisolithus tinctorius and allowed an unsatisfactory growth of another isolate from Pinus taeda, considered incompatible for this eucalyptus species. The same amounts of inhibitory proteins, when tested in vitro on the pathogen Rhizoctonia solani, did not exhibit any effect on the growth of the pathogen. These results indicate the existence of proteases inhibitors in seeds of E. urophylla which could influence the complex biochemical system that differentiates mechanisms of symbiosis and pathogenicity between plants and microorganisms.Os inibidores de proteases de plantas podem regular a hidrólise de proteínas no interior celular e também participar de seus mecanismos de defesa contra insetos herbívoros e patógenos. No presente trabalho, nós demonstramos que sementes de Eucalyptus urophylla apresentam atividades de inibidores de tripsina e papaína, duas proteases comumente encontradas em seres vivos. Pequenas quantidades de proteínas do extrato protéico bruto de sementes e de frações parcialmente purificadas por filtração em gel, com atividade inibitória de tripsina, inibiram o crescimento micelial in vitro de um isolado compatível do fungo ectomicorrízico Pisolithus tinctorius e permitiram um crescimento insatisfatório de outro isolado de Pinus taeda, considerado compatível para esta espécie de eucalipto. As mesmas concentrações de proteínas, quando testadas in vitro sobre o patógeno Rhizoctonia solani, não demonstraram qualquer efeito sobre seu crescimento. Estes resultados indicam a existência de inibidores de proteases em sementes de E. urophylla, os quais poderiam influenciar o complexo sistema bioquímico que diferencia mecanismos de simbiose e patogenicidade entre plantas e microrganismos.

  10. Detection of trypsin inhibitor in seeds of Eucalyptus urophylla and its influence on the in vitro growth of the fungi Pisolithus tinctorius and Rhizoctonia solani / Descoberta de inibidor de tripsina em sementes de Eucalyptus urophylla e sua influência sobre o crescimento in vitro dos fungos Pisolithus tinctorius e Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Célia Regina, Tremacoldi; Sérgio Florentino, Pascholati.

    2002-12-01

    Full Text Available Os inibidores de proteases de plantas podem regular a hidrólise de proteínas no interior celular e também participar de seus mecanismos de defesa contra insetos herbívoros e patógenos. No presente trabalho, nós demonstramos que sementes de Eucalyptus urophylla apresentam atividades de inibidores de [...] tripsina e papaína, duas proteases comumente encontradas em seres vivos. Pequenas quantidades de proteínas do extrato protéico bruto de sementes e de frações parcialmente purificadas por filtração em gel, com atividade inibitória de tripsina, inibiram o crescimento micelial in vitro de um isolado compatível do fungo ectomicorrízico Pisolithus tinctorius e permitiram um crescimento insatisfatório de outro isolado de Pinus taeda, considerado compatível para esta espécie de eucalipto. As mesmas concentrações de proteínas, quando testadas in vitro sobre o patógeno Rhizoctonia solani, não demonstraram qualquer efeito sobre seu crescimento. Estes resultados indicam a existência de inibidores de proteases em sementes de E. urophylla, os quais poderiam influenciar o complexo sistema bioquímico que diferencia mecanismos de simbiose e patogenicidade entre plantas e microrganismos. Abstract in english Inhibitors of plant proteases can regulate the hydrolysis of proteins inside the cells and also participate in the mechanisms of plant defense against herbivore insects and pathogens. Here, we demonstrated that seeds of Eucalyptus urophylla exhibit activities of trypsin and papain inhibitors, two pr [...] oteases commonly found in living cells. Low amounts of proteins of the crude protein extract of seeds and fractions partially purified by gel filtration, with inhibitory activity against trypsin, inhibited in vitro the mycelial growth of a compatible isolate of the ectomycorrhizal fungus Pisolithus tinctorius and allowed an unsatisfactory growth of another isolate from Pinus taeda, considered incompatible for this eucalyptus species. The same amounts of inhibitory proteins, when tested in vitro on the pathogen Rhizoctonia solani, did not exhibit any effect on the growth of the pathogen. These results indicate the existence of proteases inhibitors in seeds of E. urophylla which could influence the complex biochemical system that differentiates mechanisms of symbiosis and pathogenicity between plants and microorganisms.

  11. Características de aislamientos de Rhizoctonia solani Huhn y su importancia como patógenos de Stylosanthes guianensis (Aubl. Sw.

    Directory of Open Access Journals (Sweden)

    Lenne Jilliam M.

    1986-06-01

    Full Text Available Se encontró considerable variación en el crecimiento, color, zonificación, esclerocios, textura del micelio y en la virulencia de siete aislamientos de R. solani. Como seis aislamientos fueron multinucleados y uno binucleado, se demostró que es indispensable determinar ésta característica en ensayos con R. solani. Los aislamientos se ubicaron en los grupos de anastomosis AG -1, AG-2, AG-4; pero en los ensayos con electroforesis de isoenzirnas los modelos de bandas para los a islamientos probadores de los AG y los probados en éste estudio fueron diferentes, lo que llevó a cuestionar la importancia de los AG. Los ecotípos de Centrosema spp y P. phaseoloides fueron más afectados que los de S. guianensis, D. ovalifolium y S. capitata. La reacción al daño de R. solani fue diferencial en los ecotipos CIAT 1283 (tardío y 184 (común y tuvo mucha relación con la edad; en general, la enfermedad se incrementó con la edad en el eco tipo tardío y disminuyó con ésta o fue independiente en el ecotipo común; el ecotipo más fectado fue el tardío; las pérdidas de forraje no fueron considerables, pero el efecto en la digestibilidad fue notorio; la capacidad de rebrote fue buena en 184. Se observó un estímulo en el crecimiento de las plantas de S.guianensis y D. ovalifolium.Considerable variation was found in the growth, color, zonation, sclerotia, mycelial texture and virulence of seven isolates of R. solani. Six multinuclease and one binuclease isolates were determined, demonstrating that it is indispensable to determine this characteristic in trials with this pathogen. The isolates were placed in three anastomosis group AG -1, AG -2 and AG -4; but with electrophoresis of isoenzymes it was found that the band models were different for the known rest AG iso lates and those isolates proven in this study which questions the importance of anastomosis qroups. Ecotypes of Centrosema spp. and P. phaseoloides were more affected than those of S. guianensis, D. ovalifolium and S. capitata. The reaction on damage by R. solani was differencial for ecotypes C IAT 1283 (tardío and 184 (comrno n and was related to age. In general, the disease increased with age in the tardio and decreased or was independent of age in the cornrnon: the tardio was more affected; forage losses were not cosiderable but the effect on the digestibility was noted; the regrowth capacity was good in the cornrnon. A stimulus in the growth of plants of S. guianensis and D. ovalifolium was observed.

  12. Characterization of genes involved in biosynthesis of a novel antibiotic from Burkholderia cepacia BC11 and their role in biological control of Rhizoctonia solani

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Y.; Carlson, R.; Tharpe, W.; Schell, M.A. [Univ. of Georgia, Athens, GA (United States)

    1998-10-01

    Genetic manipulation of fluorescent pseudomonads has provided major insight into their production of antifungal molecules and their role in biological control of plant disease. Burkholderia cepacia also produces antifungal activities, but its biological control activity is much less well characterized, in part due to difficulties in applying genetic tools. Here the authors report genetic and biochemical characterization of a soil isolate of B. cepacia relating to its production of an unusual antibiotic that is very active against a variety of soil fungi. Purification and preliminary structural analyses suggest that this antibiotic (called AFC-BC11) is a novel lipopeptide associated largely with the cell membrane. Analysis of conditions for optimal production of AFC-BC11 indicated stringent environmental regulation of its synthesis. Furthermore, the authors show that production of AFC-BC11 is largely responsible for the ability of B. cepacia BC11 to effectively control the damping-Off of cotton caused by the fungal pathogen Rhizoctonia solani in a gnotobiotic system. Using Tn5 mutagenesis, they identified, cloned, and characterized a region of the genome of strain BC11 that is required for production of this antifungal metabolite. DNA sequence analysis suggested that this region encodes proteins directly involved in the production of a nonribosomally synthesized lipopeptide.

  13. Importancia del método estadístico para el cálculo de la CE50 y CE95 de algunos isotiocianatos evaluados contra Rhizoctonia solani Kühn / Importance of the statistical method applied to calculate the EC50 and EC95 of some isothiocyanates evaluated against Rhizoctonia solani Kühn

    Scientific Electronic Library Online (English)

    Luis Federico, Molina-Vargas; Sandra Esperanza, Melo-Martínez.

    2010-08-01

    Full Text Available En el marco de la evaluación del efecto de algunos isotiocianatos (ITC) sobre el crecimiento de Rhizoctonia solani Kühn, la presente investigación establece también si el método estadístico utilizado determina diferencias considerables en los valores de la concentración efectiva media (CE50) y la co [...] ncentración efectiva 95 (CE95) de estos compuestos. Para ello se realizó un experimento in vitro, y se estimaron dichos valores mediante regresiones lineales y no lineales. Los compuestos evaluados contra R. solani AG-3 fueron: alil isotiocianato (AITC), bencil isotiocianato (BITC), fenil isotiocianato (PITC), fenetil isotiocianato (PEITC) y metil isotiocianato (MITC). El ensayo se llevó a cabo en el Laboratorio de Biotecnología de la Facultad de Agronomía de la Universidad Nacional de Colombia, sede Bogotá. Manteniendo agitación constante, se prepararon diluciones de los ITC utilizando metanol como solvente, para obtener las concentraciones 0,0; 0,01; 0,1; 1,0 y 10,0%, que correspondieron a los distintos tratamientos evaluados. En cada uno de ellos se agregaron 50 mL de una de estas soluciones a las unidades experimentales, consistentes en cajas de petri con medio PDA y micelio de R. solani AG-3, selladas herméticamente y almacenadas a temperatura ambiente. Pasadas 72 y 144 horas después de la aplicación de los tratamientos (hdt), se tomaron fotografías digitales para calcular el área de crecimiento micelial con el software MapMaker® 3.5. Esto permitió obtener la Concentración Efectiva Media (CE50) y la Concentración Efectiva 95 (CE95) mediante regresiones lineales, no lineales (modelos Gompertz, logístico y polinómico) y análisis Probit. Los valores obtenidos a partir de este último distan bastante de lo observado, que a su vez coincide con los valores encontrados por regresión lineal. A la concentración del 10%, todos los ITC, excepto PEITC, mostraron un efecto inhibitorio total. Por su parte, BITC mantuvo su efecto fungistático hasta 21 días después de aplicados los tratamientos, mientras que PITC, AITC y MITC mantuvieron un efecto fungistático más prolongado, inclusive hasta un año después de iniciados los tratamientos. Abstract in english Framed in the evaluation of the effect of some isothiocyanates (ITC) on the growth of Rhizoctonia solani Kühn, the present research also studied whether the applied statistical method determines significant differences in the values of the Median (EC50) and 95 (EC95) effective concentrations of thes [...] e compounds. For this purpose, we conducted an in vitro experiment in which said values were calculated by different statistical methods. In vitro efficacy against R. solani AG-3 was tested of allyl isothiocyanate (AITC), benzyl isothiocyanate (BITC), phenyl isothiocyanate (PITC), phenethyl isothiocyanate (PEITC) and methyl isothiocyanate (MITC). Under constant shaking we prepared stock solutions by mixing ITC with methanol as solvent, to get concentrations of 0.0, 0.01, 0.1, 1.0, and 10%, corresponding to the different studied treatments; each of which consisted in the addition of 50 mL of one of these solutions to the experimental units. The latter were Petri dishes containing potato-dextrose-agar medium (PDA) and mycelium of R. solani AG-3. These containers were then sealed with two layers of parafilm and incubated at room temperature. Digital pictures were taken to obtain the colony areas using MapMaker 3.5® software, 72 and 144 hours after the treatments were applied. The Median (EC50) and 95 (EC95) effective concentrations were calculated through linear and non-linear (Gompertz, logistic, and polynomial models) regressions, as well as probit analysis. The values obtained through the latter were found to be considerably different from the actual ones, which in turn coincided with those found by means of linear regressions. All of ITC at 10% concentration were completely inhibitory, with the exception of PEITC. Whereas BITC was fungistatic up to twenty one days after the treatments were applied, PITC, AITC, and MITC h

  14. Potencial de preparados de cavalinha (Equisetum sp.) na síntese de metabólitos de defesa em cotilédones de soja (Glycine max L.) e o efeito sobre o crescimento de Rhizoctonia solani Kuhn, in vitro. / Potential of horsetail (Equisetum sp.) derivatives on the synthesis of defense metabolites using soybean ( Glycine max L.) cotyledons and their effect on the in vitro growth of Rhizoctonia solani Kuhn

    Scientific Electronic Library Online (English)

    SS, GUIMARÃES; SM, MAZARO; ÁR, FREDDO; A, WAGNER JÚNIOR.

    2015-03-01

    Full Text Available Foram desenvolvidos dois experimentos com objetivo de avaliar o potencial de preparados de cavalinha (Equisetum sp.) na síntese de metabólitos de defesa em cotilédones de soja (Glycinemax L.) e o efeito sobre o crescimento de Rhizoctonia solani, in vitro. O delineamento experimental utilizado para o [...] s experimentos foi inteiramente casualizado em esquema fatorial 3x5 (formas de extração x concentrações), com quatro repetições. As formas de extração foram extrato alcoólico, infusão e maceração, nas concentrações de zero; 1; 10, 20 e 40%. No primeiro experimento foi avaliada a indução de compostos de defesa vegetal em cotilédones de soja em resposta aos derivados a base de cavalinha, sendo quantificada a atividade da enzima fenilalanina amônia-liase (FAL), via espectofotometria, a fitoalexina gliceolina, e o teor de fenóis totais. No segundo experimento, in vitro, a unidade experimental foi uma placa de Petri, sendo os preparados de cavalinha incorporados ao meio BDA (Batata-dextrose e Agar) e avaliado o crescimento micelial de R. Solani. Os preparados de extrato alcoólico, infusão e maceração de cavalinha apresentaram capacidade de indução das fitoalexinas gliceolinas em cotilédones de soja, bem como, ativaram o metabolismo de compostos fenólicos. Entre os preparados, o extrato alcoólico e a maceração, se sobressaem sobre a infusão. Os preparados de extrato alcoólico, infusão e maceração de cavalinha em todas as suas concentrações inibem o crescimento do fungo R. solani, in vitro. Abstract in english Two experiments were carried out in the Federal Technological University of Paraná - Dois Vizinhos Campus - with the aim to evaluate the potential of horsetail (Equisetum sp.) derivatives for the synthesis of defense metabolites in soybean (Glycine max L.) cotyledons and their effect on the in vitro [...] growth of Rhizoctonia solani. The experimental design was completely randomized in a 3 x 5 factorial design (extraction form x concentration), with four replications. The extraction forms were alcoholic extract, infusion and maceration and the concentrations tested were zero, 1, 10, 20 and 40%. In the first experiment, we evaluated the induction of plant defense in soybean cotyledons as a response to horsetail derivatives through spectrophotometry according to phytoalexin glyceollin, phenylalanine ammonia lyase enzyme activity (PAL) and total phenols. In the second experiment, in vitro, the experimental unit was a Petri dish, and the horsetail derivatives were incorporated into medium culture (potato dextrose agar), and we evaluated the mycelial growth of R. solani. The alcoholic extract, infusion and maceration of horsetail derivatives presented phytoalexin glyceolin induction in soybean cotyledons, in addition to activating the metabolism of phenolic compounds. Among the derivatives, the alcoholic extract and the maceration form of extraction were superior in relation to the infusion. The alcoholic extract, infusion and maceration of horsetail derivatives inhibited the in vitro growth of R. solani in all concentrations.

  15. Interaction of Collimonas strain IS343 with Rhizoctonia solani at low carbon availability in vitro and in soil (online first)

    OpenAIRE

    Senechkin, I. V.; Overbeek, L. S.; Er, H. L.; Vos, O. J.; Bruggen, A. H. C.

    2013-01-01

    Collimonas sp. IS343, isolated from an organically-farmed arable soil and characterized as a broad-range oligotrophic bacterium, was shown to degrade chitin and to suppress R. solani mycelium growth under in vitro conditions at high and low carbon availabilities. In contrast to C. fungivorans Ter331, strain IS343 did not respond with an increase in growth rate to higher carbon levels in liquid medium, it reached higher cell numbers in carbon-poor media and it showed better survival in bulk so...

  16. Improved genome sequence of the phytopathogenic fungus Rhizoctonia solani AG1-IB 7/3/14 as established by deep mate-pair sequencing on the MiSeq (Illumina) system.

    Science.gov (United States)

    Wibberg, Daniel; Rupp, Oliver; Jelonek, Lukas; Kröber, Magdalena; Verwaaijen, Bart; Blom, Jochen; Winkler, Anika; Goesmann, Alexander; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas

    2015-06-10

    The phytopathogenic fungus Rhizoctonia solani AG1-IB of the phylum Basidiomycota affects various economically important crops comprising bean, rice, soybean, figs, cabbage and lettuce. The R. solani isolate 7/3/14 of the anastomosis group AG1-IB was deeply resequenced on the Illumina MiSeq system applying the mate-pair mode to improve its genome sequence. Assembly of obtained sequence reads significantly reduced the amount of scaffolds and improved the genome sequence of the isolate compared to the previous sequencing approach. The genome sequence of the AG1-IB isolate 7/3/14 now provides an up-graded basis to analyze genome features predicted to play a role in pathogenesis and for the development of strategies to antagonize the pathogenic impact of this fungus. PMID:25801332

  17. Effect of Combined Use of Bacillus subtilis CA32 and Trichoderma harzianum RU01 on Biological Control of Rhizoctonia solani on Solanum melongena and Capsicum annuum

    OpenAIRE

    Abeysinghe, S.

    2009-01-01

    A combination of two compatible biological control agents, Bacillus subtilis CA32 and Trichoderma harzianum RU01, both antagonistic to the pathogen Rhizoctonia solani, was used to control damping-off in Solanum melongena and Capsicum annuum. Radial growth of the mycelium of R. solani was inhibited by T. harzianum RU01 in dual Petri plate assay. T. harzianum RU01 was capable to invading the whole surface of the pathogen colony, sporulating on it and suppress the production of sclerotia...

  18. Effects of damping-off caused by Rhizoctonia solani anastomosis group 2-1 on roots of wheat and oil seed rape quantified using X-ray Computed Tomography and real-time PCR

    Science.gov (United States)

    Sturrock, Craig J.; Woodhall, James; Brown, Matthew; Walker, Catherine; Mooney, Sacha J.; Ray, Rumiana V.

    2015-01-01

    Rhizoctonia solani is a plant pathogenic fungus that causes significant establishment and yield losses to several important food crops globally. This is the first application of high resolution X-ray micro Computed Tomography (X-ray ?CT) and real-time PCR to study host–pathogen interactions in situ and elucidate the mechanism of Rhizoctonia damping-off disease over a 6-day period caused by R. solani, anastomosis group (AG) 2-1 in wheat (Triticum aestivum cv. Gallant) and oil seed rape (OSR, Brassica napus cv. Marinka). Temporal, non-destructive analysis of root system architectures was performed using RooTrak and validated by the destructive method of root washing. Disease was assessed visually and related to pathogen DNA quantification in soil using real-time PCR. R. solani AG2-1 at similar initial DNA concentrations in soil was capable of causing significant damage to the developing root systems of both wheat and OSR. Disease caused reductions in primary root number, root volume, root surface area, and convex hull which were affected less in the monocotyledonous host. Wheat was more tolerant to the pathogen, exhibited fewer symptoms and developed more complex root systems. In contrast, R. solani caused earlier damage and maceration of the taproot of the dicot, OSR. Disease severity was related to pathogen DNA accumulation in soil only for OSR, however, reductions in root traits were significantly associated with both disease and pathogen DNA. The method offers the first steps in advancing current understanding of soil-borne pathogen behavior in situ at the pore scale, which may lead to the development of mitigation measures to combat disease influence in the field. PMID:26157449

  19. EFFECT OF THE TREATMENT OF SEEDS WITH FUNGICIDES IN CONTROLLING DAMPING OFF OF THE BEAN (Phaseolus vulgaris L CAUSED BY Rhizoctonia solani Kuhn EFEITO DO TRATAMENTO DE SEMENTES COM FUNGICIDAS NO CONTROLE DO TOMBAMENTO EM FEIJOEIRO (Phaseolus vulgaris L. CAUSADO POR Rhizoctonia solani Kuhn

    Directory of Open Access Journals (Sweden)

    Rosângela Vera

    2007-09-01

    Full Text Available

    Some fungicides were tested in control of Rhizoctonia solani in bean (Phaseolus vulgaris planted in soil inoculated with this fungus. The evaluations were made at 10, 20 and 30 days after sowing, observing germination and damping-off. The results showed that the fungicides thiram (280g. a.i./ 100kg seeds have no increased plant stand in Phaseolus vulgaris, in relation to the non treated control. Seed treatments with PCNB (450g a.i./ 100kg seeds, iprodione + thiram (200g a.i/l00kg seeds and iprodione + thirarn (240g a.i./100kg seeds, increased plant stand in percentages varying from 65 to 73%, respectively in relation to non treated control, but the best treatment was with iprodione + thiram (320g a.i./l00kg seeds, presenting an increase around 83%.

    Foram testados alguns fungicidas no controle de Rhizoctonia solani em feijoeiro (Phaseolus vulgaris L., semeado em vasos com solo previamente inoculado por este fungo. As avaliações foram feitas aos 10, 20 e 30 dias após o plantio, levando-se em consideração ausência de germinação e plântulas tombadas. Os resultados mostraram que o fungicida thiram (280g i.a./100kg de sementes, não aumentou o stand de plantas em relação à testemunha. Sementes tratadas com PCNB (450g i.a./l00kg de sementes, com iprodione + thiram (200g i.a./l00kg de sementes e com iprodione + thiram (240g i.a./l00kg de sementes aumentaram o stand em percentagens que variaram de 65 a 73%, em relação à testemunha, mas o melhor resultado foi obtido com iprodione + thiram na concentração de 320g i.a./ 100kg de sementes, que promoveu aumento do stand em cerca de 83%.

  20. Efecto inhibitorio in vitro de cinco monoterpenos de aceites esenciales sobre un aislado de Rhizoctonia solani en papa (Solanum tuberosum L.) / Inhibitory Effect in vitro of Five Monoterpens from Essentials Oils on a Rhizoctonia solani Isolate in Potato (Solanum tuberosum L.)

    Scientific Electronic Library Online (English)

    Daymara, Vaillant Flores; Carlos, Romeu Carballo; Elda, Ramos Ramos; Marleny, González García; Rebeca, Ramírez Ochoa; Johan, González Pentón.

    2009-09-01

    Full Text Available En los últimos años la sociedad mundial ha priorizado los aspectos ambientales, y ha conducido un grupo de investigaciones hacia el descubrimiento de nuevas alternativas para el manejo integrado de plagas y enfermedades, con menos efectos negativos al ambiente. Los aceites esenciales, que hasta hace [...] poco eran empleados solamente en la industria farmacéutica y cosmética, en la actualidad tienen gran importancia por su efecto en el control de plagas y enfermedades de las plantas. Basado en este criterio, se evaluó la actividad fungicida de cinco monoterpenos (mentol, timol, alcanfor, citronelal y 1,8 cineol) comúnmente encontrados en aceites esenciales. Se empleó el método de envenenamiento del medio de cultivo a concentraciones de 0,5; 0,1 y el 0,05% p/v para evaluar el efecto inhibitorio de cada uno sobre un aislado de Rhizoctonia solani, causante de la rizoctoniasis en papa. Se calculó el porcentaje de inhibición y los resultados se analizaron estadísticamente. Se obtuvo que timol, mentol y citronelal tuvieron el 100% de inhibición al 0,1 y el 0,5%; Por otra parte, alcanfor y 1,8 cineol mostraron resultados por debajo del 100%; pero se valorarán para posteriores estudios, donde el rango de concentración sea mayor. Abstract in english The looking for new alternative to chemical control for integrated pest management to reduce the environmental impact has received attention internationally in last decades. Essentials oils have been using in pharmaceutical and cosmetic industry, recently they have become in an interesting possibili [...] ty for pest and disease control. The fungicide activity of five monoterpens (menthol, thymol, camphor, citronellal and 1,8 cineol), commonly found in essentials oils was evaluated. The method of culture media poisoning was used with concentration of 0,5; 0,1 y 0,05% w/v. The inhibitory effect was evaluated on a Rhizoctonia solani isolate, pathogen which causes rizoctoniasis in potato crops. The inhibition percentage was calculated and the results were statistically analyzed. Thymol, menthol and citronellal showed 100% of inhibition at 0,5 and 0,1%. The monoterpens camphor and 1, 8 cineol showed lower values of inhibition percentage, but they will taking into account for future studies with a wider range of concentration.

  1. Effect of carbon and nitrogen sources on growth and biological efficacy of Pseudomonas fluorescens and Bacillus subtilis against Rhizoctonia solani, the causal agent of bean damping-off.

    Science.gov (United States)

    Peighamy-Ashnaei, S; Sharifi-Tehrani, A; Ahmadzadeh, M; Behboudi, K

    2007-01-01

    One of the most important environmental factors that regulate the growth and antagonistic efficacy of biocontrol agents is the medium. The aim of this paper was to find the nitrogen and carbon sources that provide maximum biomass production of strains P-5 and P-6 (Pseudomonas fluorescens), B-3 and B-16 (Bacillus subtilis) and minimum cost of media, whilst maintaining biocontrol efficacy. All of the strains were grown in seven liquid media (pH=6.9) including: sucrose + yeast extract, molasses of sugar beet + yeast extract in 2:1 and 1:1 w/w ratios, molasses of sugar beet + urea, nutrient broth, molasses and malt extract, at an initial inoculation of 1 x 10(5) CFU ml(-1). Cells from over night cultures used to inoculate soil at 1 x 10(9) CFU cm(-3) soil. At the same time, fungal inoculum (infected millet seed with Rhizoctonia solani) was added to soil at the rate of 2 g kg(-1) soil. Results indicated that growth of P-6, B-3 and B-16 in molasses + yeast extract (1:1 w/w) medium was significantly higher than in the other media. Molasses + yeast extract (1:1 and 2:1 w/w) media supported rapid growth and high cell yields in P-5. In greenhouse condition, results indicated that the influence of the media on the biocontrol efficacy of P-5, P-6, B-3 and B-16 was the same and Pseudomonas fluorescens P-5 in molasses and malt extract media reduced the severity of disease up to 72.8 percent. On the other hand, there were observed significant differences on bean growth after one month in greenhouse. P-5 in molasses + yeast extract (1:1 w/w) medium had the most effects on bean growth promotion. In this study molasses media showed good yield efficacy in all of the strains. The high sucrose concentration in molasses justifies the high biomass in all of the strains. Also, the low cost of molasses allows its concentration to be increased in media. On the other hand, yeast extract was the best organic nitrogen source for antagonist bacteria but it is expensive for an industrial process. So it should be replaced by another industrial product instead of yeast extract, which confirm by an economic and technological study. The results obtained in this study could be used to provide a reliable basis to increase the population of biocontrol agents in fermentation process. PMID:18396833

  2. Research on possibilities of utilization of chosen Brassicaceae plants in protection of cucumber against damping-off caused by Rhizoctonia solani Kühn and Fusarium culmorum (W.G.SmithSacc.

    Directory of Open Access Journals (Sweden)

    Zbigniew J. Burgie?

    2005-12-01

    Full Text Available The aim of the work was to determine the usefulness of dried leaves of savoy cabbage, red cabbage, horse radish and fringed cabbage in protection of cucumber against damping-off caused by fungi Rhizoctonia solani and Fusarium culmorum. In the laboratory experiments, pathogens were grown on PDA containing dried leaves (3g·100 cm-3 and in atmosphere containing volatile substances evolved from plant material. The addition of radish horse leaves into PDA caused total inhibition of R. solani development. Remaining plants were also characterized by high fungistatic activity (% of growth inhibition about 85%. F. culmorum was less sensitive. The horse radish leaves showed the strongest activity (65 %, weakest in combination with fringed cabbage leaves (38,9%. The similar regularity in the case of fumigation activity was observed. The effectiveness of dried leaves in protection of cucumber against damping-off was confirmed in greenhouse experiment. The amendment of soil inoculated with R. solani in dose 2 g per 500 cm3 of soil significantly increased the number of cucumber sprouts compared to the control. In the experiment with F. culmorum only in combination with horse radish and red cabbage leaves significant action was observed.

  3. Efeito do tratamento de sementes de algodoeiro com fungicidas no controle do tombamento de plântulas causado por Rhizoctonia solani, sob condições de casa de vegetação / of cotton seed treatment with fungicides in the control of Rhizoctonia solani seedling damping-off under greenhouse conditions

    Scientific Electronic Library Online (English)

    Augusto César Pereira, Goulart.

    2008-10-01

    Full Text Available O objetivo deste trabalho foi avaliar a eficácia do tratamento de sementes de algodoeiro com fungicidas no controle do tombamento de plântulas causado por Rhizoctonia solani. O ensaio foi conduzido na casa de vegetação da Embrapa Agropecuária Oeste, em Dourados, Mato Grosso do Sul. Sementes não trat [...] adas e tratadas com os fungicidas foram semeadas em areia contida em bandejas plásticas, dispostas em orifícios individuais, eqüidistantes e a 3 cm de profundidade. A inoculação com R. solani AG-4 foi feita utilizando-se 5g do inóculo do fungo/bandeja, distribuídos de forma homogênea na superfície do substrato. O fungo foi cultivado por 35 dias em sementes de aveia preta autoclavadas e trituradas em moinho (1mm). Foi observado efeito significativo do tratamento fungicida na emergência inicial e final de plântulas, bem como no controle do tombamento de pré e pós-emergência do algodoeiro, com os melhores resultados sendo obtidos pelos tratamentos tolylfluanid+pencycuron+triadimenol e azoxystrobin+fludioxonil+mefenoxan, seguidos de carboxin+thiram, PCNB e pencycuron. O fungicida menos eficiente foi o carbendazim+thiram. Melhores resultados com relação às variáveis estudadas foram obtidos com a utilização de misturas de fungicidas em comparação ao uso isolado de um determinado produto. Não foram observadas diferenças significativas com relação ao índice de velocidade de emergência, altura e peso fresco das plântulas. Abstract in english The objective of this work was to evaluate the efficacy of cotton seed treatment with fungicides in the control of R. solani seedling damping-off. This experiment was carried out under greenhouse conditions at Embrapa Agropecuária Oeste, in Dourados city, Mato Grosso do Sul State, Brazil. Treated an [...] d untreated seeds of the cultivar DeltaOpal were sowed in sand contained in plastic trays, placed in individual and equidistant wells, 3cm deep. Into each plastic tray were put 5g of the pathogen inoculum. The inoculation of R. solani AG-4 was done by the homogeneous distribution of the fungus inoculum onto the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill (1mm). The evaluations were done based on symptoms development and seedling survival. The significant effect of the fungicide treatment on initial and final seedling emergence, as well as in the control of pre and post-emergence damping-off was observed. The best results were obtained with tolylfluanid+pencycuron+triadimenol and azoxystrobin+fludioxonil+mefenoxan, followed by carboxin+thiram, PCNB and pencycuron. The least efficient fungicide was carbendazim+thiram. Seed treatment with fungicide combinations provided better results than the use of the single ones. No significant effect was observed in relation to speed of emergence index, seedling height and seedling fresh weight.

  4. Efeito do tratamento de sementes de algodoeiro com fungicidas no controle do tombamento de plântulas causado por Rhizoctonia solani, sob condições de casa de vegetação of cotton seed treatment with fungicides in the control of Rhizoctonia solani seedling damping-off under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Augusto César Pereira Goulart

    2008-10-01

    Full Text Available O objetivo deste trabalho foi avaliar a eficácia do tratamento de sementes de algodoeiro com fungicidas no controle do tombamento de plântulas causado por Rhizoctonia solani. O ensaio foi conduzido na casa de vegetação da Embrapa Agropecuária Oeste, em Dourados, Mato Grosso do Sul. Sementes não tratadas e tratadas com os fungicidas foram semeadas em areia contida em bandejas plásticas, dispostas em orifícios individuais, eqüidistantes e a 3 cm de profundidade. A inoculação com R. solani AG-4 foi feita utilizando-se 5g do inóculo do fungo/bandeja, distribuídos de forma homogênea na superfície do substrato. O fungo foi cultivado por 35 dias em sementes de aveia preta autoclavadas e trituradas em moinho (1mm. Foi observado efeito significativo do tratamento fungicida na emergência inicial e final de plântulas, bem como no controle do tombamento de pré e pós-emergência do algodoeiro, com os melhores resultados sendo obtidos pelos tratamentos tolylfluanid+pencycuron+triadimenol e azoxystrobin+fludioxonil+mefenoxan, seguidos de carboxin+thiram, PCNB e pencycuron. O fungicida menos eficiente foi o carbendazim+thiram. Melhores resultados com relação às variáveis estudadas foram obtidos com a utilização de misturas de fungicidas em comparação ao uso isolado de um determinado produto. Não foram observadas diferenças significativas com relação ao índice de velocidade de emergência, altura e peso fresco das plântulas.The objective of this work was to evaluate the efficacy of cotton seed treatment with fungicides in the control of R. solani seedling damping-off. This experiment was carried out under greenhouse conditions at Embrapa Agropecuária Oeste, in Dourados city, Mato Grosso do Sul State, Brazil. Treated and untreated seeds of the cultivar DeltaOpal were sowed in sand contained in plastic trays, placed in individual and equidistant wells, 3cm deep. Into each plastic tray were put 5g of the pathogen inoculum. The inoculation of R. solani AG-4 was done by the homogeneous distribution of the fungus inoculum onto the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill (1mm. The evaluations were done based on symptoms development and seedling survival. The significant effect of the fungicide treatment on initial and final seedling emergence, as well as in the control of pre and post-emergence damping-off was observed. The best results were obtained with tolylfluanid+pencycuron+triadimenol and azoxystrobin+fludioxonil+mefenoxan, followed by carboxin+thiram, PCNB and pencycuron. The least efficient fungicide was carbendazim+thiram. Seed treatment with fungicide combinations provided better results than the use of the single ones. No significant effect was observed in relation to speed of emergence index, seedling height and seedling fresh weight.

  5. Efeito do tratamento de sementes de algodoeiro com fungicidas no controledo tombamento em relação à densidade de inóculo de Rhizoctonia solani / Effect of cotton seed treatments with fungicides to control damping-off in relation to inoculum densities of Rhizoctonia solani

    Scientific Electronic Library Online (English)

    Augusto César Pereira, Goulart.

    2006-09-01

    Full Text Available O fungo Rhizoctonia solani Kuhn é considerado o principal agente causal do tombamento de plântulas do algodoeiro no Brasil. A maneira mais eficiente e econômica de controlar essa doença é através do tratamento das sementes com fungicidas. A performance dos fungicidas depende, dentre outros fatores, [...] da população desse fungo no solo. Este trabalho foi desenvolvido, em condições de casa de vegetação, na Embrapa Agropecuária Oeste, em Dourados, MS, com o objetivo de determinar o efeito do tratamento de sementes de algodoeiro com fungicidas, no controle do tombamento, em relação a diferentes densidades de inóculo de R. solani no solo. Sementes da cultivar DeltaOpal, tratadas e não tratadas com diferentes fungicidas, foram semeadas a 3 cm de profundidade em areia contida em bandejas plásticas. As sementes foram dispostas em orifícios individuais e eqüidistantes. A inoculação com o fungo foi feita pela distribuição homogênea do inóculo na superfície do substrato. O fungo foi cultivado por 35 dias em sementes de aveia preta autoclavadas e trituradas em moinho (1 mm). Quatro densidades de inóculo foram testadas: 1 g; 2 g; 3 g e 4 g/bandeja plástica de 56x35x10 cm. Foi observado efeito do tratamento fungicida na emergência inicial e final de plântulas, bem como no controle do tombamento de pré e pós-emergência. O tratamento das sementes com a mistura de fungicidas proporcionou os melhores resultados no controle do tombamento em comparação ao seu uso isolado. A interação fungicidas x densidade de inóculo foi significativa, indicando que a eficiência dos fungicidas foi influenciada pela densidade de inóculo do fungo. A performance dos fungicidas testados foi melhor na presença dos níveis mais baixos de inóculo do fungo (1,0 g e 2,0 g/bandeja). A eficiência dos fungicidas testados foi menor para as populações de 3,0g e 4,0g do patógeno, sendo que a maioria dos tratamentos fungicidas apresentou perda significativa de eficiência na presença desses níveis de R. solani. Os fungicidas usados neste estudo não apresentaram efeitos fitotóxicos às plântulas de algodoeiro. Abstract in english The fungus Rhizoctonia solani Kuhn is considered the most important cause of cotton damping-off in Brazil. Treatment of seeds with fungicides is the most efficient and economical procedure to control this disease. The performance of fungicides depends, among many other factors, of the pathogen popul [...] ation in the soil. This work was carried out, under greenhouse conditions at Embrapa Agropecuária Oeste, Dourados, MS, with the goal to determine the effect of treatment of cotton seeds with fungicides to control damping-off at different inoculum densities of R. solani in the soil. Seeds of cultivar DeltaOpal treated or not with different fungicides were sowed 3 cm deep in sand contained in plastic flats. Seeds were placed in individual and equidistant wells. Inoculum of the fungus was homogeneously distributed in the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill until reach the size of 1mm. Four inoculum densities were tested: 1 g; 2 g; 3 g e 4 g/plastic flat with dimensions of 56x35x10 cm. The effect of the fungicide treatment on initial and final seedling emergence, as well as, in the control of post and pre-emergence damping-off was observed. Treatment of seed with a combinations of fungicides gave the best results in controlling damping-off as compared to the use of each fungicide alone. The interaction fungicides x inoculum densities, was significant indicating that the efficiency of the fungicides was somehow affected by the fungus densities. Fungicides had the best performance at low inoculum densities (1g and 2g/flat). As for fungi populations of 3g and 4g/flat, the efficiency of all fungicides tested decreased sharply, with a reduced control of the disease. The fungicides used in this study did not have any phytotoxic effect on cotton seedlings.

  6. Evaluación de un biofungicida para el control de la mancha bandeada del maíz causada por Rhizoctonia Solani Kühn en siembras comerciales en Portuguesa, Venezuela / Evaluation of a biofungicide for the control of maize banded stripe Rhizoctonia Solani Kühn on commercial fields at the Portuguesa state, Venezuela

    Scientific Electronic Library Online (English)

    Pedro J, García M; Samuel R, Cabrera P; Jimmy J, Sánchez; Alberto A, Pérez C.

    2008-12-01

    Full Text Available El objetivo principal de este trabajo fue evaluar el efecto de un biofungicida, a base de Trichoderma harzianum, sobre la incidencia y la severidad de la enfermedad mancha bandeada del maíz causada por el hongo Rhizoctonia solani Kühn, anamorfo de Thanathephorus cucumeris, en parcelas comerciales en [...] el estado Portuguesa, Venezuela, durante el ciclo de lluvias de 2001. Se seleccionaron parcelas en 8 localidades donde se presentaba la enfermedad en forma endémica. Las mismas fueron subdivididas en 2 lotes de aproximadamente 5 ha c/u; uno se trató con el biofungicida y el otro se dejó sin tratar. La aplicación se hizo en 2 fases: tratando la semilla con 100 g del biofungicida /20 kg de semilla y una segunda aplicación a los 30 días después de la siembra usando 3,0 l del producto comercial /ha. En cada parcela la siembra de los lotes tratados y no tratados se realizó de manera simultánea. La incidencia y la severidad de la enfermedad se determinaron a los 70 días después de la emergencia, seleccionando 5 puntos de muestreo distri­buidos uniformemente en cada lote. La incidencia fue determinada utilizando un arreglo factorial en un diseño de bloques al azar con 5 repeticiones y la severidad por vía no paramétrica mediante la prueba de Friedman. En promedio, el biofungicida disminuyó cerca de 50% la incidencia de la enfermedad en todas las localidades. Los resultados mostraron el efecto benéfico del biofungicida, representando una alternativa viable, eficaz y amigable con el ambiente para el control de la enfermedad. Abstract in english The objective of this study was to determine the effect of a biofungicide, Trichoderma harzianum, on the incidence and severity of the disease maize banded leaf caused by Rhizoctonia solani Kühn fungus, anamorph of Thanathephorus cucumeris, in commercial fields of corn, at the Portuguesa State, Vene [...] zuela, during the rainy season of the 2001 year. We selected commercial plots in eight locations normally affected by the disease. In each place the plots were divided in two areas, each one of about 5 ha; in each place one of the 5 ha was treated with the biofungicide, and the other one was allowed without any application. The biofungicide dose was split: at the sowing time in the seed (100 g of biofungicide /20 kg of seed), and 30 days after sowing in a dose of 3 liters of the commercial product /ha. Treated and no treated plots were sowed at the same time. We evaluated the incidence and severity of the fungus at about 70 days of the crop cycle, in 5 areas inside each plot. The incidence was analyzed using a factorial arrangement in a randomized block design with 5 replications, while the severity was analyzed using the Friedman non-parametric test. We found that the biofungicide reduced the disease in 50% in all locations. This result showed the beneficial effects of the biofungicide, and it represent a valuable, successful and environmental friendly alternative to control the disease.

  7. A double-stranded RNA element from a hypovirulent strain of Rhizoctonia solani occurs in DNA form and is genetically related to the pentafunctional AROM protein of the shikimate pathway

    OpenAIRE

    Lakshman, Dilip K.; Jian, Jianhua; Tavantzis, Stellos M.

    1998-01-01

    M2 is a double-stranded RNA (dsRNA) element occurring in the hypovirulent isolate Rhs 1A1 of the plant pathogenic basidiomycete Rhizoctonia solani. Rhs 1A1 originated as a sector of the virulent field isolate Rhs 1AP, which contains no detectable amount of the M2 dsRNA. The complete sequence (3,570 bp) of the M2 dsRNA has been determined. A 6.9-kbp segment of total DNA from either Rhs 1A1 or Rhs 1AP hybridizes with an M2-specific cDNA probe. The sequences of M2 dsRNA and of PCR products gener...

  8. Impact of Gamma Irradiation Stresses II. Control of Sugarbeet Pathogens Rhizoctonia solani Kuhn and Sclerotium rolfsii Sacc.

    OpenAIRE

    Moussa, Tarek A. A.; Rizk, Mohamed A.

    2003-01-01

    To control the fungal pathogens attacked sugarbeet plant, we subjected R. solani and S. rolfsii to different gamma irradiation doses (0.0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 and 7.0 kGy for R. solani and 0.0, 0.5, 1.0, 2.0, 3.0 and 4.0 kGy for S. rolfsii). The growth activities of R. solani were completely inhibited at dose 7.0 kGy, while S. rolfsii at 4.0 kGy. The infection percentage was inhibited with gamma irradiation doses increased for both R. solani and S. rolfsii. This was confirmed by...

  9. Lippia graveolens and Carya illinoensis Organic Extracts and there in vitro Effect Against Rhizoctonia Solani Kuhn

    OpenAIRE

    Hernandez-castillo, Francisco D.; Francisco Castillo-Reyes; Gabriel Gallegos-Morales; Raul Rodriguez-Herrera; Aguilar-gonzalez, Cristobal N.

    2010-01-01

    Problem statement: Plant extracts with polyphenolic compounds obtained with different solvents have been evaluated against plant pathogens. However, most of these extract have been obtained using solvents no allowed under an organic production context. Approach: In the present research was to evaluate the inhibitory effect of polyphenolic extracts from L. graveolens and C. illinoensis, obtained with alternative organic solvents (lanolin and cocoa butter), water and ethanol against R. solani i...

  10. Biocontrol capacity of wild and mutant Trichoderma harzianum (Rifai) strains on Rhizoctonia solani 618: effect of temperature and soil type during storage

    Scientific Electronic Library Online (English)

    Jaime, Montealegre; Luis, Valderrama; Rodrigo, Herrera; Ximena, Besoaín; Luz M, Pérez.

    2009-10-15

    Full Text Available Wild (Th11, Th12 and Th650) and mutant (Th11A80.1, Th12A40.1, Th12C40.1 and Th650-NG7) Trichoderma harzianum strains were stored for 180 days at 5ºC or at 22ºC, in two types of soils. Strains recovered at 90, 120 and 180 days from the two types of soils, retained their full capacity to biocontrol Rh [...] izoctonia solani 618, that produces crown and root rot of tomatoes. Recovery, estimated as colony forming units (cfu) of the wild and mutant strains, showed that all increased their cfu after storage independently of the type of soil and temperature, although kinetic behavior differed among strains. Ratios of recovery after storage in type B soil/ type A soil or at 22ºC/5ºC, higher or lower than one respectively, allowed to establish that Th11 and Th12 were the most appropriate strains for the biocontrol of R. solani in conditions where growth of the phytopathogen is optimal.

  11. Development of SCAR markers and UP-PCR cross-hybridization method for specific detection of four major subgroups of Rhizoctonia from infected turfgrasses

    Science.gov (United States)

    Several species and hyphal anastomosis groups (AG) of Rhizoctonia solani (sensu lato) cause brown patch diseases of turfgrasses. Conventional methods of identification of Rhizoctonia pathogens are time consuming and often inaccurate. A rapid identification assay for Waitea circinata (anamorph: Rhizo...

  12. Review. Biology and Systematics of the forn genus Rhizoctonia

    OpenAIRE

    Gonza?lez Garci?a, V.; Portal, M. A?ngeles; Rubio, Vi?ctor

    2006-01-01

    Members of the form genus Rhizoctonia D.C. are considered as a complex mixture of filamentous fungi, having in common the possession of a non-spored imperfect state, usually referred to as the Rhizoctonia anamorph. The group includes several of the most devastating crop pathogens like Thanatephorus cucumeris (Frank) Donk (anamorph = Rhizoctonia solani Kühn), the majority of orchid mycorrhizal symbionts (mainly belonging to genus Ceratobasidium D.P. Rogers) and a collection of saprotrophic...

  13. A double-stranded RNA element from a hypovirulent strain of Rhizoctonia solani occurs in DNA form and is genetically related to the pentafunctional AROM protein of the shikimate pathway.

    Science.gov (United States)

    Lakshman, D K; Jian, J; Tavantzis, S M

    1998-05-26

    M2 is a double-stranded RNA (dsRNA) element occurring in the hypovirulent isolate Rhs 1A1 of the plant pathogenic basidiomycete Rhizoctonia solani. Rhs 1A1 originated as a sector of the virulent field isolate Rhs 1AP, which contains no detectable amount of the M2 dsRNA. The complete sequence (3,570 bp) of the M2 dsRNA has been determined. A 6.9-kbp segment of total DNA from either Rhs 1A1 or Rhs 1AP hybridizes with an M2-specific cDNA probe. The sequences of M2 dsRNA and of PCR products generated from Rhs 1A1 total DNA were found to be identical. Thus this report describes a fungal host containing full-length DNA copies of a dsRNA element. A major portion of the M2 dsRNA is located in the cytoplasm, whereas a smaller amount is found in mitochondria. Based on either the universal or the mitochondrial genetic code of filamentous fungi, one strand of M2 encodes a putative protein of 754 amino acids. The resulting polypeptide has all four motifs of a dsRNA viral RNA-dependent RNA polymerase (RDRP) and is phylogenetically related to the RDRP of a mitochondrial dsRNA associated with hypovirulence in strain NB631 of Cryphonectria parasitica, incitant of chestnut blight. This polypeptide also has significant sequence similarity with two domains of a pentafunctional polypeptide, which catalyzes the five central steps of the shikimate pathway in yeast and filamentous fungi. PMID:9600982

  14. Manejo de Pythium sp. y Rhizoctonia solani Kuhn en bancos de enraizamiento de Gypsophila paniculata L. Management of Pythium sp. and Rhizoctonía solaní kuhn in rooting benches of Gypsophíla paniculata L.

    Directory of Open Access Journals (Sweden)

    Garcés de Granada Emira

    1994-12-01

    Full Text Available

    En este trabajo, se evaluó el efecto que sobre los patógenos Pythium sp. Y Rhizoctonia solani Kuhn., tienen los aislamientos de Trichoderma harzianum (T 17 y T 13 y Trichoderma sp. (T18, lo mismo que tratamientos químicos aplicados en bancos de enraizamiento de Gypsophila paniculata L., con altos índices de contaminación. Para evaluar el control de la pudrición del cuello de la raíz de Gypsophila paniculata L., se realizaron observaciones semanales en las cuales se tuvieron en cuenta los porcentajes de esquejes sanos, de esquejes muertos y de esquejes en los cuales se desarrollaban raíces. Los resultados muestran que es más efectivo el control de la pudrición con la aplicación semanal de fungicidas. Sin embargo, se recomienda el empleo de cepas de Trichoderma sp., pero aplicadas con una frecuencia, por lo menos igual, a la empleada con los fungicidas, ya que se observa su efecto inmediato, pero no permanente y, además, porque parecen influir sobre el desarrollo de las plantas.

  15. A New Disease of Gladiolus Caused by Binucleate Rhizoctonia sp.

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Soleimani

    2005-01-01

    Full Text Available Fungi with Rhizoctonia-like mycelia were isolated from root and stem of Gladiolus (Gladiolus hybrida L. grown in commercial glasshouse in Mahallat, Iran, during the summer and fall of 2003. Isolated fungi were identified as either binucleate or multi nucleate Rhizoctonia sp. On the basis of hyphal characteristics and nuclear number, twenty three isolates of Rhizoctonia sp. were obtained from infected corms and stems. Of the 23 isolate, 9 had binucleate and 14 had multinucleate vegetative hyphal cells. Representative isolates of binucleate Rhizoctonia sp. were characterized for anastomosis, optimum temperature in vitro and virulence on Gladiolus. Isolates of binucleate Rhizoctonia failed to anastomose with tester isolates of Anastomosis Groups (AG-A throug-S (not including AG-J and AG-M. The optimum temperature range for growth rate of binucleate Rhizoctonia sp. was 24-28?C. Growth rate of binucleate Rhizoctonia sp. was more rapid than R. solani. Five isolates from each group caused severe corm rot and mortality of plant during rooting. Isolates of binucleate Rhizoctonia caused corm and stem rot and mortality only on 35-day-old plants. This is the first detailed report of corm and stem rot disease of Gladiolus caused by binucleate Rhizoctonia. Further field studies are needed on the ecology and pathogenicity of Rhizoctonia sp. to formulate steps for controlling corm and stem rot of Gladiolus.

  16. Interactions between cauliflower and Rhizoctonia anastomosis groups with different levels of aggressiveness

    OpenAIRE

    Höfte Monica; Pannecoucque Joke

    2009-01-01

    Abstract Background The soil borne fungus Rhizoctonia is one of the most important plant pathogenic fungi, with a wide host range and worldwide distribution. In cauliflower (Brassica oleracea var. botrytis), several anastomosis groups (AGs) including both multinucleate R. solani and binucleate Rhizoctonia species have been identified showing different levels of aggressiveness. The infection and colonization process of Rhizoctonia during pathogenic interactions is well described. In contrast, ...

  17. Determination of the Anastomosis Grouping and Virulence of Rhizoctonia spp. Associated with Potato Tubers Grown in Lincoln, New Zealand

    OpenAIRE

    Reza Farrokhi-Nejad; Cromey, Matthew G.; Ali Moosawi-jorf, S.

    2007-01-01

    A total of 58 isolates of Rhizoctonia spp. (46 R. solani and 12 binucleate Rhizoctonia) were recovered from potato tubers showing black scurf disease symptom during the 2004 growing season in Lincoln, New Zealand. The isolates were assigned to 5 Anastomosis Groups (AG) of R. solani AG-3 (54.34%), AG-5 (28.26%), AG-8 (8.69%), AG-4 (6.52%) and AG-2-2 IIIB (2.17%) and six anastomosis groups of binucleate Rhizoctonia, AG-K (25%), AG-Bi (25%), AG-Ba (8.33%), AG-C (8.33%), AG-D (8.33%) and AG-E (8....

  18. Characterisation of bi- and polynucleate antagonistic Rhizoctonia strains

    OpenAIRE

    Valentino, Danila; Tamietti, Giacomo; Cardinale, Francesca; Ferraris, Lucia

    2004-01-01

    Two isolates of Rhizoctonia, R2 binucleate and R3 polynucleate, effective against R. solani on radish were investigated for their mode of action. Tomato seedlings were grown in soil colonised with R2, R3, a non-pathogenic suppressive Fusarium oxysporum strain, as standard, or in steamed soil. Plant leaves were challenge inoculated with Botrytis cinerea. Laminarinase and chitinase activity was determined in leaves before and after inoculation with B. cinerea. Microscopic obse...

  19. Rhizoctonia Crown and Root Rot Resistance of Beta PI's from the USDA-ARS NPGS, 2009.

    Science.gov (United States)

    Beta vulgaris plant introductions (PI) were screened for Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. Inoculum of R. solani isolate R-9 (AG-2-2), colonized to dry barley and course ground, was applied to the crown of plants at a rate of 4.8 g/m. Beets were lifted...

  20. Comparison of bacterial communities from inside and outside of Rhizoctonia bare patches in wheat

    Science.gov (United States)

    Rhizoctonia solani AG-8 causes distinct patches of stunted wheat in the field. Bacterial communities from bulk soil and rhizospheres of wheat were analyzed with pyrosequencing. Replicated samples were taken from inside and outside of patches; and from patches that had recovered the previous 1–2 year...

  1. Molecular and genetic aspects of controlling the soilborne necrotrophic pathogens Rhizoctonia and Pythium.

    Science.gov (United States)

    Okubara, Patricia A; Dickman, Martin B; Blechl, Ann E

    2014-11-01

    The soilborne necrotrophic pathogens Rhizoctonia and Pythium infect a wide range of crops in the US and worldwide. These pathogens pose challenges to growers because the diseases they cause are not adequately controlled by fungicides, rotation or, for many hosts, natural genetic resistance. Although a combination of management practices are likely to be required for control of Rhizoctonia and Pythium, genetic resistance remains a key missing component. This review discusses the recent deployment of introduced genes and genome-based information for control of Rhizoctonia, with emphasis on three pathosystems: Rhizoctonia solani AG8 and wheat, R. solani AG1-IA and rice, and R. solani AG3 or AG4 and potato. Molecular mechanisms underlying disease suppression will be addressed, if appropriate. Although less is known about genes and factors suppressive to Pythium, pathogen genomics and biological control studies are providing useful leads to effectors and antifungal factors. Prospects for resistance to Rhizoctonia and Pythium spp. will continue to improve with growing knowledge of pathogenicity strategies, host defense gene action relative to the pathogen infection process, and the role of environmental factors on pathogen-host interactions. PMID:25438786

  2. Determination of the Anastomosis Grouping and Virulence of Rhizoctonia spp. Associated with Potato Tubers Grown in Lincoln, New Zealand

    Directory of Open Access Journals (Sweden)

    Reza Farrokhi-Nejad

    2007-01-01

    Full Text Available A total of 58 isolates of Rhizoctonia spp. (46 R. solani and 12 binucleate Rhizoctonia were recovered from potato tubers showing black scurf disease symptom during the 2004 growing season in Lincoln, New Zealand. The isolates were assigned to 5 Anastomosis Groups (AG of R. solani AG-3 (54.34%, AG-5 (28.26%, AG-8 (8.69%, AG-4 (6.52% and AG-2-2 IIIB (2.17% and six anastomosis groups of binucleate Rhizoctonia, AG-K (25%, AG-Bi (25%, AG-Ba (8.33%, AG-C (8.33%, AG-D (8.33% and AG-E (8.33%. Two isolates of BNR did not anastomose with any of the tester strains and remain unidentified. In pathogenicity tests that were carried out on radish, carrot, lettuce, onion, tomato and hemp, it was found that all the isolates of both R. solani and binucleate Rhizoctonia to be virulent at varying degrees to these 6 plants species from different families. In these tests, isolates of AG-3 and AG-8 from R. solani population caused the highest and lowest disease severity on all 6 plant species, respectively. In population of binucleate Rhizoctonia, on the other hand, the highest and lowest disease severities were caused by the isolates of AG-D and AG-Ba on all test plants, respectively. When the results of the pathogenicity tests were examined in terms of the susceptibility levels of the plants, the most resistant plant was tomato against different AGs of R. solani and BNR. On the other hand, radish was the most susceptible plant species tested in this study against both R. solani and BNR isolates.

  3. Interactions between cauliflower and Rhizoctonia anastomosis groups with different levels of aggressiveness

    Directory of Open Access Journals (Sweden)

    Höfte Monica

    2009-07-01

    Full Text Available Abstract Background The soil borne fungus Rhizoctonia is one of the most important plant pathogenic fungi, with a wide host range and worldwide distribution. In cauliflower (Brassica oleracea var. botrytis, several anastomosis groups (AGs including both multinucleate R. solani and binucleate Rhizoctonia species have been identified showing different levels of aggressiveness. The infection and colonization process of Rhizoctonia during pathogenic interactions is well described. In contrast, insights into processes during interactions with weak aggressive or non-pathogenic isolates are limited. In this study the interaction of cauliflower with seven R. solani AGs and one binucleate Rhizoctonia AG differing in aggressiveness, was compared. Using microscopic and histopathological techniques, the early steps of the infection process, the colonization process and several host responses were studied. Results For aggressive Rhizoctonia AGs (R. solani AG 1-1B, AG 1-1C, AG 2-1, AG 2-2 IIIb and AG 4 HGII, a higher developmental rate was detected for several steps of the infection process, including directed growth along anticlinal cell walls and formation of T-shaped branches, infection cushion formation and stomatal penetration. Weak or non-aggressive AGs (R. solani AG 5, AG 3 and binucleate Rhizoctonia AG K required more time, notwithstanding all AGs were able to penetrate cauliflower hypocotyls. Histopathological observations indicated that Rhizoctonia AGs provoked differential host responses and pectin degradation. We demonstrated the pronounced deposition of phenolic compounds and callose against weak and non-aggressive AGs which resulted in a delay or complete block of the host colonization. Degradation of pectic compounds was observed for all pathogenic AGs, except for AG 2-2 IIIb. Ranking the AGs based on infection rate, level of induced host responses and pectin degradation revealed a strong correlation with the disease severity caused by the AGs. Conclusion The differences in aggressiveness towards cauliflower observed among Rhizoctonia AGs correlated with the infection rate, induction of host defence responses and pectin breakdown. All Rhizoctonia AGs studied penetrated the plant tissue, indicating all constitutive barriers of cauliflower were defeated and differences in aggressiveness were caused by inducible defence responses, including cell wall fortifications with phenolic compounds and callose.

  4. DNA fingerprinting and anastomosis grouping reveal similar genetic diversity in Rhizoctonia species infecting turfgrasses in the transition zone of USA.

    Science.gov (United States)

    Amaradasa, B S; Horvath, B J; Lakshman, D K; Warnke, S E

    2013-01-01

    Rhizoctonia blight is a common and serious disease of many turfgrass species. The most widespread causal agent, Thanatephorus cucumeris (anamorph: R. solani), consists of several genetically different subpopulations. In addition, Waitea circinata varieties zeae, oryzae and circinata (anamorph: Rhizoctonia spp.) also can cause the disease. Accurate identification of the causal pathogen is important for effective management of the disease. It is challenging to distinguish the specific causal pathogen based on disease symptoms or macroscopic and microscopic morphology. Traditional methods such as anastomosis reactions with tester isolates are time consuming and sometimes difficult to interpret. In the present study universally primed PCR (UP-PCR) fingerprinting was used to assess genetic diversity of Rhizoctonia spp. infecting turfgrasses. Eighty-four Rhizoctonia isolates were sampled from diseased turfgrass leaves from seven distinct geographic areas in Virginia and Maryland. Rhizoctonia isolates were characterized by ribosomal DNA internal transcribed spacer (rDNA-ITS) region and UP-PCR. The isolates formed seven clusters based on ITS sequences analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering of UP-PCR markers, which corresponded well with anastomosis groups (AGs) of the isolates. Isolates of R. solani AG 1-IB (n = 18), AG 2-2IIIB (n = 30) and AG 5 (n = 1) clustered separately. Waitea circinata var. zeae (n = 9) and var. circinata (n = 4) grouped separately. A cluster of six isolates of Waitea (UWC) did not fall into any known Waitea variety. The binucleate Rhizoctonia-like fungi (BNR) (n = 16) clustered into two groups. Rhizoctonia solani AG 2-2IIIB was the most dominant pathogen in this study, followed by AG 1-IB. There was no relationship between the geographic origin of the isolates and clustering of isolates based on the genetic associations. To our knowledge this is the first time UP-PCR was used to characterize Rhizoctonia, Waitea and Ceratobasidium isolates to their infra-species level. PMID:23709576

  5. O papel de Rhizoctonia spp. binucleadas na indução de resistência a mela da soja / The role of binucleate Rhizoctonia spp. inducing resistance to the soybean foliar blight

    Scientific Electronic Library Online (English)

    Marco Antonio, Basseto; Walter Veriano, Valério Filho; Elaine Costa, Souza; Paulo Cezar, Ceresini.

    2008-06-01

    Full Text Available O papel de Rhizoctonia spp. binucleadas (RBN), no biocontrole de doenças causadas por R. solani Kühn em várias culturas, tem sido relatado na literatura. No entanto, não há informação, no Brasil, sobre o potencial de RBN como agentes de biocontrole contra doenças causadas por Rhizoctonia na soja. A [...] hipótese testada foi de que isolados de RBN podem induzir resistência na soja contra a mela, causada por R. solani do grupo de anastomose (AG) 1 IA. Desta forma, o objetivo deste trabalho foi avaliar isolados de RBN, obtidos de amendoim, feijão e soja quanto à capacidade de induzir resistência na soja contra a mela, em condições de casa de vegetação. Esta pesquisa evidencia a ação de RBN na indução de resistência em plantas de soja contra a mela. Entretanto, a manifestação e a efetividade do fenômeno de indução de resistência são dependentes da época de cultivo da soja. Abstract in english The role of non-pathogenic binucleate Rhizoctonia spp. (BNR) on the biocontrol of diseases caused by R. solani on many crops has been reported in the literature. However, in Brazil, there is no information about the potential of BNR as biocontrol agents against Rhizoctonia diseases on soybean. On th [...] is research we tested the hypothesis that BNR can induce resistance on soybean against the foliar blight caused by R. solani anastomosis group (AG) 1 IA. Thus, the objective of this research was to evaluate BNR isolates isolated from peanuts, snapbeans and soybean according to their ability for inducing resistance on soybean against the foliar blight disease, under greenhouse conditions. This research evidenced the role of BNR inducing resistance on soybeans against the foliar blight. However, both the occurrence and effectiveness of the phenomenon of induced resistance are dependent on the soybean cultivation season.

  6. O papel de Rhizoctonia spp. binucleadas na indução de resistência a mela da soja = The role of binucleate Rhizoctonia spp. inducing resistance to the soybean foliar blight

    Directory of Open Access Journals (Sweden)

    Marco Antonio Basseto

    2008-04-01

    Full Text Available O papel de Rhizoctonia spp. binucleadas (RBN, no biocontrole de doenças causadas por R. solani Kühn em várias culturas, tem sido relatado na literatura. No entanto, não há informação, no Brasil, sobre o potencial de RBN como agentes de biocontrole contradoenças causadas por Rhizoctonia na soja. A hipótese testada foi de que isolados de RBN podem induzir resistência na soja contra a mela, causada por R. solani do grupo de anastomose (AG 1 IA. Desta forma, o objetivo deste trabalho foi avaliar isolados de RBN, obtidos de amendoim, feijão e soja quanto à capacidade de induzir resistência na soja contra a mela, em condições de casa de vegetação. Esta pesquisa evidencia a ação de RBN na indução de resistência em plantas de soja contra a mela. Entretanto, a manifestação e a efetividade do fenômeno de indução de resistência são dependentes da época de cultivo da soja.The role of non-pathogenic binucleate Rhizoctonia spp. (BNR onthe biocontrol of diseases caused by R. solani on many crops has been reported in the literature. However, in Brazil, there is no information about the potential of BNR as biocontrol agents against Rhizoctonia diseases on soybean. On this research we tested thehypothesis that BNR can induce resistance on soybean against the foliar blight caused by R. solani anastomosis group (AG 1 IA. Thus, the objective of this research was to evaluate BNR isolates isolated from peanuts, snapbeans and soybean according to their ability forinducing resistance on soybean against the foliar blight disease, under greenhouse conditions. This research evidenced the role of BNR inducing resistance on soybeans against the foliar blight. However, both the occurrence and effectiveness of the phenomenon of induced resistance are dependent on the soybean cultivation season.

  7. Agroecological factors correlated to soil DNA concentrations of Rhizoctonia in dryland wheat production zones of Washington state, USA.

    Science.gov (United States)

    Okubara, Patricia A; Schroeder, Kurtis L; Abatzoglou, John T; Paulitz, Timothy C

    2014-07-01

    The necrotrophic soilborne fungal pathogens Rhizoctonia solani AG8 and R. oryzae are principal causal agents of Rhizoctonia root rot and bare patch of wheat in dryland cropping systems of the Pacific Northwest. A 3-year survey of 33 parcels at 11 growers' sites and 60 trial plots at 12 Washington State University cereal variety test locations was undertaken to understand the distribution of these pathogens. Pathogen DNA concentrations in soils, quantified using real-time polymerase chain reaction, were correlated with precipitation, temperature maxima and minima, and soil texture factors in a pathogen-specific manner. Specifically, R. solani AG8 DNA concentration was negatively correlated with precipitation and not correlated with temperature minima, whereas R. oryzae concentration was correlated with temperature minima but not with precipitation. However, both pathogens were more abundant in soils with higher sand and lower clay content. Principal component analysis also indicated that unique groups of meteorological and soil factors were associated with each pathogen. Furthermore, tillage did not affect R. oryzae but affected R. solani AG8 at P = 0.06. Lower soil concentrations of R. solani AG8 but not R. oryzae occurred when the previously planted crop was a broadleaf (P R. solani AG8 concentrations were consistent with the general distribution of bare patch symptoms, based on field observations and surveys of other pathogens, but was present at many sites in which bare patch symptoms were not evident. Management of Rhizoctonia root rot and bare patch should account for the likelihood that each pathogen is affected by a unique group of agroecological variables. PMID:24915426

  8. Método fácil y confiable para teñir núcleos en hongos del complejo Rhizoctonia Easy and reliable method for nuclei staining of Rhizoctonia complex fungi

    Directory of Open Access Journals (Sweden)

    Luis Cedeño

    2008-12-01

    Full Text Available En el complejo Rhizoctonia la morfología hifal y configuración del septo permiten diferenciar los géneros, mientras que las especies pueden ser distinguidas por la condición nuclear y el grosor de hifas “guías” ó la morfometría del teleomorfo. Para caracterizar las especies en uni, bi y multinucleadas se han desarrollado varios métodos de tinción nuclear con acridina naranja, azules de anilina y tripano, diamina fenil indol (DAPI, giemsa, hematoxilina, orceina y safranina O. Algunos de esos procedimientos son rápidos, pero otros requieren técnicas especiales (fluorescencia o consumen mucho tiempo y limitan la cantidad de muestras a procesar. Un nuevo método fue desarrollado durante análisis de anastomosis (AGs en aislamientos de R. solani que atacan la papa cultivada en Mérida, Venezuela. El procedimiento es rápido, fácil, confiable y permite la manipulación simultánea de un número considerable de especimenes, y tanto el núcleo como el nucléolo conservan su integridad. El método fue probado exitosamente en 10 patrones de AGs de R. solani, y permitió separar 173 cepas multinucleadas y 3 binucleadas, todas del género Rhizoctonia. El método fue efectivo utilizando sustrato de agua-agar 2,4 % más PDA 0,39 %, en cultivos de 18 a 48 h fijado con formaldehído 4 % y coloreado con fucsina ácida 0,025 en ácido láctico 50 %.Hyphal morphology and septal structure configuration of the fungi included in Rhizoctonia complex allows for differentiation of genus, while species may be distinguished by nuclear condition and thickness of the runner hyphae, or teleomorph morphometry. For characterization of species in uni, bi, and multinucleate diverse methods of staining have been developed using acridine orange, aniline and trypan blue, diamine phenyl indole (DAPI, giemsa, hematoxiline, orcein and saphranin O. Some of these procedures are quick to perform, while others require special techniques (fluorescence or are time consuming, which impose a limit on the number of samples that can be processed at a time. A new method of nuclei staining was developed during the analysis of anastomosis groups (AGs of R. solani strains isolated from potato plants cultivated in Mérida, Venezuela. The procedure is quick, easy, and reliable, and allows for simultaneous manipulation of a significant number of samples, and both nucleus and nucleolus maintain their integrity. The method was successfully assayed in 10 different AGs testers of R. solani, and allowed separation of 173 multinucleate and 3 binucleate Rhizoctonia strains. Method effectiveness depends upon growth medium (water agar 2.4 % plus PDA 0.39 %, culture age (18-48 h, fixing agent (formaldehyde 4 %, and stain (fuchsin acid 0.025 % in lactic acid 50 %.

  9. Método fácil y confiable para teñir núcleos en hongos del complejo Rhizoctonia / Easy and reliable method for nuclei staining of Rhizoctonia complex fungi

    Scientific Electronic Library Online (English)

    Luis, Cedeño.

    2008-12-01

    Full Text Available En el complejo Rhizoctonia la morfología hifal y configuración del septo permiten diferenciar los géneros, mientras que las especies pueden ser distinguidas por la condición nuclear y el grosor de hifas “guías” ó la morfometría del teleomorfo. Para caracterizar las especies en uni, bi y multinuclead [...] as se han desarrollado varios métodos de tinción nuclear con acridina naranja, azules de anilina y tripano, diamina fenil indol (DAPI), giemsa, hematoxilina, orceina y safranina O. Algunos de esos procedimientos son rápidos, pero otros requieren técnicas especiales (fluorescencia) o consumen mucho tiempo y limitan la cantidad de muestras a procesar. Un nuevo método fue desarrollado durante análisis de anastomosis (AGs) en aislamientos de R. solani que atacan la papa cultivada en Mérida, Venezuela. El procedimiento es rápido, fácil, confiable y permite la manipulación simultánea de un número considerable de especimenes, y tanto el núcleo como el nucléolo conservan su integridad. El método fue probado exitosamente en 10 patrones de AGs de R. solani, y permitió separar 173 cepas multinucleadas y 3 binucleadas, todas del género Rhizoctonia. El método fue efectivo utilizando sustrato de agua-agar 2,4 % más PDA 0,39 %, en cultivos de 18 a 48 h fijado con formaldehído 4 % y coloreado con fucsina ácida 0,025 en ácido láctico 50 %. Abstract in english Hyphal morphology and septal structure configuration of the fungi included in Rhizoctonia complex allows for differentiation of genus, while species may be distinguished by nuclear condition and thickness of the runner hyphae, or teleomorph morphometry. For characterization of species in uni, bi, an [...] d multinucleate diverse methods of staining have been developed using acridine orange, aniline and trypan blue, diamine phenyl indole (DAPI), giemsa, hematoxiline, orcein and saphranin O. Some of these procedures are quick to perform, while others require special techniques (fluorescence) or are time consuming, which impose a limit on the number of samples that can be processed at a time. A new method of nuclei staining was developed during the analysis of anastomosis groups (AGs) of R. solani strains isolated from potato plants cultivated in Mérida, Venezuela. The procedure is quick, easy, and reliable, and allows for simultaneous manipulation of a significant number of samples, and both nucleus and nucleolus maintain their integrity. The method was successfully assayed in 10 different AGs testers of R. solani, and allowed separation of 173 multinucleate and 3 binucleate Rhizoctonia strains. Method effectiveness depends upon growth medium (water agar 2.4 % plus PDA 0.39 %), culture age (18-48 h), fixing agent (formaldehyde 4 %), and stain (fuchsin acid 0.025 % in lactic acid 50 %).

  10. Identification, molecular characterization, and evolution of group I introns at the expansion segment D11 of 28S rDNA in Rhizoctonia species.

    Science.gov (United States)

    González, Dolores

    2013-09-01

    The nuclear ribosomal DNA of Rhizoctonia species is polymorphic in terms of the nucleotide composition and length. Insertions of 349-410 nucleotides in length with characteristics of group I introns were detected at a single insertion point at the expansion segment D11 of 28S rDNA in 12 out of 64 isolates. Eleven corresponded to Rhizoctonia solani (teleomorph: Thanatephorous) and one (AG-Q) to Rhizoctonia spp. (teleomorph: Ceratobasidium). Sequence data showed that all but AG-Q contained conserved DNA catalytic core regions (P, Q, R, and S) essential for selfsplicing. The predicted secondary structure revealed that base-paired helices corresponded to subgroup IC1. Isolates from same anastomosis group and even subgroups within R. solani were variable with regard to possession of introns. Phylogenetic analyses indicated that introns were vertically transmitted. Unfortunately, sequence data from the conserved region from all 64 isolates were not useful for delimiting species. Analyses with IC1 introns at same insertion point, of both Ascomycota and Basidiomycota indicated the possibility of horizontal transfer at this site. The present study uncovered new questions on evolutionary pattern of change of these introns within Rhizoctonia species. PMID:24012302

  11. Plant Disease Lesson: Rhizoctonia Diseases of Turfgrass

    Science.gov (United States)

    Lane P. Tredway (University of Georgia, Athens; )

    2001-11-09

    This plant disease lesson on Rhizoctonia diseases of turfgrass (caused by the fungi Rhizoctonia species) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.

  12. Caracterização de isolados de Rhizoctonia spp., associados à mela do feijão-caupi (Vigna unguiculata), coletados em Roraima / Characterization of Rhizoctonia spp. associated with cowpea web (Vigna unguiculata) blight in Roraima, Brazil

    Scientific Electronic Library Online (English)

    Kátia L., Nechet; Bernardo A., Halfeld-Vieira.

    2006-10-01

    Full Text Available A mela causada pelo fungo Rhizoctonia solani (teleomorfo Thanatephorus cucumeris) é a principal doença que afeta a cultura do feijão-caupi (Vigna unguiculata) no Estado de Roraima. Este trabalho teve como objetivo caracterizar 28 isolados de Rhizoctonia spp. obtidos de plantas de feijão-caupi com si [...] ntoma de mela, coletados em ecossistemas de mata e de cerrado em Roraima. Foram avaliados o número de núcleos, a taxa de crescimento micelial, a formação e o tamanho de microescleródios, o grupo de anastomose e realizado teste de patogenicidade. Um isolado proveniente do cerrado foi identificado como binucleado e os demais isolados, de mata e de cerrado, como multinucleados. A taxa de crescimento micelial, em meio batata-dextrose-agar a 25 ºC e escuro contínuo, variou de 2,1-5,3 cm.dia-1 para os isolados de mata e de 2,7-5,8 cm.dia-1 para os isolados de cerrado. Nestas mesmas condições, após três a quatro dias foi observada a formação de microescleródios. Dois grupos foram diferenciados: um grupo com formação de 10-50 microescleródios.placa-1, em forma de tufos, inicialmente brancos e tornando-se marrom claro, de 1-2 mm (maioria dos isolados de mata) e outro grupo com mais de 100 microescleródios.placa-1, de coloração marrom e 68-541 µm (maioria dos isolados de cerrado). Dos 28 isolados coletados, 24 foram identificados como pertencentes ao grupo de anastomose GA1-1A de Rhizoctonia solani. Abstract in english The web blight caused by the fungus Rhizoctonia solani (teleomorph Thanatephorus cucumeris) is an important disease of cowpea [Vigna unguiculata (L.) Walp.] in Roraima state, Brazil. The aim of this work was to characterize 28 Rhizoctonia spp. isolates from cowpea plants with web blight, collected i [...] n two ecosystems (savannah and forest) in Roraima state. The characteristics evaluated were nuclear number, radial growth rate, the presence and morphology of microsclerotia, anastomosis group (AG) and pathogenicity test. One savannah isolate was binucleate and the others, savannah and forest isolates, were multinucleate. The radial growth rate on potato-dextrose-aga, at 25 ºC in the dark, was 2.1 to 5.3 cm.day-1 for forest isolates and 2.7 to 5.8 cm.day-1 for savannah isolates. In these conditions, after three to four days, microsclerotia formation was observed. Two types of microsclerotia were differentiated: one type of 10 to 50 microsclerotia.Petri dish-1, formed as flat sclerotia mass, which was white when young and pale brown at maturity, 1 to 2 mm in diameter (most forest isolates) and another type of 100 microsclerotia.Petri dish-1, brown color, 68 to 541 µm in diameter (most savannah isolates). Among 28 Rhizoctonia isolates collected in Roraima state, 24 anastomosed with AG1-1A of Rhizoctonia solani.

  13. Caracterização de isolados de Rhizoctonia spp., associados à mela do feijão-caupi (Vigna unguiculata, coletados em Roraima Characterization of Rhizoctonia spp. associated with cowpea web (Vigna unguiculata blight in Roraima, Brazil

    Directory of Open Access Journals (Sweden)

    Kátia L. Nechet

    2006-10-01

    Full Text Available A mela causada pelo fungo Rhizoctonia solani (teleomorfo Thanatephorus cucumeris é a principal doença que afeta a cultura do feijão-caupi (Vigna unguiculata no Estado de Roraima. Este trabalho teve como objetivo caracterizar 28 isolados de Rhizoctonia spp. obtidos de plantas de feijão-caupi com sintoma de mela, coletados em ecossistemas de mata e de cerrado em Roraima. Foram avaliados o número de núcleos, a taxa de crescimento micelial, a formação e o tamanho de microescleródios, o grupo de anastomose e realizado teste de patogenicidade. Um isolado proveniente do cerrado foi identificado como binucleado e os demais isolados, de mata e de cerrado, como multinucleados. A taxa de crescimento micelial, em meio batata-dextrose-agar a 25 ºC e escuro contínuo, variou de 2,1-5,3 cm.dia-1 para os isolados de mata e de 2,7-5,8 cm.dia-1 para os isolados de cerrado. Nestas mesmas condições, após três a quatro dias foi observada a formação de microescleródios. Dois grupos foram diferenciados: um grupo com formação de 10-50 microescleródios.placa-1, em forma de tufos, inicialmente brancos e tornando-se marrom claro, de 1-2 mm (maioria dos isolados de mata e outro grupo com mais de 100 microescleródios.placa-1, de coloração marrom e 68-541 µm (maioria dos isolados de cerrado. Dos 28 isolados coletados, 24 foram identificados como pertencentes ao grupo de anastomose GA1-1A de Rhizoctonia solani.The web blight caused by the fungus Rhizoctonia solani (teleomorph Thanatephorus cucumeris is an important disease of cowpea [Vigna unguiculata (L. Walp.] in Roraima state, Brazil. The aim of this work was to characterize 28 Rhizoctonia spp. isolates from cowpea plants with web blight, collected in two ecosystems (savannah and forest in Roraima state. The characteristics evaluated were nuclear number, radial growth rate, the presence and morphology of microsclerotia, anastomosis group (AG and pathogenicity test. One savannah isolate was binucleate and the others, savannah and forest isolates, were multinucleate. The radial growth rate on potato-dextrose-aga, at 25 ºC in the dark, was 2.1 to 5.3 cm.day-1 for forest isolates and 2.7 to 5.8 cm.day-1 for savannah isolates. In these conditions, after three to four days, microsclerotia formation was observed. Two types of microsclerotia were differentiated: one type of 10 to 50 microsclerotia.Petri dish-1, formed as flat sclerotia mass, which was white when young and pale brown at maturity, 1 to 2 mm in diameter (most forest isolates and another type of 100 microsclerotia.Petri dish-1, brown color, 68 to 541 µm in diameter (most savannah isolates. Among 28 Rhizoctonia isolates collected in Roraima state, 24 anastomosed with AG1-1A of Rhizoctonia solani.

  14. SIDEROPHORE PRODUCING Pseudomonas AS PATHOGENIC Rhisoctonia solani AND Botrytis cinerea ANTAGONISTS

    Directory of Open Access Journals (Sweden)

    Martha Páez

    2005-06-01

    Full Text Available Pseudomonas aeruginosa, Pseudomonas putida biovar B, Pseudomonas marginalis y Burkholderia cepacia, aisladas de rizosfera y filosfera de plantas de rosa y alstroemeria, identificadas por ensayos bioquímicos y cultivadas en medio King B, mostraron propiedades antagónicas contra los patógenos (se usó medio PDA agar par el cultivo Rhizoctonia solani y Botrytis cinerea. Estas propiedades coincidieron con la presencia de un sideróforo, sustancia polar con bandas de absorción en 260 nm y 402 nm. Se observó incremento del crecimiento longitudinal de las plantas, medido sobre el tallo central, por influencia de P. putida biovar B, P. aeruginosa y P. marginalis. El crecimiento de rizomas (a: 0.05 fue notorio bajo la influencia de P. marginalis.

  15. Cropping systems and cultural practices determine the Rhizoctonia anastomosis groups associated with Brassica spp. in Vietnam.

    Science.gov (United States)

    Hua, Gia Khuong Hoang; Bertier, Lien; Soltaninejad, Saman; Höfte, Monica

    2014-01-01

    Ninety seven Rhizoctonia isolates were collected from different Brassica species with typical Rhizoctonia symptoms in different provinces of Vietnam. The isolates were identified using staining of nuclei and sequencing of the rDNA-ITS barcoding gene. The majority of the isolates were multinucleate R. solani and four isolates were binucleate Rhizoctonia belonging to anastomosis groups (AGs) AG-A and a new subgroup of A-F that we introduce here as AG-Fc on the basis of differences in rDNA-ITS sequence. The most prevalent multinucleate AG was AG 1-IA (45.4% of isolates), followed by AG 1-ID (17.5%), AG 1-IB (13.4%), AG 4-HGI (12.4%), AG 2-2 (5.2%), AG 7 (1.0%) and an unknown AG related to AG 1-IA and AG 1-IE that we introduce here as AG 1-IG (1.0%) on the basis of differences in rDNA-ITS sequence. AG 1-IA and AG 1-ID have not been reported before on Brassica spp. Pathogenicity tests revealed that isolates from all AGs, except AG-A, induced symptoms on detached leaves of several cabbage species. In in vitro tests on white cabbage and Chinese cabbage, both hosts were severely infected by AG 1-IB, AG 2-2, AG 4-HGI, AG 1-IG and AG-Fc isolates, while under greenhouse conditions, only AG 4-HGI, AG 2-2 and AG-Fc isolates could cause severe disease symptoms. The occurrence of the different AGs seems to be correlated with the cropping systems and cultural practices in different sampling areas suggesting that agricultural practices determine the AGs associated with Brassica plants in Vietnam. PMID:25372406

  16. Caracterização de isolados de Rhizoctonia spp. e identificação de novos grupos de anastomose em jardim clonal de eucalipto / Characterization of isolates of Rhizoctonia spp. and identification of new anastomosis groups in eucalyptus clonal nurseries

    Scientific Electronic Library Online (English)

    Eugenio, Sanfuentes; Acelino C., Alfenas; Luiz A., Maffia; Reginaldo G., Mafia.

    2007-06-01

    Full Text Available Espécies de Rhizoctonia causam queima foliar em brotações de jardim clonal e podridão de estacas durante o enraizamento, que podem limitar a clonagem do eucalipto, por estaquia. Diante da importância do patógeno para a cultura e da falta de estudos sobre a diversidade de isolados, esse trabalho obje [...] tivou caracterizar isolados e relatar novos grupos de anastomose de Rhizoctonia spp. em jardim clonal de eucalipto. Os isolados obtidos nas diferentes fases de propagação por estaquia foram caracterizados quanto ao número de núcleos nas células vegetativas, agrupados segundo as características morfológicas das colônias e identificados quanto aos grupos de anastomose, incluindo auxotrofia por tiamina. Avaliou-se, também, a virulência ao eucalipto e o efeito da temperatura no crescimento micelial dos isolados. Não se detectou correlação entre os agrupamentos morfológicos e reações de anastomose. Constatou-se, também, que a população de Rhizoctonia spp., nos solos de jardins clonais, é constituída por ampla gama de isolados, predominantemente binucleados, com diferentes graus de virulência a eucalipto. Os isolados binucleados e os multinucleados, tiveram a mesma tendência de crescimento em relação à temperatura, com ótimo para a taxa de crescimento entre 25-30 ºC. Observou-se, pela primeira vez, isolados de R. solani AG2-2 IIIB e os binucleados de Rhizoctonia spp., AG-P e AG-O, como agentes etiológicos da podridão de estacas em casa de vegetação, e os isolados binucleados AG-A e AG-L em solo de jardim clonal de eucalipto. Abstract in english Rhizoctonia spp. cause shoot and leaf blight of eucalyptus in clonal hedges as well as cuttings. Despite the importance of Rhizoctonia spp. to eucalyptus, little is known about their diversity. Thus, we characterized isolates and report new anastomosis groups in a eucalyptus clonal hedge. Isolates o [...] btained at different stages of cutting propagation were characterized according to the number of nuclei in vegetative cells, grouped by morphological characteristics of the colony, anastomosis group, and thiamine auxotrophism. The isolates were also evaluated for virulence on eucalyptus and effect of temperature on their mycelial growth. No correlation between morphological grouping and anastomosis reaction was detected. A wide range of isolates, predominantly binucleate, forms the population of Rhizoctonia spp. present in the soil of clonal hedges, which differed in virulence to eucalyptus. Binucleate and multinucleate isolates had similar growth features at different temperatures, with an optimum growth rate between 25-30 ºC. Isolates of R. solani AG2-2 IIIB and binucleate isolates of Rhizoctonia spp., AG-P and AG-O, as agents of cutting rot, and binucleate isolates AG-A and AG-L in the soil of eucalyptus clonal hedge are reported for the first time.

  17. Extracellular mycosynthesis of gold nanoparticles using Fusarium solani

    Science.gov (United States)

    Gopinath, K.; Arumugam, A.

    2014-08-01

    The development of eco-friendly methods for the synthesis of nanomaterial shape and size is an important area of research in the field of nanotechnology. The present investigation deals with the extracellular rapid biosynthesis of gold nanoparticles using Fusarium solani culture filtrate. The UV-vis spectra of the fungal culture filtrate medium containing gold ion showed peak at 527 nm corresponding to the plasmon absorbance of gold nanoparticles. FTIR spectra provide an evidence for the presence of heterocyclic compound in the culture filtrate, which increases the stability of the synthesized gold nanoparticles. The X-ray analysis respects the Bragg's law and confirmed the crystalline nature of the gold nanoparticles. AFM analysis showed the results of particle sizes (41 nm). Transmission electron microscopy (TEM) showed that the gold nanoparticles are spherical in shape with the size range from 20 to 50 nm. The use of F. solani will offer several advantages since it is considered as a non-human pathogenic organism. The fungus F. solani has a fast growth rate, rapid capacity of metallic ions reduction, NPs stabilization and facile and economical biomass handling. Extracellular biosynthesis of gold nanoparticles could be highly advantageous from the point of view of synthesis in large quantities, time consumption, eco-friendly, non-toxic and easy downstream processing.

  18. Caracterização de isolados de Rhizoctonia associados à queima foliar em Roraima = Characterization of Rhizoctonia isolates associated with foliar blight in Roraima.

    Directory of Open Access Journals (Sweden)

    Dayane Rodrigues Youssef

    2012-08-01

    Full Text Available O objetivo desse trabalho foi caracterizar isolados do fungo Rhizoctonia associados à queima foliar, obtidos de hospedeiros de importância econômica no estado de Roraima. Os isolados foram obtidos de plantas de feijão-caupi (Vigna unguiculata, soja (Glycine max, seringueira (Hevea brasiliensis, melancia (Citrullus lanatus, alface (Lactuca sativa e feijão-guandu (Cajanus cajan. Os parâmetros utilizados foram números de núcleos, grupo de anastomose e as características culturais da colônia, taxa de crescimento micelial e a formação de escleródios nos meios de cultura: batata dextrose agar (BDA, BDA+asparagina, BDA+extrato de levedura, Czapek Agar, maltose-peptona-agar, soil extract agar, sacarose-yeast-asparagina e V-8. Todos os 10 isolados estudados foram caracterizados como multinucleados e pertencentes à espécie Rhizoctonia solani. Três isolados de feijão-caupi, um de soja e o isolado de melancia foram identificados como AGI-1A e um isolado de feijãocaupi, um de soja e o isolado de feijão-guandu como AGI-1B. O isolado de seringueira não foi identificado como nenhum dos padrões de anastomose utilizado. Para a maioria dos isolados as maiores taxas de crescimento micelialforam obtidas no meio de cultura Soil Extract Agar. Dois tipos de escleródios, característicos do grupo AGI, foram observados: formação de 2-20 tufos placa-1 coloração variável, 1-2 mm e formação de 38-611 microescleródios placa-1, de coloração marrom, medindo 100 ?m. A produção e o tipo de escleródio variaram com o isolado e o meio de cultura utilizado.The aim of this work was to characterize Rhizoctonia isolates associated with foliar blight symptom from hosts with economic importance at Roraima state. The isolates were recovered from cowpea (Vigna unguiculata, soybean (Glycine max, rubber tree (Hevea brasiliensis, watermelon (Citrullus lanatus, lettuce (Lactuca sativa and pigeonpea (Cajanus cajan. The evaluated characteristics were nuclear number, anastomosis group (AG and cultural characteristics, radial growth rate and the presence and morphology of sclerotia on the following media: potato dextrose agar (PDA, PDA+asparagine, PDA+yeast extract, Czapek Agar, maltose-peptone-agar,soil extract agar, sucrose-yeast-asparagine and V-8. All the 10 isolates evaluated were multinucleate and identified as Rhizoctonia solani. Three cowpea isolates, one soybean isolate and the watermelon isolate anastomosed with AG1-1A and one cowpea isolates, one soybean isolate and the pigeonpea isolate with AGI-1B. The rubber treeisolate was not identified with no anastomosis groups used in this study. Biggest radial growth rates were observed on the medium Soil Extract for most of the isolates. Two types of sclerotia, AGI typic were differentiated: one type of 2-20 flat sclerotia.Petri dish-1, variable colors, 1 to 2 mm in diameter and another type of 38-611 microsclerotia. Petri dish-1, brown color, 100 ?m in diameter. The number and sclerotia type were variable with the isolate and themedia used.

  19. SELECCIÓN DE AISLAMIENTOS DE Trichoderma spp. CANDIDATOS A BIOFUNGICIDAS PARA EL CONTROL DE Rhizoctonia sp. EN ARROZ / SELECTION OF Trichoderma spp. ISOLATE CANDIDATES TO BIOFUNGICIDES FOR THE CONTROL OF Rhizoctonia sp. ON RICE

    Scientific Electronic Library Online (English)

    B, Martínez; Yusimy, Reyes; Danay, Infante; E, González; Heyker, Baños; A, Cruz.

    2008-08-01

    Full Text Available El Tizón de la Vaina, causado por el hongo Rhizoctonia solani Kühn, es considerada la segunda enfermedad de importancia en el cultivo del arroz, en Cuba y el mundo. La potencialidad de aislados del género Trichoderma como antagonista de patógenos del suelo es reconocida y muestra resultados positivo [...] s sobre R. solani. El presente trabajo tiene como objetivo seleccionar los aislamientos de Trichoderma spp. más promisorios en dependencia de su antagonismo in vitro y su eficacia en condiciones semicontroladas y de campo, para el biocontrol de Rhizoctonia sp. El antagonismo se evaluó por el método del cultivo dual, donde se observó la competencia por el sustrato, micoparasitismo y la antibiosis. Se calculó el porcentaje de inhibición del crecimiento radial (PICR) a las 72 horas y los aislados que presentaron más de un 60 PICR y al menos dos tipos de interacción hifal se seleccionaron para evaluar su eficacia técnica (ET) sobre el patógeno en condiciones semicontroladas. Los aislamientos con una ET superior al 80% fueron seleccionados para ser evaluados en canteros tecnificados en campo. Los resultados mostraron que el 98,31% de los aislados presentaron alta capacidad antagónica, con diferentes tipos de interacción hifal como lisis, vacuolización, enrollamiento y penetración, de los que fueron seleccionados once. De ellos siete mostraron una ET superior al 80% en condiciones semicontroladas. Como promisorios para el control de la enfermedad en campo se destacaron los aislamientos 17, 75 y 78 con una ET superior al 90%. Abstract in english Sheath blight, caused by Rhizoctonia solani Kühn is considered the second important disease on rice in Cuba and the world. Trichoderma potentiality as antagonist of soil pathogen is recognized with positive results on R. solani. The present work had as objective to select the best Trichoderma isolat [...] es according to their in vitro antagonism and efficacy in the control of Rhizoctonia sp. in greenhouse and in the field. Antagonism was evaluated by the dual culture method, where the competition by the substrate, mycoparasitism and antibiosis were observed. The inhibition percentage of radial growth (IPRG) was calculated at 72 hours. The isolates with more than 60 PICR and at least two types of hyphal interaction were selected for being tested under greenhouse conditions, where the selection criterion was the technical efficacy (TE) under these conditions. Isolates with a TE higher than 80% were selected for field screening. The results showed that the 98,31% of the isolates had high antagonist capacity. They presented several hyphal interaction types such as lyses, vacuolization, coiling and penetration. Eleven Trichoderma isolates were selected in vitro. Of them, seven showed a TE higher than 80% in greenhouse. As promissories for the disease control in the field, isolates: 17, 75 and 78 with a TE higher than 90% were those highlighted under these conditions.

  20. Characteristics and diversity of Rhizoctonia spp. population in soil of selected forest bare-root nurseries in Poland

    Directory of Open Access Journals (Sweden)

    Marta Be?ka

    2014-12-01

    Full Text Available Fourty three Rhizoctonia isolates obtained from four forest nurseries situated in the Wielkopolska region (central-western Poland has been proved as multinucleate (anamorph – R. solani. They represented four anastomosis groups (AG: AG1-IC, AG-5, AG4-HG2 and AG2-1. Three AGs were found in Jarocin nursery (AG-5, AG4-HG2 and AG2-1, two in ?opuchówko (AG-5 and AG4-HG2 and one in Konstantynowo (AG1-IC and Pniewy (AG-5. All isolates were highly pathogenic to Scots pine (Pinus sylvestris seedlings and pose a large damping-off threat to the seedlings in the nurseries with single AG and in those where more AGs exists.

  1. The heterogeneity of the rDNA-ITS sequence and its phylogeny in Rhizoctonia cerealis, the cause of sharp eyespot in wheat.

    Science.gov (United States)

    Li, Wei; Sun, Haiyan; Deng, Yuanyu; Zhang, Aixiang; Chen, Huaigu

    2014-02-01

    The sequence heterogeneity of the ribosomal internal transcribed spacer (ITS) region was investigated for Rhizoctonia cerealis isolates from the anastomosis group AG-DI. Although sequence variability of the ITS has been reported in a few multinucleate R. solani isolates, it has very rarely been reported in binucleate Rhizoctonia spp. isolates and has never been described in R. cerealis, the pathogen of wheat sharp eyespot. In this study, the ITS regions of 15 R. cerealis isolates were cloned and sequenced. The results revealed more than one different ITS sequence within each isolate. This is the first evidence of ITS sequence heterogeneity in R. cerealis. Based on these ITS sequences, different sequences of one isolate did not cluster in one clade, but all of the sequences of the 15 isolates were clustered in the anastomosis subgroup AG-DI, suggesting that the heterogeneity of the ITS did not affect the molecular identification of their anastomosis group. Haplotype analyses indicated that there might be three evolutionary origins of R. cerealis, or a recombination event could be the cause of different ITS sequences in one genome. This study demonstrates the variability and the evolution of Rhizoctonia, especially binucleate R. cerealis. These findings will help design disease control strategies. PMID:23839120

  2. Lignin Degradation by Fusarium solani f. sp. glycines

    Science.gov (United States)

    Sudden death syndrome (SDS), caused by the soilborne fungal pathogen Fusarium solani f. sp. glycines, is one of the most important diseases of soybean. Lignin degradation may play a role in the infection, colonization, and survival of the fungus in root tissue . Lignin degradation by F. solani f. sp...

  3. Development of SCAR markers and UP-PCR cross-hybridization method for specific detection of four major subgroups of Rhizoctonia from infected turfgrasses.

    Science.gov (United States)

    Amaradasa, Bimal S; Lakshman, Dilip; Horvath, Brandon J; Amundsen, Keenan L

    2014-01-01

    A rapid identification assay for Waitea circinata (anamorph: Rhizoctonia spp.) varieties zeae and circinata causing patch diseases on turfgrasses was developed based on the universally primed PCR (UP-PCR) products cross-blot hybridization. Tester isolates belonging to the two varieties of W. circinata were amplified with a single UP primer L21, which generated multiple DNA fragments for each variety. Probes were prepared with UP-PCR products of each tester isolate by labeling with digoxigenin. Fieldcollected W. circinata isolates and representative isolates of different R. solani anastomosis groups (AG) and AG subgroups were amplified with L21, immobilized on nylon membrane and cross hybridized with the two probes. Isolates within a W. circinata variety cross-hybridized strongly, while non-homologous isolates did not cross-hybridize or did so weakly. Closely related W. circinata varieties zeae and circinata were clearly distinguished with this assay. Sequence-characterized amplified region (SCAR) markers also were developed from UP-PCR products to identify isolates of Thanatephorus cucumeris (anamorph: R. solani) AG 1-IB and AG 2-2IIIB. These two AGs are commonly isolated from diseased, cool-season turfgrasses. The specific SCAR markers that were developed could differentiate isolates of AG 1-IB or AG 2-2IIIB groups. These SCAR markers did not amplify a product from genomic DNA of nontarget isolates of Rhizoctonia. The specificities and sensitivities of the SCAR primers were tested on total DNA extracted from several field-grown, cool-season turf species having severe brown-patch symptoms. First, the leaf samples from diseased turf species were tested for the anastomosis groups of the causal pathogen, and thereafter the total DNA was amplified with the specific primers. The specific primers were sensitive and unique enough to produce a band from total DNA of diseased turfgrasses infected with either AG 1-IB or AG 2-2IIIB. PMID:24396105

  4. Controle químico da queima de folhas e da mela de estacas de eucalipto, causadas por Rhizoctonia spp. Chemical control of leaf scorch and web blight of eucalypt cuttings, caused by Rhizoctonia spp.

    Directory of Open Access Journals (Sweden)

    Silvaldo Felipe da Silveira

    2003-12-01

    Full Text Available Visando ao controle químico da queima de folhas e mela de estacas de eucalipto (Eucalyptus spp. em viveiros florestais, avaliou-se a eficiência de 12 fungicidas em inibir in vitro o crescimento micelial de um isolado epifítico de Rhizoctonia solani AG1-IB (RH-2. Sete fungicidas que inibiram totalmente o crescimento micelial do fungo, a concentrações inferiores a 100 ppm, foram pré-selecionados: methyl-tolclophos, benomyl, pencycuron, iprodione, thiabendazol, thiram e captan. Avaliou-se, ainda, a sensibilidade (EC50 = dose provável que inibe o crescimento micelial em 50% aos fungicidas methyl-tolclophos, benomyl, iprodione e pencycuron de mais oito isolados patogênicos ao eucalipto, que diferem entre si quanto a virulência, morfologia, grupo de anastomose, número de núcleos por célula vegetativa e padrões eletroforéticos de proteínas e isoenzimas. Embora variações nos valores de EC50 entre algumas combinações de fungicidas e isolados tenham ocorrido, todos os isolados foram sensíveis aos quatro fungicidas testados (EC50 To achieve the chemical control of leaf scorch and web blight of eucalyptus (Eucalyptus spp. cuttings in forest nurseries, 12 fungicides were assayed against one isolate of Rhizoctonia solani AG1-IB (RH-2. Seven fungicides (methyl-tolclophos, benomyl, pencycuron, iprodione, thiabendazol and captan completely inhibited mycelial growth under concentrations lower than 100 ppm of active ingredient on PDA culture. Additionally, the sensibility (EC50 = estimated dose for 50% inhibition of mycelial growth to methyl-tolclophos, benomyl, pencycuron and iprodione of another eight isolates differing in virulence, morphology, anastomosis groups, and proteins and isozyme profiles was evaluated. Little differences in sensitivity was observed in some combinations of fungicides-isolates. However, the eight isolates were sensitive to the four tested fungicides (EC50 < 11 ppm. Under artificial conditions of inoculations, sprays of iprodione (1,5 g/l, benomyl (1 g/l, methyl-tolclophos (1,5 g/l, thiram (2,1 g/l, captan (2 g/l, and pencycuron (2 g/l significantly (alpha=5% reduced the incidence of leaf scorch on shoots of plants in vessels. Pruning of diseased shoots in clonal gardens (field associated with weekly sprays of iprodione (1 g/l or mixtures of benomyl (0,5 g/l + captan (1 g/l alternating with benomyl (0,5 g/l + thiram (1 g/l, reduced the incidence of web blight on cuttings under shade house conditions (alpha=5%.

  5. Immobilization of lipase from Fusarium solani FS1 / Imobilização de lipase de Fusarium solani FS1

    Scientific Electronic Library Online (English)

    Kirsty, Knight; Maria do Carmo Barros, Pimentel; Marcia Maria Camargo de, Morais; William M., Ledingham; José Luiz de, Lima Filho; Maria de Mascena Diniz, Maia.

    2000-09-01

    Full Text Available Lipase de Fusarium solani FS1 foi imobilizada por ligação covalente usando esferas de poliacrilamida e Dacron magnetizado, retendo 12%, e 97% de atividade, respectivamente. A lipase foi também enclausurada em esferas de poliacrilamida e reteve 53% de sua atividade específica. Investigações sobre o c [...] omportamento cinético usando trioleína como substrato mostraram que as lipases imobilizadas não seguem a cinética de Michaelis-Menten. Abstract in english Lipase from Fusarium solani FS1 was immobilized by covalent attachment to polyacrylamide beads and onto magnetized Dacron, retaining 12% and 97% of activity, respectively. Lipase was also entrapped within polyacrylamide beads, retaining 53% of activity. Investigations of the kinetic characteristics [...] of the immobilized derivatives using triolein as substrate showed that lipase immobilized onto polyacrilamide beads and Dacron did not follow Michaelis-Menten kinetics.

  6. Immobilization of lipase from Fusarium solani FS1 Imobilização de lipase de Fusarium solani FS1

    Directory of Open Access Journals (Sweden)

    Kirsty Knight

    2000-09-01

    Full Text Available Lipase from Fusarium solani FS1 was immobilized by covalent attachment to polyacrylamide beads and onto magnetized Dacron, retaining 12% and 97% of activity, respectively. Lipase was also entrapped within polyacrylamide beads, retaining 53% of activity. Investigations of the kinetic characteristics of the immobilized derivatives using triolein as substrate showed that lipase immobilized onto polyacrilamide beads and Dacron did not follow Michaelis-Menten kinetics.Lipase de Fusarium solani FS1 foi imobilizada por ligação covalente usando esferas de poliacrilamida e Dacron magnetizado, retendo 12%, e 97% de atividade, respectivamente. A lipase foi também enclausurada em esferas de poliacrilamida e reteve 53% de sua atividade específica. Investigações sobre o comportamento cinético usando trioleína como substrato mostraram que as lipases imobilizadas não seguem a cinética de Michaelis-Menten.

  7. Compost Tea and Poultry Litter Extract: Alternative Organic Management Approaches for Stem Canker of Potato Caused by Rhizoctonia solani

    OpenAIRE

    Md. Rashidul Islam; Chhoa Mondal; Ismail Hossain; M. Bahadur Meah

    2013-01-01

    An experiment was conducted in the field laboratory, Department of Plant pathology, Bangladesh Agricultural University, Mymensingh to know the efficacy of compost tea and poultry litter extract in controlling stem canker of potato under natural infection condition. Significant effect of different treatments was observed on the incidence of stem canker of potato as compared to control. The results evidently showed the lowest stem canker incidence recorded in plots when IPM Lab Biopesticde was ...

  8. In vitro selection of beans (Phaseolus vulgaris) from Costa Rica for resistance to fungal pathogen Thanatephorus cucumeris (Rhizoctonia solani)

    International Nuclear Information System (INIS)

    The research has been realized in the Laboratory of Plant Pathology and Laboratory of Plant Tissue Cultures of the Department of Botany in the Palacky University, Olomouc during the period 3 September - 21 December 2007. In vitro cultivation of beans seeds.The culture medium AC agar (Sigma) was used for Thanatephorus cucumeris. The next three isolates from Costa Rica were tested: 007-3242, 007-3241, 007-3077. For each pathogen isolate three different doses were evaluated: 1%, 5% and 10%. The medium was added before it was autoclaved. Two bean varieties (Brunca /black color/ and Bribri /red color/) were used during this procedure. In order to cultivate the bean seeds the Murashige/Skoog (MS) (Duchefa) culture medium was used. The bean seeds were sterilized with Chloramine B (2.5%) for 30 min, washing them three times with distilled sterile water and then leaving the seeds into distilled sterile water for 24 hours. The seed coat was eliminated, and then the embryos were extirpated, and placed in Petri dishes for two days, after two days of incubation the roots were cut and transferred to Erlenmeyer flasks. They were cultivated in the growth chamber at a temperature of 24 + 2 deg. C and a photoperiod of 16 hours /8 day/night. The evaluations were made during the 30, 40 and 50 days of incubation. The spray method was used in order to inoculate Thanatephorus cucumeris from the in vitro bean seedlings. After three weeks of incubation the seedlings were inoculated (by using n the seedlings were inoculated (by using a glass sprayer) with T. cucumeris (treatments of 1%, 5%, 10%, 2 ml per/ Erlenmeyer flask) in aseptic conditions. The evaluation was made 12 days after the inoculation. The results obtained so far are preliminary, the collected data needs to be analyzed statistically, so it can be published this year. (author)

  9. Compost Tea and Poultry Litter Extract: Alternative Organic Management Approaches for Stem Canker of Potato Caused by Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Md. Rashidul Islam

    2013-09-01

    Full Text Available An experiment was conducted in the field laboratory, Department of Plant pathology, Bangladesh Agricultural University, Mymensingh to know the efficacy of compost tea and poultry litter extract in controlling stem canker of potato under natural infection condition. Significant effect of different treatments was observed on the incidence of stem canker of potato as compared to control. The results evidently showed the lowest stem canker incidence recorded in plots when IPM Lab Biopesticde was applied followed by foliar spray of Ridomil, compost tea, and BAU-Biofungicide while the highest stem canker incidence was recorded in untreated control plot. However, the soil drenching of compost tea and poultry litter extract also performed better as compared to control in reducing the incidence of stem canker. Significant effect of the treatments was observed on the plant height and yield except number of plant raised per tuber. Foliar and soil application of compost tea, poultry litter and mustard oil cake showed better performance in increasing the plant height and yield as compared to all other treatments. Benefit cost analyses of the treatments revealed that foliar application of compost tea showed highest BCR (65.20 followed by Soil application of IPM Lab Biopesticide with BCR 54.38. The treatments viz. foliar spray of Ridomil and BAU-Biofungicide resulted 35.31 and 38.88 BCR, respectively which were the second best treatments as compared to untreated control. The results indicated that an investment of Tk. 1.00 may lead to a profit up to Tk. 65.20 by foliar application of compost tea which shows the maximum profit in the present study. Therefore, compost tea as foliar spray may be used as an alternative environment-friendly approach to control stem canker of potato along with other biological means with maximum economic return.

  10. First Report of a Root and Crown Disease caused by Rhizoctonia solani on Centaurea maculosa in Russia

    Science.gov (United States)

    Spotted knapweed (SKW) (Centaurea maculosa Lamarck) is a non-indigenous species that is invasive over large areas in the U.S., especially in the western U. S. and Canada. It has been estimated that infestations of SKW cause $42 million in direct and indirect economic losses annually and the weed cou...

  11. In vitro production of conidia of Alternaria solani / Produção in vitro de conídios de Alternaria solani

    Scientific Electronic Library Online (English)

    Tatiana T.M.S, Rodrigues; Luiz A, Maffia; Onkar D, Dhingra; Eduardo S.G, Mizubuti.

    2010-08-01

    Full Text Available A esporulação de Alternaria solani in vitro pode ser escassa e tende a reduzir após sucessivas repicagens. Conduziram-se vários experimentos para avaliar o efeito da umidade, injúria da colônia, qualidade de luz e fotoperíodo, bem como do meio de cultura na produção de conídios. Adaptou-se a técnica [...] bifásica para induzir esporulação, por meio de injúria de micélio e desidratação do meio de cultura. Obtiveram-se melhores resultados quando colônias cresceram em meio V8 a 25ºC, no escuro, sob agitação durante sete dias; a massa de micélio foi triturada e a suspensão depositada em meio BDA (pH 6,5) em placas de Petri, incubando-se a 25 ± 2ºC, sob luz negra com 12 h de fotoperíodo. Validou-se o protocolo para 30 isolados de A. solani distintos quanto ao hospedeiro, local de origem, idade e forma de armazenamento. Quantificaram-se a produção, germinação e infectividade de conídios. Dos 30 isolados, 75% esporularam e a germinação mínima de conídios foi de 68%. Todos os isolados foram patogênicos em seus respectivos hospedeiros. Avaliou-se, também, o efeito de repicagens sucessivas na esporulação. Todos os isolados produziram conídios após seis repicagens sucessivas. Abstract in english Sporulation of Alternaria solani can be scarce and is often reduced when the fungus is cultivated in vitro. A series of experiments were conducted to assess the effects of moisture, mycelial wounding, light quality and photoperiod, and culture media on conidial production. A procedure to induce spor [...] ulation based on mycelial wounding and dehydration was adapted and validated. Best results were obtained when fungal colonies were grown in V8 medium at 25ºC in the dark with agitation for seven days; the mycelium mass was ground, poured into potato dextrose agar (pH 6.5) in plates, and incubated at 25 ± 2ºC under near ultraviolet light and 12 h-photoperiod. The procedure was validated with 30 isolates of A. solani from different hosts, sampling locations, ages, and storage conditions. Conidial production, germination, and infectivity were quantified. Seventy-five percent of the isolates sporulated and the lowest germination rate was 68%. Inoculations of conidial suspension of all isolates resulted in lesions on tomato and potato plants. The effect of subculturing on A. solani sporulation was also assessed. After six subcultures, every seven days, there was no reduction in sporulation of colonies that were induced with the protocol.

  12. Biogenesis of pipecolic acid in Rhizoctonia leguminicola

    International Nuclear Information System (INIS)

    This laboratory has long been interested in the biogenesis and biological properties of two indolizidine alkaloids, slaframine and swainsonine that are produced by the fungal parasite Rhizoctonia Leguminicola. Slaframine, (1S,6S,8aS-1 acetoxy-6-aminooctahydroindolizine) is a parasympathetic secretagogue, and swainsonine (1S,2R,8R,8aR-1,2,8-trihydroxyoctahydroindolizine) is a potent ?-mannosidase inhibitor. This thesis concerns the initial steps of the biosynthesis of these alkaloids from lysine, via the common intermediate pipecolic acid, in whole cells and cell free enzyme systems of R. leguminicola. In confirmation of earlier work performed in this laboratory, L-lysine was used preferentially for pipecolate biosynthesis in R. Leguminicola. This pathway was supported by the finding that cell free extracts of R. leguminicola consistently converted L-[U-14C]-lysine to three labelled metabolites: saccharopine, peak II, and pipecolic acid. Peak II was subsequently identified by appropriate proton NMR studies to be ?1-piperideine-6-carboxylate, and the following pathway of pipecolic acid formation was postulated: L-lysine ? saccharopine ? ?1-piperideine-6-carboxylate ? pipecolate. This pathway was confirmed by demonstration of each enzymatic step in vitro from purified radiolabeled substrates

  13. Studies of genetic polymorphism in the isolates of Fusarium solani

    OpenAIRE

    Gupta, Vijai K.; Misra, Ashok K.; Gaur, R.; Pandey, R.; Chauhan, U. K.

    2009-01-01

    Fusarium solani is the important pathogen causing wilt disease of guava in India. In the present investigation six representative isolate of Fusarium solani, collected from different places of India were subjected to analysis of genetic variability in terms of Carboxylesterases isozyme pattern and DNA polymorphism using RAPD-PCR. Pattern of Carboxylesterase revealed a similar isozyme cluster in the isolate namely, Allahabad (isolate-3), Faizabad, (isolate-4), Unnao (isolate-5) and Lucknow (i...

  14. Studies of genetic polymorphism in the isolates of Fusarium solani

    Directory of Open Access Journals (Sweden)

    Vijai K. Gupta

    2009-03-01

    Full Text Available Fusarium solani is the important pathogen causing wilt disease of guava in India. In the present investigation six representative isolate of Fusarium solani, collected from different places of India were subjected to analysis of genetic variability in terms of Carboxylesterases isozyme pattern and DNA polymorphism using RAPD-PCR. Pattern of Carboxylesterase revealed a similar isozyme cluster in the isolate namely, Allahabad (isolate-3, Faizabad, (isolate-4, Unnao (isolate-5 and Lucknow (isolate-6. Similar results were obtained when 10 randomly amplified polymorphic DNA markers (OPA1-OPA10 tested in the genome of Fusarium solani and grouped on basis of obtained allelic data. This pattern of genetic variability in the isolate was also supported by the analysis of the similarity indices and UPGMA dendrogram.

  15. Técnica de obtenção de filtrado de cultura de Alternaria solani

    Directory of Open Access Journals (Sweden)

    GOMES-OLIVEIRA IÁRA V.

    2001-01-01

    Full Text Available This work was developed to adapt culture filtrates of Alternaria solani to be used in vitro selection of resistant potato. Three isolates of A. solani (I1 and I2 from Eldorado do Sul and Rio Pardo were used. Two liquid media, V8 and Czapek, were used to grow each of the fungal isolate, giving six culture filtrates (I1V8, I2V8, I3V8, I1Cz, I2Cz and I3Cz. Two sterilization forms, Millipore and autoclave were tested. There was no difference in these two sterilization forms. Tissue culture and toxic filtrates of A. solani have a potential to reduce the time in selection of resistant potato.

  16. A New Disease of Gladiolus Caused by Binucleate Rhizoctonia sp.

    OpenAIRE

    Mohammad Javad Soleimani; Leila Kashi

    2005-01-01

    Fungi with Rhizoctonia-like mycelia were isolated from root and stem of Gladiolus (Gladiolus hybrida L.) grown in commercial glasshouse in Mahallat, Iran, during the summer and fall of 2003. Isolated fungi were identified as either binucleate or multi nucleate Rhizoctonia sp. On the basis of hyphal characteristics and nuclear number, twenty three isolates of Rhizoctonia sp. were obtained from infected corms and stems. Of the 23 isolate, 9 had binucleate and 14 had multinucleate vegetative hyp...

  17. Evaluation of a Biological Agent for Control of Helminthosporium solani

    Directory of Open Access Journals (Sweden)

    Steven B. Johnson

    2007-01-01

    Full Text Available Silver scurf of potatoes is an economically important disease of potato caused by Helminthosporium solani Durieu and Mont. Serenade ASOTM, a biological control agent for H. solani, was tested as postharvest treatment for silver scurf control in 2004 and 2005. Serenade ASO reduced both the incidence and the severity of silver scurf under low disease pressure and the severity of silver scurf under high disease pressure. Under low disease pressure, Serenade ASO delayed the onset of silver scurf until 5 months of storage. Serenade ASO has potential as a biological control of silver scurf under low disease pressure.

  18. Técnica de obtenção de filtrado de cultura de Alternaria solani / Technique to obtain of Alternaria solani culture filtrate

    Scientific Electronic Library Online (English)

    IÁRA V., GOMES-OLIVEIRA; AIDA T. S., MATSUMURA.

    2001-03-01

    Full Text Available [...] Abstract in english This work was developed to adapt culture filtrates of Alternaria solani to be used in vitro selection of resistant potato. Three isolates of A. solani (I1 and I2) from Eldorado do Sul and Rio Pardo were used. Two liquid media, V8 and Czapek, were used to grow each of the fungal isolate, giving six c [...] ulture filtrates (I1V8, I2V8, I3V8, I1Cz, I2Cz and I3Cz). Two sterilization forms, Millipore and autoclave were tested. There was no difference in these two sterilization forms. Tissue culture and toxic filtrates of A. solani have a potential to reduce the time in selection of resistant potato.

  19. Synthesis of Silver Nanoparticles by a Bryophilous Rhizoctonia species

    OpenAIRE

    Daniel B. Raudabaugh; Marian B. Tzolov; Joseph P. Calabrese; Barrie E. Overton

    2013-01-01

    We demonstrate the synthesis of silver nanoparticles by a potentially benign species of bryophilous Rhizoctonia in two different media. The first medium supports fungal growth and the up?regulation of nitrate reductase, while the second medium supports fungal growth and the repression of nitrate reductase. For both media, the resulting silver nanoparticles were ca. 25? 50nm and were subglobose to broadly ellipsoidal in shape. The optical analysis of the silver nano...

  20. Fusarium solani infection in a kidney transplant recipient

    OpenAIRE

    Mohanty, N. K.; S.SAHU

    2014-01-01

    Hyalo hypho mycosis due to Fusarium species mainly occurs in immunocompromised hosts. The clinical presentation varies from localized to disseminated involvement. A case of localized cutaneous fusariosis caused by Fusarium solani in a renal transplant patient is described and the skin manifestations of the disease are discussed.

  1. Mild hydrolysis of nitriles by Fusarium solani strain O1.

    Czech Academy of Sciences Publication Activity Database

    Vejvoda, Vojt?ch; Kaplan, Ond?ej; Klozová, Jana; Masák, J.; ?ejková, A.; Jirk?, V.; Stloukal, R.; Martínková, Ludmila

    2006-01-01

    Ro?. 51, ?. 4 (2006), s. 251-256. ISSN 0015-5632 R&D Projects: GA AV ?R IAA4020213; GA ?R GA203/05/2267; GA MŠk LC06010 Institutional research plan: CEZ:AV0Z50200510 Keywords : fusarium solani Subject RIV: EE - Microbiology, Virology Impact factor: 0.963, year: 2006

  2. Chemical and Hot Water Treatments to Eliminate Rhizoctonia From Azalea Stem Cuttings: Failures and Successes

    Science.gov (United States)

    Azalea web blight is an annual problem on some evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. The binucleate Rhizoctonia species, which cause the disease, are spread on new shoot growth harvested for propagation. Rhizoctonia can be eli...

  3. Optimization of Xylanase Production from Fusarium solani F7

    OpenAIRE

    Yadav, I. J.; Kumar, P.; Gautam, N.; Gaur, R.; Gupta, V. K.; Darmwal, N. S.

    2009-01-01

    The purpose of this study was to characterization of xylanase producing Fusarium solani isolate and optimization of cultural conditions for xylanase enzyme production. Screening of Fusarium solani isolate was based on the diameter of the clear zone formation in oat spelt xylan agar plates, Fusarium solani isolate F7 was selected and optimized for xylanase enzyme production using cheaper substrate like wheat straw, rice straw, rice bran and wood husk. Maximum enzyme activity was observe...

  4. Enhanced amylase production by fusarium solani in solid state fermentation

    International Nuclear Information System (INIS)

    The present study illustrates the investigation carried out on the production of amylase by Fusarium species under solid state fermentation. All the tested Fusarium species were capable of producing amylase. A selected F. solani isolate SY7, showed the highest amylase production in solid state fermentation. Different substrates were screened for enzyme production. Among the several agronomic wastes, wheat bran supported the highest yield of amylase (141.18 U/g of dry substrate) after 3 days of incubation. Optimisation of the physical parameters revealed the optimum pH, temperature and moisture level for amylase production by the isolate as 8.0, 25 C and 70%, respectively. The above results indicate that the production of amylase by F. solani isolate SY7 could be improved by a further optimisation of the medium and culture conditions. (author)

  5. Purification and characterization of nitrilase from Fusarium solani IMI196840.

    Czech Academy of Sciences Publication Activity Database

    Vejvoda, Vojt?ch; Kubá?, David; Davidová, A.; Kaplan, Ond?ej; Šulc, Miroslav; Šveda, Ond?ej; Chaloupková, R.; Martínková, Ludmila

    2010-01-01

    Ro?. 45, ?. 7 (2010), s. 1115-1120. ISSN 1359-5113 R&D Projects: GA AV ?R IAA500200708; GA MŠk(CZ) LC06010; GA MŠk OC09046; GA ?R GD305/09/H008; GA MPO FT-TA5/043 Institutional research plan: CEZ:AV0Z50200510 Keywords : fusarium solani * nitrilase * purification Subject RIV: EE - Microbiology, Virology Impact factor: 2.648, year: 2010

  6. Analysis of genetic and pathogenic variation among Alternaria solani in a potato production region

    Science.gov (United States)

    A two-year survey was conducted in a potato production region to investigate the genetic variability within naturally infecting populations of Alternaria solani, the cause of early blight in potato, and between species A. solani and A. dauci. Genetic diversity among 151 isolates was assessed using s...

  7. Potencial antagônico de Trichoderma spp. originários de diferentes agroecossistemas contra Sclerotinia sclerotiorum e Fusarium solani / Antagonist potential of Trichoderma spp. from distinct agricultural ecosystems against Sclerotinia sclerotiorum and Fusarium solani

    Scientific Electronic Library Online (English)

    Gisele Angélica de Souza, Louzada; Daniel Diego Costa, Carvalho; Sueli Corrêa Marques, Mello; Murillo, Lobo Júnior; Irene, Martins; Leonardo Minaré, Braúna.

    2009-09-01

    Full Text Available A partir de 40 amostras de solo, provenientes dos estados do Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás e Tocantins, uma coleção de 230 isolados monospóricos de Trichoderma spp. foi estabelecida, usando o meio seletivo TSM. Com o objetivo de selecionarem-se isolados com potencial para [...] controle biológico de doenças, foram conduzidos testes de pareamento de culturas em meio BDA, a 20 ºC para Sclerotinia sclerotiorum e a 25 ºC para Fusarium solani f.sp. phaseoli. Antagonismo contra os dois patógenos foi observado em 10% dos isolados. Avaliações ao microscópio eletrônico de varredura de sete isolados selecionados in vitro mostraram que nem todos promoveram o hiperparasitismo dos patógenos, sugerindo a existência de outros mecanismos de antagonismo, como antibiose ou competição. Abstract in english From 40 soil samples collected in the Rio Grande do Sul, Minas Gerais, São Paulo, Bahia, Goiás and Tocantins states, Brazil, a collection of 230 monosporic isolates of Trichoderma spp. was established using TSM selective media. In order to select efficient isolates for biological control, dual cultu [...] re tests were carried out on PDA media at 20 ºC for Sclerotinia sclerotiorum and at 25 ºC for Fusarium solani f.sp. phaseoli. From the whole collection, 50 isolates presented antagonism against F. solani and 111 isolates to S. sclerotiorum. The antagonism against both pathogens was found in only 10% of the isolates. Scanning electron microscopy assessments with seven in vitro selected isolates showed that not all promoted hyperparasitism on the pathogens, suggesting the existence of other mechanisms of antagonism, as antibiosis or competition.

  8. ANTIFUNGAL ACTIVITY OF SOME PLANT EXTRACT S AGAINST FUSARIUM SOLANI

    Directory of Open Access Journals (Sweden)

    S.K. BHARADWAJ

    2007-01-01

    Full Text Available The aqueous extracts of twenty plants were screened for their antifungal activity Fusarium solani, causal organism if Sudden Death Syndrome (SDS of Soybean (Glycine max wilt diseases, soft rot of potato. The maximum inhibitory effect was shown by leaf extracts of Camellia sinensis (67.17%, root extracts of Asparagus racemosus (54.43%. Some of the other plants showed moderate to intermediate inhibition against the mycelium growth of test fungi whcih varied in the following range Callistemon lanceolatus> Agegle marmelos> Azadirachta> Acacia catechu> Aloevera.

  9. Óleo essencial de Baccharis tridentata Vahl: composição química, atividade antioxidante e fungitóxica, e caracterização morfológica das estruturas secretoras por microscopia eletrônica de varredura / Baccharis tridentata Vahl essential oil: chemical composition, and antioxidant and fungitoxic activities and morphological characterization of secretory structures by scanning electron microscopy

    Scientific Electronic Library Online (English)

    S.P., Souza; M.G., Cardoso; P.E., Souza; L.G.L., Guimarães; J., Andrade; A.C.T., Mallet; D.L., Nelson.

    Full Text Available Este trabalho teve como objetivos avaliar a composição química do óleo essencial de Baccharis tridentata Vahl, as atividades antioxidante e fungitóxica, e estudar a morfologia das estruturas secretoras do óleo essencial presentes na superfície foliar por meio de microscopia eletrônica de varredura ( [...] MEV). A extração do óleo essencial foi realizada por hidrodestilação, as análises quantitativas e qualitativas foram executadas por meio de cromatografia em fase gasosa com detector de ionização de chamas (FID) e acoplada à espectrometria de massas, respectivamente. A atividade antioxidante foi realizada empregando-se os métodos de redução do radical estável DPPH e o ensaio de oxidação do sistema ?-caroteno/ácido linoleico. As atividades fungitóxicas foram avaliadas utilizando o teste bioanalítico in vitro, sobre a inibição do crescimento micelial dos fitopatógenos Fusarium oxysporum, Colletotrichum gloeosporioides e Rhizoctonia solani. A composição química revelou a presença de 28 compostos, sendo o ?-tujeno (22,93%) o constituinte majoritário; não foi observada atividade antioxidante por meio dos ensaios utilizados, no entanto, observou-se atividade fungitóxica sobre o crescimento micelial dos fitopatógenos estudados. Já os estudos da superfície foliar por MEV revelaram a presença de tricomas glandulares em ambas as superfícies abaxial e adaxial. Abstract in english This study aimed to evaluate the chemical composition and the antioxidant and fungitoxic activities of Baccharis tridentata essential oil, as well as to study the morphology of its secretory structures present on the leaf surface by scanning electron microscopy (SEM). The essential oil was extracted [...] by hydrodistillation; the quantitative and qualitative analyses were performed on a gas chromatograph equipped with a flame ionization detector (FID) and coupled to a mass spectrometer, respectively. The antioxidant activity was determined by the methods of reduction of the DPPH stable radical and oxidation of the ?-carotene/linoleic acid system. Fungitoxic activities were assessed by the in vitro bioanalytical test on the inhibition of the mycelial growth of the plant pathogens Fusarium oxysporum, Colletotrichum gloeosporioides and Rhizoctonia solani. The chemical composition revealed the presence of 28 compounds, with ?-thujene (22.93%) as the major constituent. No antioxidant activity was observed in the tests used; however, there was fungitoxic activity against the mycelial growth of plant pathogens. Leaf surface studies by SEM revealed the presence of glandular trichomes on both abaxial and adaxial surfaces.

  10. Tratamentos biológico e químico em sementes de Cedrela fissilis para controle de Rhizoctonia sp. / Biological and chemical treatment of Cedrela fissilis seeds for controlling Rhizoctonia sp.

    Scientific Electronic Library Online (English)

    Marília, Lazarotto; Marlove Fátima Brião, Muniz; Rafael, Beltrame; Álvaro Figueredo dos, Santos; Jucéli, Müller; Maristela Machado, Araújo.

    2013-03-01

    Full Text Available Neste trabalho, objetivou-se avaliar o efeito de um fungicida protetor e de um produto biológico, utilizados isoladamente e combinados, no controle de patógenos presentes em sementes de cedro (Cedrela fissilis), especialmente de Rhizoctonia sp. Anteriormente ao tratamento das sementes, parte das sem [...] entes foi previamente inoculada com Rhizoctonia sp., isolado de sementes de cedro, e parte recebeu os tratamentos sem a inoculação. Após, as sementes foram submetidas a tratamentos com produto biológico em pó à base de Trichoderma spp. (aplicado isoladamente), fungicida Captan em pó (também aplicado isoladamente), combinação dos dois produtos aplicados em uma dose considerada máxima (100%) e combinação de metade da dose de ambos os produtos (50%) e ainda a testemunha. As avaliações constaram dos testes de germinação, sanidade em papel-filtro, emergência e das avaliações de mudas. Nenhum tratamento conseguiu erradicar Rhizoctonia sp. das sementes inoculadas, porém o tratamento com 100% da dose de ambos os produtos reduziu sua incidência. A combinação de produto químico e biológico, apresenta-se como uma alternativa viável para o tratamento de sementes de cedro, especialmente no controle de Rhizoctonia sp. Abstract in english This research evaluated the effect of a fungicide and a biological product, singly and combined, for the control of pathogens, especially Rhizoctonia sp., in seeds of Cedrela fissilis. Before the seeds treatment, the inoculation of Rhizoctonia sp., isolated from C. fissilis seeds in blotter-test and [...] considered pathogenic for the specie, was done on half of the seeds used. After, the seeds were subjected to treatments with powder organic product based on Trichoderma spp. (singly), powder fungicide Captan (also singly), combination of two products in a maximum dose considered (100%) and combination of half dose of both products, besides the control. After the seeds treatments the following tests were done: germination, emergence in vermiculite, with evaluations of seedlings and sanitary by blotter-test. No treatment could eradicate Rhizoctonia sp. inoculated seed, but the treatment with 100% of the dose of both products reduced its incidence. The combination of chemical and biological products can be a viable alternative for the treatment of C. fissililis seeds, especially in the control of Rhizoctonia sp.

  11. RESISTÊNCIA DE TOMATEIRO (Lycopersicon esculentum AO PATÓGENO Alternaria solani RESISTANCE OF TOMATO (Lycopersicon esculentum TO Alternaria solani PATHOGEN

    Directory of Open Access Journals (Sweden)

    Wilson Ferreira de Oliveira

    2007-09-01

    Full Text Available

    O objetivo deste trabalho foi avaliar níveis de resistência de variedades comerciais de tomateiro ao patógeno Alternaria solani. Os genótipos são pertencentes ao banco de germoplasma do CNPH-Embrapa, compreendendo híbridos F1, que foram avaliados em condições de campo. Os ensaios foram conduzidos nos campos experimentais da Escola de Agronomia e Engenharia de Alimentos da Universidade Federal de Goiás, em Goiânia-GO, a uma altitude de 730 m, latitude de 16° 41'S e longitude de 49° 17'W. As avaliações foram realizadas aos 36, 43, 50, 57, 64, 71, 78 e 85 dias após o transplantio, combinando-se escala diagramática e de notas. As variedades Ohio 4013 e CNPH 738 foram as mais resistentes entre os materiais tutorados. Entre os materiais rasteiros os mais resistentes foram o híbrido F1 Hawaii 7998 x Monense e Rotam 4. O genótipo Ohio 4013 e híbrido F1 Hawaii 7998 x Monense foram os que mais se destacaram para resistência a este patógeno, podendo ser indicados para futuros programas de melhoramento.

    PALAVRAS-CHAVE: Tomateiro; resistência; Alternaria solani.

    The main objective of this study was to test levels of resistance of commercial varieties, genotypes belonging to the germoplasm bank of CNPH-Embrapa and hibrids F1 of tomat to Alternaria solani, in field condition. The trials were conduced at the experimental fields of the Federal University of Goiás, Goiânia-GO, Brasil. It is located at an altitude of 730 m, latitude of 16° 41'S and longitude of 49° 17'W. The evaluations were accomplished at the 36, 43, 50, 57, 64, 71, 78 and 85 days after the seedlings planting, combining diagramatic scale and grades. Among indeterminate cultivars Ohio 4013 and CNPH 738 were the most resistants. Among determined ones the most resistant were F1 hibrid Hawaii 7998 x Monense and Rotam 4. The genotypes Ohio 4013 and the F1 Hawaii 7998 x Monense hibrid were the ones that more stood out for resistance to these pathogen and could be suitable for future breeding programs.

    KEY-WORDS: Tomato; resistance; Alternaria solani.

  12. In vitro effect of essential oils on Alternaria solani Sorauer / Efecto in vitro de aceites esenciales sobre Alternaria solani Sorauer

    Scientific Electronic Library Online (English)

    Yanisia, Duarte; Oriela, Pino; Danay, Infante; Yaima, Sánchez; María del Carmen, Travieso; B, Martínez.

    2013-04-01

    Full Text Available Este trabajo tuvo como objetivo determinar la actividad antifúngica in vitro de diez aceites esenciales sobre Alternaria solani Sorauer, importante patógeno de las solanáceas. Se evaluó el efecto por contacto directo y por exposición a los vapores. Los bioensayos se realizaron según diseño completam [...] ente aleatorizado, se utilizó el método de discos de papel inoculados con los aceites, enfrentados a discos del fitopatógeno y se evaluó el crecimiento radial del hongo. Todos los aceites, excepto Citrus sinensis (L.) Osbeck (naranjo dulce), inhibieron el crecimiento micelial hasta los 7 días. A los 14 días se observó inhibición total en los tratamientos con los aceites de Pimpinella anisum L. (anís), Ocimum basilicum L. (albahaca blanca), Ocimum basilicum L. variedad genovese (albahaca genovesa) y Piper auritum Kunth (caisimón de anís). Los metabolitos volátiles de los aceites no mostraron efecto fungicida; no obstante se observó inhibición del crecimiento micelial de A. solani en los tratamientos con los extractos de Ruta chalepensis L. (ruda) y Piper auritum. Los resultados abren nuevas perspectivas para el control de este patógeno. Abstract in english The aim of this work was to determine the in vitro antifungal activity of ten essential oils on Alternaria solani SORAUER. The effect by direct contact and exposure to vapors was evaluated. The bioassays were performed using a completely randomized design and the method of paper discs inoculated wit [...] h the oils facing phytopathogen discs; the fungal radial growth was evaluated. All the oils, except those from Citrus sinensis (L.) Osbeck (sweet orange), inhibited the mycelial growth until the seventh day. At day 14, a total inhibition was observed in the treatments with the oils from Pimpinella anisum L. (anise), Ocimum basilicum L. (white basil), Ocinum basilicum L. var. genovese (Genovese basil), and Piper auritum Kunth (anise caisimon). No fungicidal effect was shown by the volatile metabolites of the oils; however, the inhibition of A. solani mycelial growth was observed in the treatments with the extracts of Ruta chalepensis L. (ruda) and P. auritum. These results open new perspectives for the control of this pathogen.

  13. In vitro toxin production by Fusarium solani f. sp. piperis

    Directory of Open Access Journals (Sweden)

    Duarte Maria de Lourdes R.

    2003-01-01

    Full Text Available Fusarium solani f. sp. piperis (teleomorph: Nectria haematococca f. sp. piperis, causal agent of root rot and stem blight on black pepper (Piper nigrum, produces secondary metabolites with toxigenic properties, capable of inducing vein discoloration in detached leaves and wilting in transpiring microcuttings. Production of F. solani f. sp. piperis (Fsp toxic metabolites reached a peak after 25 days of static incubation on potato sucrose broth at 25 ºC under illumination. Changes in the pH of the culture filtrate did not alter the effect of toxic metabolites. However, when the pH was changed before the medium had been autoclaved, a more intense biological response was observed, with an optimum at pH 6.0. Isolates that produced red pigments in liquid cultures were more efficient in producing biologically active culture filtrates than those which produced pink coloured or clear filtrates suggesting that these pigments could be related to toxigenic activity. Detached leaves of seven black pepper cultivars and Piper betle showed symptoms of vein discoloration after immersion in autoclaved and non-autoclaved Fsp culture filtrates indicating the thermostable nature of these toxic metabolites.

  14. Detection of trypsin inhibitor in seeds of Eucalyptus urophylla and its influence on the in vitro growth of the fungi Pisolithus tinctorius and Rhizoctonia solani

    OpenAIRE

    Tremacoldi Célia Regina; Pascholati Sérgio Florentino

    2002-01-01

    Inhibitors of plant proteases can regulate the hydrolysis of proteins inside the cells and also participate in the mechanisms of plant defense against herbivore insects and pathogens. Here, we demonstrated that seeds of Eucalyptus urophylla exhibit activities of trypsin and papain inhibitors, two proteases commonly found in living cells. Low amounts of proteins of the crude protein extract of seeds and fractions partially purified by gel filtration, with inhibitory activity against trypsin, i...

  15. Effect of above-ground plant species on soil microbial community structure and its impact on suppression of Rhizoctonia solani AG3

    OpenAIRE

    Garbeva, P.; Postma, J.; Veen, J. A.; Elsas, J. D.

    2006-01-01

    The extent of soil microbial diversity is seen to be critical to the maintenance of soil health and quality. Different agricultural practices are able to affect soil microbial diversity and thus the level of suppressiveness of plant diseases. In a 4-year field experiment, we investigated the microbial diversity of soil under different agricultural regimes. We studied permanent grassland, grassland turned into arable land, long-term arable land and arable land turned into grassland. The divers...

  16. Distribution And Efficacy Of Drip-Applied Metam-Sodium Against The Survival Of Rhizoctonia Solani And Yellow Nutsedge In Plastic-Mulched Sandy Soil Beds

    Science.gov (United States)

    The effects of metam-sodium application rate on soil residence time, spatial and temporal distributions of methyl isothiocyanate and pest control efficacy were studied in a Georgia sandy soil. Metam-sodium 420 gL-1 SL was drip applied at rates of 147 and 295Lha-1 in plastic-mulched raised beds. Meth...

  17. Liquid culture production of microsclerotia and submerged conidia by Trichoderma harzianum active against damping-off disease caused by Rhizoctonia solani.

    Science.gov (United States)

    Kobori, Nilce N; Mascarin, Gabriel M; Jackson, Mark A; Schisler, David A

    2015-04-01

    Media and culturing protocols were identified that supported the formation of submerged conidia and microsclerotia (MS) by Trichoderma harzianum Rifai strain T-22 using liquid culture fermentation. Liquid media with a higher carbon concentration (36 g L(-1)) promoted MS formation at all C:N ratios tested. Hyphae aggregated to form MS after 2 d growth and after 7 d MS were fully melanized. This is the first report of MS formation by T. harzianum or any species of Trichoderma. Furthermore, submerged conidia formation was induced by liquid culture media, but yields, desiccation tolerance, and storage stability varied with C:N ratio and carbon rate. Air-dried MS granules (harzianum as a potential biofungicide for use in integrated management programs against soilborne diseases. PMID:25813507

  18. Rhizoctonia anastomosis groups associated with diseased rooibos seedlings and the potential of compost as soil amendment for disease suppression

    Science.gov (United States)

    Rhizoctonia spp. associated with rooibos in the Western Cape province of South Africa were recovered during the 2008 season by planting seedlings in rhizosphere soils collected from 14 rooibos nurseries. Seventy five Rhizoctonia isolates were obtained and 67 were multinucleate and 8 binucleate Rhiz...

  19. Bilateral endogenous Fusarium solani endophthalmitis in a liver-transplanted patient : a case report

    DEFF Research Database (Denmark)

    JØrgensen, Jesper Skovlund; Prause, Jan Ulrik

    2014-01-01

    Endogenous Fusarium endophthalmitis is a rare disease predominantly described in immunocompromised patients often due to leukemia. We report a case of bilateral endogenous Fusarium solani endophthalmitis in a liver-transplanted patient.

  20. Morphological and Physiological Characterization of Alternaria solani Isolated from Tomato in Jordan Valley

    Directory of Open Access Journals (Sweden)

    Khalaf M. Alhussaen

    2012-01-01

    Full Text Available Alternaria solani is known economically important and the casual agent of early blight on potato and tomato. Identification of plant pathogens is very important in helping to find effective disease control or management methods. Morphology and physiology characteristics of Alternaria solani were investigated for identification and variability. The optimum pH levels of Alternaria solani grow in vitro were 6-7 and the optimum growing temperatures of the isolates recovery in this study was 25 and 30°C. The mycelial width between 0.8-1.5 ?m and the conidia are 35-75 ?m in length and 10-20 ?m in width and 2-7 transverse septa and 1-4 longitudinal septa. This study pointed that there was a variation in the population of Alternaria solani isolated from Jordan valley based on morphology and physiology characteristics.

  1. Aspectos biológicos y poblacionales de Nasonovia ribisnigri y Aulacorthum solani sobre lechuga

    Directory of Open Access Journals (Sweden)

    Vasicek Araceli

    2002-01-01

    Full Text Available Se estimó la influencia de los cultivares Criolla Blanca, Cuatro Estaciones y Gallega, sobre la biología y los parámetros poblacionales de Nasonovia ribisnigri y Aulacorthum solani (Homoptera: Aphidoidea a 10±1ºC y HR de 90%. Los períodos ninfal, pre-reproductivo y post-reproductivo de N. ribisnigri fueron más largos sobre Cuatro Estaciones, no así el reproductivo. En A. solani el período ninfal fue más largo sobre Criolla Blanca y Cuatro Estaciones resultando el reproductivo mayor sobre Cuatro Estaciones. Las tasas intrínsecas de crecimiento natural (r m de N. ribisnigri y A. solani fueron mayores sobre Criolla Blanca y Gallega, respectivamente. De acuerdo a la especie predominante convendría utilizar Cuatro Estaciones para N. ribisnigri y Criolla Blanca para A. solani, en épocas frías.

  2. Secondary metabolite profiling of Alternaria dauci, A. porri, A. solani, and A. tomatophila

    DEFF Research Database (Denmark)

    Andersen, Birgitte; Dongo, Anita

    2008-01-01

    Chemotaxonomy (secondary metabolite profiling) has been shown to be of great value in the classification and differentiation in Ascomycota. However, few studies have investigated the use of metabolite production for classification and identification purposes of plant pathogenic Alternaria species. The purpose of the present study was to describe the methodology behind metabolite profiling in chemotaxonomy using A. dauci, A. porri, A. solani, and A. tomatophila strains as examples of the group. The results confirmed that A. dauci, A. solani, and A. tomatophila are three distinct species each with their own specific metabolite profiles, and that A. solani and A. tomatophila both produce altersolanol A, altertoxin 1, and macrosporin. By using automated chemical image analysis and other multivariate statistic analyses, three sets of species-specific metabolites could be selected, one each for A. dauci, A. solani, and A. tomatophila.

  3. [Tinea pedis due to Fusarium solani in Dakar].

    Science.gov (United States)

    Diongue, K; Ndiaye, M; Badiane, A S; Seck, M C; Ndoye, N W; Diallo, S; Diallo, M A; Ndir, O; Ndiaye, D

    2015-06-01

    A patient presented with intertrigo at the second, third and fourth interdigitals spaces lasting for four years in which Fusarium solani was highlighted. The search for contributing factors revealed a concept of foot washing with water at least five times a day for ablutions, associated with wearing closed shoes all day and the absence of immunosuppression and diabetes. The diagnosis of Fusarium was made on the basis of direct examination and culture. Combined treatment with griseofulvin oral and topical ciclopirox was introduced and allowed healing after 45days at which an antifungal powder was prescribed for relay. This case adds to the rare cases of intertrigo Fusarium sp. and confirms the frequent practice of ablutions as favoring factor. PMID:25835156

  4. Atividade alelopática do filtrado de cultura produzido por Fusarium solani / Allelopathic activity of culture filtrate produced by Fusarium solani

    Scientific Electronic Library Online (English)

    A.P.S., Souza Filho; M.L.R., Duarte.

    2007-03-01

    Full Text Available As plantas daninhas se constituem no principal problema a impor limitação à exploração da agropecuária nas áreas tropicais. Entretanto, o controle químico dessas plantas tem gerado insatisfações de ordem social, quer porque contaminam as fontes de recursos naturais ou por comprometerem a qualidade d [...] os alimentos da dieta dos animais, em geral, e dos humanos, em particular. Os objetivos deste trabalho foram identificar e caracterizar a atividade alelopática do filtrado de cultura produzido pelo fungo Fusarium solani f. sp. pipers. Foram avaliados os efeitos das toxinas, nas concentrações de 1,0 e 4,0%, sobre a germinação de sementes e o desenvolvimento da radícula e do hipocótilo das plantas daninhas malícia (Mimosa pudica) e mata-pasto (Senna obtusifolia). Os resultados mostraram presença de atividade alelopática inibitória, com variações de acordo com a concentração e a planta receptora. A intensidade dos efeitos inibitórios induzidos pelo extrato esteve positivamente associada à concentração, com efeitos mais intensos verificados a 4,0%. Independentemente da concentração e do bioensaio, a espécie malícia se mostrou mais sensível aos efeitos do filtrado da cultura. O desenvolvimento da radícula foi o fator da planta mais intensamente inibido. Os resultados indicam a existência de potencial de utilização da toxina produzida pelo fungo, como fonte alternativa no controle de plantas daninhas, o que justifica estudos mais avançados. Abstract in english Weeds are a major problem limiting agriculture and cattle raising activities in the tropics. Current chemical control measures have raised environmental concerns due to their potential of contaminating natural resources and compromising the quality of animal feed. The objective of this paper was to [...] identify and characterize the potential allelopathic activity of Fusarium solani f. sp. pipers culture filtrate. The effects of the toxin were analyzed at 1% and 4% concentration, on seed germination and radicle and hypocotyl elongation of the weeds Mimosa pudica and Senna obtusifolia. The results showed potential inhibitory allelopathic activity of the Fusarium culture filtrate, varying according to concentration and receiving plants. The intensity of the inhibition effects promoted by the extracts was clearly associated to concentration, with the major effect being observed at 4%. Regardless of concentration and bioassays, Mimosa pudica was more sensitive to the toxin effects of the culture filtrate. Radicle elongation was more intensely inhibited by the culture filtrate toxins. The results showed potential for the use of the toxins produced by Fusarium solani f. sp. pipers, as an alternative source to control weeds. However, further studies should be carried out.

  5. Evaluation of the anti-alternaria solani activity of allium hirtifolium boiss

    International Nuclear Information System (INIS)

    The inhibitory effect of methanolic extract of 100 plant species from 45 plant families were investigated on mycelial growth of Alternaria solani, the cause of early blight of tomatoes, based on paper disc diffusion method. The study was conducted in a completely randomized design with 4 replications. The results showed that methanolic extracts of 21 species exhibited measurable inhibitory effect on mycelial growth of A. solani. The stongest inhibitory effect was obtained for the extracts of Allium hirtifolium and Teucrium chamaedrys with radius inhibitory zones of 19.08 mm +- 0.48 and 15.58 mm +- 0.48, respectively. Furthermore, an experiment was performed to investigate synergistic effect of A. hirtifolium, Ferula assa-foetida and Artemisia sieberi separately and in combinations with each other based on agar dilution method on the growth of A. solani. Results indicated that a mixture of Allium hirtifolium and F. assa-foetida extracts caused complete mycelial growth inhibition of A. solani. The IC50 and IC95 values for A. hirtifolium bulbs were equal to 78 and 946 ppm, respectively. Moreover, methanolic extract of A. hirtifolium bulb significantly showed the highest inhibitory effect on mycelial growth of A. solani when compared with other plant parts. The results of inhibitory effect of fractions obtained by thin layer chromatography of A. hirtifolium bulbs showed that one band with Rf= 0.41 had an inhibitory effect against A. solani. (author)

  6. Produção de enzimas extracelulares por Fusarium solani de maracujazeiro amarelo / Production of extracellular enzymes by Fusarium solani from yellow passion fruit

    Scientific Electronic Library Online (English)

    César Júnior, Bueno; Ivan Herman, Fischer; Daniel Dias, Rosa; Edson Luiz, Furtado.

    2009-10-01

    Full Text Available Uma das principais doenças do maracujazeiro, na maioria dos estados produtores do Brasil, é a podridão do colo, causada por Fusarium solani. Pouco se sabe a respeito da fisiologia deste patógeno do maracujazeiro amarelo, principalmente quanto à produção de enzimas extracelulares. O objetivo do prese [...] nte trabalho foi verificar, em meios de cultura individuais e apropriados, a produção das enzimas extracelulares amilase, lipase, celulase, proteases (caseinase e gelatinase), lacase (oxidase) e catalase por isolados de F. solani, provenientes de maracujazeiro amarelo. O delineamento experimental adotado foi o inteiramente casualizado, em esquema de dois fatores (nove isolados versus sete enzimas), com três repetições. Todos os isolados de F. solani produziram, de maneira semiquantitativa, as enzimas extracelulares amilase, lipase, celulase, caseinase (protease) e lacase (oxidase). No entanto, a quantidade produzida de cada enzima foi significativamente diferente entre os isolados. As enzimas extracelulares gelatinase (protease) e catalase foram produzidas em pouca quantidade e de maneira igual por todos os isolados do fungo. Abstract in english In most Brazilian producer states, one of the main diseases of the passion fruit is collar rot caused by Fusarium solani. Little is known about the physiology of this pathogen from yellow passion fruit, which mainly involves the production of extracellular enzymes. The objective of this work was to [...] verify, in individual and appropriate culture media, the production of the extracellular enzymes amylase, lipase, cellulase, proteases (caseinase and gelatinase), lacase (oxydase) and catalase by isolates of F. solani from yellow passion fruit. The experimental design adopted was an entirely randomized two-factor scheme (nine isolates and seven enzymes) with three repetitions. All the isolates of F. solani produced, in a semi-quantitative manner, the extracellular enzymes amylase, lipase, cellulase, caseinase (protease) and lacase. However, the amount of each enzyme produced was significantly different among the isolates. The extracellular enzymes gelatinase (protease) and catalase were produced in a small amount and in an equal manner by all the isolates of the fungus.

  7. Produção de enzimas extracelulares por Fusarium solani de maracujazeiro amarelo Production of extracellular enzymes by Fusarium solani from yellow passion fruit

    Directory of Open Access Journals (Sweden)

    César Júnior Bueno

    2009-10-01

    Full Text Available Uma das principais doenças do maracujazeiro, na maioria dos estados produtores do Brasil, é a podridão do colo, causada por Fusarium solani. Pouco se sabe a respeito da fisiologia deste patógeno do maracujazeiro amarelo, principalmente quanto à produção de enzimas extracelulares. O objetivo do presente trabalho foi verificar, em meios de cultura individuais e apropriados, a produção das enzimas extracelulares amilase, lipase, celulase, proteases (caseinase e gelatinase, lacase (oxidase e catalase por isolados de F. solani, provenientes de maracujazeiro amarelo. O delineamento experimental adotado foi o inteiramente casualizado, em esquema de dois fatores (nove isolados versus sete enzimas, com três repetições. Todos os isolados de F. solani produziram, de maneira semiquantitativa, as enzimas extracelulares amilase, lipase, celulase, caseinase (protease e lacase (oxidase. No entanto, a quantidade produzida de cada enzima foi significativamente diferente entre os isolados. As enzimas extracelulares gelatinase (protease e catalase foram produzidas em pouca quantidade e de maneira igual por todos os isolados do fungo.In most Brazilian producer states, one of the main diseases of the passion fruit is collar rot caused by Fusarium solani. Little is known about the physiology of this pathogen from yellow passion fruit, which mainly involves the production of extracellular enzymes. The objective of this work was to verify, in individual and appropriate culture media, the production of the extracellular enzymes amylase, lipase, cellulase, proteases (caseinase and gelatinase, lacase (oxydase and catalase by isolates of F. solani from yellow passion fruit. The experimental design adopted was an entirely randomized two-factor scheme (nine isolates and seven enzymes with three repetitions. All the isolates of F. solani produced, in a semi-quantitative manner, the extracellular enzymes amylase, lipase, cellulase, caseinase (protease and lacase. However, the amount of each enzyme produced was significantly different among the isolates. The extracellular enzymes gelatinase (protease and catalase were produced in a small amount and in an equal manner by all the isolates of the fungus.

  8. Cutinase of Fusarium solani F. sp. pisi: mechanism of induction and relatedness to other Fusarium species

    International Nuclear Information System (INIS)

    Three studies were made on the extracellular cutinase of the phytopathogenic fungus Fusarium solani f. sp. pisi. I. The production of cutinase was found to be induced in spores of F. solani f. sp. pisi, strain T-8, by cutin and cutin hydrolysate. Fractionation and analysis of the cutin hydrolysate indicated that dihydroxy-C16 acid and trihydroxy-C18 acid were the cutin monomers most active for inducing cutinase. Measurement of cutinase-specific RNA levels by dot-blot hybridization with a [32P]-labeled cutinase cDNA showed that the cutinase gene transcripts could be detected within 15 min after addition of the inducers. The results indicated that the fungal spores have the capacity to recognize the unique monomer components of the plant cuticle and rapidly respond by the synthesis of cutinase. II. Analysis of the genomic DNA's of seven strains of F. solani f. sp. pisi indicated that both high and low cutinase-producing strains contain at least one copy of the cutinase structural gene and a homologous promoter region. The data suggest a different promoter sequence exists in these additional copies. III. Relatedness of five phytopathogenic Fusarium species to F. solani f. sp. pisi was determined by their cutinase antigenic properties and gene homologies of cutinase cDNA from F. solani f. sp. pisi. The results suggest that formae specialis of F. solani are phylogenetically identical and that F. solani is quite distinct from the other Fusarani is quite distinct from the other Fusarium species tested

  9. CONTROLE DE ALTERNARIA SOLANI COM FUNGICIDAS NA CULTURA DO TOMATEIRO CONTROL OF ALTERNARIA SOLANI WITH FUNGICIDES IN TOMATO PLANTS

    Directory of Open Access Journals (Sweden)

    Fabrício Silva Coelho

    2011-06-01

    Full Text Available A pinta-preta, causada pelo fungo Alternaria solani, caracteriza-se por ser uma importante e destrutiva doença da cultura do tomate, sob condições de alta temperatura e umidade. Objetivou-se avaliar a eficiência de diferentes fungicidas no controle da Alternaria solani na cultura do tomateiro na região de Lavras (MG. O experimento foi desenvolvido na Universidade Federal de Lavras - Departamento de Agricultura, no período de novembro de 2004 a janeiro de 2005. O delineamento experimental foi o de blocos casualizados com 10 tratamentos e quatro repetições. Cada parcela composta por 12 plantas. As aplicações foram realizadas com um pulverizador costal manual (45 lbf/pol2, volume de aplicação de 800 L•ha-1, totalizando sete aplicações, com intervalos de sete dias. Foram realizadas cinco avaliações para a severidade foliar da doença com o uso de escala diagramática. Todos os fungicidas apresentaram potencial de controle da pinta-preta dentro das características inerentes ao seu grupo químico. Os melhores níveis de controle foram obtidos com os tratamentos Chlorothalonil 500 g•L-1 + Tetraconazole 20 g•L-1 (dosagem 200 mL•100 L-1, Chlorothalonil 400 g•L-1+ Oxicloreto de Cobre 420 g•kg-1 e Chlorothalonil 750 g•kg-1 + Tetraconazole 20 g•kg-1 (dosagem 150 g•100 L-1. Tetraconazole 100 g•L-1 proporcionou os menores níveis de controle.The early blight disease on tomato, caused by the fungus Alternaria solani, is referred to in importance due its destructive power, under conditions of high temperature and humidity. This study aimed to evaluate the effectiveness of various fungicides in your control in the region of Lavras-MG, Brazil. The experiment was conducted at the Federal University of Lavras, Department of Agriculture in the period from November 2004 to January 2005. The experimental design was randomized blocks with 10 treatments and four replications, each plot comprise 12 plants. The applications were made with a manual spray costal (45 lbf/pol2, volume for the application of 800 L•ha-1 and seven applications in an interval of seven days. Five evaluations were accomplished for the leaf severity of the disease with the use of a diagrammatic scale. All the fungicides presented potential for the control of early blight inside of the inherent characteristics in their chemical group. The best control levels were obtained with the treatments Chlorothalonyl 500 g•L-1 + Tetraconazol 20 g•L-1 (dosage 200 mL•100 L-1, Chlorothalonyl 400 g•L-1 + Copper oxychloride 420 g•kg-1 and Chlorothalonyl 750 g•kg-1 + Tetraconazol 20 g•kg-1 (dosage 150 g•100 L-1. Tetraconazol 100 g•L-1 provided the smallest control levels.

  10. CONTROLE DE ALTERNARIA SOLANI COM FUNGICIDAS NA CULTURA DO TOMATEIRO / CONTROL OF ALTERNARIA SOLANI WITH FUNGICIDES IN TOMATO PLANTS

    Scientific Electronic Library Online (English)

    Fabrício, Silva Coelho; Marco Antônio, Rezende Alvarenga; Armindo, Bezerra Leão; Leandro, Rodrigues.

    2011-06-01

    Full Text Available A pinta-preta, causada pelo fungo Alternaria solani, caracteriza-se por ser uma importante e destrutiva doença da cultura do tomate, sob condições de alta temperatura e umidade. Objetivou-se avaliar a eficiência de diferentes fungicidas no controle da Alternaria solani na cultura do tomateiro na reg [...] ião de Lavras (MG). O experimento foi desenvolvido na Universidade Federal de Lavras - Departamento de Agricultura, no período de novembro de 2004 a janeiro de 2005. O delineamento experimental foi o de blocos casualizados com 10 tratamentos e quatro repetições. Cada parcela composta por 12 plantas. As aplicações foram realizadas com um pulverizador costal manual (45 lbf/pol2), volume de aplicação de 800 L•ha-1, totalizando sete aplicações, com intervalos de sete dias. Foram realizadas cinco avaliações para a severidade foliar da doença com o uso de escala diagramática. Todos os fungicidas apresentaram potencial de controle da pinta-preta dentro das características inerentes ao seu grupo químico. Os melhores níveis de controle foram obtidos com os tratamentos Chlorothalonil 500 g•L-1 + Tetraconazole 20 g•L-1 (dosagem 200 mL•100 L-1), Chlorothalonil 400 g•L-1+ Oxicloreto de Cobre 420 g•kg-1 e Chlorothalonil 750 g•kg-1 + Tetraconazole 20 g•kg-1 (dosagem 150 g•100 L-1). Tetraconazole 100 g•L-1 proporcionou os menores níveis de controle. Abstract in english The early blight disease on tomato, caused by the fungus Alternaria solani, is referred to in importance due its destructive power, under conditions of high temperature and humidity. This study aimed to evaluate the effectiveness of various fungicides in your control in the region of Lavras-MG, Braz [...] il. The experiment was conducted at the Federal University of Lavras, Department of Agriculture in the period from November 2004 to January 2005. The experimental design was randomized blocks with 10 treatments and four replications, each plot comprise 12 plants. The applications were made with a manual spray costal (45 lbf/pol2), volume for the application of 800 L•ha-1 and seven applications in an interval of seven days. Five evaluations were accomplished for the leaf severity of the disease with the use of a diagrammatic scale. All the fungicides presented potential for the control of early blight inside of the inherent characteristics in their chemical group. The best control levels were obtained with the treatments Chlorothalonyl 500 g•L-1 + Tetraconazol 20 g•L-1 (dosage 200 mL•100 L-1), Chlorothalonyl 400 g•L-1 + Copper oxychloride 420 g•kg-1 and Chlorothalonyl 750 g•kg-1 + Tetraconazol 20 g•kg-1 (dosage 150 g•100 L-1). Tetraconazol 100 g•L-1 provided the smallest control levels.

  11. Weather-Based forecasting of Rhizoctonia web blight development on container grown azalea

    Science.gov (United States)

    Fungicides are the only approach currently used to control Rhizoctonia web blight on container-grown azalea. The most reliable criterion for timing fungicides has been a fixed calendar date with adjustment for year-to-year differences in disease progression made by monitoring early-season increase o...

  12. Polycyclic aromatic hydrocarbons storage by Fusarium solani in intracellular lipid vesicles

    International Nuclear Information System (INIS)

    Accumulation and elimination of polycyclic aromatic hydrocarbons (PAHs) were studied in the fungus Fusarium solani. When the fungus was grown on a synthetic medium containing benzo[a]pyrene, hyphae of F. solani contained numerous lipid vesicles which could be stained by the lipid-specific dyes: Sudan III and Rhodamine B. The fluorescence produced by Rhodamine B and PAH benzo[a]pyrene were at the same locations in the fungal hyphae, indicating that F. solani stored PAH in pre-existing lipid vesicles. A passive temperature-independent process is involved in the benzo[a]pyrene uptake and storage. Sodium azide, a cytochrome c oxidation inhibitor, and the two cytoskeleton inhibitors colchicine and cytochalasin did not prevent the transport and accumulation of PAH in lipid vesicles of F. solani hyphae. F. solani degraded a large range of PAHs at different rates. PAH intracellular storage in lipid vesicles was not necessarily accompanied by degradation and was common to numerous other fungi. - Fungi can store PAHs intracellularly in lipid vesicles independently of their PAH degradation abilities

  13. Preparation of Somatic Antigen from Fusarium Solani for Serological Diagnosis of Fusariosis

    Directory of Open Access Journals (Sweden)

    M.R. Aghamirian

    2005-10-01

    Full Text Available Introduction & Objective: Fusariosis is one of the most important systemic mycosis, often caused by Fusarium Solani and resist to antifungal drugs. The appropriate F. Solani antigen preparation could be useful in serodiagnosis of fusariosis. Materials & Methods : The extraction procedure was preformed using F.Solani strain 7419 UAMH. The antigenic extract was obtained through grinding of fungal mass yielding from broth culture medium. Results : Following fractionation of somatic antigen, two different component, that is, crude antigen as well as antigenic fractions (12,28 were collected. The antigenic fractions in comparison with the crude antigen, demonstrated more effective antibody responses using ELISA method. Conclusion: Availability of a suitable antigenic source could play a key role for serologic detecting of opportunistic fungal disease including fusariosis. Injection of this antigenic preparation in Rabbit resulted antibody response.

  14. Detection of trypsin inhibitor in seeds of Eucalyptus urophylla and its influence on the in vitro growth of the fungi Pisolithus tinctorius and Rhizoctonia solani Descoberta de inibidor de tripsina em sementes de Eucalyptus urophylla e sua influência sobre o crescimento in vitro dos fungos Pisolithus tinctorius e Rhizoctonia solani

    OpenAIRE

    Célia Regina Tremacoldi; Sérgio Florentino Pascholati

    2002-01-01

    Inhibitors of plant proteases can regulate the hydrolysis of proteins inside the cells and also participate in the mechanisms of plant defense against herbivore insects and pathogens. Here, we demonstrated that seeds of Eucalyptus urophylla exhibit activities of trypsin and papain inhibitors, two proteases commonly found in living cells. Low amounts of proteins of the crude protein extract of seeds and fractions partially purified by gel filtration, with inhibitory activity against trypsin, i...

  15. Optimum Timing for Spraying Out Greenbridge with Roundup to Control Rhizoctonia in Barley

    Science.gov (United States)

    A field experiment was conducted in 2007 in a field at the ARS Palouse Conservation Farm with a high level of both R. solani and R. oryzae. Volunteer and weeds were allowed to grow over the winter, and plots were sprayed out with Roundup at 8 wks, 6 wks, 4 wks, 2 wks, 1 wk, and 2 days before plantin...

  16. Natural occurrence of the Fusarium solani on Tityus stigmurus (Thorell, 1876) (Scorpiones: Buthidae) / Ocorrência natural de Fusarium solani em Tityus stigmurus (Thorell, 1876) (Scorpions: Buthidae)

    Scientific Electronic Library Online (English)

    PL., Santana-Neto; CMR., Albuquerque; APP., Silva; VM., Svedese; EALA., Lima.

    2010-02-01

    Full Text Available Ocorrência natural de Fusarium solani em Tityus stigmurus (Thorell, 1876) (Scorpiones: Buthidae). Membros do complexo de espécies de Fusarium solani são freqüentemente referidos como agentes de micoses humanas, podendo também afetar plantas e outros animais. Contudo, esse fungo ainda não foi registr [...] ado como causador de infecções em escorpiões. Dez espécimes de Tityus stigmurus coletados em campo e apresentando micélio branco cobrindo a superfície do corpo foram usados para analisar a presença de fungo após a sua morte. A identificação do fungo foi baseada nas características da cultura e morfológicas. O fungo foi isolado de quelíceras e regiões intersegmentais. Indivíduos infectados tiveram seu comportamento modificado, reduzindo sua alimentação e locomoção. Nenhum dos indivíduos infectados sobreviveu. É possível que este fungo possa ter um papel na regulação da população de campo desse escorpião. Abstract in english Members of the Fusarium solani species complex are agents of human mycoses, also affecting plants and other animals. Nevertheless, this fungus has not been reported on scorpions. Ten specimens of Tityus stigmurus collected in the field and showing their surface covered by white mycelia were used to [...] assess fungus presence in the animal after its death. Identification of the fungi was based upon the cultural and morphological characteristics. The fungus was isolated from chelicerae and intersegmental regions. Infected individuals had their behaviour modified by reducing feeding and locomotion. None of the infected individuals survived. It is likely that this fungus may have a role in the regulation of field scorpion populations.

  17. OPTIMIZATION OF XYLANASE PRODUCTION FROM FREE AND IMMOBILIZED CELLS OF FUSARIUM SOLANI F7

    Directory of Open Access Journals (Sweden)

    Vijai Kumar Gupta

    2009-08-01

    Full Text Available The aim of the present investigation was to characterize a xylanase-producing Fusarium solani isolate and to optimize cultural conditions for xylanase enzyme production from free and immobilized cells. Screening of Fusarium solani isolate was based on the diameter of the clear zone formation in oat spelt xylan agar plates. Fusarium solani isolate F7 was selected and optimized for xylanase enzyme production using cheaper substrates such as wheat straw, rice straw, rice bran, and wood husk. Maximum enzyme activity was observed in wheat straw (78.32 U ml-1 for free cells and 94.68 U ml-1 for immobilized cells. Optimum pH and temperature for xylanase activity were found to be 5.5 and 30°C at 3% substrate concentration for free cells and 5.0 and 30°C at 3% substrate concentration for immobilized cells. In the purification step, 75% ammonium sulphate saturation was found to be suitable, giving maximum xylanase activity. Production of xylanase was greater from immobilized cells than from free cells. Purified xylanase from free cells yielded a single band with a molecular weight of 89kDa, while it was 92.8kDa for immobilized cells. The use of wheat straw as a major carbon source is particularly valuable, because oat spelt xylan is very expensive. The Fusarium solani F7 isolate proved to be a promising microorganism for xylanase production.

  18. In Vitro and In Vivo Experimental Activities of Antifungal Agents against Fusarium solani

    OpenAIRE

    Guarro, J.; Pujol, I.; Mayayo, E

    1999-01-01

    In the treatment of disseminated Fusarium infections, amphotericin B either alone or in combination with flucytosine and rifampin is the drug therapy most frequently used. The efficacy of these antifungal drugs was evaluated in a murine disseminated-infection model, with five strains of Fusarium solani. All the treatments were clearly ineffective.

  19. Formation of trichothecenes by Fusarium solani var. coeruleum and Fusarium sambucinum in potatoes.

    OpenAIRE

    el-Banna, A A; Scott, P M; Lau, P Y; Sakuma, T; Platt, H.W.; Campbell, V

    1984-01-01

    Fusarium solani var. coeruleum can form deoxynivalenol in potato tubers and in liquid medium, although concentrations observed in the rot were highly variable; acetyldeoxynivalenol and HT-2 toxin were detected in 1 to 3 tubers only (of 57). Trichothecenes were also detected in a very few (3 of 20) cultures of Fusarium sambucinum in potato tubers.

  20. Resistance to alternaria solani in hybrids between a Solanum tuberosum haploid and S. raphanifolium

    Science.gov (United States)

    Early blight of potato (Solanum tuberosum L.), caused by the foliar fungal pathogen Alternaria solani is a major cause of economic loss in many potato growing regions. Genetic resistance offers an opportunity to decrease fungicide usage while maintaining yield and quality. In this study, an early bl...

  1. Genetic variability within Fusarium solani specie as revealed by PCR-fingerprinting based on pcr markers Variabilidade genética em espécies de Fusarium solani revelada pela técnica de impressão genética baseada em marcadores PCR

    OpenAIRE

    Bereneuza Tavares Ramos Valente Brasileiro; Maria Raquel Moura Coimbra; Marcos Antonio de Morais Jr; Neiva Tinti de Oliveira

    2004-01-01

    Fusarium solani fungus (teleomorph Haematonectria haematococca) is of relevance for agriculture, producing a disease that causes significant losses for many cultivars. Moreover, F. solani is an opportunistic pathogen to animals and humans. The complexity associated to its correct identification by traditional methods justifies the efforts of using molecular markers for isolates characterization. In this work, three PCR-based methods (one PCR-ribotyping and two PCR-fingerprinting) were used to...

  2. Fusarium solani is responsible for mass mortalities in nests of loggerhead sea turtle, Caretta caretta, in Boavista, Cape Verde

    OpenAIRE

    Sarmiento-rami?rez, Jullie M.; Abella, Elena; Marti?n, Mari?a P.; Telleri?a, Mari?a T.; Lo?pez-jurado, Luis F.; Marco, Adolfo; Die?guez-uribeondo, Javier

    2010-01-01

    The fungus Fusarium solani (Mart.) Saccardo (1881) was found to be the cause of infections in the eggs of the sea turtle species Caretta caretta in Boavista Island, Cape Verde. Egg shells with early and severe symptoms of infection, as well as diseased embryos were sampled from infected nests. Twenty-five isolates with similar morphological characteristics were obtained. Their ITS rRNA gene sequences were similar to the GenBank sequences corresponding to F. solani and their maximum identity r...

  3. Recurrent Colonization of Successively Implanted Tracheoesophageal Vocal Prostheses by a Member of the Fusarium solani Species Complex

    OpenAIRE

    Honraet, K.; Vos, M. M.; Summerbell, R. C.; Kempen, I.; Saeger, S.; Vermeersch, H.; Peteghem, C.; Nelis, H. J.

    2005-01-01

    Tracheoesophageal vocal prostheses (TVP) in laryngectomized patients commonly deteriorate due to overgrowth by yeasts, particularly Candida species. We describe the first case of colonization of such devices by a member of the Fusarium solani species complex in a patient with a history of glottal carcinoma. Three isolates, from three prostheses, were found morphologically consistent with the traditional picture of F. solani. Ribosomal sequence analysis showed that the isolates belonged to a d...

  4. Seleção de antagonistas fúngicos a Fusarium solani e Fusarium oxysporum em substrato comercial para mudas / Selection of fungi antagonistic to Fusarium solani and Fusarium oxysporum in commercial substrate for seedlings

    Scientific Electronic Library Online (English)

    Luciana Zago, Ethur; Elena, Blume; Marlove Fátima Brião, Muniz; Maria Georgina Veiga, Flores.

    1801-18-01

    Full Text Available Testes in vitro são geralmente utilizados para a seleção inicial de agentes de biocontrole contra fungos de solo, faltando metodologias que utilizem solo e/ou substrato. O objetivo deste trabalho foi realizar a seleção massal de isolados fúngicos antagônicos a F. solani e F. oxysporum em substrato c [...] omercial para mudas. Foram realizados dois experimentos com os patógenos F. solani e F. oxysporum e com 98 possíveis antagonistas fúngicos, dos gêneros Penicillium claviforme, Penicillium, Aspergillus e Cladosporium. A suspensão dos patógenos foi inserida no substrato, em copos plásticos, sendo acrescentada, cinco dias depois, a suspensão dos demais fungos. Avaliou-se o número de unidades formadoras de colônia de F. solani e F. oxysporum por grama de substrato após nove dias. Dos 98 isolados utilizados contra F. solani, 43 % não diferiram da testemunha e 57% reduziram o seu desenvolvimento em substrato, sendo que os três melhores isolados fúngicos foram do gênero Penicillium claviforme. Os três isolados de Penicillium claviforme selecionados para F. solani também foram eficientes para F. oxysporum. Abstract in english Tests in vitro are usually used for the initial selection of biocontrol agents against soil fungi, lacking methodologies using soil and/or substrate. The objective of this research was to accomplish the mass selection of fungi isolates antagonistic to F. solani and F. oxysporum in commercial substra [...] te for seedlings. Two experiments were conducted, with the pathogens F. solani and F. oxysporum, and 98 possible antagonistic fungi of the genera Penicillium claviforme, Penicillium, Aspergillus and Cladosporium. The suspension of the pathogens was inoculated in the substrate, in plastic cups, and the suspension of the other fungi was added five days later. The number of colony-forming unit of F. solani and F. oxysporum/g of substrate was counted after nine days. Of the 98 isolates used against F. solani, 43% did not differ from the control, and 57% reduced its development in the substrate, with the three best isolates belonging to the genus Penicillium claviforme. The three isolates of Penicillium claviforme selected for F. solani were also efficient against F. oxysporum.

  5. Seleção de antagonistas fúngicos a Fusarium solani e Fusarium oxysporum em substrato comercial para mudas Selection of fungi antagonistic to Fusarium solani and Fusarium oxysporum in commercial substrate for seedlings

    Directory of Open Access Journals (Sweden)

    Luciana Zago Ethur

    2007-12-01

    Full Text Available Testes in vitro são geralmente utilizados para a seleção inicial de agentes de biocontrole contra fungos de solo, faltando metodologias que utilizem solo e/ou substrato. O objetivo deste trabalho foi realizar a seleção massal de isolados fúngicos antagônicos a F. solani e F. oxysporum em substrato comercial para mudas. Foram realizados dois experimentos com os patógenos F. solani e F. oxysporum e com 98 possíveis antagonistas fúngicos, dos gêneros Penicillium claviforme, Penicillium, Aspergillus e Cladosporium. A suspensão dos patógenos foi inserida no substrato, em copos plásticos, sendo acrescentada, cinco dias depois, a suspensão dos demais fungos. Avaliou-se o número de unidades formadoras de colônia de F. solani e F. oxysporum por grama de substrato após nove dias. Dos 98 isolados utilizados contra F. solani, 43 % não diferiram da testemunha e 57% reduziram o seu desenvolvimento em substrato, sendo que os três melhores isolados fúngicos foram do gênero Penicillium claviforme. Os três isolados de Penicillium claviforme selecionados para F. solani também foram eficientes para F. oxysporum.Tests in vitro are usually used for the initial selection of biocontrol agents against soil fungi, lacking methodologies using soil and/or substrate. The objective of this research was to accomplish the mass selection of fungi isolates antagonistic to F. solani and F. oxysporum in commercial substrate for seedlings. Two experiments were conducted, with the pathogens F. solani and F. oxysporum, and 98 possible antagonistic fungi of the genera Penicillium claviforme, Penicillium, Aspergillus and Cladosporium. The suspension of the pathogens was inoculated in the substrate, in plastic cups, and the suspension of the other fungi was added five days later. The number of colony-forming unit of F. solani and F. oxysporum/g of substrate was counted after nine days. Of the 98 isolates used against F. solani, 43% did not differ from the control, and 57% reduced its development in the substrate, with the three best isolates belonging to the genus Penicillium claviforme. The three isolates of Penicillium claviforme selected for F. solani were also efficient against F. oxysporum.

  6. Assessment on early blight of potato in order to compare the two methods in vitro using pathogenic fungi Alternaria solani

    OpenAIRE

    Hamid Reza Mirkarimi; Ahmad Abasi-Moghadam; Javad Mozafari

    2013-01-01

    Potato (Solanum tuberosum) early blight, caused by Alternaria solani is one of the most destructive fungal foliar diseases. This research was done in order to study methods comparison of evaluation by culture filtrate of A. solani in in vitro condition for selecting resistance cultivars to early blight. Plantlets of potato viruse free were obtained from the National plant gene bank of Iran, and were inoculated in vitro methods with a culture filtrate of A. solani. In in vi...

  7. Antifungal Activity of (KWn or (RWn Peptide against Fusarium solani and Fusarium oxysporum

    Directory of Open Access Journals (Sweden)

    Yoonkyung Park

    2012-11-01

    Full Text Available The presence of lysine (Lys or arginine (Arg and tryptophan (Trp are important for the antimicrobial effects of cationic peptides. Therefore, we designed and synthesized a series of antimicrobial peptides with various numbers of Lys (or Arg and Trp repeats [(KW and RWn-NH2, where n equals 2, 3, 4, or 5]. Antifungal activities of these peptides increased with chain length. Light microscopy demonstrated that longer peptides (n = 4, 5 strongly inhibited in vitro growth of Fusarium solani, and Fusarium oxysporum, at 4–32 ?M. Furthermore, longer peptides displayed potent fungicidal activities against a variety of agronomical important filamentous fungi, including F. solani and F. oxysporum, at their minimal inhibitory concentrations (MICs. However, RW series peptides showed slightly higher fungicidal activities than KW peptides against the two strains. Taken together, the results of this study indicate that these short peptides would be good candidates for use as synthetic or transgenic antifungal agents.

  8. EVALUACION DE LA ACTIVIDAD ANTAGÓNICA DE TRECE AISLAMIENTOS DE Trichoderma spp. SOBRE Rhizoctonia sp. / EVALUATION OF THE ANTAGONISTIC ACTIVITY OF THIRTEEN Trichoderma spp. isolates ON Rhizoctonia sp.

    Scientific Electronic Library Online (English)

    Yusimy, Reyes; B, Martínez; Danay, Infante.

    2008-08-01

    Full Text Available El Tizón de la Vaina o mancha oriental, se considera la segunda enfermedad de importancia en Cuba y el mundo en el cultivo del arroz. Los métodos utilizados para su control aún no son efectivos; en la actualidad existe una tendencia al uso del Control Biológico, donde se reconoce la potencialidad de [...] Trichoderma, con resultados positivos como antagonista sobre Rhizoctonia y otros patógenos del suelo. El presente trabajo tiene como objetivo seleccionar los aislamientos de Trichoderma promisorios en dependencia de su antagonismo in vitro y su eficacia en condiciones semicontroladas para el biocontrol de Rhizoctonia sp . El antagonismo se evaluó por el método del cultivo dual, donde se observó la competencia por el sustrato, micoparasitismo y la antibiosis . Se calculó el porcentaje de inhibición del crecimiento radial (PICR) a las 96 horas. Los aislados que presentaron más de un 50 PICR y al menos dos tipos de interacción hifal se seleccionaron para el ensayo en condiciones semicontroladas donde se evaluó la eficacia técnica sobre el patógeno en bandejas de acero inoxidable de 0,30m². Los resultados mostraron que el 100% de los aislados presentaron alta capacidad antagónica, con diferentes tipos de interacción hifal : lisis, vacuolización , enrollamiento y penetración, p or lo que se pudieron seleccionar cinco aislados. De estos tres mostraron una efectividad técnica del 50% en condiciones semicontroladas . Los aislamientos 39, 56 y 78 resultaron promisorios para ser evaluados en condiciones de campo. Abstract in english The sheath blight or blot easterly is considered the second important disease on rice in Cuba and worldwide. The methods used to control this disease have not been effective and, at present, there is a tendency to use the biological control. Trichoderma is recognized as a potential antagonist of soi [...] l pathogens, with positive results as an antagonist to Rhizoctonia . The objective of this work was to select promising strains of Trichoderma spp . according to their in vitro antagonism and effectiveness to control Rhizoctonia sp. under semicontrolled conditions. Antagonism was evaluated using the dual culture method, where the competition for the substrate, mycoparasitism and antibiosis could be observed. The colony radial growth was measured with a graduated ruler and the inhibition percentage was calculated after 96 hours. Micoparasitism was also observed using an optic microscope with 400x magnification, where the interaction between strains was evaluated. Strains showing a radial growth inhibition higher than 50 % and at least two types of hyphae interaction were selected to be tested under semicontrolled conditions for evaluating the technical effectiveness on the pathogen in stainless steel trays of 0,30cm². The 100 % of the strains had high antagonism capabilities with different types of hyphal interactions, lysis , vacuolization, rolling, and penetration. Five strains were selected, three of them showing a technical effectiveness of 50% under semicontrolled conditions. Strains 39, 56 and 78 resulted promising to control the disease under field conditions.

  9. Glutathione S-transferases of Aulacorthum solani and Acyrthosiphon pisum: partial purification and characterization.

    OpenAIRE

    Francis, Frédéric(*); Haubruge, Eric; Gaspar, Charles; Dierickx, P. J.

    2001-01-01

    Glutathione S-transferases (GST) play an important role in the detoxification of many substances including allelochemicals from plants. Brassicaceae plants contain glucosinolates and emit volatile isothiocyanates which affect the GST system. A comparison of the GST of two aphid species, the generalist Aulacorthum solani found on Brassicaceae and the Fabaceae specialist Acyrthosiphon pisum, was made to try to explain their respective feeding behaviour. Differences of GST were determined among ...

  10. Genotyping of 44 Isolates of Fusarium solani, the Main Agent of Fungal Keratitis in Brazil

    OpenAIRE

    Godoy, Patricio; Cano, Josep; Gene?, Josepa; Guarro, Josep; Ho?fling-lima, Ana Luisa; Lopes Colombo, Arnaldo

    2004-01-01

    In a retrospective study performed over 6 years in Brazil, Fusarium solani was found to be the most common species causing mycotic keratitis. The genetic diversity of 44 isolates from 39 patients was assessed by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and PCR restriction fragment length polymorphism (PCR-RFLP) fingerprinting. ERIC-PCR was more discriminatory than PCR-RFLP for differentiating the strains. By combining of the results of both techniques, we identified 40 g...

  11. Tomato early blight (Alternaria solani): the pathogen, genetics and breeding for resistance

    OpenAIRE

    Chaerani, R.; Voorrips, R. E.

    2006-01-01

    Alternaria solani causes diseases on foliage (early blight), basal stems of seedlings (collar rot), stems of adult plants (stem lesions), and fruits (fruit rot) of tomato. Early blight is the most destructive of these diseases and hence receives considerable attention in breeding. For over 60 years, breeding for early blight resistance has been practiced, but the development of cultivars with high levels of resistance has been hampered by the lack of sources of strong resistance in the cultiv...

  12. Phylogenetic Analysis of Fusarium solani Associated with the Asian Longhorned Beetle, Anoplophora glabripennis

    OpenAIRE

    Kelli Hoover; Ming Tien; Scully, Erin D.; Maria del Mar Jimenez-Gasco; Carlson, John E.; Geib, Scott M.

    2012-01-01

    Culture-independent analysis of the gut of a wood-boring insect, Anoplophora glabripennis (Coleoptera: Cerambycidae), revealed a consistent association between members of the fungal Fusarium solani species complex and the larval stage of both colony-derived and wild A. glabripennis populations. Using the translation elongation factor 1-alpha region for culture-independent phylogenetic and operational taxonomic unit (OTU)-based analyses, only two OTUs were detected, suggesting that genetic var...

  13. Ecological distribution of Fusarium solani and its opportunistic action related to mycotic keratitis in Cali, Colombia.

    OpenAIRE

    Cuero, R. G.

    1980-01-01

    Corneal ulcera in patients treated at the University Hospital Cali, Colombia have been attributed to the fungus Fusarium solani, which was isolated from patients' eyes by deep scraping. The fungus, which was characterized by culture and morphology, was found to grow well at 37 degrees C in Sabouraud and potato dextrose agars and in liquid asparagine medium, in which it produced very few spores; at 40 degrees C, it survived for 3 weeks. Different levels of pathogenicity were shown by the fungu...

  14. Virulence of ‘Dickeya solani’ and Dickeya dianthicola biovar-1 and -7 strains on potato (Solanum tuberosum)

    OpenAIRE

    Czajkowski, R. L.; Boer, W. J.; Zouwen, P. S.; Kastelein, P.; Jafra, S.; Haan, E. G.; Bovenkamp, G. W.; Wolf, J. M.

    2013-01-01

    Studies were conducted to explain the relative success of ‘Dickeya solani’, a genetic clade of Dickeya biovar 3 and a blackleg-causing organism that, after recent introduction, has spread rapidly in seed potato production in Europe to the extent that it is now more frequently detected than D. dianthicola. In vitro experiments showed that both species were motile, had comparable siderophore production and pectinolytic activity, and that there was no antagonism between them when growing. Bo...

  15. UV-B-irradiation effect on growth reactions of phytopathogenic fungus fusarium solani

    International Nuclear Information System (INIS)

    The UV-B irradiation effect on spore germination and hyphae growth of phythopathogenic fungus Fusarium solani was studied. Spores irradiation by small doses of 0,1 - 1,0 kJ/m2 results in growth stimulation of primary hyphae. Adaptive effect of UV-B small doses for fungi was shown. Preliminary irradiation in doses of 0,1 - 0,5 kJ/m2 increased spore radioresistance and diminished the effect of the next damaging dose

  16. Impact of water potential on growth and germination of Fusarium solani soilborne pathogen of peanut

    Scientific Electronic Library Online (English)

    Sofia, Palacios; Francisco, Casasnovas; María L., Ramirez; María. M., Reynoso; Adriana M., Torres.

    1105-11-01

    Full Text Available Studies were conducted to determine the effect of osmotic and matric stress on germination and growth of two Fusarium solani strains, the etiological agent responsible of peanut brown root rot. Both strains had similar osmotic and matric potential ranges that allowed growth, being the latter one nar [...] rower. F. solani showed the ability to grow down to -14 MPa at 25 °C in non-ionic modified osmotic medium, while under matric stress this was limited to -8.4 MPa at 25 °C. However, both strains were seen to respond differently to decreasing osmotic and matric potentials, during early stages of germination. One strain (RC 338) showed to be more sensitive to matric than osmotic (non ionic) and the other one (RC 386) showed to be more sensitive to osmotic than matric imposed water stress. After 24 h of incubation, both isolates behaved similarly. The minimum water potential for germination was -8.4 MPa on glycerol amended media and -5.6 MPa for NaCl and PEG amended media, respectively. The knowledge of the water potential range which allow mycelia growth and spore germination of F. solani provides an inside to the likely behaviour of this devastating soilborne plant pathogen in nature and has important practical implications.

  17. Efficacy and Safety of Some Plant Extracts against Tomato Early Blight Disease Caused by Alternaria solani

    Directory of Open Access Journals (Sweden)

    A.B. El-Sayed

    2011-01-01

    Full Text Available In an attempt to establish new control practices with low mammalian toxicity and low persistence in the environment against plant pathogens, crude extracts of seven plant species (Cassia senna, Caesalpinia gilliesii, Thespesia populnea var. acutiloba, Chrysanthemum frutescens, Euonymus japonicus, Bauhinia purpurea and Cassia fistula were evaluated against Alternaria solani in tomato under laboratory and greenhouse conditions. Furthermore, GC-MS analysis was carried to identify the biologically active components of the most effective extract against A. solani. Moreover, the safety of the most effective extract was evaluated with respect to histological changes in treated rats organs. The results showed that, B. purpurea was most effective plant extract against early blight pathogen under laboratory and greenhouse conditions. The GC-MS analysis for the most effective plant extract showed the presence of different bioactive chemical components than known by its antifungal activity. The most effective plant extract showed low toxicity on rats relative to control. The results revealed that, the using of plant extracts can be regarded as effective and safe control of A. solani in tomato.

  18. RESISTANCE OF TOMATO (Lycopersicon esculentum Mill. TO THE Stemphylium solani Weber RESISTÊNCIA DE TOMATEIRO (Lycopersicon esculentum Mill. A Stemphylium solani Weber

    Directory of Open Access Journals (Sweden)

    Wilson Ferreira de Oliveira

    2007-09-01

    Full Text Available

    In the climate conditions of the Brazilian central west regions, tomato can be cultivated the whole year. However, the production is low and quite onerous in function of different factors Besides, different diseases affect the crop. Among the most being the fungal important is the fungi Stemphylium solani, responsible for damages of qualitative and quantitative nature in tomato. With the objective of finding a way to minimize the effect of these pathogen, an experiment was conduced at the experimental fields of the Federal University of Goiás, Goiânia-GO, Brazil. It is located at an altitude of 730 m, latitude of 16° 41’S and longitude of 49° 17’W, with temperature varying among 20 to for 40ºC, relative humidity (average of the month of 80% in August, 83% in September and 85% in October. Precipitation in August, September and October of 1999 was respectively 0.0 mm, 69.6 mm, and 118.4 mm. The main objectives were to test levels of resistance of commercial varieties, genotypes belonging to the bank of germoplasm of Embrapa-CNPH and F1 generations of tomato Lycopersicon esculentum in field conditions to S. solani. The evaluations were accomplished at the 36, 43, 50, 57, 64, 71, 78 and 85 days after the seedlings planting combining diagramatic scale and grades. Was considered the percentage of infected area on the leaf (PIAL and the also grades: 1 – without symptoms; 2 – spraid lesions; 3 – gathering lesions; 4 – partial dryness of the leaf; 5 – death of the leaf and 6 – death of the plant. The differentiation among genotypes was made through analysis of variance of the values of area under disease progress curve and by of Tukey’s test at the level of 5% of probability and also the logistic model. Regarding resistance to S. solani, Ohio 4013, Yoshimatusu and TSW-10 behaved as resistant, among the indeterminate. Among the determined ones, F1 (Hawaii 7998 x Monense showed higher resistance. The genotypes Ohio 4013 and the F1 (Hawaii 7998 x Monense were the ones that more stood out for resistance to these pathogens and could be suitable for future breeding programs.

    KEY-WORDS: Tomato; resistance; Stemphylium solani.

    Na Região Centro-Oeste, dadas as condições climáticas, o tomateiro pode ser cultivado o ano inteiro. A produção, no entanto, é baixa e bastante onerosa, em função de diferentes fatores dentre os quais incluem-se as doenças de diferentes etiologias, com destaque para a fúngica provocada por Stemphylium solani, responsável por danos de natureza qualitativa e quantitativa no tomate. Conduziram-se experimentos na Escola de Agronomia da Universidade Federal de Goiás, Goiânia - GO, a uma altitude de 730 m, latitude de 16° 41’S e longitude de 49° 17’W, com temperatura, umidade relativa e precipitação pluviométrica (médias de 23ºC, 82,7 e 62,7mm, respectivamente. O objetivo principal era testar níveis de resistência de variedades comerciais, genótipos pertencentes ao banco de germoplasma da Embrapa-CNPH e geração F1 de tomateiro, em condições de campo a S. solani. As avaliações foram realizadas aos 36, 43, 50, 57, 64, 71, 78 e 85 dias, após o transplantio, combinando escala diagramática e de notas. A diferenciação dos genótipos foi feita através da análise de variância dos valores da área abaixo da curva de progresso de doença, pelo teste de Tukey a 5% de probabilidade e pelo modelo logístico. Dentre as cultivares avaliadas quanto à resistência e/ou à suscetibilidade a S. solani, Ohio 4013, Yoshimatusu e TSW-10 comportaram-se como resistentes, entre os tutorados. Entre os rasteiros, verificou-se este fato na geração F1 (Hawaii 7998 x Monense. Os gen

  19. Relationships between M. enterolobii and F. solani: spatial and temporal dynamics in the occurrence of guava decline

    Directory of Open Access Journals (Sweden)

    Vicente Martins Gomes

    2014-08-01

    Full Text Available Guava decline, caused by the interaction between the phytonematode Meloidogyne enterolobii and the fungus Fusarium solani, has caused direct and indirect losses to the whole productive chain of guava. Aiming to understand the interaction mechanisms between M. enterolobii and F. solani, this study carried out a bioassay on guava plants with roots in two different treatments: inoculated separatelyor together with the fungus and/or nematode. The nematode parasitism not triggered an systemic effect on the plant become susceptible to root rot caused by the fungus.Therefore, it was concluded that there was a local effect of parasitism by M. enterolobii on the pathogenicity of F. solani in guava roots, making it necessary for the two pathogens to occupy the same space at the same time for occurrence of guava decline. Keywords: complex disease, Fusarium solani, guava root-knot nematode, Meloidogyne enterolobii, Psidium guajava. Cite as Gomes VM, Souza RM, Almeida AM, Dolinski C. Relationships between M. enterolobii and F. solani: spatial and temporal dynamics in the occurrence of guava decline.

  20. In vitro toxin production by Fusarium solani f. sp. piperis / Produção de toxinas in vitro por Fusarium solani f. sp. piperis

    Scientific Electronic Library Online (English)

    Maria de Lourdes R., Duarte; Simon A., Archer.

    2003-06-01

    Full Text Available Fusarium solani f. sp. piperis (teleomórfico: Nectria haematococca f. sp. piperis) agente causal da podridão-das-raízes e do secamento-dos-ramos da pimenteira-do-reino (Piper nigrum) produz metabólitos secundários com propriedades tóxicas capazes de induzir descoloração das nervuras em folhas destac [...] adas e murcha em micro-estacas. A produção de metabólitos tóxicos alcançou o pico após 25 dias de incubação, sob iluminação. Variações no pH do filtrado da cultura não aumentaram o efeito tóxico, entretanto, quando o pH foi ajustado antes da esterilização do meio de cultura, uma resposta biológica mais intensa foi observada, atingindo o máximo em pH 6,0. Isolados que produziram pigmentos vermelhos no meio de cultura foram mais eficientes em produzir filtrados biologicamente ativos do que aqueles que produziram filtrados de coloração rósea ou branca sugerindo que estes pigmentos podem estar relacionados com atividade toxigênica. Folhas destacadas de sete cultivares de pimenta-do-reino e Piper betle exibiram sintomas de descoloração das nervuras após imersão em filtrados autoclavado e não-autoclavado indicando a natureza termoestável destes metabólitos tóxicos. Abstract in english Fusarium solani f. sp. piperis (teleomorph: Nectria haematococca f. sp. piperis), causal agent of root rot and stem blight on black pepper (Piper nigrum), produces secondary metabolites with toxigenic properties, capable of inducing vein discoloration in detached leaves and wilting in transpiring mi [...] crocuttings. Production of F. solani f. sp. piperis (Fsp) toxic metabolites reached a peak after 25 days of static incubation on potato sucrose broth at 25 ºC under illumination. Changes in the pH of the culture filtrate did not alter the effect of toxic metabolites. However, when the pH was changed before the medium had been autoclaved, a more intense biological response was observed, with an optimum at pH 6.0. Isolates that produced red pigments in liquid cultures were more efficient in producing biologically active culture filtrates than those which produced pink coloured or clear filtrates suggesting that these pigments could be related to toxigenic activity. Detached leaves of seven black pepper cultivars and Piper betle showed symptoms of vein discoloration after immersion in autoclaved and non-autoclaved Fsp culture filtrates indicating the thermostable nature of these toxic metabolites.

  1. 'Candidatus Phytoplasma solani', a novel taxon associated with stolbur- and bois noir-related diseases of plants.

    Science.gov (United States)

    Quaglino, Fabio; Zhao, Yan; Casati, Paola; Bulgari, Daniela; Bianco, Piero Attilio; Wei, Wei; Davis, Robert Edward

    2013-08-01

    Phytoplasmas classified in group 16SrXII infect a wide range of plants and are transmitted by polyphagous planthoppers of the family Cixiidae. Based on 16S rRNA gene sequence identity and biological properties, group 16SrXII encompasses several species, including 'Candidatus Phytoplasma australiense', 'Candidatus Phytoplasma japonicum' and 'Candidatus Phytoplasma fragariae'. Other group 16SrXII phytoplasma strains are associated with stolbur disease in wild and cultivated herbaceous and woody plants and with bois noir disease in grapevines (Vitis vinifera L.). Such latter strains have been informally proposed to represent a separate species, 'Candidatus Phytoplasma solani', but a formal description of this taxon has not previously been published. In the present work, stolbur disease strain STOL11 (STOL) was distinguished from reference strains of previously described species of the 'Candidatus Phytoplasma' genus based on 16S rRNA gene sequence similarity and a unique signature sequence in the 16S rRNA gene. Other stolbur- and bois noir-associated ('Ca. Phytoplasma solani') strains shared >99 % 16S rRNA gene sequence similarity with strain STOL11 and contained the signature sequence. 'Ca. Phytoplasma solani' is the only phytoplasma known to be transmitted by Hyalesthes obsoletus. Insect vectorship and molecular characteristics are consistent with the concept that diverse 'Ca. Phytoplasma solani' strains share common properties and represent an ecologically distinct gene pool. Phylogenetic analyses of 16S rRNA, tuf, secY and rplV-rpsC gene sequences supported this view and yielded congruent trees in which 'Ca. Phytoplasma solani' strains formed, within the group 16SrXII clade, a monophyletic subclade that was most closely related to, but distinct from, that of 'Ca. Phytoplasma australiense'-related strains. Based on distinct molecular and biological properties, stolbur- and bois noir-associated strains are proposed to represent a novel species level taxon, 'Ca. Phytoplasma solani'; STOL11 is designated the reference strain. PMID:23334879

  2. Herança da resistência a stemphylium solani e insensibilidade a sua fitotoxina em cultivares de algodoeiro

    Directory of Open Access Journals (Sweden)

    MEHTA YESHWANT R.

    2001-01-01

    Full Text Available A mancha preta do algodoeiro (Gossypium hirsutum causada por Stemphylium solani ocorre em várias regiões produtoras de algodão do Brasil, causando severos prejuízos em rendimento especialmente no Estado do Paraná. Estudou-se a herança da resistência a S. solani e sua fitotoxina, em três cultivares de algodoeiro. As cultivares de algodoeiro PR 94-82, PR 94-215 e CNPA Precoce 2 identificadas como resistentes foram cruzadas com a cultivar suscetível IAPAR 71, inclusive cruzamentos recíprocos. Aos 30 dias de idade, duas folhas de cada planta foram inoculadas com um isolado agressivo de S. solani, e outras duas da mesma planta foram infiltradas com seu filtrado contendo fitotoxina(s na diluição de 1:1. A severidade da área foliar infetada (AFI pelo patógeno e a área foliar necrosada pelo filtrado (AFN foram avaliadas sete dias após a inoculação/infiltração. Considerando as reações de 740 plantas segregantes, o coeficiente de correlação entre AFI e AFN foi alto (r = 0,70. Os modelos de média e de variância confirmaram a predominância de efeitos genéticos aditivos para AFI e AFN. O modelo de segregação simples incluindo um único gene na determinação do caráter produzindo uma proporção de 1:2:1 foi aceito pelo teste de qui-quadrado para os cruzamentos IAPAR 71 x PR94-82 e IAPAR 71 x CNPA-PRECOCE 2. Para o cruzamento IAPAR 71 x PR94-215, o padrão de segregação incluindo dois genes e epistasia (9:6:1 foi aceito pelo teste de qui-quadrado.

  3. Purification and characterization of a nitrilase from Fusarium solani O1.

    Czech Academy of Sciences Publication Activity Database

    Vejvoda, Vojt?ch; Kaplan, Ond?ej; Bezouška, Karel; Pompach, Petr; Šulc, Miroslav; Cantarella, M.; Benada, Old?ich; Uhnáková, Bronislava; Rinágelová, Anna; Lutz-Wahl, S.; Fischer, L.; K?en, Vladimír; Martínková, Ludmila

    2008-01-01

    Ro?. 50, 2-4 (2008), s. 99-106. ISSN 1381-1177 R&D Projects: GA AV ?R IAA500200708; GA ?R GA203/05/2267; GA MŠk(CZ) LC06010; GA MŠk OC D25.002 Grant ostatní: AV ?R(CZ) D10-CZ25/06-07 Institutional research plan: CEZ:AV0Z50200510 Keywords : nitrilase * fusarium solani * nitrile hydrolysis Subject RIV: EE - Microbiology, Virology Impact factor: 2.015, year: 2008

  4. Characterization and taxonomic placement of Rhizoctonia-like endophytes from orchid roots.

    Science.gov (United States)

    Shan, X C; Liew, E C Y; Weatherhead, M A; Hodgkiss, I J

    2002-01-01

    Twenty-one Rhizoctonia-like fungal strains were isolated from the roots of four terrestrial orchid species from various locations in Hong Kong. The cultural morphology, nuclear number of the hyphal cell, pore ultrastructure, and RAPD and CAPS analyses of rDNA fragments revealed that most of these isolates were associated with the genera Ceratorhiza and Epulorhiza. RAPD analysis showed the presence of genetic diversity between the isolates from different hosts and locations. The compatibility between a selection of these Ceratorhiza and Epulorhiza isolates and 14 orchid species was determined using a symbiotic germination method. The germination and development of three orchid species, Arundina chinensis, Spathoglottis pubescens, and Spiranthes hongkongensis, were strongly stimulated by the Epulorhiza isolates. Habenaria dentata was found to form symbionts successfully with a Ceratorhiza isolate. PMID:21156492

  5. Analysis of Growth and Resistance to Different Population of Fusarium Solani in Soybean Legume Plant

    Directory of Open Access Journals (Sweden)

    N. Hamid

    2011-03-01

    Full Text Available Experiment was conducted to study the effect of different concentrations (10,000, 100,000 and 1000, 000 cfu of Fusariumsolani on growth and resistance to soybean (Glycine max (L. Merr leguminous plant. Sterilized seeds of Glycine max were sown in 350g of acid washed sand. The plants were regularly watered with complete Nutrient Hoagland solution. Leaves samples were weekly collected for analysis of biochemical tests. The growth and morphology of G. max were adversely affected with F. solani which show damping off seedling root rot. The symptom was first appearing in root. Infected seedling of G. max showed a marked decreased in root, shoot length and discoloration and decay in roots. Stem diameter was also decreased in infected plants as compared with the control plants. There were not marked differences occurring in leaf area but the color of leaves turn yellowish green in infected plants. The infected tissues of soybean with different colonies of F. solani showed the highest level of total phenolic content as compared to healthy tissues.

  6. Enhanced camptothecin production by ethanol addition in the suspension culture of the endophyte, Fusarium solani.

    Science.gov (United States)

    Venugopalan, Aarthi; Srivastava, Smita

    2015-07-01

    Ethanolic extract of a non-camptothecin producing plant, Catharanthus roseus when added in the suspension culture of the endophyte Fusarium solani known to produce camptothecin, resulted in enhanced production of camptothecin by 10.6-fold in comparison to that in control (2.8?g/L). Interestingly, addition of pure ethanol (up to 5% v/v) in the suspension culture of F. solani resulted in maximum enhancement in camptothecin production (up to 15.5-fold) from that obtained in control. In the presence of ethanol, a reduced glucose uptake (by ?40%) and simultaneous ethanol consumption (up to 9.43g/L) was observed during the cultivation period (14days). Also, the total NAD level and the protein content in the biomass increased by 3.7- and 1.9-fold, respectively, in comparison to that in control. The study indicates a dual role of ethanol, presumably as an elicitor and also as a carbon/energy source, leading to enhanced biomass and camptothecin production. PMID:25603728

  7. Genetic variability within Fusarium solani specie as revealed by PCR-fingerprinting based on pcr markers / Variabilidade genética em espécies de Fusarium solani revelada pela técnica de impressão genética baseada em marcadores PCR

    Scientific Electronic Library Online (English)

    Bereneuza Tavares Ramos Valente, Brasileiro; Maria Raquel Moura, Coimbra; Marcos Antonio de, Morais Jr; Neiva Tinti de, Oliveira.

    2004-09-01

    Full Text Available O fungo Fusarium solani (teleomorfo Haematonectria haematococca) apresenta uma expressiva importância na agricultura por ser considerado patógeno para várias culturas de interesse econômico causando doença conhecida por podridão das raízes, além de ser patógeno aos animais e ao homem, provocando nes [...] tes últimos, micoses superficiais e sistêmicas. A complexidade associada a sua identificação correta através de métodos tradicionais justifica os esforços de usar marcadores moleculares para caracterização dos isolados. Neste trabalho, três métodos baseados na tecnologia da PCR (um por ribotipagem por PCR e dois por impressão genética por PCR) foram utilizados para investigar a variabilidade molecular de dezoito isolados de F. solani de quatro Estados brasileiros, coletados de diferentes substratos. A análise genética revelou a variabilidade intraespecífica dos isolados de F. solani, sem qualquer correlação para a origem geográfica e substrato. Seu polimorfismo foi observado até mesmo na seqüência conservada do locus do rDNA, e o marcador SPAR (GTG)5 mostrou o mais alto polimorfismo. Em conjunto, estes resultados poderão auxiliar nos estudos da relação entre variabilidade do perfil genético de isolados e os fenótipos de resistência de determinados cultivares às doenças provocadas pelo fungo, orientando programas de melhoramento vegetal. Abstract in english Fusarium solani fungus (teleomorph Haematonectria haematococca) is of relevance for agriculture, producing a disease that causes significant losses for many cultivars. Moreover, F. solani is an opportunistic pathogen to animals and humans. The complexity associated to its correct identification by t [...] raditional methods justifies the efforts of using molecular markers for isolates characterization. In this work, three PCR-based methods (one PCR-ribotyping and two PCR-fingerprinting) were used to investigate the molecular variability of eighteen F. solani isolates from four Brazilian States, collected from different substrates. Genetic analysis revealed the intraspecific variability within the F. solani isolates, without any correlation to their geographical origin and substrate. Its polymorphism was observed even in the very conserved sequence of rDNA locus, and the SPAR marker (GTG)5 showed the highest polymorphism. Together, those results may contribute to understand the relation between fungal genetic variability and cultivars resistance phenotypes to fungal-caused diseases, helping plant-breeding programs.

  8. Genetic variability within Fusarium solani specie as revealed by PCR-fingerprinting based on pcr markers Variabilidade genética em espécies de Fusarium solani revelada pela técnica de impressão genética baseada em marcadores PCR

    Directory of Open Access Journals (Sweden)

    Bereneuza Tavares Ramos Valente Brasileiro

    2004-09-01

    Full Text Available Fusarium solani fungus (teleomorph Haematonectria haematococca is of relevance for agriculture, producing a disease that causes significant losses for many cultivars. Moreover, F. solani is an opportunistic pathogen to animals and humans. The complexity associated to its correct identification by traditional methods justifies the efforts of using molecular markers for isolates characterization. In this work, three PCR-based methods (one PCR-ribotyping and two PCR-fingerprinting were used to investigate the molecular variability of eighteen F. solani isolates from four Brazilian States, collected from different substrates. Genetic analysis revealed the intraspecific variability within the F. solani isolates, without any correlation to their geographical origin and substrate. Its polymorphism was observed even in the very conserved sequence of rDNA locus, and the SPAR marker (GTG5 showed the highest polymorphism. Together, those results may contribute to understand the relation between fungal genetic variability and cultivars resistance phenotypes to fungal-caused diseases, helping plant-breeding programs.O fungo Fusarium solani (teleomorfo Haematonectria haematococca apresenta uma expressiva importância na agricultura por ser considerado patógeno para várias culturas de interesse econômico causando doença conhecida por podridão das raízes, além de ser patógeno aos animais e ao homem, provocando nestes últimos, micoses superficiais e sistêmicas. A complexidade associada a sua identificação correta através de métodos tradicionais justifica os esforços de usar marcadores moleculares para caracterização dos isolados. Neste trabalho, três métodos baseados na tecnologia da PCR (um por ribotipagem por PCR e dois por impressão genética por PCR foram utilizados para investigar a variabilidade molecular de dezoito isolados de F. solani de quatro Estados brasileiros, coletados de diferentes substratos. A análise genética revelou a variabilidade intraespecífica dos isolados de F. solani, sem qualquer correlação para a origem geográfica e substrato. Seu polimorfismo foi observado até mesmo na seqüência conservada do locus do rDNA, e o marcador SPAR (GTG5 mostrou o mais alto polimorfismo. Em conjunto, estes resultados poderão auxiliar nos estudos da relação entre variabilidade do perfil genético de isolados e os fenótipos de resistência de determinados cultivares às doenças provocadas pelo fungo, orientando programas de melhoramento vegetal.

  9. Morphological and molecular characterization of Fusarium. solani and F. oxysporum associated with crown disease of oil palm

    Scientific Electronic Library Online (English)

    R., Hafizi; B., Salleh; Z., Latiffah.

    2013-09-01

    Full Text Available Crown disease (CD) is infecting oil palm in the early stages of the crop development. Previous studies showed that Fusarium species were commonly associated with CD. However, the identity of the species has not been resolved. This study was carried out to identify and characterize through morphologi [...] cal approaches and to determine the genetic diversity of the Fusarium species. 51 isolates (39%) of Fusarium solani and 40 isolates (31%) of Fusarium oxysporum were recovered from oil palm with typical CD symptoms collected from nine states in Malaysia, together with samples from Padang and Medan, Indonesia. Based on morphological characteristics, isolates in both Fusarium species were classified into two distinct morphotypes; Morphotypes I and II. Molecular characterization based on IGS-RFLP analysis produced 27 haplotypes among the F. solani isolates and 33 haplotypes for F. oxysporum isolates, which indicated high levels of intraspecific variations. From UPGMA cluster analysis, the isolates in both Fusarium species were divided into two main clusters with the percentage of similarity from 87% to 100% for F. solani, and 89% to 100% for F. oxysporum isolates, which was in accordance with the Morphotypes I and II. The results of the present study indicated that F. solani and F. oxysporum associated with CD of oil palm in Malaysia and Indonesia were highly variable.

  10. Effect of Entomopathogenic Nematodes and Trichoderma harzianum on the Strawberry Black Root Rot Pathogens Pratylenchus penetrans and Rhizoctonia fragariae

    OpenAIRE

    Lamondia, J. A.; Cowles, R. S.

    2002-01-01

    The effects of inundative releases of entomopathogenic Steinernema carpocapsae and S. feltiae infective juveniles and applications of the biological control fungus Trichoderma harzianum T-22 (RootShield) on Pratylenchus penetrans and strawberry black root rot caused by Rhizoctonia fragariae were determined in field microplots and small plots. Entomopathogenic nematodes were applied as a soil drench at rates of 7.4 or 14.8 billion per ha in May or August for 3 years. RootShield was applied as ...

  11. Production of extracellular lipase by the phytopathogenic fungus Fusarium solani FS1 Produção de lipase extracelular pelo fungo fitopatogênico Fusarium solani FS1

    Directory of Open Access Journals (Sweden)

    Maria de Mascena Diniz Maia

    1999-12-01

    Full Text Available A Brazilian strain of Fusarium solani was tested for extracellular lipase production in peptone-olive oil medium. The fungus produced 10,500 U.l-1 of lipase after 72 hours of cultivation at 25oC in shake-flask at 120 rpm in a medium containing 3% (w/v peptone plus 0.5% (v/v olive oil. Glucose (1% w/v was found to inhibit the inductive effect of olive oil. Peptone concentrations below 3% (w/v resulted in a reduced lipase production while increased olive oil concentration (above 0.5% did not further stimulate lipase production. The optimum lipase activity was achieved at pH 8.6 and 30oC and a good enzyme stability (80% activity retention was observed at pH ranging from 7.6 to 8.6, and the activity rapidly dropped at temperatures above 50oC. Lipase activity was stimulated by the addition of n-hexane to the culture medium supernatants, in contrast to incubation with water-soluble solvents.

  12. Potencial antifúngico de extratos de plantas e de basidiomicetos nativos sobre Colletotrichum acutatum, Alternaria solani e Sclerotium rolfsii Antifungal potential of extracts of native plants and basidiomycetes on Colletotrichum acutatum, Alternaria solani and Sclerotium rolfsii

    Directory of Open Access Journals (Sweden)

    Ricardo José Domingues

    2011-09-01

    Full Text Available O emprego de fungicidas na agricultura, principalmente quando utilizados de forma inadequada, tem provocado danos tanto ao homem como ao ambiente. O presente trabalho teve por objetivo o estudo in vitro da eficácia de extratos de três plantas e de dois basidiomicetos nativos do Brasil no controle dos fungos Alternaria solani e Colletotrichum acutatum, causadores de graves prejuízos às culturas de tomate e morango, respectivamente, além de Sclerotium rolfsii, considerado como patógeno polífago. No trabalho foram avaliados: a a inibição de crescimento micelial dos três fitopatógenos, b inibição da germinação de conídios de A. solani e C. acutatum e c inibição da germinação de escleródios de S. rolfsii. Os melhores resultados foram obtidos com o extrato de Oudemansiella canarii, que proporcionou os menores valores de crescimento micelial dos três patógenos, além inibir totalmente a germinação de conídios de A. solani e C. acutatum e de escleródios de S. rolfsii. O extrato de Irpex lacteus inibiu parcialmente o crescimento micelial dos patógenos estudados e o extrato de Avicennia schaueriana promoveu apenas 16 % de inibição do crescimento micelial de S. rolfsii. Nenhum efeito sobre os patógenos foi verificado com os extratos de Senna spectabilis e Senna multijuga nas condições em que foram realizados os experimentos.The use of fungicides in agriculture, especially when inadequate, has caused damages to both the environment and humans. The present study aimed to investigate in vitro the efficacy of extracts of three plants and two basidiomycetes of the Brazilian flora in controlling Alternaria solani and Colletotrichum acutatum, which causes serious damages to tomato and strawberry crops, respectively, and Sclerotium rolfsii, considered as non-specific pathogen. This work evaluated: a mycelial growth inhibition for the three phytopathogens, b conidial germination inhibition (A. solani and C. acutatum and c sclerotial germination inhibition for S. rolfsii. The best results were obtained with Oudemansiella canarii extract, which provided the lowest mycelial growth values for the three pathogens, besides totally inhibiting A. solani and C. acutatum conidial germination and S. rolfsii sclerotial germination. I. lacteus extract partially inhibited the mycelial growth of the pathogens and Avicennia schaueriana promoted only 16% inhibition in S. rolfsii mycelial growth. Senna spectabilis and Senna multijuga extracts had no effect on the pathogens under the conditions of the present experiments.

  13. Potencial antifúngico de extratos de plantas e de basidiomicetos nativos sobre Colletotrichum acutatum, Alternaria solani e Sclerotium rolfsii / Antifungal potential of extracts of native plants and basidiomycetes on Colletotrichum acutatum, Alternaria solani and Sclerotium rolfsii

    Scientific Electronic Library Online (English)

    Ricardo José, Domingues; Maria Cláudia Marx, Young; Jesus Guerino, Töfoli; Dácio Roberto, Matheus.

    2011-09-01

    Full Text Available O emprego de fungicidas na agricultura, principalmente quando utilizados de forma inadequada, tem provocado danos tanto ao homem como ao ambiente. O presente trabalho teve por objetivo o estudo in vitro da eficácia de extratos de três plantas e de dois basidiomicetos nativos do Brasil no controle do [...] s fungos Alternaria solani e Colletotrichum acutatum, causadores de graves prejuízos às culturas de tomate e morango, respectivamente, além de Sclerotium rolfsii, considerado como patógeno polífago. No trabalho foram avaliados: a) a inibição de crescimento micelial dos três fitopatógenos, b) inibição da germinação de conídios de A. solani e C. acutatum e c) inibição da germinação de escleródios de S. rolfsii. Os melhores resultados foram obtidos com o extrato de Oudemansiella canarii, que proporcionou os menores valores de crescimento micelial dos três patógenos, além inibir totalmente a germinação de conídios de A. solani e C. acutatum e de escleródios de S. rolfsii. O extrato de Irpex lacteus inibiu parcialmente o crescimento micelial dos patógenos estudados e o extrato de Avicennia schaueriana promoveu apenas 16 % de inibição do crescimento micelial de S. rolfsii. Nenhum efeito sobre os patógenos foi verificado com os extratos de Senna spectabilis e Senna multijuga nas condições em que foram realizados os experimentos. Abstract in english The use of fungicides in agriculture, especially when inadequate, has caused damages to both the environment and humans. The present study aimed to investigate in vitro the efficacy of extracts of three plants and two basidiomycetes of the Brazilian flora in controlling Alternaria solani and Colleto [...] trichum acutatum, which causes serious damages to tomato and strawberry crops, respectively, and Sclerotium rolfsii, considered as non-specific pathogen. This work evaluated: a) mycelial growth inhibition for the three phytopathogens, b) conidial germination inhibition (A. solani and C. acutatum) and c) sclerotial germination inhibition for S. rolfsii. The best results were obtained with Oudemansiella canarii extract, which provided the lowest mycelial growth values for the three pathogens, besides totally inhibiting A. solani and C. acutatum conidial germination and S. rolfsii sclerotial germination. I. lacteus extract partially inhibited the mycelial growth of the pathogens and Avicennia schaueriana promoted only 16% inhibition in S. rolfsii mycelial growth. Senna spectabilis and Senna multijuga extracts had no effect on the pathogens under the conditions of the present experiments.

  14. Screening of peas for resistance to Fusarium wilt and root rot (Fusarium oxysporum, Fusarium solani)

    International Nuclear Information System (INIS)

    In the introduction to this chapter, two fungal pathogens (Fusarium solani and F. oxysporum) are reviewed from the viewpoint of their incidence, importance, symptoms, mode of infection, harmfullness for peas, and known resistance resources. Further, this chapter gives detailed information about the screening of germplasm and plant breeding material, including the methods of pathogen isolation, cultivation and maintenance, preparation of plant material for screening and inoculum preparation. Three types of laboratory screening methods (tube tests, seed soaking test, root submersion test) are described. The results of testing are assessed via root and shoot symptom expression and further evaluated as a degree of infection. In F. oxysporum f. sp. pisi, six races are described, including the reaction to them on a set of differential genotypes. Finally, practical applications of these screening methods are summarised. (author)

  15. Effect of Neem (Azardirachta indica A. Juss) Seeds and Leaves Extract on Some Plant Pathogenic Fungi

    OpenAIRE

    Moslem, M. A.; El-kholie, E. M.

    2009-01-01

    In this study plant pathogenic fungi Alternaria solani, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum were chosen to study the effect of ethanolic, hexane and methanolic extracts of neem seeds and leaves. Antifungal effects of neem leave and seed extracts obtained by ethanol, hexane and ptrolium ether were examined separately in vitro against Fusarium oxysporum, Rhizoctonia solani, Alternaria solani and Sclerotinia sclerotiorum. Results indicated that seeds and leaves ex...

  16. Antagonismo in vitro de Trichoderma harzianum Rifai sobre Fusarium solani (Mart.) Sacc., asociado a la marchitez en maracuyá / Trichoderma harzianum Rifai in vitro antagonism against Fusarium solani (Mart.) Sacc., associated to withering in passion fruit

    Scientific Electronic Library Online (English)

    Carol Libeth, Suárez Meza; Reinel José, Fernández Barbosa; Nelson Osvaldo, Valero; Rocío Margarita, Gámez Carrillo; Alberto Rafael, Páez Redondo.

    2008-07-01

    Full Text Available Cultivos de maracuyá de la región Caribe colombiana presentan problemas de marchitez y el hongo Fusarium solani (Mart.) Sacc., está asociado a esta patología. Plantas de maracuyá de la Estación Experimental (E.E Caribia de Corpoica) poseen este problema y por tal razón se determinó el antagonismo in [...] vitro de aislamientos de Trichoderma harzianum Rifai, frente a F. solani, aislado de plantas enfermas de maracuyá (Passiflora edulis). Utilizando la técnica de cultivo dual en platos Petri con Agar Sabouraud, se evaluaron competencia por nutrientes y espacio, micoparasitismo y porcentaje de inhibición del crecimiento radial (PICR), empleando un diseño estadístico factorial 2x6x1 con arreglo completamente aleatorio. Se obtuvieron tres aislamientos nativos de T. harzianum (TCN-009, TCN-010, TCN-014) de suelo de Palma de Aceite (Elaeis guineensis) de la E.E Caribia, y se compararon con tres aislamientos comerciales (TCC-001, TCC-005, TCC-006). TCC-001 y TCN-014, reportaron ser más competentes por nutrientes y espacio, con el mayor radio de crecimiento de 7,50 y 7,32 cm el día 10, comparado a FSM-011 en el cual solo fue de 2,30 cm. Aunque, TCN-014 mostró micoparasitismo grado 4 con ambos aislamientos de F. solani y TCC-005 únicamente con FSM-012, el cual fue más susceptible a ser micoparasitado. En cuanto al PICR, los tratamientos con mejores porcentajes de inhibición fueron TA-9, TA-12 y TA-6 con valores de 70,56, 68,52 y 65,32% respectivamente. El aislamiento del patógeno mayormente inhibido fue FSM-011. Todos estos resultados demuestran que hubo antagonismo in vitro al utilizar los aislamientos nativos y comerciales de T. harzianum sobre F. solani. Abstract in english Passion fruit cultivation of the Colombian Caribbean region presents problems withering and the fungus Fusarium solani (Mart.) Sacc., this associated with this pathology. Plant of passion fruit of the experimental station of Corpoica Caribia EE. presented this problem and for that reason it was dete [...] rmined the antagonism in Vitro of isolations of Trichoderma harzianum Rifai, compared with F. solani, isolated from diseased plant of passion fruit (Passiflora edulis). Using the technique of cultivation dual petri dishes with Sabouraud agar was evaluated competition for space and nutrients, mycoparasitism and percentage of inhibition of radial growth (PICR), using a factorial design 2x6x1 under completely random. Three native isolations of T. harzianum were obtained (TCN-009, TCN-010, TCN-014) in soil of oil palm (Elaeis guineensis) in Caribia EE and were compared with three commercial isolations (TCC-001, TCC-005, TCC-006). TCC- 001 and TCN-014 resulting be more competent for nutrients and space, the native isolations with the highest growth of 7.50 and 7.32 radius of centimeters the day 10, compared to FSM-011 in which was only 2.30cm. Although, TCN-014 showed mycoparasitism degree 4 with both isolations of F. solani and TCC-005 only with FSM-012 which was more susceptible to micoparasitism. As for the PICR, treatments with better percentages of inhibition were TA-9, TA-12 and TA-6 with values of 70.56%, 68.52% and 65.32% respectively. The pathogenic isolation largely inhibited was FSM-011. All these results demonstrate that there was antagonism in Vitro to use the native and commercial isolations of T. harzianum on F. solani.

  17. Enanismo y podredumbre basal de eustoma grandiflorum y su relación con la densidad de fusarium solani en el suelo Stunt and basal rot of Eustoma grandiflorum and its relationship with Fusarium solani density in the soil

    Directory of Open Access Journals (Sweden)

    SILVIA M. WOLCAN

    2001-12-01

    Full Text Available En cultivos comerciales de lisianthus de La Plata y alrededores (Argentina, se observó que Fusarium solani afecta al 100% de los establecimientos productivos provocando enanismo y podredumbre basal. Se realizó un ensayo para analizar la densidad de F. solani del suelo bajo el efecto de distintos tratamientos y relacionarla con la evolución de ambas patologías. Los análisis del suelo se hicieron en 3 épocas: antes del transplante (octubre, al inicio (enero y al final (marzo de la floración. En enero y marzo se evaluó la incidencia de cada enfermedad y se cuantificaron las plantas cosechadas. La población de F. solani no varió en las 3 épocas y se redujo significativamente con los fumigantes y el vapor. Esto determinó una incidencia del enanismo (enero de 0 a 9,5% con los primeros y de 31,4% con el vapor. Para el testigo y los fungicidas la incidencia varió entre el 87,9 y el 100%, disminuyendo las plantas cosechadas. La podredumbre basal comenzó con el ingreso del patógeno a través de las heridas producidas por la cosecha. Ésta fue significativamente mayor con los fumigantes (90,7 a 99% y también con el vapor (76,8%, produciéndose la mayor incidencia en marzo (15,7 a 22,2 y 10,1% respectivamente, reduciéndose el período productivo. Se destaca la importancia de disminuir la densidad de F. solani en el momento del transplante. Entre los métodos de control el Metam sodio y Dazomet podrían ser eficaces sustitutos del Bromuro de metilo, seguidos por el vapor.Fusarium solani was recorded in 100% of the commercial crops of lisianthus (Eustoma grandiflorum located around La Plata (Argentina. The pathogen causes stunt and basal rot. A trial was carried out to analyse the F. solani soil density and its relation to the development of both diseases. Soil samples were analysed at three times: before transplant (October, at the beginning of flowering (January and at the ending of flowering (March of flowering. The incidence of each disease was evaluated in January and March, and the plants harvested were quantified. The soil density of F. solani was not altered during the three times for each treatment, and fumigants and steam decrease it significantly. In January the stunt incidence reached 0 to 9.5% with the fumigants and 31.4% with the steam treatment. In the control and fungicide plots, the incidence reached 87.9 to 100%, and a consequent reduction of flower production was observed. Stem rot began after the flowers were harvested as a result of pathogen entry through the wounds. The major values of harvested plants were obtained with fumigants (90.7 to 99% and steam (76.8%, so the greatest stem rot incidence was 15.7 to 22.2 and 10.1%, respectively, in March, and the productive period was shortened. The need of reducing F. solani soil density before lisianthus transplant is emphasized. Among soil control treatments, Metham sodium and Dazomet could be effective substitutes for Methil bromide followed by steam treatment.

  18. Metabolites change in Jatropha plants due to seed treatment with rhizobacteria and Rhizoctonia bataticola

    Directory of Open Access Journals (Sweden)

    Surender Kumar

    2013-11-01

    Full Text Available An experiment on the metabolite [salicylic acid (SA, jasmonicacid (JA, hydrocyanic acid (HCN and chitinase activity] changes owing to seed treatment with pathogen, plant growth promoting rhizobacteria (PGPRs - (P. maltophilia, P. fluorescens and Bacillus subtilis alone and in combination was conducted at Chaudhary Charan Singh, Haryana Agricultural University, Regional Research Station, Bawal. Jatropha curcas plants raised from root rot pathogen (Rhizoctonia bataticola treated seeds showed an initial increase in SA and hydrocyanic acid HCN content and an opposite trend was observed for JA level and chitinase activity. Though, PGPRs inoculation resulted in higher increase in SA level, JA level and chitinaseactivity in both the cases alone as well as in integration with pathogen, however, maximum increase in JA content was explicited in plants raised after seed treatment with P. fluorescens, the most effective rhizobacteria amongst PGPRs studied. Highest increase in HCN content (45 ?g g-1 over control (24 ?g g-1 was noticed for P. fluorescens followed by co-seed inoculation with P. fluorescens + pathogen (43 ?g g-1 at 10 DPI. The co-seed inoculation elicited 68 units at 10 DPI whereas the pathogen challenged plants showed lower chitinase activity with 42 units. All the metabolites declinedslightly or sharply with age of the plant irrespective of inoculations.

  19. Identificação de genótipos do gênero Solanum (secção Lycopersicon) com resistência a Stemphylium solani e S. lycopersici Identification of Solanum (section Lycopersicon) accessions with resistance to Stemphylium solani and S. lycopersici

    OpenAIRE

    Bruno Eduardo C de Miranda; Leonardo S. Boiteux; Ailton Reis

    2010-01-01

    A mancha-de-estenfílio do tomateiro, causada pelos fungos Stemphylium solani e S. lycopersici, foi considerada, por muito tempo, como uma doença secundária devido à utilização combinada de fungicidas e variedades resistentes. Recentemente, severas epidemias da mancha-de-estenfilio têm sido relatadas nas várias regiões produtoras sugerindo a necessidade de retomar o emprego de cultivares com resistência a esta enfermidade. O objetivo do presente trabalho foi avaliar a reação de gen...

  20. Histopathological features of infections caused by Fusarium oxysporum and F. solani in purple passionfruit plants (Passiflora edulis Sims) / Características hispatologicas da infecção causada por Fusarium oxysporum e F. solani em maracujá-roxo (Passiflora edulis Sims). Summa Phytopathologica

    Scientific Electronic Library Online (English)

    Emiro, Ortiz; Marisol, Cruz; Luz Marina, Melgarejo; Xavier, Marquínez; Lilliana, Hoyos-Carvajal.

    2014-06-01

    Full Text Available O maracujá roxo Passiflora edulis Sims., destaca-se posicionado em segundo lugar na exportação de frutas da Colômbia, cujo mercado europeu é o principal destino. No entanto, a produção é afetada por várias doenças, incluindo a presença de fusariose. Este trabalho apresenta as características histopa [...] tológicas de diferentes tecidos afetados elos patógenos Fusarium oxysporum e Fusarium solani. Ambos os organismos produzem efeitos semelhantes sobre a planta: colonização dos vasos do xilema por hifas e microconídios, hipertrofia e hiperplasia do câmbio, xilema e floema; destruição de fibras do xilema e amiloplastos em células parenquimatosas, também a produção de géis pela planta. No entanto, existem diferenças no mecanismo de colonização, F. solani entra e se concentra principalmente na área do colo enquanto F. oxysporum penetra nas raízes e move-se através do sistema vascular para colonizar a planta. Abstract in english The purple passionfruit plant, Passifloraedulis Sims, ranks second in fruit exportation in Colombia, and its main destination is the European market. However, its production is affected by several diseases, including fusariosis. This paper presents the histopathological features of different tissues [...] affected by the pathogens Fusarium oxysporum and Fusarium solani. Both microorganisms produce similar responses on the plant: colonization of xylem vessels by hyphae and microconidia, hypertrophy and hyperplasia of the cambium, xylem and phloem; destruction of xylem fibers and amyloplasts in parenchymatous cells; and production of gels by the plant. However, there are differences in the colonization mechanism, F. solani penetrates and is concentrated especially at the collar zone, while F. oxysporum penetrates the roots and moves through the vascular system to colonize the plant.

  1. Potencial de rizobactérias no controle de Fusarium solani (Mart. Sacc. em pepino (Cucumis sativum L. Potential of rhizobacteria in the control of Fusarium solani (Mart. Sacc. in cucumber (Cucumis sativum L.

    Directory of Open Access Journals (Sweden)

    I S. de Melo

    1995-08-01

    Full Text Available Rizobactérias, isoladas da rizosfera de diferentes hospedeiros foram selecionadas in vitro quanto ao antagonismo contra Fusarium solam agente causai da podridão radicular. In vitro, foram selecionadas 18 bactérias isoladas da rizosfera de plantas sadias de pepino e, destas, somente três foram eficientes em inibir consideravelmente o crescimento micelial do patógeno. Dois isolados de Bacillus subtilis e dois de Pseudomonas sp., antagônicos a outros fungos fitopatogênicos foram incluidos nos testes, os quais mostraram-se capazes de antagonizar F. solani. Em condições de casa-de-vegetação, B. subtilis, linhagem 0G, controlou totalmente o patógeno em todos os ensaios realizados. Promoção do crescimento de plantas foi verificada pela inoculação com linhagens 0G (B. subtilis, St. Barb. e CBPN (Pseudomonas sp.Rhizobacteria, isolated from the rhizosphere of different hosts were selected in vitro, based on the antagonism against Fusarium solani, agent of root rot. In vitro, 18 bacterias were selected from rhizosphere of healthy plants of cucumber and, from those, only three were efficient in inhibiting the micelial growth of the pathogen. In these tests two isolates of Bacillus subtilis (0G and 5G, and two of Pseudomonas (CBPN and St Barb., antagonistic to some pathogenic fungi, were included. These bolates also inhibited the growth of F solani. The bolate OG of B. subtilis reduced significantly the root rot of cucumber. Beneficial effects were obtained with the bolates St Barb., 0G and CBPN in relation to plant growth.

  2. Continuous hydrolysis of 4-cyanopyridine by nitrilases from Fusarium solani O1 and Aspergillus niger K10.

    Czech Academy of Sciences Publication Activity Database

    Malandra, Anna; Cantarella, M.; Kaplan, Ond?ej; Vejvoda, Vojt?ch; Uhnáková, Bronislava; Št?pánková, B.; Kubá?, David; Martínková, Ludmila

    2009-01-01

    Ro?. 85, ?. 2 (2009), s. 277-284. ISSN 0175-7598 R&D Projects: GA AV ?R IAA500200708; GA MŠk(CZ) LC06010; GA MPO FT-TA5/043; GA ?R GD305/09/H008; GA MŠk OC09046 Institutional research plan: CEZ:AV0Z50200510 Keywords : nitrilase * aspergillus niger * fusarium solani Subject RIV: EE - Microbiology, Virology Impact factor: 2.896, year: 2009

  3. Antifungal Effects of Thyme, Agastache and Satureja Essential Oils on Aspergillus fumigatus, Aspergillus flavus and Fusarium solani

    OpenAIRE

    Karim Mardani; Samira Ebrahimzadeh; Abbas Hasani; Abdulghaffar Ownagh

    2010-01-01

    Growth inhibition of Aspergillus fumigatus,Aspergillus flavus and Fusarum solani exposed to the essential oils including Thyme, Agastache and Satureja were studied. Disc Diffusion Method was used to evaluate the fungal growth inhibitory effects of the essential oils. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of the oils were determined and compared with each other. The results showed that all three essential oils examined, had antifungal effects against...

  4. Antagonismo in vitro de Trichoderma harzianum Rifai sobre Fusarium solani (Mart. Sacc., asociado a la marchitez en maracuyá

    Directory of Open Access Journals (Sweden)

    Carol Libeth Suárez Meza

    2009-01-01

    Full Text Available Cultivos de maracuyá de la región Caribe colombiana presentan problemas de marchitez y el hongo Fusarium solani (Mart. Sacc., está asociado a esta patología. Plantas de maracuyá de la Estación Experimental (E.E Caribia de Corpoica poseen este problema y por tal razón se determinó el antagonismo in vitro de aislamientos de Trichoderma harzianum Rifai, frente a F. solani, aislado de plantas enfermas de maracuyá (Passiflora edulis. Utilizando la técnica de cultivo dual en platos Petri con Agar Sabouraud, se evaluaron competencia por nutrientes y espacio, micoparasitismo y porcentaje de inhibición del crecimiento radial (PICR, empleando un diseño estadístico factorial 2x6x1 con arreglo completamente aleatorio. Se obtuvieron tres aislamientos nativos de T. harzianum (TCN-009, TCN-010, TCN-014 de suelo de Palma de Aceite (Elaeis guineensis de la E.E Caribia, y se compararon con tres aislamientos comerciales (TCC-001, TCC-005, TCC-006. TCC-001 y TCN-014, reportaron ser más competentes por nutrientes y espacio, con el mayor radio de crecimiento de 7,50 y 7,32 cm el día 10, comparado a FSM-011 en el cual solo fue de 2,30 cm. Aunque, TCN-014 mostró micoparasitismo grado 4 con ambos aislamientos de F. solani y TCC-005 únicamente con FSM-012, el cual fue más susceptible a ser micoparasitado. En cuanto al PICR, los tratamientos con mejores porcentajes de inhibición fueron TA-9, TA-12 y TA-6 con valores de 70,56, 68,52 y 65,32% respectivamente. El aislamiento del patógeno mayormente inhibido fue FSM-011. Todos estos resultados demuestran que hubo antagonismo in vitro al utilizar los aislamientos nativos y comerciales de T. harzianum sobre F. solani.  Palabras clave: Passiflora, competencia, micoparasitismo, inhibición, antagonismo.

  5. Morphological and molecular characterization of Fusarium. solani and F. oxysporum associated with crown disease of oil palm

    OpenAIRE

    Hafizi, R.; Salleh, B.; Latiffah, Z.

    2014-01-01

    Crown disease (CD) is infecting oil palm in the early stages of the crop development. Previous studies showed that Fusarium species were commonly associated with CD. However, the identity of the species has not been resolved. This study was carried out to identify and characterize through morphological approaches and to determine the genetic diversity of the Fusarium species. 51 isolates (39%) of Fusarium solani and 40 isolates (31%) of Fusarium oxysporum were recovered from oil palm with typ...

  6. Studies on the interactions of Meloidogyne incognita, Radopholus similis and Fusarium solani on black pepper (Piper nigrum L.).

    OpenAIRE

    Mustika, I.

    1990-01-01

    This study on the interactions between various cultivars of the black pepper plant (Piper nigrum L. ) and three of its pathogens, Meloidogyne Incognita (Kofoid & White) , Radopholus similis (Cobb) , Thorne and Fusarium solani f. sp. piperi Albuquerque was initiated to search for a biological cause of "yellow disease" of black pepper.This disease was described already in 1932 by Van der Vecht as "geelziektel" and its symptoms on the aerial parts of the pepper plants were yellowing of the leave...

  7. Efficacy and Safety of Some Plant Extracts against Tomato Early Blight Disease Caused by Alternaria solani

    OpenAIRE

    A.B. El-Sayed; M.S. El-Mahrouk; A.S. Derbalah

    2011-01-01

    In an attempt to establish new control practices with low mammalian toxicity and low persistence in the environment against plant pathogens, crude extracts of seven plant species (Cassia senna, Caesalpinia gilliesii, Thespesia populnea var. acutiloba, Chrysanthemum frutescens, Euonymus japonicus, Bauhinia purpurea and Cassia fistula) were evaluated against Alternaria solani in tomato under laboratory and greenhouse conditions. Furthermore, GC-MS analysis was carried to identify the biological...

  8. Evaluation of the in vitro antimicrobial properties of ultraviolet A/riboflavin mediated crosslinking on Candida albicans and Fusarium solani

    Directory of Open Access Journals (Sweden)

    Bing Sun

    2014-04-01

    Full Text Available AIM:To evaluate the antimicrobial properties of ultraviolet A (UVA (365 nm/riboflavin against Candida albicans and Fusarium solani.METHODS:Two fungus isolates were cultured in vitro and prepared with 10-fold serial PBS dilutions of cell concentration. For each dilution of fungus suspension, the concentration (colony-forming units/mL, CFU/mL and the inactivation ratio of fungal cells were evaluated under 4 conditions:no treatment (control, UVA (365 nm/riboflavin, riboflavin, and UVA (365 nm.RESULTS:The cell concentration decreased in UVA (365 nm/riboflavin group for Candida albicans at each dilution and Fusarium solani at dilutions of 104, 103, 102 CFU/mL, when compared with that in control, riboflavin, and UVA (365 nm groups (P<0.01. No difference of cell concentration was detected amongst the culture of control, riboflavin, and UVA (365 nm groups for the two fungus. There is a negative correlation between suspension concentration (log-transformed and the inactivation ratio in UVA (365 nm/riboflavin group for Candida albicans and Fusarium solani (P<0.01.CONCLUSION: According to the standard protocol of corneal collagen cross-linking, UVA (365 nm/riboflavin combination treatment is found to moderately inactivate the viability of Candida albicans and Fusarium solaniin vitro. The inactivation ratio was found to increase with the decrease of cell concentration under UVA (365 nm/riboflavin condition.

  9. First Report of Antifungal Spectra of Activity of Iranian Actinomycetes Strains Against Alternaria solani, Alternaria alternate, Fusarium solani, Phytophthora megasperma, Verticillium dahliae and Saccharomyces cerevisiae

    OpenAIRE

    Aghighi, S.; Shahidi Bonjar, G. H.; Rawashdeh, R.; Batayneh, S.; Saadoun, I.

    2004-01-01

    This is the first report of antifungal activity of Iranian Actinomycetes isolates against Alternaria solani Sorauer, Alternaria alternata (Fr.) Keissler, Fusarium solani (Mart.) Sacc., Phytophthora megasperma Drechsler, Verticillium dahliae Klebahn and Saccharomyces cerevisiae Meyen ex Hansen. Biological control of plant diseases has received worldwide attention in recent years mainly as a response to public concern about the use of hazardous chemicals in the environment. Soil Actinomycetes p...

  10. Genetic diversity in Fusarium solani f. sp. pisi based on SSR markers

    Directory of Open Access Journals (Sweden)

    Ni Xiang

    2012-11-01

    Full Text Available Pea root rot, caused by Fusarium solani f. sp. pisi (Fsp, is one of the most important diseases on pea (Pisum sativum. Assessing the genetic diversity of the pathogen isolates from different geographical regions is crucially important for understanding of the genetic background of this pathogen and intelligently deploying host resistance. We screened SSRs in complete genome sequence of Nectria haematococca MPVI, and 107 SSR loci were selected for designing markers, from which 24 polymorphic primer pairs were developed. The 24 primer pairs were used to assess genetic diversity of 96 Fsp isolates from different geographical regions. Among 24 SSR markers, a total of 132 alleles were detected among the 96 Fsp isolates, the number ofalleles for each of the loci ranged from 3 to 15 with an average of 5.5. The genetic diversity was estimated to range from 0.4855 to 0.8264 with the average value of 0.738. Using these markers, 93 genotypes were detected. When the genetic similarity coefficient was 0.8, 96 Fsp isolates were clustered into 10 groups by phylogeneticanalysis. There was no correlation between SSR profile and either geographic origin or pathogenicity. Analysis of AMOVA revealed that variation mainly presented within Fsp populations (86.14%, and genetic differentiation of Fsp was significantly affected by geographical conditions and ecological environment.

  11. Nonomuraea solani sp. nov., an actinomycete isolated from eggplant root (Solanum melongena L.).

    Science.gov (United States)

    Wang, Xiangjing; Zhao, Junwei; Liu, Chongxi; Wang, Jidong; Shen, Yue; Jia, Feiyu; Wang, Liang; Zhang, Ji; Yu, Chao; Xiang, Wensheng

    2013-07-01

    A novel actinomycete, designated strain NEAU-Z6(T), was isolated from eggplant (Solanum melongena L.) root. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain NEAU-Z6(T) belonged to the genus Nonomuraea, with highest sequence similarity to Nonomuraea monospora PT 708(T) (98.83 %), Nonomuraea rosea GW 12687(T) (98.55 %) and Nonomuraea rhizophila YIM 67092(T) (98.02 %). Sequence similarities between strain NEAU-Z6(T) and other species of the genus Nonomuraea ranged from 97.94 % (Nonomuraea candida HMC10(T)) to 96.30 % (Nonomuraea wenchangensis 210417(T)). Key morphological, physiological and chemotaxonomic characteristics of strain NEAU-Z6(T) were congruent with the description of the genus Nonomuraea. The G+C content of the genomic DNA was 64.51 mol%. DNA-DNA relatedness and comparative analysis of physiological, biochemical and chemotaxonomic data allowed genotypic and phenotypic differentiation of strain NEAU-Z6(T) from closely related species. Thus, strain NEAU-Z6(T) represents a novel species of the genus Nonomuraea, for which the name Nonomuraea solani sp. nov. is proposed. The type strain is NEAU-Z6(T) ( = CGMCC 4.7037(T) = DSM 45729(T)). PMID:23203622

  12. Suppression of Fusarium solani f. sp. phaseoli on Bean by Aluminum in Acid Soils.

    Science.gov (United States)

    Furuya, H; Takahashi, T; Matsumoto, T

    1999-01-01

    ABSTRACT The severity of bean root rot caused by Fusarium solani f. sp. phaseoli in vitro was studied with regard to exchangeable soil aluminum for 25 soil samples collected from northeastern Honshyu island, Japan. Of these, 24 were Andosols, typically acidic and of volcanic ash origin. Disease severity was assessed based on the number of lesions produced by the pathogen on a 6-cm section of bean stem buried and incubated for 8 days at 25 degrees C in artificially infested soil samples. The number of lesions differed considerably among soil samples. In all soils in which disease incidence was very low, macroconidial germination was strongly inhibited. The inhibition was observed in all soil samples with exchangeable aluminum contents of at least 0.4 meq/100 g of soil, although it is unclear if this concentration is the lowest limit for inhibition. When soil pH was 5.6 or lower, higher amounts of exchangeable aluminum were detected from soils in which the major clay mineralogy was chloritized 2:1 minerals, while no or limited amounts of aluminum were detected from soils in which the major clay mineralogy was allophane/imogolite. Macroconidial germination and disease incidence are thus closely related to clay mineralogy, which regulates the behavior of exchangeable aluminum. PMID:18944802

  13. Isolation and In Vivo and In Vitro Antifungal Activity of Phenylacetic Acid and Sodium Phenylacetate from Streptomyces humidus

    OpenAIRE

    Hwang, Byung Kook; Lim, Song Won; Kim, Beom Seok; Lee, Jung Yeop; Moon, Surk Sik

    2001-01-01

    The antifungal substances SH-1 and SH-2 were isolated from Streptomyces humidus strain S5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. SH-1 and SH-2 completely inhibited the growth of Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Saccharomyces cerevisiae, and Pseudomonas syringa...

  14. Possibilidade de transmissão de Fusarium solani f.sp. glycines, agente causal da podridão vermelha da raiz da soja, através da semente Possible transmission of Fusarium solani f. sp. glycines, causal agent of Sudden Death Syndrome, through soybean seed

    Directory of Open Access Journals (Sweden)

    Clarice R. Balardin

    2005-12-01

    Full Text Available Um isolado de Fusarium solani f.sp. glycines, coletado em plantas de soja (Glycine max na região de Cruz Alta - RS, foi utilizado em experimentos conduzidos com o objetivo de avaliar a possibilidade de a semente ser um veículo eficiente de disseminação da podridão vermelha da raiz na cultura da soja. A transferência de propágulos do patógeno para sementes de soja, armazenada durante um, seis e 12 meses, foi realizada através da mistura de grãos de sorgo (Sorghum bicolor, solo e resíduos de colheita, previamente esterilizados e posteriormente infetados, em condições de laboratório, com F. solani f.sp. glycines. As evidências de que sementes de soja podem ser uma das fontes de inóculo primário de Podridão Vermelha da Raiz relacionaram-se à presença de clamidósporos aderidos externamente às sementes, após seis meses de armazenamento. As sementes apresentando crescimento do fungo após 12 meses de armazenamento, um mínimo de 75 unidades formadoras de colônias/ml removidas do tegumento das sementes de soja e plântulas formadas a partir das sementes infetadas após 12 meses de armazenamento mostrando sintomas da doença.A Fusarium solani f.sp. glycines isolate collected in Cruz Alta RS, Brazil, was utilized in these experiments to evaluate the possibility of the Sudden Death Syndrome (SDS pathogen being transmitted by soybean (Glycine max seeds. The seedborne nature of SDS pathogen was demonstrated using infected sorghum (Sorghum bicolor seeds, infested soil, and infected plant debris as transport vehicles of inoculum. The following evidence of soybean seeds being the primary inoculum of SDS pathogen was chlamidospores were externally adhered to the soybean seeds after six months; soybean seeds had with the fungus mycelium after 12 months of storage; 75 c.f.u./ml were removed from the seed coat after 12 months of storage; and the fungus was transmissible after 12 months of storage.

  15. Possibilidade de transmissão de Fusarium solani f.sp. glycines, agente causal da podridão vermelha da raiz da soja, através da semente / Possible transmission of Fusarium solani f. sp. glycines, causal agent of Sudden Death Syndrome, through soybean seed

    Scientific Electronic Library Online (English)

    Clarice R., Balardin; Alisson F., Celmer; Ervandil C., Costa; Rosana C., Meneghetti; Ricardo S., Balardin.

    2005-12-01

    Full Text Available Um isolado de Fusarium solani f.sp. glycines, coletado em plantas de soja (Glycine max) na região de Cruz Alta - RS, foi utilizado em experimentos conduzidos com o objetivo de avaliar a possibilidade de a semente ser um veículo eficiente de disseminação da podridão vermelha da raiz na cultura da soj [...] a. A transferência de propágulos do patógeno para sementes de soja, armazenada durante um, seis e 12 meses, foi realizada através da mistura de grãos de sorgo (Sorghum bicolor), solo e resíduos de colheita, previamente esterilizados e posteriormente infetados, em condições de laboratório, com F. solani f.sp. glycines. As evidências de que sementes de soja podem ser uma das fontes de inóculo primário de Podridão Vermelha da Raiz relacionaram-se à presença de clamidósporos aderidos externamente às sementes, após seis meses de armazenamento. As sementes apresentando crescimento do fungo após 12 meses de armazenamento, um mínimo de 75 unidades formadoras de colônias/ml removidas do tegumento das sementes de soja e plântulas formadas a partir das sementes infetadas após 12 meses de armazenamento mostrando sintomas da doença. Abstract in english A Fusarium solani f.sp. glycines isolate collected in Cruz Alta RS, Brazil, was utilized in these experiments to evaluate the possibility of the Sudden Death Syndrome (SDS) pathogen being transmitted by soybean (Glycine max) seeds. The seedborne nature of SDS pathogen was demonstrated using infected [...] sorghum (Sorghum bicolor) seeds, infested soil, and infected plant debris as transport vehicles of inoculum. The following evidence of soybean seeds being the primary inoculum of SDS pathogen was chlamidospores were externally adhered to the soybean seeds after six months; soybean seeds had with the fungus mycelium after 12 months of storage; 75 c.f.u./ml were removed from the seed coat after 12 months of storage; and the fungus was transmissible after 12 months of storage.

  16. Aceites Esenciales y Extractos Acuosos para el Manejo in vitro de Fusarium oxysporum f. sp. lycopersici y F. solani / Essential Oils and Aqueous Extracts for the in vitro Management of Fusarium oxysporum f. sp. lycopersici and F. solani

    Scientific Electronic Library Online (English)

    Daniel Antonio, Vásquez Covarrubias; Roberto, Montes Belmont; Alfredo, Jiménez Pérez; Hilda Elizabet, Flores Moctezuma.

    Full Text Available El uso de fungicidas sintéticos favorece la aparición de hongos fitopatógenos resistentes, por lo que se requieren nuevos productos para el manejo de enfermedades. Una alternativa son los aceites esenciales (AE) y extractos acuosos (EA) de origen vegetal. En este trabajo se evaluaron distintas conce [...] ntraciones de AE y EA de cinco especies de la familia Chenopodiaceae sobre el crecimiento micelial y esporulación de Fusarium oxysporum f. sp. lycopersici (FOL) y F. solani. Se encontró que existe una respuesta diferencial entre las razas 2 y 3 de FOL e incluso entre aislamientos de una misma raza. Los AE de Chenopodium album [0.3 %] y C. ambrosioides [2 %] inhibieron totalmente el crecimiento y esporulación en ambas especies de Fusarium. De los EA probados, el de Beta vulgaris ejerció la mayor reducción del crecimiento micelial (38 %) y esporulación (61 %). Los EA al 5 %, de las cinco especies evaluadas, mostraron una estimulación del 27 al 183 % en el crecimiento micelial en las cuatro cepas empleadas. Al 10 %o, Beta vulgaris, C. album, C. berlandieri subsp. nuttalliae y C. graveolens redujeron entre 11 y 38 % el crecimiento de F. solani y FOL raza 2 (aislamiento Yautepec) con respecto al testigo. Abstract in english The use of synthetic pesticides favors the appearance of resistant pathogens and pest; therefore, new products are needed for disease management. The use of essential oils (EO) and aqueous extracts (AE) are an alternative option. In this work, different concentrations of EO and AE of five Chenopodia [...] ceae species were evaluated on micelial growth and spore production of Fusarium oxysporum f. sp. lycopersici (FOL) and F. solani. It was found that there is a differential response between races 2 and 3 of FOL and even among isolates of the same race. EO of Chenopodium album [0.3 %] and C. ambrosioides [2 %] inhibited micelial growth and spore production on both Fusarium species. Of the EA tested, Beta vulgaris exercised the greatest reduction in mycelial growth (38 %) and sporulation (61 %). The EA 5 %, of the five species tested showed a stimulation by 27 to 183 % in mycelial growth on the four strains used. At 10 %, Beta vulgaris, C. album, C. berlandieri subsp. nuttalliae and C. graveolens reduced between 11 and 38 % growth of F. solani and FOL race 2 (isolate Yautepec) compared with the control.

  17. Morphological and comparative genomic analyses of pathogenic and non-pathogenic Fusarium solani isolated from Dalbergia sissoo.

    Science.gov (United States)

    Arif, M; Zaidi, N W; Haq, Q M R; Singh, Y P; Taj, G; Kar, C S; Singh, U S

    2015-06-01

    Sissoo or shisham (Dalbergia sissoo Roxb.) is one of the finest wood of South Asia. Fusarium solani is a causal organism of sissoo wilt, decline, or dieback. It is also a potential causal organism associated with other valuable tree species. Thirty-eight Fusarium isolates including 24 F. solani and 14 Fusarium sp., were obtained in 2005 from different geographical locations in India. All 38 (18 pathogenic and 20 non-pathogenic) isolates were characterized for genomic analysis, growth behaviour, pigmentation and sensitivity to carbendazim. Based on growth pattern, growth rate, pigmentation and sensitivity to carbendazim, all 38 isolates showed a wide range of variability, but no correlation with pathogenicity or geographical distribution. Three techniques were used for comparative genomic analysis: random amplified polymorphic DNA (RAPD); inter simple sequence repeats (ISSR); and simple sequence repeats (SSR). A total of 90 primers targeting different genome regions resulted a total of 1159 loci with an average of 12.88 loci per primer. These primers showed high genomic variability among the isolates. The maximum loci (14.64) per primer were obtained with RAPD. The total variation of the first five principal components for RAPD, ISSR, SSR and combined analysis were estimated as 47.42, 48.21, 46.30 and 46.78 %, respectively. Among the molecular markers, highest Pearson correlation value (r = 0.957) was recorded with combination of RAPD and SSR followed by RAPD and ISSR (r = 0.952), and SSR and ISSR (r = 0.942). The combination of these markers would be similarly effective as single marker system i.e. RAPD, ISSR and SSR. Based on polymorphic information content (PIC = 0.619) and highest coefficient (r = 0.995), RAPD was found to be the most efficient marker system compared to ISSR and SSR. This study will assist in understanding the population biology of wilt causing phytopathogen, F. solani, and in assisting with integrated disease management measures. PMID:25605046

  18. Electronics

    CERN Document Server

    Mesias, Gerardo

    2012-01-01

    Electronics Theory and Practice introduces the key areas of analog electronics through practicals, worked examples and concise explanations. The author is a senior lecturer at De Montfort University and his approach is a proven way of teaching the essentials of electronics to groups with a variety of academic backgrounds. This is an ideal text for first year modules and HNC/D units - comprehensive, concise and affordable.

  19. Electronics

    CERN Document Server

    Hollar, Sherman

    2012-01-01

    Although most people would scarcely be able to make it through the day without using some type of electronic device-computers, televisions, and MP3 players, to name a few-the inner workings of such devices remain a mystery to many. This insightful volume examines various components, such as electron tubes and semiconductors, that have been essential to electronics over the years, as well as the history of the field in general and its applications in everyday life.

  20. Antifungal Effects of Thyme, Agastache and Satureja Essential Oils on Aspergillus fumigatus, Aspergillus flavus and Fusarium solani

    Directory of Open Access Journals (Sweden)

    Karim Mardani

    2010-09-01

    Full Text Available Growth inhibition of Aspergillus fumigatus,Aspergillus flavus and Fusarum solani exposed to the essential oils including Thyme, Agastache and Satureja were studied. Disc Diffusion Method was used to evaluate the fungal growth inhibitory effects of the essential oils. Minimal inhibitory concentration (MIC and minimal fungicidal concentration (MFC of the oils were determined and compared with each other. The results showed that all three essential oils examined, had antifungal effects against three fungi species. The MIC data revealed that Thyme oil was the most effective essential oil with the MIC of 62.5 ?l ml-1.

  1. Fontibacillus solani sp. nov. isolated from potato (Solanum tuberosum L.) root.

    Science.gov (United States)

    Ramírez-Bahena, Martha-Helena; Flores-Félix, José David; Cuesta, Maria José; Gil, Carmen Tejedor; Palomo, Jose Luis; Benavides, Pablo García; Igual, Jose Mariano; Pascual, Mercedes Fernández; Velázquez, Encarna; Peix, Alvaro

    2015-05-01

    A bacterial strain designated A4STR04(T) was isolated from the inner root tissue of potatoes in Spain. Phylogenetic analysis based on the 16S rRNA gene sequence placed the isolate into the genus Fontibacillus, being most closely related to Fontibacillus panacisegetis KCTC 13564(T) with 99 % identity. The isolate was observed to form Gram-positive, motile and sporulating rods. The catalase test was found to be negative and oxidase positive. Nitrate was found to be reduced to nitrite. ?-Galactosidase and caseinase were observed to be produced but the production of gelatinase, urease, arginine dehydrolase, ornithine and lysine decarboxylase was negative. Aesculin hydrolysis was found to be positive and acetoin production was negative. Growth was found to be supported by many carbohydrates and organic acids as carbon source. MK-7 was the only menaquinone detected and the major fatty acid (61.5 %) was identified as anteiso-C15:0, as occurs in the other species of genus Fontibacillus. The strain A4STR04(T) was found to display a complex lipid profile consisting of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, a glycolipid, two phospholipids, a lipid and two aminophospholipids. Mesodiaminopimelic acid was detected in the peptidoglycan. The G+C content was determined to be 50.5 mol% (Tm). Phylogenetic, chemotaxonomic and phenotypic analyses showed that strain A4STR04(T) (=LMG 28458 (T) = CECT 8693(T)) should be classified as representing a novel species of genus Fontibacillus, for which the name Fontibacillus solani sp. nov. is proposed. PMID:25772303

  2. Identificação de genótipos do gênero Solanum (secção Lycopersicon) com resistência a Stemphylium solani e S. lycopersici / Identification of Solanum (section Lycopersicon) accessions with resistance to Stemphylium solani and S. lycopersici

    Scientific Electronic Library Online (English)

    Bruno Eduardo C de, Miranda; Leonardo S, Boiteux; Ailton, Reis.

    2010-06-01

    Full Text Available A mancha-de-estenfílio do tomateiro, causada pelos fungos Stemphylium solani e S. lycopersici, foi considerada, por muito tempo, como uma doença secundária devido à utilização combinada de fungicidas e variedades resistentes. Recentemente, severas epidemias da mancha-de-estenfilio têm sido relatadas [...] nas várias regiões produtoras sugerindo a necessidade de retomar o emprego de cultivares com resistência a esta enfermidade. O objetivo do presente trabalho foi avaliar a reação de genótipos cultivados e silvestres de tomateiro [Solanum (secção Lycopersicon)] frente a isolados destas duas espécies de Stemphylium. Na primeira etapa do trabalho, 109 genótipos de Solanum (secção Lycopersicon) foram avaliados via inoculação com uma suspensão de 10(4) conídios/mL dos isolados 'EH-1740' (S. solani) e 'EH-1749' (S. lycopersici). As plantas foram transplantadas aos 18 dias da semeadura e inoculadas sete dias depois. A avaliação da resposta dos genótipos foi feita 15 dias após a inoculação. Cinqüenta e oito genótipos considerados promissores foram novamente avaliados (com os mesmos isolados) em um segundo experimento. Neste experimento a reação dos genótipos foi avaliada cada dois dias utilizando como critérios o período de incubação e a severidade da doença através de uma escala de notas de 0 a 5. Com os valores de severidade, nas diferentes leituras, foi calculada a área abaixo da curva de progresso da doença e o índice de doença. Foram identificadas 35 fontes de resistência às duas espécies de Stemphylium em genótipos das espécies S. lycopersicum, S. habrochaites, S. peruvianum e S. pimpinellifolium. Os genótipos de S. lycopersicum e S. pimpinellifolium resistentes possuem, provavelmente, o gene de resistência Sm. No entanto, os genótipos de S. peruvianum e S. habrochaites podem representar fontes de novos genes/alelos que conferem resistência às duas espécies fúngicas. Esta potencial diversidade de fatores de resistência para Stemphylium pode ser útil em futuras ações de pesquisa dentro de programas de melhoramento genético do tomateiro bem como para o manejo integrado da doença. Abstract in english The gray leaf spot disease, caused by the fungi Stemphylium solani and S. lycopersici, has been considered as a minor tomato disease in Brazil due to the use of varieties with genetic resistance in combination with fungicide sprays. However, recent reports of severe epidemics of the gray leaf spot i [...] n the various tomato-producing areas of the country suggest that the employment of resistant cultivars should be re-implemented as a control strategy. In the present study, 109 cultivated and wild Solanum (section Lycopersicon) accessions were evaluated to isolates of both S. solani and S. lycopersici. In the first assay, spore suspension (adjusted to 10(4) conidia/mL) of the isolates 'EH-1740' (S. solani) and 'EH-1749' (S. lycopersici) were employed to inoculate seedlings transplanted 15 days after sowing and kept in a greenhouse. Plants were inoculated 18 days after transplanting and evaluated 15 days after inoculation. Fifty-eight promising accessions identified in the first assay were evaluated again with the same isolates in a second experiment. The reaction of the accessions to the pathogens was evaluated every two days using as assessment criteria the incubation period, the severity of gray leaf spot, and the disease index. Disease severity values over time were used to calculate the area under the disease progress curve. Promising sources of resistance to both pathogens were identified in accessions of S. lycopersicum, S. habrochaites, S. peruvianum and S. pimpinellifolium. The resistant sources identified in S. pimpinellifolium and S. lycopersicum accessions probably have the gene Sm. However, S. habrochaites and S. peruvianum might be potential new sources of gene/alleles that confer resistance to both fungi. This diversity of Stemphylium resistance genes might be useful for tomato breeding programs in the future as well as in integrated

  3. Effects of Fusarium solani and F. oxysporum Infection on the Metabolism of Ginsenosides in American Ginseng Roots

    Directory of Open Access Journals (Sweden)

    Xiaolin Jiao

    2015-06-01

    Full Text Available American ginseng (Panax quinquefolius L. is a highly valuable herb widely used for medicinal treatments. Its pharmacologically important compounds are the ginsenosides, which are secondary metabolites in American ginseng root. The concentrations of ginsenoside in roots can be changed by fungal infection, but it is unclear what specific root tissues are impacted and whether the change is systemic. In this study, American ginseng roots were inoculated with two fungal pathogens (Fusarium solani or F. oxysporum and the levels of six ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1 were then measured in the phloem and xylem around the discolored lesions and adjacent healthy areas of the root. Results indicated that the growth of Fusarium spp. was strictly limited to phloem, and correspondingly the ginsenoside concentration was only altered in this infected phloem. The concentration of Rg1, Rd, and Rc significantly changed in phloem tissues where F. solani was inoculated, while only Rg1 and Rd changed significantly after F. oxysporum inoculation. However, no changes of any ginsenoside occurred in either xylem or phloem tissue adjacent to the inoculation point. In addition, when two Fusarium spp. were grown on ginsenoside-amended Czapek medium, the majority of ginsenosides were depleted. Therefore, pathogenic Fusarium spp. may reduce ginsenoside levels by consuming them.

  4. Effects of Fusarium solani and F. oxysporum Infection on the Metabolism of Ginsenosides in American Ginseng Roots.

    Science.gov (United States)

    Jiao, Xiaolin; Lu, Xiaohong; Chen, Amanda Juan; Luo, Yi; Hao, Jianjun J; Gao, Weiwei

    2015-01-01

    American ginseng (Panax quinquefolius L.) is a highly valuable herb widely used for medicinal treatments. Its pharmacologically important compounds are the ginsenosides, which are secondary metabolites in American ginseng root. The concentrations of ginsenoside in roots can be changed by fungal infection, but it is unclear what specific root tissues are impacted and whether the change is systemic. In this study, American ginseng roots were inoculated with two fungal pathogens (Fusarium solani or F. oxysporum) and the levels of six ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1) were then measured in the phloem and xylem around the discolored lesions and adjacent healthy areas of the root. Results indicated that the growth of Fusarium spp. was strictly limited to phloem, and correspondingly the ginsenoside concentration was only altered in this infected phloem. The concentration of Rg1, Rd, and Rc significantly changed in phloem tissues where F. solani was inoculated, while only Rg1 and Rd changed significantly after F. oxysporum inoculation. However, no changes of any ginsenoside occurred in either xylem or phloem tissue adjacent to the inoculation point. In addition, when two Fusarium spp. were grown on ginsenoside-amended Czapek medium, the majority of ginsenosides were depleted. Therefore, pathogenic Fusarium spp. may reduce ginsenoside levels by consuming them. PMID:26060917

  5. A case of mycotic keratitis caused by Fusarium solani / Um caso de ceratite micótica causada por Fusarium sotani

    Scientific Electronic Library Online (English)

    Junia Soares, Hamdan; Maria Aparecida de, Resende; Sarah Piancastelli, Franzot; Daniel Vieira, Dias; Evelin Márcia, Viana; Agnes Kiesling, Casali.

    1995-04-01

    Full Text Available O caso estudado refere-se a paciente do sexo masculino, 36 anos, feoderma, sem história de doença sistêmica ou trauma ocular, apresentando úlcera corneana no olho esquerdo. Antes do estabelecimento do diagnóstico específico, o paciente foi tratado com antibiótico associado a corticosteróides durante [...] um mês. O exame direto realizado a partir de raspado de córnea tratado com KOH revelou a presença de hifas fúngicas e clamidosporos, e o cultivo do material em ágar Sabouraud dextrose mostrou-se positivo para Fusarium solani. É enfatizada a necessidade do uso cauteloso de antibióticos e corticosteróides no tratamento de infecções da córnea, bem como de se considerar a possibilidade de etiologia fúngica destes quadros. Abstract in english A 36-year-old black man, without history of systemic disease or ocular trauma developed a corneal infection in his left eye. He was treated with antibacterial antibiotic and corticosteroids for one month prior to diagnosis. Fungal hyphae and chlamydospores were found in a KOH preparation of the corn [...] eal scrapings, and positive cultures for Fusarium solani were obtained in Sabouraud dextrose agar. It is emphasized the cautious use of antibiotics and steroids in corneal diseases, and the need of considering the involvement of opportunistic fungi in the etiology of these infections.

  6. Developmental times and life table statistics of Aulacorthum solani (Hemiptera: Aphididae) at six constant temperatures, with recommendations on the application of temperature-dependent development models.

    Science.gov (United States)

    Jandricic, S E; Wraight, S P; Bennett, K C; Sanderson, J P

    2010-10-01

    Aulacorthum solani (Kaltenbach) (known as foxglove aphid or glasshouse potato aphid) is a pest of increasing economic importance in several agricultural crops worldwide, including greenhouse vegetables and ornamentals. Developmental rates and age-specific life tables for a North American population of A. solani on pansy (Viola × wittrockiana) (Gams.) were determined at six constant temperatures, and comparisons were made to previous studies of A. solani from differing geographic regions and host crops. On pansy, A. solani developed fastest at 25°C, passing through the four nymphal instars in an average of 6.9 d. The highest intrinsic rates of population increase (0.410 and 0.445) and shortest population doubling times (1.69 and 1.56 d) were recorded at 20 and 25°C, respectively. Average total fecundity remained high from 10 to 20°C (74-68 nymphs/adult); a significant decrease to 39 nymphs/adult occurred at 25°C. For calculating developmental thresholds, we present here a method of adjusting the lower developmental threshold (t(min)) using estimates from nonlinear models to provide an improved estimate of the thermal constant (K, in degree-days). We also call attention to the necessity of using a simulation method to estimate the true upper developmental threshold (t(max)) and optimum developmental temperature (t(opt)) from the Lactin-2 model of temperature-dependent development. PMID:22546462

  7. Pathological and molecular identification of Fusarium Solani F.Sp, phaseoli isolates and determination of suitable gamma ray dose rate for mutation induction

    International Nuclear Information System (INIS)

    During 1384-1385, the plants showing root and crown rot were collected from 48 bean fields in the Khuzestan and Markazi provinces. Twenty isolates were identified as Fusarium solani based on morphological characteristics. The pathogenicity tests confirmed four isolates as Fusarium solani f.sp. phaseoli. By using specific primers for this specific form, three isolates showed concordant results with pathogenicity tests. As a result three isolates morphologically and molecularly identified as F.solani f.sp. phaseoli. In order to induce mutation, conidia scraped from F.solani f.sp. phaseoli cultures, were counted, diluted and then plated on water agar. The plates containing conidia were irradiated in a 60 Co-gamma cell (with activity of 2500 curi and 0.38 gray per second dose rates) in doses 0, 60, 90,120, 150, 180 Gy. After 18 hours, the percentage germination of spores were scored. The comparison of percentage germination and vegetative growth in different dose rates Showed that spore mutagenesis can be expected in 120-180 Gy.

  8. Evaluación de la capacidad biocontroladora de cepas nativas de Trichoderma spp sobre Rhizoctonia sp y Fusarium sp en café (Coffea arabica) en condiciones experimentales / Evaluation of biocontrol ability of native strains of Trichoderma spp on Rhizoctonia and Fusarium sp in coffee (Coffea arabica) in experimental conditions

    Scientific Electronic Library Online (English)

    Rudy, Nina; Hugh, Smeltekop; JC, Almanza; Manuel, Loza-Murguia.

    Full Text Available Debido al uso indiscriminado agroquímicos, en la agricultura convencional, se esta provocando problemas de contaminación del medio ambiente (suelo, aire y agua), de ahí que, la búsqueda de alternativas que contribuyan a una producción agrícola libre de agroquímicos haciendo sostenible la producción. [...] En este trabajo se estudia el control biológico del damping off en café (Coffea arabica) aplicando el hongo antagónico Trichoderma sp., en condiciones experimentales a escala de laboratorio, en instalaciones de la Unidad Académica Campesina Carmen Pampa, comunidad de Carmen Pampa, municipio de Coroico. El objetivo de este trabajo fue controlar biológicamente el “damping off”, se encontraron dos géneros causantes del damping off en almacigo de café: Rhizoctonia sp. y Fusarium sp. Para determinar el porcentaje de crecimiento y control en el medio de cultivo, se utilizó el método de conteo de cuadrantes, donde se obtuvieron los porcentajes del crecimiento micelial del hongo antagónico Trichoderma sp.,y de los hongos fitopatógenos Rhizoctonia sp. y Fusarium sp. Estadísticamente existió una diferencia altamente significativa en la variable porcentaje de crecimiento de Trichoderma sp. sobre los hongos patógenos Rhizoctonia sp. y Fusarium sp. a los 3, 6 y 9 días esto da a conocer que el factor tiempo y los tratamientos son dependientes entre sí. La variable de control mostró una diferencia altamente significativa en el factor tiempo y tratamiento, pero en la interacción no muestra diferencia significativa esto da a conocer que son independientes los factores, por lo que el hongo Trichoderma sp., no depende del tiempo en los tratamientos, así mostrando su poder inhibidor a Rhizoctonia sp. y Fusarium sp.. Esta prueba da referencias de que existe control del hongo antagónico sobre los hongos fitopatógenos Rhizoctonia sp. y Fusarium sp. Abstract in english Due to the indiscriminate use agrochemicals in conventional agriculture, it is causing pollution problems in the environment (soil, air and water), hence the search for alternatives that contribute to agricultural production by agro-chemical free sustainable production. This paper studies the biolog [...] ical control of damping off in coffee (Coffea arabica) by applying antagonistic fungus Trichoderma sp. Under experimental conditions at laboratory facilities of the Academic Unit Carmen Pampa Campesina, a community of Carmen Pampa, Township Coroico. The aim of this study was to biologically control the "damping off", they found two genera that cause damping off in seedbed of coffee: Rhizoctonia sp. and Fusarium sp.To determine the percentage of growth and control in the culture medium, we used the method of counting quarters, where they gave the mycelial growth of antagonistic fungus Trichoderma sp., And the fungal pathogens Rhizoctonia sp. and Fusarium sp. Statistically there was a highly significant difference in the variable growth rate of Trichoderma sp. on pathogenic fungi Rhizoctonia sp. and Fusarium sp. at 3, 6 and 9 days that announces the time factor and treatments are interdependent. The control variable showed a highly significant difference in the time factor and treatment, but the interaction shows no significant difference this makes known factors that are independent, so the fungus Trichoderma sp. not depend on time in treatment, thus showing its inhibitory power to Rhizoctonia sp. and Fusarium sp .. This test gives references that there is antagonistic fungus control on the fungal pathogens Rhizoctonia sp. and Fusarium sp.

  9. Controle de Alternaria solani em tomateiro por extratos de Curcuma longa e curcumina: I. avaliação in vitro / Control of Alternaria solani in tomato by Curcuma longa extracts and curcumin: I. In vitro evaluation

    Scientific Electronic Library Online (English)

    María I., Balbi-Peña; Andrea, Becker; José Renato, Stangarlin; Gilmar, Franzener; Mário C., Lopes; Kátia R. F., Schwan-Estrada.

    2006-06-01

    Full Text Available A descoberta de compostos secundários de plantas medicinais com atividade antimicrobiana mostra-se promissora para o controle de fitopatógenos. A cúrcuma, Curcuma longa, apresenta em seus rizomas compostos com atividade antifúngica. Assim, o objetivo deste trabalho foi avaliar a fungitoxidade in vit [...] ro dos extratos de cúrcuma e da curcumina contra Alternaria solani. Foram utilizados extratos brutos aquosos (EB) de rizomas de cúrcuma (esterilizados por autoclavagem) nas concentrações de 0, 1, 5, 10 e 20% e curcumina nas concentrações de 0, 50, 100, 200 e 400 mg/L, os quais foram incorporados em meio de cultura batata-dextrose-ágar para avaliação de crescimento micelial e esporulação do fungo. Também foram testados extratos de cúrcuma a 10 e 15% esterilizados por filtração. O efeito dos extratos de cúrcuma autoclavados e não autoclavados e da curcumina na germinação de esporos in vitro foi também avaliado. Os extratos de cúrcuma a 10 e 15% não autoclavados inibiram em 38,2% e 23,2%, respectivamente, o crescimento micelial e 71,7% e 87%, respectivamente, a esporulação do fungo. Quando autoclavados, não apresentaram inibição do crescimento micelial nem da germinação de esporos e a inibição da esporulação foi menor, indicando a presença de compostos antimicrobianos termolábeis. O extrato não autoclavado na concentração de 5% inibiu em até 15% a germinação dos esporos. A curcumina inibiu o crescimento micelial em 29,5% na maior concentração testada, sem, contudo, afetar a esporulação e a germinação de esporos in vitro. Esses resultados indicam o potencial antifúngico da cúrcuma e curcumina contra A. solani. Abstract in english The discovery of plant secondary compounds with antimicrobial activity is very promising. Turmeric, Curcuma longa, has compounds in its rhizomes with fungicidal activity. The objective of this study was to evaluate the in vitro fungitoxic activity of turmeric extracts and curcumin against Alternaria [...] solani. Four different concentrations (0, 1, 5, 10 and 20%) of aqueous extracts of turmeric rhizomes (sterilized by autoclave) and four curcumin solutions (0, 50, 100, 200 and 400 mg/L) were incorporated into potato dextrose agar medium in order to evaluate fungal mycelial growth and sporulation. To evaluate the effect of using an autoclave, 10% and 15% turmeric extracts were sterilized by filtration. The effects of autoclaved and non-autoclaved turmeric extracts and curcumin on in vitro spore germination were tested. The concentrations of 10 and 15% of non-autoclaved turmeric extracts inhibited the mycelial growth by 38.2% and 23.2% respectively and the fungal sporulation by 71.7% and 87% respectively. When turmeric extracts were autoclaved, neither mycelial growth nor spore germination was inhibited and the effect on sporulation was reduced, suggesting the presence of thermolabile antimicrobial compounds. The non-autoclaved 5% extract inhibited spore germination by up to 15%. At the highest concentration, the curcumin solution inhibited mycelial growth by 29.5%. Neither in vitro sporulation nor spore germination was affected by curcumin. These results show the fungitoxic potential of turmeric and curcumin against A. solani.

  10. Controle de Alternaria solani em tomateiro por extratos de Curcuma longa e curcumina: I. avaliação in vitro Control of Alternaria solani in tomato by Curcuma longa extracts and curcumin: I. In vitro evaluation

    Directory of Open Access Journals (Sweden)

    María I. Balbi-Peña

    2006-06-01

    Full Text Available A descoberta de compostos secundários de plantas medicinais com atividade antimicrobiana mostra-se promissora para o controle de fitopatógenos. A cúrcuma, Curcuma longa, apresenta em seus rizomas compostos com atividade antifúngica. Assim, o objetivo deste trabalho foi avaliar a fungitoxidade in vitro dos extratos de cúrcuma e da curcumina contra Alternaria solani. Foram utilizados extratos brutos aquosos (EB de rizomas de cúrcuma (esterilizados por autoclavagem nas concentrações de 0, 1, 5, 10 e 20% e curcumina nas concentrações de 0, 50, 100, 200 e 400 mg/L, os quais foram incorporados em meio de cultura batata-dextrose-ágar para avaliação de crescimento micelial e esporulação do fungo. Também foram testados extratos de cúrcuma a 10 e 15% esterilizados por filtração. O efeito dos extratos de cúrcuma autoclavados e não autoclavados e da curcumina na germinação de esporos in vitro foi também avaliado. Os extratos de cúrcuma a 10 e 15% não autoclavados inibiram em 38,2% e 23,2%, respectivamente, o crescimento micelial e 71,7% e 87%, respectivamente, a esporulação do fungo. Quando autoclavados, não apresentaram inibição do crescimento micelial nem da germinação de esporos e a inibição da esporulação foi menor, indicando a presença de compostos antimicrobianos termolábeis. O extrato não autoclavado na concentração de 5% inibiu em até 15% a germinação dos esporos. A curcumina inibiu o crescimento micelial em 29,5% na maior concentração testada, sem, contudo, afetar a esporulação e a germinação de esporos in vitro. Esses resultados indicam o potencial antifúngico da cúrcuma e curcumina contra A. solani.The discovery of plant secondary compounds with antimicrobial activity is very promising. Turmeric, Curcuma longa, has compounds in its rhizomes with fungicidal activity. The objective of this study was to evaluate the in vitro fungitoxic activity of turmeric extracts and curcumin against Alternaria solani. Four different concentrations (0, 1, 5, 10 and 20% of aqueous extracts of turmeric rhizomes (sterilized by autoclave and four curcumin solutions (0, 50, 100, 200 and 400 mg/L were incorporated into potato dextrose agar medium in order to evaluate fungal mycelial growth and sporulation. To evaluate the effect of using an autoclave, 10% and 15% turmeric extracts were sterilized by filtration. The effects of autoclaved and non-autoclaved turmeric extracts and curcumin on in vitro spore germination were tested. The concentrations of 10 and 15% of non-autoclaved turmeric extracts inhibited the mycelial growth by 38.2% and 23.2% respectively and the fungal sporulation by 71.7% and 87% respectively. When turmeric extracts were autoclaved, neither mycelial growth nor spore germination was inhibited and the effect on sporulation was reduced, suggesting the presence of thermolabile antimicrobial compounds. The non-autoclaved 5% extract inhibited spore germination by up to 15%. At the highest concentration, the curcumin solution inhibited mycelial growth by 29.5%. Neither in vitro sporulation nor spore germination was affected by curcumin. These results show the fungitoxic potential of turmeric and curcumin against A. solani.

  11. INFLUÊNCIA DA DENSIDADE DE INÓCULO DE Fusarium solani f.sp. phaseoli NA SEVERIDADE DA PODRIDÃO RADICULAR SECA DO FEIJOEIRO EFFECT OF Fusarium solani f.sp. phaseoli INOCULUM DENSITY ON DRY ROOT ROT SEVERITY IN THE COMMON BEAN

    Directory of Open Access Journals (Sweden)

    Gesimária Ribeiro Costa

    2007-09-01

    Full Text Available

    Foram testadas quatro densidades de inóculo de Fusarium solani, em gramas por litro de solo (1,0; 2,0; 4,0 e 8,0 e um tratamento testemunha, em solo tipo Latossolo Vermelho-Escuro, cultivado e não cultivado, com o objetivo de determinar a densidade mínima de inóculo no solo necessária para a ocorrência de podridão radicular seca do feijoeiro. Como variáveis respostas foram avaliadas: número de microorganismos totais do solo, número de propágulos de F. solani, atividade microbiológica total do solo e severidade da doença em plântulas. Os resultados indicaram que a densidade de inóculo do fungo variou com o tipo de solo. Para um solo não cultivado a densidade necessária para causar a doença esteve acima de 5.127 propágulos por grama de solo, enquanto para o solo cultivado a densidade de inóculo para causar doença foi de 3.701 propágulos por grama de solo. Os índices de doença em plântulas cultivadas sob o solo cultivado foram duas vezes superiores ao índice de doença de plântulas sob o solo não cultivado. A atividade microbiológica total nos solos, determinada pela desidrogenase de fluorescina diacetato, não se correlacionou com a população dos microorganismos, indicando que a simples presença desses não implica em que estejam ativos.

    PALAVRAS-CHAVE: Solo supressivo; solo conducivo; Phaseolus vulgaris.

    Four densities of Fusarium solani inoculum (1, 2, 4 and 8 g/L of soil were tested for determining the minimum inoculum density for the occurrence of bean dry root rot, in two soil types. The response variables evaluated were the total number of microorganisms in the soil, the number of F. solani f. sp. phaseoli propagules, total soil microbial activity and seedling disease severity. The results indicated that the minimum inoculum density for disease occurrence varied with the soil type. For a non-cultivated soil, the minimum inoculum density was greater than 5,127 propagules per gram of soil, while for cultivated soil, the minimum inoculum density was 3,701 propagules per gram of soil. Disease severity in seedlings grown in cultivated soil was twice as great as for those grown in non-cultivated soil. Total soil microbial activity, as determined by dehydrogenase of fluorescein diacetate, did not correlate with the population of the pathogen, indicating that the mere presence of these organisms in the samesoils does not imply that they are active.

    KEY-WORDS: Suppressive soil; conducive soil; Phaseolus vulgaris.

  12. Overexpression of a tea flavanone 3-hydroxylase gene confers tolerance to salt stress and Alternaria solani in transgenic tobacco.

    Science.gov (United States)

    Mahajan, Monika; Yadav, Sudesh Kumar

    2014-08-01

    Flavan-3-ols are the major flavonoids present in tea (Camellia sinensis) leaves. These are known to have antioxidant and free radical scavenging properties in vitro. Flavanone 3-hydroxylase is considered to be an important enzyme of flavonoid pathway leading to accumulation of flavan-3-ols in tea. Expression analysis revealed the upregulation in transcript levels of C. sinensis flavanone 3-hydroxylase (CsF3H) encoding gene under salt stress. In this study, the biotechnological potential of CsF3H was evaluated by gene overexpression in tobacco (Nicotiana tabacum cv. Xanthi). Overexpression of CsF3H cDNA increased the content of flavan-3-ols in tobacco and conferred tolerance to salt stress and fungus Alternaria solani infection. Transgenic tobaccos were observed for increase in primary root length, number of lateral roots, chlorophyll content, antioxidant enzyme expression and their activities. Also, they showed lesser malondialdehyde content and electrolyte leakage compared to control tobacco plants. Further, transgenic plants produced higher degree of pectin methyl esterification via decreasing pectin methyl esterase (PME) activity in roots and leaves under unstressed and salt stressed conditions. The effect of flavan-3-ols on pectin methyl esterification under salt stressed conditions was further validated through in vitro experiments in which non-transgenic (wild) tobacco seedlings were exposed to salt stress in presence of flavan-3-ols, epicatechin and epigallocatechin. The in vitro exposed seedlings showed similar trend of increase in pectin methyl esterification through decreasing PME activity as observed in CsF3H transgenic lines. Taken together, overexpression of CsF3H provided tolerance to salt stress and fungus A. solani infection to transgenic tobacco through improved antioxidant system and enhanced pectin methyl esterification. PMID:24880475

  13. Inhibitory activity of Indian spice plant Cinnamomum zeylanicum extracts against Alternaria solani and Curvularia lunata, the pathogenic dematiaceous moulds

    Directory of Open Access Journals (Sweden)

    Sharma Bechan

    2009-03-01

    Full Text Available Abstract Background Dematiaceous moulds are pathogenic microorganisms and act as etiological agents of mycoses with different degrees of severity in humans and animals. These moulds also cause loss of food crops and storage food products. The information regarding antimicrobial efficacy of the plant preparations on these moulds is scanty. The present study reveals phytochemical characterization and the effect of bark and leaf extracts of Indian spice plant, Cinnamomum zeylanicum (Cz, against the growth of two species of dematiaceous moulds, Alternaria solani and Curvularia lunata. Methods Cz bark and leaf samples were sequentially extracted in different solvents using Soxhlet apparatus. Phytochemical analyses of extracts were done as per standard protocols. The antifungal bioassay of extracts was done by hanging drop technique. The inhibition of fungal spore germination was monitored under influence of three different concentrations of extracts. Results The lowest test concentration (50 ?g/ml of extracts of Cz bark prepared into acetone and that of Cz leaf into petroleum ether and ethanol exhibited complete inhibition (100% of spore germination in both the moulds. At 100 ?g/ml concentration all the extracts showed about 50 to 100% inhibition. However, the treatment of the spores of the two fungal species with highest concentration (500 ?g/ml of bark and leaf extracts in all the solvents showed 100% fungicidal activity as it completely arrested the germination of spores. Relatively lower activity of aqueous extracts at 50 and 100 ?g/ml concentrations suggests that the antifungal ingredients present in Cz bark and leaf are more soluble in organic solvents than water. Conclusion The results demonstrated that the Cz bark and leaves contain certain fungicidal constituents exhibiting potential antimould activity against A. solani and C. lunata.

  14. Analysis of Phylogenetic Relationship of Cylindrocarpon lichenicola and Acremonium falciforme to the Fusarium solani Species Complex and a Review of Similarities in the Spectrum of Opportunistic Infections Caused by These Fungi

    OpenAIRE

    Summerbell, R. C.; Schroers, H. -j

    2002-01-01

    An emerging pattern of similarity in medical case reports led to a project to compare the phylogenetic affinities of two well-known tropical fungal opportunistic pathogens, Cylindrocarpon lichenicola and Acremonium falciforme, to members of the Fusarium solani species complex. C. lichenicola and A. falciforme, despite their deviating conidial morphologies, were shown via sequencing of the ribosomal large subunit to be well instituted within a clade mainly consisting of typical F. solani strai...

  15. Electronics

    CERN Document Server

    Bishop, Owen

    2010-01-01

    Owen Bishop's First Course starts with the basics of electricity and component types, introducing students to practical work almost straight away. No prior knowledge of electronics is required. The approach is student-centred with self-test features to check understanding, including numerous activities suitable for practicals, homework and other assignments. Multiple choice questions are incorporated throughout the text in order to aid student learning. Key facts, formulae and definitions are highlighted to aid revision, and theory is backed up by numerous examp

  16. Isolation and characterization of a novel wheat cysteine-rich receptor-like kinase gene induced by Rhizoctonia cerealis

    Science.gov (United States)

    Yang, Kun; Rong, Wei; Qi, Lin; Li, Jiarui; Wei, Xuening; Zhang, Zengyan

    2013-10-01

    Cysteine-rich receptor kinases (CRKs) belong to the receptor-like kinase family. Little is known about CRK genes in wheat. We isolated a wheat CRK gene TaCRK1 from Rhizoctonia cerealis-resistant wheat CI12633 based on a differentially expressed sequence identified by RNA-Sequencing (RNA-Seq) analysis. TaCRK1 was more highly expressed in CI12633 than in susceptible Wenmai 6. Transcription of TaCRK1 in wheat was induced in CI12633 after R. cerealis infection and exogenous abscisic acid (ABA) treatment. The deduced TaCRK1 protein contained a signal peptide, two DUF26 domains, a transmembrane domain, and a serine/threonine protein kinase domain. Transient expression of a green fluorescence protein fused with TaCRK1 in wheat and onion indicated that TaCRK1 may localize to plasma membranes. Characterization of TaCRK1 silencing induced by virus-mediated method in CI12633 showed that the downregulation of TaCRK1 transcript did not obviously impair resistance to R. cerealis. This study paves the way to further CRK research in wheat.

  17. Microbiological Systems in Organic Synthesis: Preparative-Scale Resolution of (RS)-Glaucine by Fusarium solani and Stereospecific Oxidation of (R)-(?)-Glaucine by Aspergillus flavipes

    OpenAIRE

    Davis, Patrick J.; Talaat, R. E.

    1981-01-01

    The destructive resolution of (6aR,S)-glaucine (Ic) was accomplished by oxidation of the (6aS)-(+)-enantiomer (Ia), using Fusarium solani ATCC 12823 to yield the unnatural alkaloid (6aR)-(?)-glaucine (Ib). Eighteen cultures were examined for their ability to metabolize the (6aR)-(?)-enantiomer (Ib), and Aspergillus flavipes ATCC 1030 was found to catalyze the stereoselective oxidation of this substrate to didehydroglaucine. Thus, it has been demonstrated that “R” and “S” organisms...

  18. Functional Analyses of the Diels-Alderase Gene sol5 of Ascochyta rabiei and Alternaria solani Indicate that the Solanapyrone Phytotoxins Are Not Required for Pathogenicity.

    Science.gov (United States)

    Kim, Wonyong; Park, Chung-Min; Park, Jeong-Jin; Akamatsu, Hajime O; Peever, Tobin L; Xian, Ming; Gang, David R; Vandemark, George; Chen, Weidong

    2015-04-01

    Ascochyta rabiei and Alternaria solani, the causal agents of Ascochyta blight of chickpea (Cicer arietinum) and early blight of potato (Solanum tuberosum), respectively, produce a set of phytotoxic compounds including solanapyrones A, B, and C. Although both the phytotoxicity of solanapyrones and their universal production among field isolates have been documented, the role of solanapyrones in pathogenicity is not well understood. Here, we report the functional characterization of the sol5 gene, which encodes a Diels-Alderase that catalyzes the final step of solanapyrone biosynthesis. Deletion of sol5 in both Ascochyta rabiei and Alternaria solani completely prevented production of solanapyrones and led to accumulation of the immediate precursor compound, prosolanapyrone II-diol, which is not toxic to plants. Deletion of sol5 did not negatively affect growth rate or spore production in vitro, and led to overexpression of the other solanapyrone biosynthesis genes, suggesting a possible feedback regulation mechanism. Phytotoxicity tests showed that solanapyrone A is highly toxic to several legume species and Arabidopsis thaliana. Despite the apparent phytotoxicity of solanapyrone A, pathogenicity tests showed that solanapyrone-minus mutants of Ascochyta rabiei and Alternaria solani were equally virulent as their corresponding wild-type progenitors, suggesting that solanapyrones are not required for pathogenicity. PMID:25372118

  19. Controle de Alternaria solani em tomateiro por extratos de Curcuma longa e curcumina: II. Avaliação in vivo Control of Alternaria solani in tomato by Curcuma longa extracts and curcumin: II. In vivo evaluation

    Directory of Open Access Journals (Sweden)

    María I. Balbi-Peña

    2006-08-01

    Full Text Available A pinta preta, causada por Alternaria solani, é uma das mais importantes doenças da cultura do tomateiro no Brasil. Várias alternativas aos fungicidas têm sido avaliadas nos últimos anos na busca de produtos que controlem satisfatoriamente as doenças, tenham pequeno impacto ambiental e baixa toxicidade aos seres vivos. A cúrcuma, Curcuma longa, apresenta em seus rizomas compostos com comprovada atividade antimicrobiana. Dessa forma, o objetivo deste trabalho foi avaliar o controle de pinta preta em tomateiro utilizando extratos de cúrcuma e curcumina em condições de casa de vegetação. Os tratamentos utilizados foram: extrato de cúrcuma (1 e 10%, curcumina (50 e 100 mg/L, acibenzolar-S-metil (ASM (25 mg do i.a./L, oxicloreto de cobre (1.100 mg do i.a./L, azoxystrobin (80 mg do i.a./L e testemunha (água. A curcumina e os extratos brutos de cúrcuma apresentaram níveis de controle de pinta preta similares ao tratamento com fungicida cúprico, mas inferior ao azoxystrobin. Não houve diferenças estatísticas na produção comercial de tomate entre tratamentos. Somente o tratamento de curcumina 50 mg/l apresentou maior porcentagem de frutos grandes em relação à testemunha. Esses resultados indicam o potencial de controle de pinta preta em tomateiro com cúrcuma e curcumina.Early blight, caused by Alternaria solani, is one of the most important diseases of tomato in Brazil. New alternatives to fungicides with low environmental impact and low toxicity to living beings have been tested to evaluate their ability to control diseases. Turmeric, Curcuma longa, has compounds in its rhizomes with proven antimicrobial activity. Therefore, the objective of this study was to evaluate the potential of turmeric extracts and curcumin on the control of tomato early blight under greenhouse conditions. The treatments were: 1 and 10% turmeric extracts, 50 and 100 mg/L curcumin solutions, acibenzolar-S-metil (ASM (25 mg a.i./L, copper oxychloride (1,100 mg a.i./L, azoxystrobin (80 mg a.i./L and control (water. The disease control showed by turmeric extracts and curcumin solutions was similar to cupric fungicide, but inferior to azoxystrobin control. There was no statistical difference in commercial fruit production between treatments. Only 50 mg/L curcumin treatment had a higher percentage of bigger fruits compared to the control. These results show the potential of turmeric and curcumin for the control of tomato early blight.

  20. Métodos de inoculação para quantificação de resistência em soja a Fusarium solani f. sp. glycines, em casa-de-vegetação Inoculation methods for identification of resistance in soybean to Fusarium solani f. sp. glycines under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Luiza H. Klingelfuss

    2007-02-01

    Full Text Available A síndrome da morte súbita (SMS, causada por Fusarium solani f. sp. glycines, tem se mostrado uma das mais importantes doenças da soja, devido aos prejuízos provocados e à dificuldade de controle. Este trabalho teve como objetivo selecionar os métodos de inoculação mais eficientes para a avaliação de resistência genética de genótipos de soja à SMS. Foram realizados dois experimentos em delineamento de blocos casualizados, sendo seis tratamentos e 12 repetições, no primeiro experimento, e seis tratamentos e 16 repetições, no segundo. Cada parcela foi constituída por um vaso contendo uma planta de soja da cultivar FT Estrela, altamente suscetível à SMS e outra planta de "Conquista", moderadamente resistente. As plantas foram avaliadas quanto à incidência e à severidade da SMS a cada três dias e durante 15 dias, com início no 15 dia após a emergência. A partir dos resultados, foi estimada a área abaixo da curva de progresso da doença (AACPD para os tratamentos. As inoculações com grãos de sorgo e milho colonizados pelo patógeno foram mais eficientes em causar doença, no primeiro experimento, e com grãos de milho, no segundo. Entretanto, nos dois experimentos, apenas a inoculação com grãos de milho foi capaz de separar a reação das cultivares quanto à resistência à SMS, de acordo com o teste de