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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.

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    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.

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

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    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.

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

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    Lakshman, Dilip K; Natarajan, Savithiry S; Lakshman, Sukla; Garrett, Wesley M; Dhar, Arun K

    2008-01-01

    Rhizoctonia solani (Teleomorph: Thanatephorus cucumeris, T. praticola) is a basidiomycetous fungus and a major cause of root diseases of economically important plants. Various isolates of this fungus are also beneficially associated with orchids, may serve as biocontrol agents or remain as saprophytes with roles in decaying and recycling of soil organic matter. R. solani displays several hyphal anastomosis groups (AG) with distinct host and pathogenic specializations. Even though there are reports on the physiological and histological basis of Rhizoctonia-host interactions, very little is known about the molecular biology and control of gene expression early during infection by this pathogen. Proteamic technologies are powerful tools for examining alterations in protein profiles. To aid studies on its biology and host pathogen interactions, a two-dimensional (2-D) gel-based global proteomic study has been initiated. To develop an optimized protein extraction protocol for R. solani, we compared two previously reported protein extraction protocols for 2-D gel analysis of R. solani (AG-4) isolate Rs23. Both TCA-acetone precipitation and phosphate solubilization before TCA-acetone precipitation worked well for R. solani protein extraction, although selective enrichment of some proteins was noted with either method. About 450 spots could be detected with the densitiometric tracing of Coomassie blue-stained 2-D PAGE gels covering pH 4-7 and 6.5-205 kDa. Selected protein spots were subjected to mass spectrometric analysis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Eleven protein spots were positively identified based on peptide mass fingerprinting match with fungal proteins in public databases with the Mascot search engine. These results testify to the suitability of the two optimized protein extraction protocols for 2-D proteomic studies of R. solani. PMID:19202841

  4. Novel mitoviruses in Rhizoctonia solani AG-3PT infecting potato.

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

    2016-03-01

    Double-stranded RNA (dsRNA) elements are ubiquitous in Rhizoctonia solani. Total dsRNA was randomly amplified from a R. solani isolate (RS002) belonging to anastomosis group-3PT (AG-3PT), associated with black scurf in potato. Assembly of resulting cDNA sequences identified a nearly complete genome of a novel virus related to the genus Mitovirus (family Narnaviridae), herein named Rhizoctonia mitovirus 1 RS002 (RMV-1-RS002). The 2797 nucleotide partial genome of RMV-1-RS002 is A-U rich (59.06 %), and can be folded into stable stem-loop structures at 5' and 3' ends. Universal and mold mitochondrial codon usages revealed a large open reading frame in the genome, putatively encoding an 826 amino acid polypeptide, which has conserved motifs for mitoviral RNA-dependent RNA polymerase. The full length putative polypeptide shared 25.6 % sequence identity with the corresponding region of Tuber excavatum mitovirus (TeMV). The partial genome of a second mitovirus (proposed name Rhizoctonia mitovirus 2 RS002 (RMV-2-RS002)) was also amplified from RS002. A nearly identical copy of RMV-1-RS002 was detected in two additional AG-3PT isolates. These data indicate that multiple mitoviruses can exist in a single isolate of R. solani AG-3PT, and that mitoviruses such as RMV-1-RS002 are probably widespread in this pathogen. The roles of mitoviruses in the biology of R. solani AG-3PT remain unknown. PMID:26895862

  5. Badania nad patogenicznością grzyba Rhizoctonia solani Kühn na lnie [Investigations of Rhizoctonia solani Kühn pathogenicity to flax

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    St. Sadowski

    2015-06-01

    Full Text Available The investigations on the pathogenicity of four Rhizoctonia solani isolates were carried out in relation to three varieties of flax; LCSD - 210, LCSD - 200 and Wiera. Variety LCSD - 210 was found to be the most resistant. Isolates obtaind from flax and potatoes were especially pathogenic. Rhizoctonia solani was parasitic during the whole vegetation season, but particularly in the course of emergence. Parasitism of this fungus is of great economical significance.

  6. TEMPERATURE EFFECT ON RHIZOCTONIA SOLANI ANALYZED BY MICROCALORIMETRY

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    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.

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

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    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...

  8. Caracterizao morfolgica de fontes de resistncia de meloeiro a Rhizoctonia solani / Reaction of melon accessions to Rhizoctonia solani

    Scientific Electronic Library Online (English)

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

    2015-06-01

    Full Text Available A rizoctoniose, ocasionada pelo fungo Rhizoctonia solani, uma doena frequente em reas cultivadas, intensivamente com melo (Cucumis melo) no nordeste brasileiro. O objetivo do presente trabalho foi identificar e caracterizar morfologicamente fontes de resistncia de meloeiro a R. solani. No prim [...] eiro ensaio foi avaliado o nvel de resistncia 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 reao aos isolados RS-22 e RS-23 em um segundo ensaio. Utilizou-se o delineamento inteiramente casualizado com cinco repeties. Foram identificados como fontes de resistncia os acessos T-A-08, T-A-09, T-A-19 e a linhagem ACP-AF-06. Nos dois ensaios de inoculao, as sementes foram plantadas em solo infestado com o patgeno pela incorporao de 50 mg de substrato (gros de arroz) colonizado/kg de solo. A avaliao dos acessos foi realizada aps 45 dias, com o auxlio de escala de notas de 0 a 4, para agrupamento de cada gentipo em cinco classes. As fontes de resistncia foram caracterizadas morfologicamente em um ensaio em blocos casualizados com trs repeties. A caracterizao identificou os acessos T-A-08 e T-A-19 como sendo pertencentes variedade botnica momordica e o acesso T-A-09 e a linhagem ACP-AF-06, pertencentes s variedades acidulus e inodorus, respectivamente. As fontes de resistncia podero ser utilizadas em futuros programas de melhoramento gentico visando obter gentipos (linhagens e hbridos 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.

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

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    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...

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

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    RAQUEL GHINI

    2001-03-01

    Full Text Available reas de uma microbacia sem a incidncia de doenas causadas por Rhizoctonia solani GA 4 foram agrupadas estatisticamente, pelo mtodo de Ward, com relao supressividade dos solos ao patgeno, avaliada pela taxa de crescimento micelial. Entre os grupos formados, foi definido um gradiente de supressividade. A relao entre gradientes de supressividade e tipos de cobertura vegetal foi descrita com auxlio da anlise de correspondncias mltiplas, sendo que, de modo geral, o pasto e o pousio, seguidos da mata, tornaram os solos mais supressivos, ao passo que a cana-de-acar (Saccharum officinarum, o milho (Zea mays , o caf (Coffea arabica e o solo arado tornaram os solos mais conducentes. Porm, os resultados mostraram que outros fatores, alm da cobertura vegetal, podem estar afetando a supressividade. Um tratamento biocida (fumigao dos solos mais supressivos promoveu um maior incremento da taxa de crescimento do patgeno 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

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

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    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 stud...

  13. The Role of Pathogenesis-Related Proteins in the Tomato-Rhizoctonia solani Interaction

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    Parissa Taheri; Saeed Tarighi

    2012-01-01

    Rhizoctonia solani is one of the most destructive pathogens causing foot rot disease on tomato. In this study, the molecular and cellular changes of a partially resistant (Sunny 6066) and a susceptible (Rio Grande) tomato cultivar after infection with necrotrophic soil-borne fungus R. solani were compared. The expression of defense-related genes such as chitinase (LOC544149) and peroxidase (CEVI-1) in infected tomato cultivars was investigated using semiquantitative reverse transcription-poly...

  14. 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, Gmez Peralta; Rebeca, Ramrez Ochoa.

    2014-06-01

    Full Text Available Los lquenes son hongos que establecen una relacin de simbiosis con uno o varios organismos fotosintticos (algas o cianobacterias). En esta relacin el hongo (micobionte) produce un determinado nmero de metabolitos secundarios con actividad antibitica. De acuerdo a esta afirmacin 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 cultiv en medio agar papa dextrosa (PDA), posteriormente se ferment 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 liqunico en PDA donde se sembraron discos de R. solani y se determin el porcentaje de inhibicin del crecimiento micelial. El extracto liqunico mostr 100% de inhibicin 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.

  15. Susceptibility of leguminous green manure species to Rhizoctonia solani and Sclerotium rolfsii

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    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.

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

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    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.

  17. Bioactive saponin from tea seed pomace with inhibitory effects against Rhizoctonia solani.

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    Kuo, Ping-Chung; Lin, Tsung-Chun; Yang, Cheng-Wei; Lin, Chih-Lung; Chen, Guo-Feng; Huang, Jenn-Wen

    2010-08-11

    The present study was aimed to characterize the antifungal principles in methanol extract of tea ( Camellia oleifera ) seed pomace. Totally, two flavonoids, camelliasides A (1) and B (2), and one saponin mixture composed of camelliasaponin B(1) (3) were identified from the methanol extract. These constituents were tested for their ability to reduce the infection of cabbage seedlings by Rhizoctonia solani Kuhn AG-4 and to inhibit growth of the pathogen on potato dextrose agar plates. The saponin mixture is a potential candidate as a new plant-derived pesticide to control Rhizoctonia damping-off of vegetable seedlings. PMID:20681650

  18. Rhizoctonia solani as a potato pathogen : Variation of isolates in Finland and host response

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    Lehtonen, Mari

    2009-01-01

    Rhizoctonia solani is a soil inhabiting basidiomycetous fungus able to induce a wide range of symptoms in many plant species. This genetically complex species is divided to 13 anastomosis groups (AG), of which AG-3 is specialized to infect potato. However, also a few other AGs are able to infect or live in close contact with potato. On potato, R. solani infection causes two main types of diseases including stem canker observed as a dark brown lesions on developing stems and stolons, and black...

  19. Micoflora asociada a dos sustratos orgnicos y su efecto en el control de rhizoctonia solani khn

    OpenAIRE

    Gudez, Clemencia

    2010-01-01

    Los abonos orgnicos se vienen utilizando como ente supresor de enfermedades de la raz de la planta, debido a la gran cantidad de microorganismos que interactan en ellos, lo que ha llevado a considerarlos como parte de las estrategias de control biolgico. En este contexto, se evalu la diversidad de la micoflora de dos sustratos orgnicos (suelo orgnico y lombricompuesto) y su efecto sobre el control del hongo Rhizoctonia solani. La diversidad de la micoflora de los sustratos se determin...

  20. RSIADB, a collective resource for genome and transcriptome analyses in Rhizoctonia solani AG1 IA

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    Ai, Peng; Zhang, Jinfeng; Deng, Qiming; Wang, Shiquan; Li, Shuangcheng; Zhu, Jun; Li, Ping; Zheng, Aiping

    2016-01-01

    Rice [Oryza sativa (L.)] feeds more than half of the world’s population. Rhizoctonia solani is a major fungal pathogen of rice causing extreme crop losses in all rice-growing regions of the world. R. solani AG1 IA is a major cause of sheath blight in rice. In this study, we constructed a comprehensive and user-friendly web-based database, RSIADB, to analyse its draft genome and transcriptome. The database was built using the genome sequence (10 489 genes) and annotation information for R. solani AG1 IA. A total of six RNAseq samples of R. solani AG1 IA were also analysed, corresponding to 10, 18, 24, 32, 48 and 72 h after infection of rice leaves. The RSIADB database enables users to search, browse, and download gene sequences for R. solani AG1 IA, and mine the data using BLAST, Sequence Extractor, Browse and Construction Diagram tools that were integrated into the database. RSIADB is an important genomic resource for scientists working with R. solani AG1 IA and will assist researchers in analysing the annotated genome and transcriptome of this pathogen. This resource will facilitate studies on gene function, pathogenesis factors and secreted proteins, as well as provide an avenue for comparative analyses of genes expressed during different stages of infection. Database URL: http://genedenovoweb.ticp.net:81/rsia/index.php PMID:27022158

  1. Efficacy of Bacillus subtilis V26 as a biological control agent against Rhizoctonia solani on potato.

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    Ben Khedher, Saoussen; Kilani-Feki, Olfa; Dammak, Mouna; Jabnoun-Khiareddine, Hayfa; Daami-Remadi, Mejda; Tounsi, Slim

    2015-12-01

    The aim of this study is to evaluate the efficacy of the strain Bacillus subtilis V26, a local isolate from the Tunisian soil, to control potato black scurf caused by Rhizoctonia solani. The in vitro antifungal activity of V26 significantly inhibited R.solani growth compared to the untreated control. Microscopic observations revealed that V26 caused considerable morphological deformations of the fungal hyphae such as vacuolation, protoplast leakage and mycelia crack. The most effective control was achieved when strain V26 was applied 24h prior to inoculation (protective activity) in potato slices. The antagonistic bacterium V26 induced significant suppression of root canker and black scurf tuber colonization compared to untreated controls with a decrease in incidence disease of 63% and 81%, respectively, and promoted plant growth under greenhouse conditions on potato plants. Therefore, B.subtilis V26 has a great potential to be commercialized as a biocontrol agent against R.solani on potato crops. PMID:26563555

  2. 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, ...

  3. 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

    OpenAIRE

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

    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. ...

  4. RSIADB, a collective resource for genome and transcriptome analyses in Rhizoctonia solani AG1 IA.

    Science.gov (United States)

    Chen, Lei; Ai, Peng; Zhang, Jinfeng; Deng, Qiming; Wang, Shiquan; Li, Shuangcheng; Zhu, Jun; Li, Ping; Zheng, Aiping

    2016-01-01

    Rice [Oryza sativa(L.)] feeds more than half of the world's population.Rhizoctonia solaniis a major fungal pathogen of rice causing extreme crop losses in all rice-growing regions of the world.R. solaniAG1 IA is a major cause of sheath blight in rice. In this study, we constructed a comprehensive and user-friendly web-based database, RSIADB, to analyse its draft genome and transcriptome. The database was built using the genome sequence (10 489 genes) and annotation information forR. solaniAG1 IA. A total of six RNAseq samples ofR. solaniAG1 IA were also analysed, corresponding to 10, 18, 24, 32, 48 and 72 h after infection of rice leaves.The RSIADB database enables users to search, browse, and download gene sequences forR. solaniAG1 IA, and mine the data using BLAST, Sequence Extractor, Browse and Construction Diagram tools that were integrated into the database. RSIADB is an important genomic resource for scientists working withR. solaniAG1 IA and will assist researchers in analysing the annotated genome and transcriptome of this pathogen. This resource will facilitate studies on gene function, pathogenesis factors and secreted proteins, as well as provide an avenue for comparative analyses of genes expressed during different stages of infection.Database URL:http://genedenovoweb.ticp.net:81/rsia/index.php. PMID:27022158

  5. 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 Khn 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.

  6. IN-VITRO EVALUATION OF FUNGICIDES, BIOCONTROL AGENTS AND PLANT EXTRACTS AGAINST RICE SHEATH BLIGHT PATHOGEN RHIZOCTONIA SOLANI

    Directory of Open Access Journals (Sweden)

    P. Srinivas

    2014-02-01

    Full Text Available Of the fourteen fungicides of different groups evaluated in-vitro against Rhizoctonia solani , Metalaxyl (0.1%, Mancozeb (0.1%, Tricyclazole (0.1%, Thiophenate methyl (0.1%, Carbendizm+ Mancozeb (0.1% were proved to be most effective in inhibiting the growth of the fungus. Among the bio-agents screened, Trichoderma viride was most effective in restricting the growth of Rhizoctonia solani followed by Penicillium notatum where as Aspergillus niger was proved least effective. Among the thirteen plant extracts evaluated garlic extract (10% was most effective in inhibiting the growth of fungus followed by calotropis (10%. Datura leaf extract (10% was found to be least effective in inhibiting the growth of Rhizoctonia solani.

  7. Rhizoctonia root rot (Rhizoctoni solani K h n of sugar beet in province Vojvodina

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    Stojin Vera B.

    2006-01-01

    Full Text Available Sugar beet root rot appears regularly each year, but its intensity depends on agro ecological conditions. The predominant causers of root rot in Vojvodina are fungi from Fusarium genus and species Macrophomina phaseolina. Over the last couple of years, more intense occurrence of Rhizoctonia root rot has been observed. Rhizoctonia solani, the causal agent of root rot is present in sugar beet fields. During 2000-2005, on the territory of Vojvodina, the frequency of Rhizoctonia solani in phytopathological isolations from rotted sugar beet roots was between 0,0-18,2%. The intensity of the disease depends on localities, agro ecological conditions and genotypes. Symptoms of Rhizoctonia root rot were registered at some localities in all regions of Vojvodina: Srem, Banat and Ba?ka. The disease appearance is above all local. It occurs in small patches, on heavy, non-structured soil and on depressed wet parts of plots. Individual diseased plants can be found during July. Brown rot appears on sugar beet roots, with dried tissue on surface, which is present on the tail as well as on the middle part and the head of root. Tissues with described symptoms are deeper regarding the healthy part of root. On vertical root section, the necrotic changes are clearly visible comparing to tissue section without symptoms. The heavily infected tissue forms fissures on roots in most cases. Besides the above-mentioned symptoms on roots, the plant wilting and leaf handle necrosis as well as leaf dying are also observed. When rot spreads to the whole root head, plants quickly die.

  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 st...

  9. 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

  10. Studies on Characterization of Molecular Variability Using RAPD Markers in Rhizoctonia solani Isolated from Different Gerographical Regions of South India

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    Krishna Kumari

    2015-12-01

    Full Text Available Molecular techniques have become reliable and are highly suitable tools for identifying pathogen species and for genetic variation. The molecular marker is a useful tool for assessing genetic variations. RAPD (Random Amplified Polymorphic DNA markers have been used to characterize the numerous filamentous fungi collected from different fields of experimental mycology. Rhizoctonia solani is a plant pathogenic fungus which cause sheath blight in rice. Present work focused on polymorphic identification and characterization of Rhizoctonia solani isolate. Twenty eight samples were collected from different locations of South India and Punjab. Rhizoctonia solani (teleomorph: Thanatephorus cucumeris were isolated and used polymorphic examination by molecular markers. Molecular analysis was done with OPC-5, OPC-2, OPA-8 and OPA-11primers and the variability of isolated fungus DNA, allowed the visualization of 265 polymorphic bonds with molecular weight ranging from 0.5kb to 20kb significant differences in RAPD profiles of 28 isolates of R. Solani were found with two primers OPC-5 and OPC-2. To analyze the resolving ability of these primers, cumulative RAPD profiles generated by the primers were analyzed by UPGMA. The dendrogram constructed using 265 polymorphic bonds obtained from 28 isolates with 5 primers was divided into 7 clusters. Based on these results it was concluded that there was a molecular variability among the isolates of R. solani was depicted.

  11. Development of artificial conidia for ecological studies of Rhizoctonia solani in soil.

    Science.gov (United States)

    Liu, Tung-Hsen; Lin, Mei-Ju; Ko, Wen-Hsiung

    2011-01-31

    Artificial conidia of Rhizoctonia solani were developed by releasing protoplasts from young mycelia with lytic enzymes and by inducing cell wall formation in stabilizer solution. Conidia produced in this way were spherical with sizes ranging from 10 to 20μm in diameter. Artificial conidia were sensitive to soil fungistasis. Young hyphae originated from artificial conidia were also sensitive to fungistasis and mycolysis in soils. These results demonstrate that the previously reported insensitivity of R. solani to fungistasis and mycolysis in soils is due to special ability of propagules used rather than the inherited nature of the organism. Germination rates of artificial conidia on soils were inversely correlated with the amount of fungicide Flutolanil added. When germination of artificial conidia was used to detect suppressive soils, 3 out of 30 soil samples collected from different parts of Taiwan were suppressive to R. solani and all these suppressive soils were low in pH. Using artificial conidia for assay of fungicide activity in soil and detection of suppressive soils has the advantages of being fast and precise in comparison with relative hyphal growth. However, preparation of artificial conidia at this stage is tedious and time-consuming. PMID:20713193

  12. A quitosana como fungistático no crescimento micelial de Rhizoctonia solani Kuhn

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    Álvaro Rodrigo Freddo

    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 testada 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.

  13. 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.

  14. Unraveling Aspects of Bacillus amyloliquefaciens Mediated Enhanced Production of Rice under Biotic Stress of Rhizoctonia solani.

    Science.gov (United States)

    Srivastava, Suchi; Bist, Vidisha; Srivastava, Sonal; Singh, Poonam C; Trivedi, Prabodh K; Asif, Mehar H; Chauhan, Puneet S; Nautiyal, Chandra S

    2016-01-01

    Rhizoctonia solani is a necrotrophic fungi causing sheath blight in rice leading to substantial loss in yield. Excessive and persistent use of preventive chemicals raises human health and environment safety concerns. As an alternative, use of biocontrol agents is highly recommended. In the present study, an abiotic stress tolerant, plant growth promoting rhizobacteria Bacillus amyloliquefaciens (SN13) is demonstrated to act as a biocontrol agent and enhance immune response against R. solani in rice by modulating various physiological, metabolic, and molecular functions. A sustained tolerance by SN13 primed plant over a longer period of time, post R. solani infection may be attributed to several unconventional aspects of the plants' physiological status. The prolonged stress tolerance observed in presence of SN13 is characterized by (a) involvement of bacterial mycolytic enzymes, (b) sustained maintenance of elicitors to keep the immune system induced involving non-metabolizable sugars such as turanose besides the known elicitors, (c) a delicate balance of ROS and ROS scavengers through production of proline, mannitol, and arabitol and rare sugars like fructopyranose, β-D-glucopyranose and myoinositol and expression of ferric reductases and hypoxia induced proteins, (d) production of metabolites like quinazoline and expression of terpene synthase, and (e) hormonal cross talk. As the novel aspect of biological control this study highlights the role of rare sugars, maintenance of hypoxic conditions, and sucrose and starch metabolism in B. amyloliquefaciens (SN13) mediated sustained biotic stress tolerance in rice. PMID:27200058

  15. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat

    Science.gov (United States)

    Foley, Rhonda C.; Kidd, Brendan N.; Hane, James K.; Anderson, Jonathan P.; Singh, Karam B.

    2016-01-01

    Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS) production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT), 3,3'-diaminobenzidine (DAB) and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction. PMID:27031952

  16. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat.

    Science.gov (United States)

    Foley, Rhonda C; Kidd, Brendan N; Hane, James K; Anderson, Jonathan P; Singh, Karam B

    2016-01-01

    Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS) production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT), 3,3'-diaminobenzidine (DAB) and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction. PMID:27031952

  17. 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

  18. 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.

  19. Allelopathic Effect of Some Cruciferous Seeds on Rhizoctonia solani kuhn and Gossypium barbadense L.

    Directory of Open Access Journals (Sweden)

    I.M.El-Refai

    2004-01-01

    Full Text Available Phenolic substances, lipoidal matters and fatty acid contents of some cruciferous powdered seeds, Raphanus sativus L., Brassica oleracea L. var capitata, Sinapis alba L., Brassica nigra Koch, Eruca sativa Mill, Brassica napus L. and Lipidium sativum L., were determined. The results indicated that R. sativus L., B. napus L. and B. oleracea L. var capitata contained higher percentage of phenolic compounds, lipoidal matters and unsaturated fatty acids, respectively, compared to other tested plants. The aqueous and ethanolic extracts of the above seeds were prepared. The alcoholic extract was fractionated with petroleum ether 60-80oC, chloroform and ethyl acetate, respectively. The prepared extracts and fractions were subjected to phytochemical screening and the results indicated the presence of various active constituents. Their allelopathic effect on Rhizoctonia solani Kuhn was tested in vitro. The tested extracts have variable inhibitory effect on R. solani Kuhn. The effect depends on the concentration of the extracts, plant species and the active constituents. Rhizoctania solani infested and non-infested soil sowed with cotton (Gossypium barbadense L seeds were treated with the above powdered seeds. All treatments reduced cotton seed germination, decreased significantly root length but increased seedling shoot height. The results indicated that application of powdered seeds of R. sativus L., E. sativa MILL and S. alba L., to the soil infested with R. solani Kuhn, enhanced the germination percentage of cotton, reduced damping off precentage and improved the growth criteria of the cotton seedlings. Fatty acids composition and mineral contents of the untreated cotton and infested cotton seedlings treated with seed powders were also investigated

  20. 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.

  1. 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.

  2. Efectividad in vitro de Bacillus y polifenoles de plantas nativas de Mxico 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, Hernndez-Castillo; Gabriel, Gallegos-Morales; Alberto, Flores-Olivas; Ral, Rodrguez-Herrera; Cristbal N., Aguilar.

    2015-05-01

    Full Text Available Con el objetivo de encontrar alternativas para el manejo de patgenos que provocan enfermedades en el sistema radical de las plantas se evalu el efecto in vitro de bacterias antagonista del gnero 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 endmicas del desierto Chihuahuense contra el fitopatgeno Rhizoctonia solani. Las bacterias se obtuvieron de la forma esporulada, una suspensin de suelo se calent 15 min 80 C para eliminar formas no esporuladas. Los extractos vegetales se obtuvieron por infusin. Como resultado se encontr que las cepas de Bacillus aislados presentan un efecto antagonista in vitro sobre la inhibicin micelial de Rhizoctonia solani desde 40 a 67%. La caracterizacin por secuenciacin del gen 16S del ADNr se determin que los aislamientos pertenecen a las especies de B. subtilis, B. pumilus y a B. atrophaeus, quienes estn reportadas con efecto antagnico sobre organismos fitopatgenos. Para el caso de los extractos se encontr un efecto en la inhibicin micelial hasta 100% en su mayora 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 ms 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.

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

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    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.

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

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    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.

  5. 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.

  6. 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

  7. Entomotoxic effects of fungal lectin from Rhizoctonia solani towards Spodoptera littoralis.

    Science.gov (United States)

    Hamshou, M; Van Damme, E J M; Smagghe, G

    2010-01-01

    The effects of the Rhizoctonia solani lectin (RSA) on the growth, development and survival of an economically important caterpillar in agriculture and horticulture, the cotton leafworm, Spodoptera littoralis were studied. The high lectin concentration present in the sclerotes of the soil pathogen R. solani allowed the purification of large amounts of the pure lectin for feeding experiments with cotton leafworm. Rearing of insects on a diet containing different concentrations of RSA exerted a strong effect on the larval weight gain. This effect was visible at the lowest concentration of 0.1 % RSA at day 8 and day 11. Interestingly with 1 % RSA, there was a dramatic reduction in larval weight of 89 % at the end of L6 which was followed by a high mortality rate of 82 % in the treated larvae. Furthermore, the other developmental stages of pupation and adult formation were also affected. In addition, the data demonstrated that the combination of RSA with Bt toxin yielded synergistic effects. For instance, 0.03 % RSA+0.005 % Bt toxin caused reduced growth rate and higher mortalities. These findings suggest that RSA is an interesting tool that can be used for bioengineering insect resistance in important agronomical crops. PMID:20965059

  8. 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.

  9. 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...

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

    OpenAIRE

    Erlacher, Armin; Cardinale, Massimiliano; Grosch, Rita; Grube, Martin; Berg, Gabriele

    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...

  11. Effect of organic matter on soil inoculum potential and soil suppressiveness to Gaeumannomyces graminis var. tritici and Rhizoctonia solani

    OpenAIRE

    Fayolle, Leon; Alabouvette, Claude; Bodet, J.M.; Steinberg, Christian

    2009-01-01

    It is widely recognized that organic amendments may reduce crop losses caused by soil borne plant pathogens. Most of the studies conducted so far were related to short term effects observed in vegetable cropping systems. The long term effects of compost or manure amendments in field cropping systems has been investigated in Australia and, concerning Rhizoctonia solani diseases on wheat, inconsistent results were reported. Two large field experiments were set up in 1996, at Le Rheu and la Jail...

  12. The effect of temperature upon the pathogenicity and chemical control of Rhizoctonia solani K. on potato tubers (Solanum tuberosum L.

    Directory of Open Access Journals (Sweden)

    B. Błaszczak

    2015-06-01

    Full Text Available In poe experiment, it was found that Rhizoctonia solani was most pathogenic to potato sprouts at 14.8 and 17.4°C. At a third temperature applied (9.9°C, the pathologenicity was much lower. The higher temperatures decreased the fungicidal activity of Ceresan Nassbeize and Rizokton. The addition to the soil of 1 and 3% of corn straw did not affect the pathogenicity of the fungus.

  13. 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.

  14. Fungal antagonists of the plant pathogen Rhizoctonia solani: selection, control efficacy and influence on the indigenous microbial community.

    Science.gov (United States)

    Grosch, Rita; Scherwinski, Katja; Lottmann, Jana; Berg, Gabriele

    2006-12-01

    A broad spectrum of fungal antagonists was evaluated as potential biocontrol agents (BCAs) against the soil-borne pathogen Rhizoctonia solani using a new combination of in vitro and in vivo assays. The in vitro characterisation of diverse parameters including the ability to parasitise mycelium and to inhibit the germination of Rhizoctonia sclerotia at different temperatures resulted in the selection of six potential fungal antagonists. These were genotypically characterised by their BOX-PCR fingerprints, and identified as Trichoderma reesei and T. viride by partial 18S rDNA sequencing. When potato sprouts were treated with Trichoderma, all isolates significantly reduced the incidence of Rhizoctonia symptoms. Evaluated under growth chamber conditions, the selected Trichoderma isolates either partly or completely controlled the dry mass loss of lettuce caused by R. solani. Furthermore, the antagonistic Trichoderma strains were active under field conditions. To analyse the effect of Trichoderma treatment on indigenous root-associated microbial communities, we performed a DNA-dependent SSCP (Single-Strand Conformation Polymorphism) analysis of 16S rDNA/ITS sequences. In this first assessment study for Trichoderma it was shown that the pathogen and the vegetation time had much more influence on the composition of the microbiota than the BCA treatment. After evaluation of all results, three Trichoderma strains originally isolated from Rhizoctonia sclerotia were selected as promising BCAs. PMID:17127047

  15. 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.

  16. 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; Fabin, Ochoa; Ximena, Besoain; Rodrigo, Herrera; Luz M, Prez.

    Full Text Available J.R. Montealegre, F. Ochoa, X. Besoain, R. Herrera y L.M. Prez. 2014. Biocontrol de Rhizoctonia solani in vivo y en invernadero, con cepas mejoradas de Trichoderma spp. Cien. Inv. Agr. 41(2):197-206. Se compar la capacidad de cepas de Trichoderma spp., obtenidas previamente por fusin de protoplas [...] tos, con la de sus correspondientes cepas parentales, para biocontrolar a Rhizoctonia solani. El efecto biocontrolador se analiz sobre dos cepas de R. solani: 509 (GA 2-1) y 618 (GA 4). Las cepas producto de fusin de protoplastos de Trichoderma spp. fueron ms efectivas que al menos una de las correspondientes cepas parentales. La inhibicin ms alta en experimentos de cultivos duales, se observ 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, slo logr un 60,19% de inhibicin con la cepa ThF2-1. El efecto inhibidor del desarrollo se debi principalmente a la secrecin de metabolitos difusibles. El porcentaje de mortalidad y nivel de cancro en plantas de tomate se evalu en experimentos de invernadero, en los que todas las cepas producto de la fusin 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. Prez. 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.

  17. 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

  18. 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)

  19. Silcio alterando compostos derivados da pirlise 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; Fabrcio de vila Rodrigues; Vivian Carr-Missio; Nilda de Ftima Ferreira Soares

    2013-01-01

    Este trabalho teve como objetivo elucidar, por meio da pirlise analtica acoplada cromatografia gasosa e espectrometria de massa, alteraes na composio qumica da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou no com silcio (Si) e infectadas por Rhizoctonia solani. A concentrao de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg-1) em comparao com as plantas no supridas (0,45 dag kg-1). Na pre...

  20. Fatores envolvidos na supressividade a Rhizoctonia solani em alguns solos tropicais brasileiros

    Directory of Open Access Journals (Sweden)

    F. A. Rodrigues

    1998-06-01

    Full Text Available O experimento foi realizado em condições de casa de vegetação, na Universidade Federal de Uberlândia, no período de março a agosto de 1995, visando determinar, em sete classes de solo, a supressividade ao fungo Rhizoctonia solani e estudar o possível relacionamento dessa característica com a mineralogia, propriedades físicas e químicas e populações de fungos do solo. Após proceder à inoculação dos solos com R. solani, multiplicada em grãos de sorgo autoclavados, observou-se que o índice de doença em plântulas de soja aumentou em todos eles. Tal índice foi sempre maior na camada de 0-20 cm, associando-se com o maior teor de matéria orgânica, com exceção do Solo Orgânico eutrófico (SOe, o qual apresentou um índice de doença similar nas duas profundidades (0-20 e 20-40 cm. O efeito supressivo a R. solani, observado no material do Plintossolo distrófico (PTd e no Latossolo Vermelho-Escuro álico (LEa, relacionou-se com a textura muito argilosa, com a alta saturação por alumínio e com a vegetação (fase cerrado, mesmo com a ausência de Trichoderma spp. Os materiais do Solo Orgânico eutrófico (SOe, do Latossolo Roxo distrófico (LRd e da Terra Roxa Estruturada eutrófica (TRe apresentaram maior conducividade a R. solani , possivelmente relacionada com o caráter eutrófico e com o teor da matéria orgânica, decorrente do tipo de cobertura vegetal (fase vegetação. O material do Latossolo Vermelho-Escuro álico textura média (LEam e o do Latossolo Vermelho-Amarelo álico (LVa mostraram comportamento intermediário. O índice de doença correlacionou-se negativamente com a saturação por alumínio e teor de argila e positivamente com a saturação de bases (V e com o pH. A mineralogia parece não ter influência direta na supressividade ou conducividade dos solos estudados, provavelmente por variar apenas no que se refere às formas de óxidos de ferro.

  1. 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.

  2. Variabilidad genética y detección molecular de poblaciones del hongo Rhizoctonia solani en regiones colombianas productoras de papa

    OpenAIRE

    Chavarro Mesa, Edisson

    2011-01-01

    Actualmente el complejo Rhizoctonia solani se divide en 14 grupos de anastomosis (AG1 al AG13 y AG-BI) (Carling et al. 2002). El GA-3 es el agente causal de la rhizoctoniasis siendo el grupo de anastomosis más recurrente en tubérculos de papa. El objetivo del presente estudio fue evaluar la variabilidad genética de Rhizoctonia solani y detectar mediante prueba molecular poblaciones del hongo y variantes AG en regiones colombianas productoras de papa. Los aislamientos fueron identificados m...

  3. Silcio alterando compostos derivados da pirlise de bainhas foliares de plantas de arroz infectadas por Rhizoctonia solani

    OpenAIRE

    Daniel Augusto Schurt; Fabrcio de vila Rodrigues; Vivian Carr-Missio; Nilda de Ftima Ferreira Soares

    2013-01-01

    Este trabalho teve como objetivo elucidar, por meio da pirlise analtica acoplada cromatografia gasosa e espectrometria de massa, alteraes na composio qumica da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou no com silcio (Si) e infectadas por Rhizoctonia solani. A concentrao de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg-1) em comparao com as plantas no supridas (0,45 dag kg-1). Na pre...

  4. Micoflora asociada a dos sustratos orgnicos y su efecto en el control de Rhizoctonia solani Khn

    Directory of Open Access Journals (Sweden)

    Gudez Clemencia

    2009-12-01

    Full Text Available

    Los abonos orgnicos se vienen utilizando como ente supresor de enfermedades de la raz de la planta, debido a la gran cantidad de microorganismos que interactan en ellos, lo que ha llevado a considerarlos como parte de las estrategias de control biolgico. En este contexto, se evalu la diversidad de la micoflora de dos sustratos orgnicos (suelo orgnico y lombricompuesto y su efecto sobre el control del hongo Rhizoctonia solani. La diversidad de la micoflora de los sustratos se determin a travs del mtodo de dilucin de placas de Warcup, que permiti contar el nmero de colonias e identificar los hongos. Los aislamientos ms 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 gneros, incluyendo (Penicillium sp., Aspergillus sp., Fusarium sp. y Trichoderma harzianum Rifai. En el lombricompuesto se encontr una micoflora significativamente ms abundante (P ?0,05 que en el suelo orgnico. En los cultivos duales, T. harzianum present un porcentaje de inhibicin de R. solani significativamente superior (P ?0,05 al del resto de los hongos. Con la incorporacin del lombricompuesto no se introdujeron nuevos hongos, pero s se incrementaron las poblaciones existentes en la micoflora nativa. T. harzianum result ser el hongo de mayor crecimiento y mayor porcentaje de inhibicin, lo que sugiere que es un controlador biolgico de R. solani, y que es factible incorporarlo al suelo durante la preparacin del mismo.

  5. Biocontrol of Rhizoctonia solani AG-2, the causal agent of damping-off by Muscodor cinnamomi CMU-Cib 461.

    Science.gov (United States)

    Suwannarach, Nakarin; Kumla, Jaturong; Bussaban, Boonsom; Lumyong, Saisamorn

    2012-11-01

    Rhizoctonia solani is a damping-off pathogen that causes significant crop loss worldwide. In this study, the potential of Muscodor cinnamomi, a new species of endophytic fungus for controlling R. solani AG-2 damping-off disease of plant seedlings by biological fumigation was investigated. In vitro tests showed that M. cinnamomi volatile compounds inhibited mycelial growth of pathogens. Among nine solid media tested, rye grain was the best grain for inoculum production. An in vivo experiment of four seedlings, bird pepper, bush bean, garden pea and tomato were conducted. The results indicated that treatment with 30 g of M. cinnamomi inoculum was the minimum dose that caused complete control of damping-off symptoms of all seedlings after one month of planting. The R. solani-infested soil showed the lowest percentage of seed germination. In addition, M. cinnamomi did not cause any disease symptoms. From the results it is clear that M. cinnamomi is effective in controlling R. solani AG-2 both in vitro and in vivo. PMID:22806753

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

    Science.gov (United States)

    Elkahoui, S; Djbali, 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

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

    Science.gov (United States)

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

    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. PMID:23264779

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

    OpenAIRE

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

    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. Control biológico de rhizoctonia solani en plantas de papa criolla solanum phureja usando cepas nativas de pseudomonas fluorescens

    OpenAIRE

    Bautista, Gloria; Mendoza, Henry; URIBE, DANIEL

    2011-01-01

    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 fluore...

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Fabrcio de vila Rodrigues

    1999-08-01

    Full Text Available Objetivou-se verificar o efeito da aplicao de silicato de clcio e da esterilizao na supressividade natural de um Latossolo Vermelho-Escuro (LEa lico textura muito argilosa e na conducividade natural de uma Terra Roxa Estruturada eutrfica (TRe ao fungo Rhizoctonia solani, em condies de casa de vegetao. 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; trs tratamentos (esterilizao ou no por autoclavagem, aplicao de silicato e testemunha e infestao ou no com R. solani, com trs repeties e 16 plntulas de feijoeiro por parcela. A aplicao de silicato foi feita incorporando 0,63 g do produto em 1 kg de cada material de solo, seguido de incubao por 30 dias. Para promover a infestao artificial, foram colocados 800 mg de inculo em 1 kg de cada material de solo. O silicato de clcio aumentou os teores de Ca trocvel e a soma de bases nos dois solos. Um decrscimo na saturao por Al de 70 para 19% e um aumento na saturao por bases de 9 para 21% alteraram significativamente a supressividade natural do LEa R. solani. Com relao TRe, a aplicao de silicato no teve nenhum efeito na sua conducividade, dado ao seu natural carter eutrfico, o qual j favorvel ao desenvolvimento deste fungo. A esterilizao no influiu no desenvolvimento de R. solani, o que sugere que os fatores abiticos foram os responsveis pela supressividade ou conducividade desses solos.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-replicate 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.

  12. 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.

  13. Essential oil of mustard to control Rhizoctonia solani causing seedling damping off and seedling blight in nursery Utilizao de leo 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 leo essencial extrado de sementes de mostarda (Brassica rapa na supresso do crescimento in vitro de Rhizoctonia solani, na reduo da colonizao saproftica no solo, e no tombamento e requeima de plntulas, utilizando feijo-vagem (Phaseolus vulgaris como planta indicadora. O crescimento in vitro de R. solani foi completamente inibido na concentrao de 50 mil/l. A colonizao saproftica do substrato foi drasticamente reduzida para 45% na concentrao de 150 mil/kg, 24 h aps o tratamento. Nas concentraes de 0, 50 e 75 mil/kg de solo houve 100% de colonizao do substrato. Esta taxa de recuperao diminuiu gradualmente para 6% e 60%, respectivamente, em nove dias. A irrigao de solos infestados por R. solani com gua contendo o leo 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 feijo-vagem, sem qualquer efeito aparente de fitotoxidez. O efeito do leo essencial no foi influenciado pela textura do solo e parece ser um bom substituto para o fumigante brometo de metila em viveiros.

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

    Directory of Open Access Journals (Sweden)

    Mostapha Niknejad Kazempour

    2004-01-01

    Full Text Available 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. fluorescens biovar 3. By determining the effects of volatile metabolites, secretion of extracellular and antibiotics of these isolates inhibited mycelial growth of R. solani in vitro. All P. fluorescens isolates produced siderophore on King`s medium B, inhibited the mycelial growth of the R. solani. Antagonistics isolates reduced the germination and cause the lysis of sclerotia of R. solani. In greenhouse conditions antagonistic isolates were used by seed coating, soil drenching and foliar spray. Statistical analysis of data indicated that there existed significant differences between seed, soil and plant treatments. All of the isolates in seed coating are more effective. In the field conditions foliar spray of isolate B41 mixed with benlate were applied. The disease intensity in B41 isolate for seed coating, soil drenching and seed coating + foliar spray were 10.5, 11.75 and 18.75%, respectively, while the control plants showed 52% disease intensity. These results suggest that the P. fluorescens isolates studied have an excellent potential to be used as biocontrol agents of R. solani in rice at the field conditions.

  15. Mid-infared (MidIR) and near-infared (NIR) dection of rhizoctonia solani AG 2-2 IIIB on barley based artificial inoculum

    Science.gov (United States)

    The amount of Rhizoctonia solani in the soil and how much is needed to cause disease in sugar beet (Beta vulgaris L.) is relatively unknown. This is mostly because of the usually low inoculum densities natually found in soil, and the low sensitivity of traditional serial dilution assays. We invest...

  16. 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; Nielsen, T.H.; Sørensen, D.; Hansen, M.; Nybroe, O.; Christophersen, C.; Sørensen, J.; Molin, Søren; Givskov, Michael Christian

    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...

  17. Genome Sequence of Bacillus subtilis MB73/2, a Soil Isolate Inhibiting the Growth of Plant Pathogens Dickeya spp. and Rhizoctonia solani

    OpenAIRE

    Krzyzanowska, Dorota M.; Iwanicki, Adam; Ossowicki, Adam; Obuchowski, Michał; Jafra, Sylwia

    2013-01-01

    Bacillus subilis MB73/2 is a Gram-positive bacterium isolated in Poland from a meadow soil sample. When tested in vitro, the strain shows strong antagonism toward plant pathogens—the soft rot-causing bacteria Dickeya spp. and the crown rot fungus Rhizoctonia solani. Here, we present the genome sequence of MB73/2.

  18. 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.

  19. 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.

  20. Induction of laccase activity in Rhizoctonia solani by antagonistic Pseudomonas fluorescens strains and a range of chemical treatments.

    Science.gov (United States)

    Crowe, J D; Olsson, S

    2001-05-01

    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 strains of P. fluorescens known to produce antifungal metabolites. To study laccase induction further, a range of chemical treatments was applied to R. solani liquid cultures. p-Anisidine, copper(II), manganese(II), calcium ionophore A23187, lithium chloride, calcium chloride, cyclic AMP (cAMP), caffeine, amphotericin B, paraquat, ethanol, and isopropanol were all found to induce laccase; however, the P. fluorescens metabolite viscosinamide did not do so at the concentrations tested. The stress caused by these treatments was assessed by measuring changes in lipid peroxidation levels and dry weight. The results indicated that the laccase induction seen in pairing plate experiments was most likely due to calcium or heat shock signaling in response to the effects of bacterial metabolites, but that heavy metal and cAMP-driven laccase induction was involved in sclerotization. PMID:11319086

  1. 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, Sbastien 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

  2. 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 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 dag kg-1). Na pre...

  3. REAÇÃO DE CULTIVARES DO FEIJOEIRO COMUM ÀS PODRIDÕES RADICULARES CAUSADAS POR Rhizoctonia solani E Fusarium solani f. sp. phaseoli REACTION OF COMMON BEAN CULTIVARS TO ROOT ROT CAUSED BY Rhizoctonia solani AND Fusarium solani f. sp. phaseoli

    Directory of Open Access Journals (Sweden)

    Murillo Lobo Júnior

    2007-12-01

    Full Text Available

    Rhizoctonia solani Kuhn é um fungo necrotrófico, habitante do solo, que ataca grande número de espécies vegetais. Em feijoeiro, R. solani pode induzir sintomas como tombamento, podridões de raízes e de colo da planta. Fusarium solani (Mart Sacc. f. sp. phaseoli (Burcholder ocorre em praticamente todas as regiões produtoras de feijão no Brasil e pode causar podridão radicular e morte das plantas. Neste trabalho, avaliou-se a reação de cultivares de feijoeiro comum às podridões radiculares causadas por R. solani e F. solani f. sp. phaseoli, em solo artificialmente infestado, em condições de casa de vegetação. O delineamento experimental foi inteiramente casualizado, com 24 tratamentos e quatro repetições. Utilizou-se solo Latassolo vermelho-escuro, infestado com 1,0 g de grãos de sorgo triturado e previamente infestado com R. solani para cada 1,4 kg de solo e para F. solani f. sp. phaseoli utilizaram-se oito gramas para cada 1,4 kg de solo. A avaliação da doença foi realizada 21 dias após o plantio, em plantas cujo sistema radicular foi cuidadosamente retirado e lavado em água corrente. A severidade da doença foi avaliada de acordo com escala de notas proposta por Abawi & Pastor-Corrales (1990. O comportamento das cultivares variou de acordo com o patógeno utilizado, ou seja, os genótipos reagiram diferentemente aos dois patógenos, sendo todas suscetíveis, mas com diferentes níveis de suscetibilidade. Entre as cultivares avaliadas, a cultivar Pérola mostrou ser a menos suscetível a R. solani, e Radiante, a menos suscetível a F. solani f. sp. phaseoli.

    PALAVRAS-CHAVE: Phaseolus vulgaris; patógenos de raiz.

    Rhizoctonia solani Kuhn is a necrotrophic fungus and soil inhabitant that attacks great number of vegetable species. In bean plants, R. solani can induce different symptoms including toppling, root and colon plant rottenness. Fusarium solani (Mart Sacc. f. sp. phaseoli (Burcholder occurs in practically all bean producing areas in Brazil and can cause root rots and death to bean plants. This study evaluated the reaction of commercial common bean cultivars growing in R. solani or F. solani f. sp. phaseoli infested soil, under green house conditions. The experimental design was entirely randomized, with 24 treatments and four replications. A Oxisol was infested with triturated sorghum grains that were previously colonized by R. solani (1.0 g/1.4 L of soil or F. solani f. sp phaseoli (8.0 g/1.4 L of soil. The disease evaluations were accomplished 21 days after planting. All plants were carefully removed, their root systems were washed in running water and the disease severity was evaluated according to Abawi & Pastor-Corrales (1990 scale for disease severity. The cultivar behavior ranged according to the inoculated pathogen, all cultivars were susceptible with different degrees of susceptibility. Among evaluated common bean cultivars Pérola was less susceptible to R. solani, and Radiante was less susceptible to F. solani f. sp. phaseoli.

    KEY-WORDS: Phaseolus vulgaris; resistance, soil pathogen.

  4. Diversity of Fluorescent Pseudomonas in Potato Crops of the Cundiboyacense Region and its in vitro Antagonic Activity against Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    D. Uribe

    2011-12-01

    Full Text Available Fluorescent Pseudomonas are one of the most important benefic bacteria of the rizhosphere. It is because they can control some soil borne phytopatogen agents as a result of their antagonistic capacity. There are few works about the composition and diversity of fluorescent Pseudomonas in tropical countries. In this work we studied the composition of fluorescent Pseudomonas form different potato crops located at the Cundiboyacense región between 2100 and 3200 mosl, which is the most important area of potato production in Colombia. This study also assesses the effect of some crop practices variables on rizosphere bacteria richness and diversity. Finally, it was determined the antagonistic capacity of some Pseudomonas fluorescens isolates against Rhizoctonia solani. A total of 45 rhizosphere samples were taken from 15 potato fields. To isolate the Pseudomonas it was used king B medium modified by us. Our results showed that this modified medium consistently allowed a more efficient recovery of the fluorescent Pseudomonas than the media reported in the literature. 80.7% and 82.7% of the fluorescent Pseudomonas isolated from the rizosphere and rizoplane respectively were Pseudomonas fluorescens. It suggest a low fluorescent pseudomonas diversity. Our work also denotes an effect of the maize-potato crop rotation strategy on the amount of the fluorescent Pseudomonas isolated from the rizosphere. These results may have importance in designing appropriate strategies for bio-controlling soil borne phytopathogens. In tropical countries like Colombia, this knowledge might help to improve crop yields. Finally it was found native isolates with antagonistic activity against Rhizoctonia solani in the bioassays in vitro, such results if not assure an efficient control of the pathogen in field conditions, may give an idea of the potentiality of P.fluorescens to be applied as bacterial community, strains or derived products of them.

  5. Evaluación del efecto biocontrolador de Rhizoctonia de orquídeas sobre Rhizoctonia solani kühn patogeno del suelo en arroz (Oryza sativa l.)

    OpenAIRE

    Mosquera Espinosa, Ana Teresa

    2010-01-01

    Los hongos del suelo presentan diferentes estrategias tróficas, lo que les permite interactuar con plantas como saprótrofos, simbiontes mutualistas, patógenos y/o biocontroladores de patógenos. El género-forma Rhizoctonia, cumple todas las funciones mencionadas. Con su teleomorfo en Ceratobasidium, Tulasnella, Thanatephorus y Sebacina, es micorrízico en orquídeas. Patógeno, en cultivos de importancia agrícola como arroz, donde la especie Rhizoctonia solani Kühn causa añublo o tizón de la vain...

  6. Molecular identification of thirteen isolates of Trichoderma spp. and evaluation of their pathogenicity towards Rhizoctonia solani Khn / Identificacin molecular y evaluacin patognica de trece aislamientos de Trichoderma spp. frente a Rhizoctonia solani Khn

    Scientific Electronic Library Online (English)

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

    2013-03-01

    Full Text Available La incidencia de las enfermedades causadas por Rhizoctonia solani Khn en las plantas aumenta cada ao. Su control es fundamentalmente con productos qumicos, en su mayora muy txicos. Por tal razn, se investigan alternativas bioplaguicidas. Trichoderma spp. es uno de los hongos ms utilizados par [...] a el control biolgico de plagas, por sus propiedades y mecanismos de accin: competencia por el sustrato, antibiosis y micoparasitismo. Este trabajo tuvo como objetivos la identifi cacin molecular y evaluacin patognica de 13 aislamientos del gnero Trichoderma frente a aislamientos de R. solani. Se evalu su efecto antibitico sobre aislamientos de 3 grupos de anastomosis de R. solani (AG-2.1, AG-5, AG-8) por el mtodo de celofn. La identificacin molecular parti de la secuenciacin del espaciador interno del transcrito de la regin del ADN ribosomal y del factor de elongacin de la traduccin EF1A. Ms del 70 % de los aislamientos evaluados ejerci un efecto fungisttico; mientras que el resto actu como fungicida. La evaluacin de la eficacia tcnica en condiciones de campo corrobor estos resultados. A partir de la secuenciacin y comparacin de los datos de las secuencias depositadas en TrichoBLAST/GenBank, se comprob que todos los aislamientos tenan 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 biolgico, por su alto potencial antibitico y eficacia tcnica en condiciones de campo. Abstract in english Disease caused by Rhizoctonia solani Khn 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.

  7. 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 Arajo, Fernandes.

    2013-12-01

    Full Text Available Os experimentos objetivaram avaliar em condies de casa de vegetao o biocontrole dos fitopatgenos Rhizoctonia solani (RS) e Fusarium oxysporum f.sp. phaseoli (FOP) em alface (Lactuca sativa L.) cultivar Regina, e feijo-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 base de arroz previamente colonizado por isolados de Trichoderma spp. e posteriormente triturados. Para a realizao dos testes, os biopreparados foram inoculados previamente na proporo de 10(9) condios.mL-1, em substrato comercial para produo de mudas. Aps sete dias, os patgenos foram introduzidos separadamente em duas concentraes distintas: R. solani na proporo de 144 mg de meio de arroz por kg de substrato e F. oxysporum f.sp. phaseoli inoculado na forma de suspenso contendo 4,75 x 10(6) condios.mL-1. Avaliou-se a influncia dos biopreparados na % de damping-off de ps-emergncia em plantas de alface e a severidade de murcha em plantas de feijo-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 incidncia de damping-off de ps-emergncia nessa cultura. Por outro lado, nenhum dos biopreparados apresentou efeito antagonista satisfatrio F. oxysporum f.sp. phaseoli em plantas de feijo-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.

  8. Nuclear magnetic resonance: a tool for imaging belowground damage caused by Heterodera schachtii and Rhizoctonia solani on sugar beet

    Science.gov (United States)

    Hillnhtter, C.; Sikora, R. A.; Oerke, E. -C.; van Dusschoten, D.

    2012-01-01

    Belowground symptoms of sugar beet caused by the beet cyst nematode (BCN) Heterodera schachtii include the development of compensatory secondary roots and beet deformity, which, thus far, could only be assessed by destructively removing the entire root systems from the soil. Similarly, the symptoms of Rhizoctonia crown and root rot (RCRR) caused by infections of the soil-borne basidiomycete Rhizoctonia solani require the same invasive approach for identification. Here nuclear magnetic resonance imaging (MRI) was used for the non-invasive detection of belowground symptoms caused by BCN and/or RCRR on sugar beet. Excessive lateral root development and beet deformation of plants infected by BCN was obvious 28 days after inoculation (dai) on MRI images when compared with non-infected plants. Three-dimensional images recorded at 56 dai showed BCN cysts attached to the roots in the soil. RCRR was visualized by a lower intensity of the MRI signal at sites where rotting occurred. The disease complex of both organisms together resulted in RCRR development at the site of nematode penetration. Damage analysis of sugar beet plants inoculated with both pathogens indicated a synergistic relationship, which may result from direct and indirect interactions. Nuclear MRI of plants may provide valuable, new insight into the development of pathogens infecting plants below- and aboveground because of its non-destructive nature and the sufficiently high spatial resolution of the method. PMID:21948851

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

    Directory of Open Access Journals (Sweden)

    Zbigniew Weber

    2014-08-01

    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.

  10. 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.

  11. 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

  12. Overexpression of snakin-1 gene enhances resistance to Rhizoctonia solani and Erwinia carotovora in transgenic potato plants.

    Science.gov (United States)

    Almasia, Natalia I; Bazzini, Ariel A; Hopp, H Esteban; Vazquez-Rovere, Cecilia

    2008-05-01

    Snakin-1 (SN1), a cysteine-rich peptide with broad-spectrum antimicrobial activity in vitro, was evaluated for its ability to confer resistance to pathogens in transgenic potatoes. Genetic variants of this gene were cloned from wild and cultivated Solanum species. Nucleotide sequences revealed highly evolutionary conservation with 91-98% identity values. Potato plants (S. tuberosum subsp. tuberosum cv. Kennebec) were transformed via Agrobacterium tumefaciens with a construct encoding the S. chacoense SN1 gene under the regulation of the ubiquitous CaMV 35S promoter. Transgenic lines were molecularly characterized and challenged with either Rhizoctonia solani or Erwinia carotovora to analyse whether constitutive in vivo overexpression of the SN1 gene may lead to disease resistance. Only transgenic lines that accumulated high levels of SN1 mRNA exhibited significant symptom reductions of R. solani infection such as stem cankers and damping-off. Furthermore, these overexpressing lines showed significantly higher survival rates throughout the fungal resistance bioassays. In addition, the same lines showed significant protection against E. carotovora measured as: a reduction of lesion areas (from 46.5 to 88.1% with respect to the wild-type), number of fallen leaves and thickened or necrotic stems. Enhanced resistance to these two important potato pathogens suggests in vivo antifungal and antibacterial activity of SN1 and thus its possible biotechnological application. PMID:18705874

  13. 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.

  14. Controle de Rhizoctonia solani e Fusarium oxysporum f.sp. phaseoli por biopreparados de isolados de Trichoderma spp.

    Directory of Open Access Journals (Sweden)

    Pedro Paulo Dias

    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 como 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.

  15. SUPRESSIVIDADE INDUZIDA A Rhizoctonia solani Kühn PELA ADIÇÃO DE DIFERENTES RESÍDUOS VEGETAIS AO SOLO INDUCED SUPPRESSIVENESS TO Rhizoctonia solani KÜHN BY THE ADDITION OF DIFFERENT VEGETABLE AMENDMENTS TO THE SOIL

    Directory of Open Access Journals (Sweden)

    Sheila Andrade Botelho

    2007-09-01

    Full Text Available

    A matéria orgânica de diversas origens é utilizada na agricultura visando, entre outras finalidades, a estimular a atividade microbiana para limitar a atividade dos patógenos do solo. Sua decomposição induz a atividade de alguns organismos, que se tornam úteis a outros tipos de vida, e estabelece relações sintróficas e antagônicas que mantêm o equilíbrio da comunidade biológica como um todo. O presente trabalho teve como objetivo avaliar o efeito da incorporação de diferentes restos vegetais na incidência de podridão radicular do feijoeiro, cujo agente causal é o fungo Rhizoctonia solani. Em casa-de-vegetação, foram utilizadas bandejas plásticas contendo 4 kg de solo cultivado, inoculado com 104 propágulos de Rhizoctonia solani g-1, ao qual foi incorporado o equivalente a 10 t/ha de matéria seca das seguintes origens: Panicum miliaceum, Sorghum maximum, Dolichos lab-lab, Canavaria ensiformis, Braquiaria brizanta, Panicum maximum e Crotalaria juncea. A incorporação do inóculo e dos resíduos vegetais no solo foi realizada simultaneamente. O solo, nas bandejas, foi mantido próximo da capacidade de campo por 60, 30 e 0 dias, antes de ser realizada a semeadura da cultivar Pérola. A avaliação da intensidade de sintomas foi realizada 15 dias após a emergência, utilizando-se uma escala descritiva de 0 a 8. A população microbiana foi avaliada a partir das amostras de solo coletadas das bandejas realizando-se uma diluição em série e o plaqueamento em meios de culturas seletivos. A contagem das colônias de bactérias e fungos foi realizada após sete dias e a de actinomicetos após dez dias de incubação. Os resultados obtidos indicam que apenas o solo com material vegetal incubado durante 60 dias reduziu o índice de doença, não mostrando, contudo, diferenças significativas entre as espécies vegetais estudadas. Relacionando-se o número de propágulos de fungos, actinomicetos e bactérias com o índice de doença, verificou-se que os resíduos vegetais que apresentaram maiores populações de microrganismos no solo foram os que apresentaram os menores índices de doença.

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

    Organic matter of several origins is used in the agriculture to stimulate microbial activity and to limit the activity of plant pathogens. Its decomposition induces the activity of some microorganisms that are useful to other species establishing synergistic and antagonistic relationships that maintain the biological balance. The present work aimed to evaluate the effect of different vegetable amendments incorporated in the soil on the incidence of root-rot, caused by Rhizoctonia solani. In greenhouse, plastic trays containing 4 kg of cultivated soil were inoculated with 104 propagules of Rhizoctonia solani g-1 of soil and in each tray it was incorporated the equivalent of 10 t/ha plant of debris mater of the following species: Panicum miliaceum, Sorghum maximum, Dolichos lab-lab, Canavaria ensiformis, Braquiaria brizanta, Panicum maximum and Crotalaria juncea. The incorporation of the vegetable amendments were realized simultaneous by and the soil was maintained near field capacity for 60, 30 and 0 days, before the bean cultivar Pérola was sown. Symptom intensity was evaluated 15 days after the emergence, using a descriptive scale, varying from 0 to 8. After the completion of the experimental microbial population was estimated in the soil samples collected
    from each plastic tray serial dilution test using selective culture media. Bacteria and fungi colonies were counted after a seven days incubation period and those of actinomycetes after ten days. Results showed that only vegetable materials incubated for 60 days were able to reduce disease index. No significant differences were observed among the studied plant species. The relationship among number of propagules of fungi, actinomycetes, and bacteria with the disease index revealed that the amendments with a larger induced microbial population in the soil were those that presented smaller disease index.

    KEY-WORDS: Rhizoctonia root rot; biological control; soil microbial population.

  16. EFFECT OF LABEL AND SUBLABEL RATES OF METAM SODIUM IN COMBINATION WITH TRICHODERMA HAMATUM, T. HARZIANUM, T. VIRENS, T. VIRIDE ON SURVIVAL AND SAPROPHYTIC ACTIVITY OF RHIZOCTONIA SOLANI IN SOIL

    Science.gov (United States)

    This work was undertaken to determine the effects of Trichoderma spp. combined with label and sublabel rates of metam sodium on survival and saprophytic activity of Rhizoctonia solani in soil. To study survival, sterile beet seed were colonized with R. solani and used to infest soil. Soils were al...

  17. Screening of bacterial isolates from various European soils for in vitro antagonistic activity towards Rhizoctonia solani and Fusarium oxysporum: Site-dependent composition and diversity revealed

    OpenAIRE

    Adesina, M.F.; Lembke, A.; Costa, R.; Speksnijder, A.G.C.L.; Smalla, K

    2007-01-01

    A cultivation-based approach was used to determine the in vitro antagonistic potential of soil bacteria towards Rhizoctonia solani AG3 and Fusarium oxysporum f. sp. lini (Foln3). Four composite soil samples were collected from four agricultural sites with previous documentation of disease suppression, located in France (FR), the Netherlands (NL), Sweden (SE) and the United Kingdom (UK). Similarly, two sites from Germany (Berlin, G-BR; and Braunschweig, G-BS) without documentation of disease s...

  18. 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

    Directory of Open Access Journals (Sweden)

    Flávia Rodrigues Alves Patrício

    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 plantas. 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.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.

  19. Sequence-Related Amplified Polymorphism-PCR Analysis for Genetic Diversity in Rhizoctonia solani Populations Infecting Pulse Crops in Different Agro-Ecological Regions of India

    OpenAIRE

    Aradhika Tripathi; Sunil Chandra Dubey

    2015-01-01

    Rhizoctonia solani is a destructive fungal pathogen infecting wide range of crop plants including pulses causing wet root rot or web blight disease. The present study was aimed to determine the genetic diversity of R. solani populations using Sequence-Related Amplified Polymorphism (SRAP) markers. The SRAP markers were used for genetic diversity analysis of 89 isolates of R. solani belonging to 7 Anastomosis Groups (AGs) isolated from different pulse crops representing 21 states from 16 agr...

  20. 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 evaluate the levels of natural supressiveness to R. solani of some soils previously submitted to different managements from West Central Brazil. Soil samples were collected in Itumbiara, Silvânia, Jussara and Santa Helena de Goiás counties of Goiás State, and classified as: Purple Latosol, Dark-Red Latosol, Sandy Soil and Purple Latosol, respectively. Each soil sample was collected in the layer of 0-20 cm, in contiguous areas with the following characteristics: a soil cultivated with beans irrigated with central pivot, for more than four consecutive years; b soil under native vegetation, and c soil under Brachiaria decubens pasture. Sorghum grains colonized by Rhizoctonia solani, were ground and mixed to the soil samples. Six inoculum densities were used: 0, 100, 500, 1000, 5000 and 10000 propagules per gram of soil. The experiment was conducted under greenhouse conditions, using a randomized complete block design, in a factorial scheme 6 x 4 x 3, with four replications. The experimental unit was a plastic tray with 4 kg of soil and 40 plants. Fifteen days after the emergence symptoms severity were evaluated and the McKinney index estimated. The analysis of variance revealed significance of triple interaction and the degrees of freedom were unfolded in regression analyses among the inoculum doses and the disease index in percentage, in the following exponential equation: ID = A x e (-B/dose do inóculo + 1. In the soil samples from Itumbiara and Silvânia the disease index increased with the increment of the number of propagules for gram of soil, reaching values larger than 70%. However, for both soils, there were no significant differences among the natural vegetation, pasture and bean cultivated soils. On the other hand, in soils from Jussara and Santa Helena, in spite of the disease index increment with the increase of the inoculum doses, the natural and pasture soils showed similar disease indexes for all the inoculum doses used. In soil from irrigated beans, the increment in the diseases index was smaller, not surpassing 60%.

    KEY-WORDS: Rhizoctonia root rot; biological control; soil microbial population.

  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

    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.

  2. 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.

  3. 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...

  4. 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.

  5. Proteomic Investigation of Rhizoctonia solani AG 4 Identifies Secretome and Mycelial Proteins with roles in Plant Cell Wall Degradation and Virulence

    KAUST Repository

    Lakshman, Dilip

    2016-03-28

    Rhizoctonia solani AG 4 is a soilborne necrotrophic fungal plant pathogen that causes economically important diseases on agronomic crops worldwide. Here we used a proteomics approach to characterize both intracellular proteins and the secretome of R. solani AG 4 isolate Rs23A under several growth conditions; the secretome being highly important in pathogenesis. From over 500 total secretome and soluble intracellular protein spots from 2-D gels, 457 protein spots were analyzed and 318 proteins positively matched with fungal proteins of known function by comparison with available R. solani genome databases specific for anastomosis groups 1-IA, 1-IB, and 3. These proteins were categorized to possible cellular locations and functional groups; and for some proteins their putative roles in plant cell wall degradation and virulence. The majority of the secreted proteins were grouped to extracellular regions and contain hydrolase activity.

  6. 3-Methylthiopropionic Acid of Rhizoctonia solani AG-3 and Its Role in the Pathogenicity of the Fungus

    Science.gov (United States)

    Kankam, Frederick; Long, Hai-Tao; He, Jing; Zhang, Chun-hong; Zhang, Hui-Xiu; Pu, Lumei; Qiu, Huizhen

    2016-01-01

    Studies were conducted to determine the role of 3-methylthioproprionic acid (MTPA) in the pathogenicity of potato stem canker, Rhizoctonia solani, and the concentrations required to inhibit growth of R. solani under laboratory and plant house-based conditions. The experiments were laid out in a completely randomized design with five treatments and five replications. The treatments were 0, 1, 2, 4, and 8 mM concentrations of MTPA. The purified toxin exhibited maximal activity at pH 2.5 and 30°C. MTPA at 1, 2, 4, and 8 mM levels reduced plant height, chlorophyll content, haulm fresh weight, number of stolons, canopy development, and tuber weight of potato plants, as compared to the control. MTPA significantly affected mycelial growth with 8 mM causing the highest infection. The potato seedlings treated with MTPA concentrations of 1.0–8.0 mM induced necrosis of up to 80% of root system area. Cankers were resulted from the injection of potato seedling stems with 8.0 mM MTPA. The results showed the disappearance of cell membrane, rough mitochondrial and cell walls, change of the shape of chloroplasts, and swollen endoplasmic reticulum. Seventy-six (76) hours after toxin treatment, cell contents were completely broken, cytoplasm dissolved, and more chromatin were seen in the nucleus. The results suggested that high levels of the toxin concentration caused cell membrane and cytoplasm fracture. The integrity of cellular structure was destroyed by the phytotoxin. The concentrations of the phytotoxin were significantly correlated with pathogenicity and caused damage to the cell membrane of potato stem base tissue. PMID:27147928

  7. 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

  8. 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.

  9. Development of a Rhizoctonia solani AG1-IB Specific Gene Model Enables Comparative Genome Analyses between Phytopathogenic R. solani AG1-IA, AG1-IB, AG3 and AG8 Isolates.

    Science.gov (United States)

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

    2015-01-01

    Rhizoctonia solani, a soil-born plant pathogenic basidiomycetous fungus, affects various economically important agricultural and horticultural crops. The draft genome sequence for the R. solani AG1-IB isolate 7/3/14 as well as a corresponding transcriptome dataset (Expressed Sequence Tags--ESTs) were established previously. Development of a specific R. solani AG1-IB gene model based on GMAP transcript mapping within the eukaryotic gene prediction platform AUGUSTUS allowed detection of new genes and provided insights into the gene structure of this fungus. In total, 12,616 genes were recognized in the genome of the AG1-IB isolate. Analysis of predicted genes by means of different bioinformatics tools revealed new genes whose products potentially are involved in degradation of plant cell wall components, melanin formation and synthesis of secondary metabolites. Comparative genome analyses between members of different R. solani anastomosis groups, namely AG1-IA, AG3 and AG8 and the newly annotated R. solani AG1-IB genome were performed within the comparative genomics platform EDGAR. It appeared that only 21 to 28% of all genes encoded in the draft genomes of the different strains were identified as core genes. Based on Average Nucleotide Identity (ANI) and Average Amino-acid Identity (AAI) analyses, considerable sequence differences between isolates representing different anastomosis groups were identified. However, R. solani isolates form a distinct cluster in relation to other fungi of the phylum Basidiomycota. The isolate representing AG1-IB encodes significant more genes featuring predictable functions in secondary metabolite production compared to other completely sequenced R. solani strains. The newly established R. solani AG1-IB 7/3/14 gene layout now provides a reliable basis for post-genomics studies. PMID:26690577

  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. 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.

  12. FT-ICR/MS and GC-EI/MS metabolomics networking unravels global potato sprout's responses to Rhizoctonia solani infection.

    Science.gov (United States)

    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 developed bioanalytical and bioinformatics protocols provided a snapshot of the sprout's global metabolic network and its perturbations as a result of pathogen invasion. Mevalonic acid and deoxy-xylulose pathways were substantially up-regulated leading to the biosynthesis of sesquiterpene alkaloids such as the phytoalexins phytuberin, rishitin, and solavetivone, and steroidal alkaloids having solasodine and solanidine as their common aglycons. Additionally, the perturbation of the sprout's metabolism was depicted in fluctuations of the content of their amino acids pool and that of carboxylic and fatty acids. Components of the systemic acquired resistance (SAR) and hypersensitive reaction (HR) such as azelaic and oxalic acids were detected in increased levels in infected sprouts and strategies of the pathogen to overcome plant defense were proposed. Our metabolic approach has not only greatly expanded the multitude of metabolites previously reported in potato in response to pathogen invasion, but also enabled the identification of bioactive plant-derived metabolites providing valuable information that could be exploited in biotechnology, biomarker-assisted plant breeding, and crop protection for the development of new crop protection agents. PMID:22880040

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

    Directory of Open Access Journals (Sweden)

    M. N. Reddy

    2014-08-01

    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. Reação de cultivares de feijão-caupi à mela (Rhizoctonia solani em Roraima Reaction of cowpea cultivars to web blight (Rhizoctonia solani in Roraima, Brazil

    Directory of Open Access Journals (Sweden)

    Kátia de Lima Nechet

    2007-10-01

    Full Text Available Em Roraima, uma das principais doenças que incidem na cultura do feijão-caupi (Vigna unguiculata é a mela causada pelo fungo Thanatephorus cucumeris (anamorfo Rhizoctonia solani. Este trabalho teve como objetivo avaliar a reação a esta doença de dez cultivares de feijão-caupi em área de cerrado em Roraima, em dois anos consecutivos. As cultivares de porte ereto utilizadas foram BRS-Mazagão, IT86D-719, Vita-7 (Epace-1, BR02-Bragança, Pitiúba, e as de porte prostrado, BRS-Amapá, BR03-Tracuateua, BR17-Gurguéia, BR14-Mulato e Canapuzinho. Os ensaios foram instalados em 2005 e 2006, utilizando-se o delineamento experimental em blocos completos casualizados com cinco tratamentos e quatro repetições. Avaliou-se, semanalmente, a porcentagem de área foliar lesionada para a obtenção da área baixo da curva de progresso da doença. Pelos resultados obtidos verificou-se que os genótipos de porte prostrado apresentaram menor severidade do que os de porte ereto, indicando uma relação da arquitetura da planta com a resistência à mela. As cultivares de porte prostrado, BRS-Amapá, BR03-Tracuateua, BR17-Gurguéia, BR14-Mulato e Canapuzinho, e as de porte ereto, BRS-Mazagão, Pitiúba e BR03-Bragança, foram as mais resistentes à mela e podem ser recomendadas para áreas com histórico de incidência da doença.Web blight caused by the fungus Thanatephorus cucumeris (Rhizoctonia solani is one of most important diseases of cowpea (Vigna unguiculata in the state of Roraima, Brazil. Web blight severity for ten cowpea cultivars was evaluated in Roraima in two consecutive years. The erect cowpea cultivars BRS-Mazagão, IT86D-719, Vita-7 (Epace-1, BR02-Bragança and Pitiúba, as well as the prostrate cultivars BRS-Amapá, BR03-Tracuateua, BR17-Gurguéia, BR14-Mulato and Canapuzinho, were used. The experiment was conducted during 2005 and 2006 in a complete randomized block design with five treatments and four replications. The percentage of diseased foliage was evaluated once a week and the data were used to calculate the area under the disease progress curve. Disease severity was lower on prostrate cultivars indicating a relationship between plant architecture and web blight resistance. The prostrate cultivars, BRS-Amapá, BR03-Tracuateua, BR17-Gurguéia, BR14-Mulato and Canapuzinho, and erect cultivars, BRS-Mazagão, Pitiúba and BR03-Bragança, were more resistant to web blight and can be recommended for planting in areas where the disease is known to occur.

  16. Control del mal de los almcigos 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, Freix; R, Cabalini; SE, Lopez.

    2013-12-01

    Full Text Available El mal de los almcigos causa muerte de plntulas. Los controles cultural y biolgico constituyen las nicas herramientas orgnicas para su manejo. Acerca de la eficiencia de preparaciones vegetales, slo se encuentra informacin de divulgacin. Este trabajo evala 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 fermentacin a temperatura ambiente, con o sin esterilizacin posterior. Se cultivaron los patgenos en APG suplementado con B y SB diluidos 1,7; 3,3; 8,3; 16,7 y 25%. Su crecimiento decreci con B al 8,3, 16,7 y 25%. La produccin de esclerocios por S. rolfsii disminuy con B, pero aument con SB. Penicillium purpurogenum, P. simplicissimum y Aspergillus niger aislados de B evidenciaron antibiosis, competencia e hiperparasitismo respecto de ambos patgenos. B y SB diluidos 10 y 50% fueron aplicados en almcigos de acelga (Beta vulgaris), tomate (Solanum lycopersicum), pimiento (Capsicum annuum) y berenjena (Solanum melongena) infestados. La prdida de plntulas fue menor en el tratamiento con B al 50%, en relacin al tratamiento con SB. Se concluye que la actividad antifngica de B depende de su dilucin y de su micota. La utilizacin de caldos de cebolla debera 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 qumicos y microbiolgicos de los caldos, y sus posibles cambios durante la fermentacin. 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.

  17. Is it necessary to soak rice grains to prepare Rhizoctonia solani AG-4 inoculum? É necessário embeber os grãos de arroz para o preparo de inóculo de Rhizoctonia solani AG-4?

    Directory of Open Access Journals (Sweden)

    Trazilbo J. Paula Júnior

    2007-12-01

    Full Text Available A study was conducted to evaluate the effects on the development of root rot on common bean, cv. 'Dufrix' after treatment with four volumes of water (0, 30%, 60%, and 90%, v/w added to rice grains previously immersed in water for 24 hours before autoclaving and colonization of grains by Rhizoctoniasolani AG-4. Colonized rice grains and non-infested rice grains were mixed in pots with sterilized soil and sand (2:1, where beans were sown. Based on results of area under plant emergence curve, plant height, plant dry weight, and disease severity, we conclude that inoculum is more effective in causing disease when no water is added to the rice grains before autoclaving.Foi conduzido um estudo com o objetivo de avaliar os efeitos de quatro volumes de água (0, 30%, 60% e 90%, v/p adicionados a grãos de arroz previamente embebidos em água por 24 horas antes de eles serem autoclavados e colonizados por Rhizoctonia solani sobre o desenvolvimento da podridão-radicular de feijão, cv. 'Dufrix'. Grãos de arroz colonizados e não colonizados foram misturados em vasos contendo substrato de solo e areia (2:1, com posterior semeadura de feijão. Baseados nos resultados de área abaixo da curva de emergência das plantas, altura das plantas, massa de plantas secas e severidade da doença, conclui-se que o inóculo é mais eficiente em causar doença quando não se adiciona água aos grãos de arroz antes de eles serem autoclavados.

  18. 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 Evaluacin de la actividad quitinasa en procesos de control biolgico de rhizoctonia solani y fusarium oxysporum f. sp. lycopersici en tomate, mediante fitoinvigorizacin de semillas en presencia de trichoderma koningii

    OpenAIRE

    Cotes A. M.; Clavijo A.

    1998-01-01

    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 prim...

  19. 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

    OpenAIRE

    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 μCT) 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, B...

  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

    OpenAIRE

    Vargas de Álvarez, Amparo; Fuentes', Cilia L.; Torres Torres, Enrique

    2011-01-01

    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 inci...

  1. 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...

  2. Evaluación de aislamientos de trichoderma spp. contra rhizoctonia solani y sclerotium rolfsii bajo condiciones in vitro y de invernadero

    OpenAIRE

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

    2009-01-01

    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 antagónica 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 redu...

  3. Mid-Infrared (MIR) and Near-Infrared (NIR) Detection of Rhizoctonia solani AG 2-2 IIIB on Barley-Based Artificial Inoculum.

    Science.gov (United States)

    Webb, Kimberly M; Calderón, Francisco J

    2015-10-01

    The amount of Rhizoctonia solani in the soil and how much must be present to cause disease in sugar beet (Beta vulgaris L.) is relatively unknown. This is mostly because of the usually low inoculum densities found naturally in soil and the low sensitivity of traditional serial dilution assays. We investigated the usefulness of Fourier transform mid-infrared (MIR) and near-infrared (NIR) spectroscopic properties in identifying the artificial colonization of barley grains with R. solani AG 2-2 IIIB and in detecting R. solani populations in plant tissues and inoculants. The objectives of this study were to compare the ability of traditional plating assays to NIR and MIR spectroscopies to identify R. solani in different-size fractions of colonized ground barley (used as an artificial inoculum) and to differentiate colonized from non-inoculated barley. We found that NIR and MIR spectroscopies were sensitive in resolving different barley particle sizes, with particles that were 2.0 mm) of the ground barley. This colonization was confirmed using traditional plating assays. Comparisons with the spectra from pure fungal cultures and non-inoculated barley suggest that the MIR spectrum of colonized barley is different because of the consumption of C substrates by the fungus rather than because of the presence of fungal bands in the spectra of the colonized samples. We found that MIR was better than NIR spectroscopy in differentiating the colonized from the control samples. PMID:26449805

  4. Sequence-Related Amplified Polymorphism-PCR Analysis for Genetic Diversity in Rhizoctonia solani Populations Infecting Pulse Crops in Different Agro-Ecological Regions of India

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    Aradhika Tripathi

    2015-01-01

    Full Text Available Rhizoctonia solani is a destructive fungal pathogen infecting wide range of crop plants including pulses causing wet root rot or web blight disease. The present study was aimed to determine the genetic diversity of R. solani populations using Sequence-Related Amplified Polymorphism (SRAP markers. The SRAP markers were used for genetic diversity analysis of 89 isolates of R. solani belonging to 7 Anastomosis Groups (AGs isolated from different pulse crops representing 21 states from 16 agro-ecological regions of India. Out of 30 SRAP primer combinations evaluated, 16 combinations provided amplification with 100% polymorphism and the primer combinations Me1/Em1and Me1/Em4 provided the highest number of bands (14. The isolates of R. solani showed high level of genetic variability and grouped into 7 major clusters at 35% genetic similarity by using unweighted pair group method with an arithmetic average analysis. Bootstrap analysis grouped the isolates into five major clusters at 28% genetic similarity and about 95% isolates shared common sub-grouping patterns in both the analysis. The majority of the isolates representing various AGs were grouped together into different sub-clusters. The molecular clusters did not correspond to agro-ecological regions and crops of the origin of the isolates because of the diversity in the hosts and adopt ability of the pathogen under different environmental conditions prevalent in various parts of the country. First time an attempt was made in the present study to determine the genetic variability of the R. solani populations isolated from different pulse crops representing various AGs using SRAP markers.

  5. EMS-treated hexaploid wheat genotype Scarlet has enhanced tolerance to the soilborne necrotrophic pathogens Rhizoctonia solani AG-8 and R. oryzae. 2009. Theor. Appl. Genet. 119(February): 293-303

    Science.gov (United States)

    R. solani AG-8 and R. oryzae cause Rhizoctonia root rot and pre-emergence damping-off, yield-limiting diseases that pose a barrier to the adoption of reduced tillage wheat production systems intended to reduce soil erosion. We report the first genetic resistance to necrotrophic root pathogens Rhizo...

  6. High entomotoxicity and mechanism of the fungal GalNAc/Gal-specific Rhizoctonia solani lectin in pest insects.

    Science.gov (United States)

    Hamshou, Mohamad; Van Damme, Els J M; Caccia, Silvia; Cappelle, Kaat; Vandenborre, Gianni; Ghesquire, Bart; Gevaert, Kris; Smagghe, Guy

    2013-03-01

    Whole insect assays where Rhizoctonia solani agglutinin (RSA) was fed to larval stages of the cotton leaf-worm Spodoptera littoralis and the pea aphid Acyrthosiphon pisum demonstrated a high concentration-dependent entomotoxicity, suggesting that this GalNAc/Gal-specific fungal lectin might be a good control agent for different pest insects. RSA at 10 mg/g in the solid diet of 2nd-instar caterpillars caused 84% weight reduction after 8 days with none of the caterpillars reaching the 4th-instar stage. In sucking aphids, 50% mortality was achieved after 3 days with 9 ?M of RSA in the liquid diet. Feeding of FITC-labeled RSA to both insect pest species revealed strong lectin binding at the apical/luminal side of the midgut epithelium with the brush border zone, suggesting the insect midgut as a primary insecticide target tissue for RSA. This was also confirmed with cell cultures in vitro, where there was high fluorescence binding at the microvillar zone with primary cultures of larval midgut columnar cells of S. littoralis, and also at the surface with the insect midgut CF-203 cell line without lectin uptake in the midgut cells. In vitro assays using insect midgut CF-203 cells, revealed that RSA was highly toxic with an EC50 of 0.3 ?M. Preincubation with GalNAc and saponin indicated that this action of RSA was carbohydrate-binding dependent and happened at the surface of the cells. Intoxicated CF-203 cells showed symptoms of apoptosis as nuclear condensation and DNA fragmentation, and this concurred with an increase of caspase-3/7, -8 and -9 activities. Finally, RSA affinity chromatography of membrane extracts of CF-203 cells followed by LC-MS/MS allowed the identification of 5747 unique peptides, among which four putatively glycosylated membrane proteins that are associated with apoptosis induction, namely Fas-associated factor, Apoptosis-linked gene-2, Neuroglian and CG2076, as potential binding targets for RSA. These data are discussed in relation to the physiological effects of RSA. PMID:23291362

  7. The Urochloa Foliar Blight and Collar Rot Pathogen Rhizoctonia solani AG-1 IA Emerged in South America Via a Host Shift from Rice.

    Science.gov (United States)

    Chavarro Mesa, Edisson; Ceresini, Paulo C; Ramos Molina, Lina M; Pereira, Danilo A S; Schurt, Daniel A; Vieira, José R; Poloni, Nadia M; McDonald, Bruce A

    2015-11-01

    The fungus Rhizoctonia solani anastomosis group (AG)-1 IA emerged in the early 1990s as an important pathogen causing foliar blight and collar rot on pastures of the genus Urochloa (signalgrass) in South America. We tested the hypothesis that this pathogen emerged following a host shift or jump as a result of geographical overlapping of host species. The genetic structure of host and regional populations of R. solani AG-1 IA infecting signalgrass, rice, and soybean in Colombia and Brazil was analyzed using nine microsatellite loci in 350 isolates to measure population differentiation and infer the pathogen reproductive system. Phylogeographical analyses based on the microsatellite loci and on three DNA sequence loci were used to infer historical migration patterns and test hypotheses about the origin of the current pathogen populations. Cross pathogenicity assays were conducted to measure the degree of host specialization in populations sampled from different hosts. The combined analyses indicate that the pathogen populations currently infecting Urochloa in Colombia and Brazil most likely originated from a population that originally infected rice. R. solani AG-1 IA populations infecting Urochloa exhibit a mixed reproductive system including both sexual reproduction and long-distance dispersal of adapted clones, most likely on infected seed. The pathogen population on Urochloa has a genetic structure consistent with a high evolutionary potential and showed evidence for host specialization. PMID:26222889

  8. 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.

  9. 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

    OpenAIRE

    Vargas de Álvarez Amparo; Fuentes Cilia L.; Torres Torres Enrique

    2002-01-01

    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 inci...

  10. Evaluacin de la actividad quitinasa en procesos de control biolgico de rhizoctonia solani y fusarium oxysporum f. sp. lycopersici en tomate, mediante fitoinvigorizacin 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

    OpenAIRE

    Cotes A. M.; Clavijo A.

    1998-01-01

    El propsito del presente trabajo fue el de establecer el posible papel de las quitinasas en un modelo de control, utilizando pregerminacin controlada de semillas en presencia de Trichoderma koningii. Este mtodo mostr 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 se...

  11. Cyclic Lipopeptides of Bacillus amyloliquefaciens subsp. plantarum Colonizing the Lettuce Rhizosphere Enhance Plant Defense Responses Toward the Bottom Rot Pathogen Rhizoctonia solani.

    Science.gov (United States)

    Chowdhury, Soumitra Paul; Uhl, Jenny; Grosch, Rita; Alquéres, Sylvia; Pittroff, Sabrina; Dietel, Kristin; Schmitt-Kopplin, Philippe; Borriss, Rainer; Hartmann, Anton

    2015-09-01

    The commercially available inoculant Bacillus amyloliquefaciens FZB42 is able to considerably reduce lettuce bottom rot caused by Rhizoctonia solani. To understand the interaction between FZB42 and R. solani in the rhizosphere of lettuce, we used an axenic system with lettuce bacterized with FZB42 and inoculated with R. solani. Confocal laser scanning microscopy showed that FZB42 could delay the initial establishment of R. solani on the plants. To show which secondary metabolites of FZB42 are produced under these in-situ conditions, we developed an ultra-high performance liquid chromatography coupled to time of flight mass spectrometry-based method and identified surfactin, fengycin, and bacillomycin D in the lettuce rhizosphere. We hypothesized that lipopeptides and polyketides play a role in enhancing the plant defense responses in addition to the direct antagonistic effect toward R. solani and used a quantitative real-time polymerase chain reaction-based assay for marker genes involved in defense signaling pathways in lettuce. A significant higher expression of PDF 1.2 observed in the bacterized plants in response to subsequent pathogen challenge showed that FZB42 could enhance the lettuce defense response toward the fungal pathogen. To identify if surfactin or other nonribosomally synthesized secondary metabolites could elicit the observed enhanced defense gene expression, we examined two mutants of FZB42 deficient in production of surfactin and the lipopetides and polyketides, by expression analysis and pot experiments. In the absence of surfactin and other nonribosomally synthesized secondary metabolites, there was no enhanced PDF 1.2-mediated response to the pathogen challenge. Pot experiment results showed that the mutants failed to reduce disease incidence in lettuce as compared with the FZB42 wild type, indicating, that surfactin as well as other nonribosomally synthesized secondary metabolites play a role in the actual disease suppression and on lettuce health. In conclusion, our study showed that nonribosomally synthesized secondary metabolites of FZB42 are actually produced in the lettuce rhizosphere and contribute to the disease suppression by mediating plant defense gene expression toward the pathogen R. solani. PMID:26011557

  12. Bioconversion of wheat straw and wheat straw components into single-cell protein. [Spicaria fusispora, Cochliobolus specifer, Myrothecium verrucaria, Rhizoctonia solani, and Gliocladium sp

    Energy Technology Data Exchange (ETDEWEB)

    Chahal, D.S.; Moo-Young, M.; Dhillon, G.S.

    1979-01-01

    Several fungi (Aspergillus niger, A. terreus, Cochliobolus specifer, Myrothecium verrucaria, Rhizoctonia solani, Spicaria fusispora, Penicillium sp., and Gliocladium sp.) were isolated from decomposing wheat straw and tested for their ability to utilize whole straw and its components, holocellulose (hemicellulose and cellulose) and cellulose, for the production of single-cell protein (SCP). C. specifer was the most efficient fungus for protein synthesis with the 3 substrates. Using KNO/sub 3/ as N source in mixtures of .04 g N/g substrate (0.04% wt./vol.) at pH 4.5, it was found that incubation periods of 3, 4, and 5 days were optimal for protein production on cellulose and holocellulose fractions, and whole straw, respectively. Whole native straw was the most recalcitrant to bioconversion into SCP; however, protein production was almost doubled when the lignin component was removed using a mixture of NaClO/sub 2/ and HOAc.

  13. Integrated biological and chemical control of damping-off caused by Rhizoctonia solani using Bacillus subtilis RB14-C and flutolanil.

    Science.gov (United States)

    Kondoh, M; Hirai, M; Shoda, M

    2001-01-01

    Bacillus subtilis RB14-C was isolated as a potential biological agent to control the occurrence of various plant diseases. Integrated control of damping-off in tomato plants caused by Rhizoctonia solani was carried out in pots using B. subtilis RB14-C and chemical pesticide, flutolanil. The growth of RB14-C was the same in both the flutolanil-containing and the flutolanil-free media, indicating the resistance of RB14-C to flutolanil. Although the productivity of surfactin decreased to one-third in the flutolanil-containing medium, compared with that in the flutolanil-free medium, the productivity of iturin A which is mainly associated with the suppressive ability of RB14-C against plant pathogens was unaffected. The integration of RB14-C and flutolanil reduced the amount of flutolanil used to one-fourth of that of the single use of flutolanil, with the same efficacy of reducing disease occurrence. PMID:16232970

  14. Silício alterando compostos derivados da pirólise de bainhas foliares de plantas de arroz infectadas por Rhizoctonia solani

    OpenAIRE

    Daniel Augusto Schurt; Fabrício 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 dag kg-1). Na pre...

  15. Potencial antifngico 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, Hernndez-Castillo; RH, Lira-Saldivar; L, Cruz-Chvez; G, Gallegos-Morales; Me, Galindo-Cepeda; E, Padrn-Corral; M, Hernndez-Surez.

    2008-12-01

    Full Text Available El cultivo de papa en Mxico es el que ms funguicidas requiere para prevenir y controlar diversas enfermedades, estimndose que en este cultivo se aplican el 21,3% del total de los funguicidas disponibles. Los pesticidas sintticos se destinan principalmente para combatir los hongos Phytophthora in [...] festans y Rhizoctonia solani. Esto trae como consecuencia severos daos a la salud y a los ecosistemas; es por eso que existe la necesidad de encontrar nuevas opciones para el manejo sustentable de los patgenos que atacan a este cultivo. Se realizaron investigaciones en condiciones de laboratorio, invernadero y campo con los siguientes objetivos (1) analizar el efecto antifngico de tres cepas de bacterias del gnero Bacillus (B3, B9 y B15) contra R. solani, as 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 sinrgico al mezclar las cepas de Bacillus con el extracto de L. tridentata. Los resultados indicaron que las cepas bacterianas tuvieron una clara actividad antifngica, al igual que el extracto de L. tridentata. Las cepas de Bacillus sobresalieron adems por su efecto estimulador del crecimiento de las plantas y del rendimiento de papa, as como por el efecto sinrgico al mezclar las bacterias con el extracto de Larrea; un efecto potenciador similar se observ al aplicar la mezcla de las cepas. Los resultados obtenidos con las cepas de Bacillus, as como su mezcla con el extracto de L. tridentata son alentadores. Los mismos sugieren que podran ser utilizados para apoyar programas de control biolgico contra R. solani. Sin embargo, es necesario continuar con ms 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.

  16. 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.

  17. 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.

  18. 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)

  19. 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)

    Candole, Byron L; Csinos, Alexander S; Wang, Dong

    2007-05-01

    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 g L(-1) SL was drip applied at rates of 147 and 295 L ha(-1) in plastic-mulched raised beds. Methyl isothiocyanate concentrations in soil air space were monitored from four preselected sites: 10 and 20 cm below the emitter, and 20 and 30 cm laterally away from the emitter at 3, 12, 24, 48, 72, 120 and 240 h after chemigation. A higher rate of metam-sodium application resulted in higher methyl isothiocyanate concentrations in the soil. Highest methyl isothiocyanate concentrations were found at 20 cm below the emitter, and lowest at 30 cm laterally away from the emitter. Methyl isothiocyanate concentrations decreased with time and distance from the emitter. Lower methyl isothiocyanate concentration x time product values at 20 and 30 cm away from the emitter resulted in lower mortalities of Rhizoctonia solani Khn and yellow nutsedge (Cyperus esculentus L.). The results demonstrated that methyl isothiocyanate can be delivered at lethal doses with drip-applied water downward within the beds. Lateral diffusion of methyl isothiocyanate from the point of application did not reach biologically active concentrations to affect the survival of R. solani or yellow nutsedge. Further studies on the lateral distribution of methyl isothiocyanate in sandy soils are needed to circumvent this limitation. PMID:17397113

  20. Chitinolytic Streptomyces vinaceusdrappus S5MW2 isolated from Chilika lake, India enhances plant growth and biocontrol efficacy through chitin supplementation against Rhizoctonia solani.

    Science.gov (United States)

    Yandigeri, Mahesh S; Malviya, Nityanand; Solanki, Manoj Kumar; Shrivastava, Pooja; Sivakumar, G

    2015-08-01

    A chitinolytic actinomycete Streptomyces vinaceusdrappus S5MW2 was isolated from water sample of Chilika lake, India and identified using 16S rRNA gene sequencing. It showed in vitro antifungal activity against the sclerotia producing pathogen Rhizoctonia solani in a dual culture assay and by chitinase enzyme production in a chitin supplemented minimal broth. Moreover, isolate S5MW2 was further characterized for biocontrol (BC) and plant growth promoting features in a greenhouse experiment with or without colloidal chitin (CC). Results of greenhouse experiment showed that CC supplementation with S5MW2 showed a significant growth of tomato plants and superior disease reduction as compared to untreated control and without CC treated plants. Moreover, higher accumulation of chitinase also recovered in the CC supplemented plants. Significant effect of CC also concurred with the Analysis of Variance of greenhouse parameters. These results show that the a marine antagonist S5MW2 has BC efficiency against R. solani and chitinase enzyme played important role in plant resistance. PMID:25982747

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

    Directory of Open Access Journals (Sweden)

    Maisa B. Ciampi

    2009-01-01

    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.

  2. 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%), β-bisabolene (15.4%), (E)-α-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

  3. 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.

  4. 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.

  5. 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

    Directory of Open Access Journals (Sweden)

    Yoleidy Escalona

    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 considerables. 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.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.

  6. 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

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    Yoleidy Escalona

    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 virulencia, 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.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 objectives. 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.

  7. Evaluacin de la actividad quitinasa en procesos de control biolgico de rhizoctonia solani y fusarium oxysporum f. sp. lycopersici en tomate, mediante fitoinvigorizacin de semillas en presencia de trichoderma koningii

    OpenAIRE

    Clavijo, A.; Cotes, A. M.

    2012-01-01

    El propsito del presente trabajo fue el de establecer el posible papel de las quitinasas en un modelo de control, utilizando pregerminacin controlada de semillas en presencia de Trichoderma koningii. Este mtodo mostr 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 encontr que stos presentaron niveles signific...

  8. 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

    OpenAIRE

    Clavijo, A.; Cotes, A. M.

    2012-01-01

    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 prim...

  9. Encapsulamento de Trichoderma inhamatum para o controle biológico de Rhizoctonia solani na propagaç��o clonal de Eucalyptus

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    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.

  10. 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

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    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. This relationship should be
    explored in terms of selerotial survival and germination.

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

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    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.

  12. 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

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    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.

  13. 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

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    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.

  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

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    Tremacoldi Célia Regina

    2002-01-01

    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.

  15. 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.

  16. Potencial de preparados de cavalinha (Equisetum sp.) na sntese de metablitos de defesa em cotildones 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, GUIMARES; SM, MAZARO; R, FREDDO; A, WAGNER JNIOR.

    2015-03-01

    Full Text Available Foram desenvolvidos dois experimentos com objetivo de avaliar o potencial de preparados de cavalinha (Equisetum sp.) na sntese de metablitos de defesa em cotildones 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 extrao x concentraes), com quatro repeties. As formas de extrao foram extrato alcolico, infuso e macerao, nas concentraes de zero; 1; 10, 20 e 40%. No primeiro experimento foi avaliada a induo de compostos de defesa vegetal em cotildones de soja em resposta aos derivados a base de cavalinha, sendo quantificada a atividade da enzima fenilalanina amnia-liase (FAL), via espectofotometria, a fitoalexina gliceolina, e o teor de fenis 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 alcolico, infuso e macerao de cavalinha apresentaram capacidade de induo das fitoalexinas gliceolinas em cotildones de soja, bem como, ativaram o metabolismo de compostos fenlicos. Entre os preparados, o extrato alcolico e a macerao, se sobressaem sobre a infuso. Os preparados de extrato alcolico, infuso e macerao de cavalinha em todas as suas concentraes inibem o crescimento do fungo R. solani, in vitro. Abstract in english Two experiments were carried out in the Federal Technological University of Paran - 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.

  17. 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.

  18. 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., van; Er, H.L.; Vos, O.J., de; van 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...

  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

    Directory of Open Access Journals (Sweden)

    Flávia Rodrigues Alves Patrício

    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, sobre 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.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 evaluated 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 environments as well as the fungicide pencycuron were effective to control R. solani, but the association of both treatments did not have any synergistic effect. The treatment with the isolate of Trichoderma sp. IB-17 had no effect on R. solani, and was not favored by soil solarization.

  20. Silício alterando compostos derivados da pirólise de bainhas foliares de plantas de arroz infectadas por Rhizoctonia solani

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    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.

  1. 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.

  2. Changes in the contents of metabolites and enzyme activities in rice plants responding to Rhizoctonia solani Kuhn infection: activation of glycolysis and connection to phenylpropanoid pathway.

    Science.gov (United States)

    Mutuku, J Musembi; Nose, Akihiro

    2012-06-01

    Rhizoctonia solani Kuhn causes sheath blight disease in rice, and genetic resistance against it is the most desirable characteristic. Current improvement efforts are based on analysis of polygenic quantitative trait loci (QTLs), but interpretation is limited by the lack of information on the changes in metabolic pathways. Our previous studies linked activation of the glycolytic pathway to enhanced generation of lignin in the phenylpropanoid pathway. The current studies investigated the regulation of glycolysis by examining the time course of changes in enzymatic activities and metabolite contents. The results showed that the activities of all glycolytic enzymes as well as fructose-6-phosphate (F-6-P), fructose-1,6-bisphosphate (F-1,6-P(2)), dihydroxyacetone phosphate (DHAP), glyceraldehyde-3-phosphate (GAP), 3-phosphoglycerate (3-PG), phosphoenolpyruvate (PEP) and pyruvate contents increased. These results combined with our previous findings that the expression of phosphoglucomutase (PGM), triosephosphate isomerase (TPI), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), enolase and pyruvate kinase (PK) increased after infection suggested that the additional establishment of glycolysis in the cytosol compartment occurred after infection. Further evidence for this was our recent findings that the increase in expression of the 6-phosphofructokinase (PFK) plastid isozyme Os06g05860 was accompanied by an increase in expression of three cytosolic PFK isozymes, i.e. Os01g09570, Os01g53680 and Os04g39420, as well as pyrophosphate-dependent phosphofrucokinase (PFP) isozymes Os08g25720 (α-subunit) and Os06g13810 (β-subunit) in infected rice plants of the resistant line. The results also showed that the reactions catalysed by PFK/PFP, aldolase, GAPDH + phosphoglycerate kinase (PGK) and PK in leaf sheaths of R. solani-infected rice plants were non-equilibrium reactions in vivo. This study showed that PGM, phosphoglucose isomerase (PGI), TPI and phosphoglycerate mutase (PGmu) + enolase could be regulated through coarse control whereas, PFK/PFP, aldolase, GAPDH + PGK and PK could be regulated through coarse and fine controls simultaneously. PMID:22492233

  3. Construction of pathogenic, biologic and genetic bases of the Colombian populations of Rhizoctonia solani AG-3 necessary for the development of management strategies of stem canker and black scurf diseases of potato

    OpenAIRE

    Ferrucho, Rosa Lilia

    2011-01-01

    Rhizoctonia solani AG-3 Kühn (teleomorph: Thanatephorus cucumeris (Frank) Donk) es un patógeno del suelo importante en cultivos de papa a nivel mundial. Aunque este patógeno es importante en Colombia actualmente no existe información acerca del patógeno y la enfermedad. Esta investigación se realizo utilizando pruebas moleculares y biológicas con el fin de conocer los Grupos de Anastomosis (GA) asociados a síntomas en las principales regiones productoras de papa en Colombia. Ad...

  4. Efeito do silício nas concentrações de lignina e de açúcares em bainhas de folhas de arroz infectadas por Rhizoctonia solani

    OpenAIRE

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

    2013-01-01

    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 fol...

  5. 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 μCT) 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

  6. 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

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    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%.

  7. 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

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    César Júnior Bueno

    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 plantas 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.

  8. 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. Burgieł

    2012-12-01

    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.

  9. Influence of Rhizoctonia solani and Trichoderma spp. in growth of bean (Phaseolus vulgaris L.) and in the induction of plant defense-related genes

    OpenAIRE

    Mayo, Sara; Gutiérrez, Santiago; Malmierca, Monica G.; Lorenzana, Alicia; Campelo, M. Piedad; Hermosa, Rosa; Pedro A. Casquero

    2015-01-01

    Many Trichoderma species are well-known for their ability to promote plant growth and defense. We study how the interaction of bean plants with R. solani and/or Trichoderma affect the plants growth and the level of expression of defense-related genes. Trichoderma isolates were evaluated in vitro for their potential to antagonize R. solani. Bioassays were performed in climatic chambers and development of the plants was evaluated. The effect of Trichoderma treatment and/or R. solani infection o...

  10. Relación entre la estructura de la comunidad bacteriana y la supresión al ahogamiento causado por Rhizoctonia solani en sustratos para plántulas de tomate

    Directory of Open Access Journals (Sweden)

    O. Robledo

    2010-01-01

    Full Text Available En este trabajo el objetivo fue estudiar la relación entre la supresión del ahogamiento causado por Rhizoctonia solani y la estructura de la comunidad bacteriana en sustratos orgánicos (con base en vermicomposta y composta, para el crecimiento de plántulas de tomate. Dicha estructura comunitaria se determinó mediante T-RFLP (Terminal Restriction Fragment Length Polymorphisms del gen ARNr 16S, con la enzima Hin6I. Análisis de componentes principales (PCA a partir de las abundancias relativas de los T-RFs (Fragmentos de Restricción Terminales predominantes, mostraron que los sustratos con tendencia supresiva al patógeno poseen comunidades bacterianas similares, indicando la existencia de una relación entre la estructura de la comunidad y la supresividad. Los T-RFs predominantes se relacionaron con secuencias obtenidas de una librería genómica del gen ribosomal ARNr 16S de un sustrato con tendencia supresiva. Dicho análisis de PCA reveló que entre los TRFs que contribuyen a la diferenciación de los sustratos con tendencias supresivas, se encuentran tres (64, 205 y 211 que corresponden a secuencias 16S de los siguientes géneros: Burkholderia, Duganella, Telluria, Janthinobacterium, Pseudmomonas, Stenotrophomonas y Xanthomonas. Tales géneros presentan especies con capacidad biocontroladora específica sobre el patógeno, por lo que estos resultados sugieren que los T-RFs (Hin6I 64, 205, 211 y otros, podrían ser utilizados como indicadores a priori de la capacidad supresiva de un sustrato al ahogamiento causado por Rhizoctonia solani.

  11. Eficiência de diferentes moléculas na redução dos sintomas da queima das bainhas em arroz e no crescimento de Rhizoctonia solani 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.

  12. Características de aislamientos de rhizoctonia solani huhn y su importancia como patógenos de stylosanthes guianensis (aubl.) sw.

    OpenAIRE

    Lenne Jilliam M.; Olaya H. Gilberto

    2010-01-01

    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 proba...

  13. Influencia del momento y dosis de aplicación del nitrógeno sobre el rendimiento y la incidencia de Rhizoctonia Solani en el cultivo del arroz.

    Directory of Open Access Journals (Sweden)

    Ridelmis Rodríguez Hernández

    2007-12-01

    Full Text Available El trabajo fue realizado en el 2007, en el Centro Internacional de Tsukuba, perteneciente a la prefectura de Ibaraki, Japón con el objetivo de determinar la influencia que tienen el momento de aplicación fraccionada y la dosis de nitrógeno (N sobre el Rendimiento, además de la incidencia y severidad de la enfermedad Rhizoctonia solani en la variedad de arroz japónica Akitakomachi. La aplicación de fósforo y potasio se realizaron de base antes del trasplante y las de nitrógeno fueron en tres momentos: a la hora del trasplante, en el máximo macollamiento y en la iniciación de la panícula, según el tratamiento a estudiar. Se realizaron evaluaciones de desarrollo y crecimiento de la planta de arroz, así como el rendimiento y sus componentes. En los parámetros de crecimiento evaluados, los mayores valores fueron del tratamiento 4 (75-0-45 kg de N/ha, seguido por los tratamientos 2 (50-30-0, 3 (50-0-30 y 1 (0-0-0. El tratamiento con mayor incidencia y severidad de R. solani fue el 4 (75-0-45 con 5.80 y 0.18 %, respectivamente, siendo similares el 1(0-0-0 y 2(50-30-0, con menor porcentaje en ambos parámetros fue el tratamiento 3(50-0-30 con 3.7 y 0.13, respectivamente. En cuanto al rendimiento agricola, el mayor valor lo obtuvo el tratamiento 4 (75-0-45, seguido por el 2 (50-30-0, 3 (50-0-30 y 1 (0-0-0 con 7.88, 7.39, 6.73 y 2.63 t/ha, respectivamente.

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

    OpenAIRE

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

    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...

  15. 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.

  16. 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.

  17. Importancia del método estadístico para el cálculo de la CE50 y CE95 de algunos isotiocianatos evaluados contra Rhizoctonia solani Kühn

    Directory of Open Access Journals (Sweden)

    Molina Vargas Luis Federico

    2010-08-01

    Full Text Available En el marco de la evaluación del efecto de algunos isotiocianatos
    (IT C 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 concentración
    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 (AIT C, bencil
    isotiocianato (BIT C, fenil isotiocianato (PIT C, fenetil isotiocianato
    (PEIT C y metil isotiocianato (MIT C. 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 IT C 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 IT C,
    excepto PEIT C, mostraron un efecto inhibitorio total. Por su
    parte, BIT C mantuvo su efecto fungistático hasta 21 días después
    de aplicados los tratamientos, mientras que PIT C, AIT C
    y MIT C mantuvieron un efecto fungistático más prolongado,
    inclusive hasta un año después de iniciados los tratamientos.

  18. 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.

  19. Rhizoctonia root rot resistance in experimental sugar beet cultivars in Twin Falls County, ID, 2012

    Science.gov (United States)

    Rhizoctonia root rot continues to be a concerning problem in sugar beet production areas. To investigate resistance to this disease in 26 experimental sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface ...

  20. Temperature, Moisture, and Fungicide Effects in Managing Rhizoctonia Root and Crown Rot of Sugar Beet

    Science.gov (United States)

    Rhizoctonia solani AG-2-2 is the causal agent of Rhizoctonia root and crown rot in sugar beet. To assess the capacity at which other anastomosis groups (AGs) are able to infect sugar beet, 15 AGs and subgroups were tested for pathogenicity on resistant (FC708 CMS) and susceptible (Monohikari) seedl...

  1. Influence of tillage systems on Rhizoctonia-bacterial root rot complex in sugar beet

    Science.gov (United States)

    The Rhizoctonia-bacterial root rot complex on sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventio...

  2. 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.

    Directory of Open Access Journals (Sweden)

    SS GUIMARÃES

    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 os 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.

  3. The role of bacterial communities in the natural suppression of Rhizoctonia bare patch of wheat Triticum aestivum L

    Science.gov (United States)

    Rhizoctonia bare patch and root rot of wheat, caused by Rhizoctonia solani AG-8, develops as distinct patches of stunted plants, and limits the yield of direct-seeded wheat in the Pacific Northwest (PNW) of the United States. At a long-term wheat cropping systems study site near Ritzville, WA, conve...

  4. Real-time PCR assay for detection of Rhizoctonia sp. in insect galled roots of Lepidium draba sp draba

    Science.gov (United States)

    The association of necrotrophic soil-borne pathogens, Rhizoctonia spp., with a root-attacking weevil, Ceutorhynchus assimilis, and diseased tissues of Lepidium draba, an invasive perennial weed in the U.S., has been documented in its Eurasian native range. Among all isolates of Rhizoctonia solani an...

  5. Rhizoctonia web blight

    Science.gov (United States)

    Rhizoctonia web blight, caused by several Rhizoctonia spp., is an important disease of evergreen azaleas and other ornamental plants in nurseries. The primary pathogens causing web blight are binucleate Rhizoctonia anastomosis groups (AG) (= Ceratobasidium D.P. Rogers, teleomorph). In southern AL an...

  6. 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 12 year...

  7. Nonpathogenic Binucleate Rhizoctonia spp. and Benzothiadiazole Protect Cotton Seedlings Against Rhizoctonia Damping-Off and Alternaria Leaf Spot in Cotton.

    Science.gov (United States)

    Jabaji-Hare, Suha; Neate, Stephen M

    2005-09-01

    ABSTRACT Recent reports have shown induction of resistance to Rhizoctonia root rot using nonpathogenic strains of binucleate Rhizoctonia spp. (np-BNR). This study evaluates the biocontrol ability of several np-BNR isolates against root and foliar diseases of cotton in greenhouse trials, provides evidence for induced systemic resistance (ISR) as a mechanism in this biocontrol, and compares the disease control provided by np-BNR with that provided by the chemical inducer benzothiadiazole (BTH). Pretreatment of cotton seedlings with np-BNR isolates provided good protection against pre- and post-emergence damping-off caused by a virulent strain of Rhizoctonia solani (AG-4). Seedling stand of protected cotton was significantly higher (P < 0.05) than that of nonprotected seedlings. Several np-BNR isolates significantly reduced disease severity. The combination of BTH and np-BNR provided significant protection against seedling rot and leaf spot in cotton; however, the degree of disease reduction was comparable to that obtained with np-BNR treatment alone. Significant reduction in leaf spot symptoms caused by Alternaria macrospora occurred on cotyledons pretreated with np-BNR or sprayed with BTH, and the np- BNR-treated seedlings had significantly less leaf spot than BTH-treated seedlings. The results demonstrate that np-BNR isolates can protect cotton from infections caused by both root and leaf pathogens and that disease control was superior to that observed with a chemical inducer. PMID:18943300

  8. Biological control of Rhizoctonia root rot on bean by phenazine- and cyclic lipopeptide-producing Pseudomonas CMR12a.

    Science.gov (United States)

    D'aes, Jolien; Hua, Gia Khuong Hoang; De Maeyer, Katrien; Pannecoucque, Joke; Forrez, Ilse; Ongena, Marc; Dietrich, Lars E P; Thomashow, Linda S; Mavrodi, Dmitri V; Hfte, Monica

    2011-08-01

    Pseudomonas CMR12a was previously selected as an efficient biocontrol strain producing phenazines and cyclic lipopeptides (CLPs). In this study, biocontrol capacity of Pseudomonas CMR12a against Rhizoctonia root rot of bean and the involvement of phenazines and CLPs in this ability were tested. Two different anastomosis groups (AGs) of Rhizoctonia solani, the intermediately aggressive AG 2-2 and the highly aggressive AG 4 HGI, were included in growth-chamber experiments with bean plants. The wild-type strain CMR12a dramatically reduced disease severity caused by both R. solani AGs. A CLP-deficient and a phenazine-deficient mutant of CMR12a still protected bean plants, albeit to a lesser extent compared with the wild type. Two mutants deficient in both phenazine and CLP production completely lost their biocontrol activity. Disease-suppressive capacity of CMR12a decreased after washing bacteria before application to soil and thereby removing metabolites produced during growth on plate. In addition, microscopic observations revealed pronounced branching of hyphal tips of both R. solani AGs in the presence of CMR12a. More branched and denser mycelium was also observed for the phenazine-deficient mutant; however, neither the CLP-deficient mutant nor the mutants deficient in both CLPs and phenazines influenced hyphal growth. Together, results demonstrate the involvement of phenazines and CLPs during Pseudomonas CMR12a-mediated biocontrol of Rhizoctonia root rot of bean. PMID:21405991

  9. Chitinase production by Bacillus subtilis ATCC 11774 and its effect on biocontrol of Rhizoctonia diseases of potato.

    Science.gov (United States)

    Saber, Wesam I A; Ghoneem, Khalid M; Al-Askar, Abdulaziz A; Rashad, Younes M; Ali, Abeer A; Rashad, Ehsan M

    2015-12-01

    Stem canker and black scurf of potato, caused by Rhizoctonia solani, can be serious diseases causing an economically significant damage. Biocontrol activity of Bacillus subtilis ATCC 11774 against the Rhizoctonia diseases of potato was investigated in this study. Chitinase enzyme was optimally produced by B. subtilis under batch fermentation conditions similar to those of the potato-growing soil. The maximum chitinase was obtained at initial pH 8 and 30 °C. In vitro, the lytic action of the B. subtilis chitinase was detected releasing 355 μg GlcNAc ml⁻¹ from the cell wall extract of R. solani and suggesting the presence of various chitinase enzymes in the bacterial filtrate. In dual culture test, the antagonistic behavior of B. subtilis resulted in the inhibition of the radial growth of R. solani by 48.1% after 4 days. Moreover, the extracted B. subtilis chitinase reduced the growth of R. solani by 42.3% when incorporated with the PDA plates. Under greenhouse conditions, application of a bacterial suspension of B. subtilis at 109 cell mL⁻¹ significantly reduced the disease incidence of stem canker and black scurf to 22.3 and 30%, respectively. In addition, it significantly improved some biochemical parameters, growth and tubers yield. Our findings indicate two points; firstly, B. subtilis possesses a good biocontrol activity against Rhizoctonia diseases of potato, secondly, the harmonization and suitability of the soil conditions to the growth and activity of B. subtilis guaranteed a high controlling capacity against the target pathogen. PMID:26616375

  10. 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.

  11. Influence of He-Ne laser irradiation of soybean seeds on seed mycoflora, growth, nodulation, and resistance to Fusarium solani

    International Nuclear Information System (INIS)

    Laser irradiation of soybean seeds for 3 min caused a clear reduction in the number of seed-borne fungi which became more pronounced as the irradiation time was extended. Pretreatment of the seeds with methylene blue, methyl red and carmine enhanced the effect of laser. Rhizoctonia solani, Alternaria tenuissima, Cercospora kikuchii and Colletotrichum truncatum were completely eliminated when the seeds were pretreated with a dye and irradiated for 10 min. Seed germination was stimulated on exposure of the seed to 1-min irradiation. Chlorophyll a, chlorophyll b and carotenoid content of developed plants differed, depending on the irradiation dose and dye treatment of the seeds. The number and dry mass of nodules were mostly greater (as compared to the corresponding control), when the seeds irradiated for 1 or 3 min were pretreated with methyl red, chlorophenol red, crystal violet and methylene blue. Irradiation of pre-sowing seeds greatly protected soybean stands against F. solani

  12. REVIEW ON BANDED LEAF AND SHEATH BLIGHT OF RICE CAUSED BY Rhizoctonia solani KUHN

    Directory of Open Access Journals (Sweden)

    P. Srinivas

    2013-12-01

    Full Text Available Rice (Oryza sativa L. is a graminaceous crop. It is one of the important staple foods for Asian countries. Sheath blight disease is an important fungal disease of rice. Currently, this disease is distributed in almost all the rice growing states. The disease is alarming due to its intensive cultivation of modern high yielding varieties with high doses of nitrogenous fertilizers. Crop with a high plant density and close canopy associated favors disease build up from panicle initiation onwards. Poor weed management practices and increase in frequency of irrigation have aggravated, incidence of the disease due to modified micro climatic conditions. The disease was first recorded from Japan (Miyake, 1910. In India, the disease was first reported from Gurudaspur, Punjab (Paracer and Chahal, 1963 and later it was reported from Uttar Pradesh (Kohli, 1966. The management of this disease is possible only after the detailed study of different aspect of this disease and the pathogen. Management of the disease below its economic threshold is important for increasing the production, productivity and quality of the produce. Recognizing the importance of the problem, need for the effective and socio economically feasible management of the pathogen, the present review presented by keeping the above stated factors of the disease into consideration.

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

    OpenAIRE

    Gamal Mohamedin Hassan; Zaki Ahmed El-Feky,Nada Fathi Hemada,Makram Ahmeed Sayed

    2015-01-01

    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 ITS...

  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. 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.

  16. 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 μm. 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 μm in diameter. The number and sclerotia type were variable with the isolate and themedia used.

  17. 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 %.

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

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    Marta Bełka

    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 Łopuchówko (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.

  19. Coupling auto trophic in vitro plant cultivation system to scanning electron microscope to study plant-fungal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, N. de; Decock, C.; Declereck, S.; Providencia, I. E. de la

    2010-07-01

    The interactions of plants with pathogens and beneficial micro-organisms have been seldom compared on the same host and under strict controlled auto trophic in vitro culture conditions. Here, the life cycle of two plant beneficial (Glomus sp. MUCL 41833 and Trichoderma harzianum) and one plant pathogen (Rhizoctonia solani) fungi were described on potato (Solanum tuberosum) plantlets under auto trophic in vitro culture conditions using video camera imaging and the scanning electron microscope (SEM). (i) The colony developmental pattern of the extraradical mycelium within the substrate, (ii) the reproduction structures and (iii) the three-dimensional spatial arrangements of the fungal hyphae within the potato root cells were successfully visualized, monitored and described. The combination of the autotrophic in vitro culture system and SEM represent a powerful tool for improving our knowledge on the dynamics of plant-fungal interactions. (Author) 41 refs.

  20. 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%.

  1. Phytotoxic and competitive effects of tall fescue on Ladino clover as modified by ozone and/or Rhizoctonia solani

    Energy Technology Data Exchange (ETDEWEB)

    Kochhar, M.

    1974-01-01

    An effort was made to look at the effects of fescue and/or ozone on clover decline in the grass-clover mixture. The objectives of this study were to determine (1) if chemical interactions play a role in clover decline from a clover-fescue mixture, (2) if ozone affects the growth of clover, and (3) if ozone modifies plant-plant interactions between clover and fescue.

  2. 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 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)

  3. ROLE OF SCLEROTIA, PLANT DEBRIS AND DIFFERENT HOSTS ON SURVIVAL OF RICE SHEATH BLIGHT PATHOGEN, RHIZOCTONIA SOLANI

    Directory of Open Access Journals (Sweden)

    P. Srinivas

    2014-04-01

    Full Text Available The survival of sclerotia stored under different conditions revealed that when they were kept in laboratory survived fully up to 7 months. However in soil at 5 cm and 10 cm depth, it survived 100 percent up to 8 and 10 months. The pathogen was viable in the sclerotial form for 17 months in the lab conditions however; it survived for 19 months and 20 months when kept at 5 cm and 10 cm depth in soil respectively. The survival of pathogen along with plant debris stored under different conditions revealed that it survived fully up to 3 months under lab conditions. However in soil at 5 cm and 10 cm depth, it survived 100 percent up to 5 and 6 months respectively. The pathogen survived in diseased plant debris for 9 months in lab conditions. However, the pathogen survives in plant debris up to 11 months and 13 months when kept at 5 cm and 10 cm depth of soil respectively. The viability of pathogen in plant debris was lost gradually. This states sclerotia and plant debris served as source of primary inoculum. Out of fourteen plant species belonging to three families tested, the pathogen produced disease symptoms on all the tested plants and stating pathogen has wide host range.

  4. WHEAT GENOTYPE-SPECIFIC INDUCTION OF SOIL MICROBIAL COMMUNITIES SUPPRESSIVE TO RHIZOCTONIA SOLANI AG 5 AND AG 8

    Science.gov (United States)

    Suppressive soils are characterized by the absence of disease development even though a virulent pathogen and susceptible host are present. Biotic and abiotic elements of the soil environment contribute to suppressiveness, however most defined systems have identified biological elements as primary ...

  5. Chemical disinfectants can reduce potato blackleg caused by Dickeya solani

    OpenAIRE

    Czajkowski, R.L.; Boer, W.J., de; Wolf, J. M.

    2013-01-01

    Treatments of tubers with chemical disinfectants (70 % ethanol, 1 % sodium hypochlorite, 2 % copper sulphate, 5 % peracetic acid, 10 % hydrogen peroxide, 1 % MennoClean (benzoic acid), 5 % trisodium phosphate and 0.2 % caffeine) were evaluated for control of blackleg caused by D. solani. All disinfectants effectively killed bacteria in axenic cultures within 5 min and all, except hydrogen peroxide and trisodium phosphate, were able to kill D. solani in spiked potato extracts. Treatments w...

  6. Severidade da podridão-radicular de Rhizoctonia do feijoeiro influenciada pela calagem, e pelas fontes e doses de nitrogênio Severity of Rhizoctonia root rot in beans influenced by liming, nitrogen sources and rates

    Directory of Open Access Journals (Sweden)

    Fabrício de Ávila Rodrigues

    2002-09-01

    Full Text Available Avaliou-se o efeito da calagem e de doses e fontes de N na severidade da podridão-radicular de Rhizoctonia (PRR em feijoeiro em condições controladas. No primeiro ensaio, utilizaram-se as doses de 0, 1,75, 2,25, 2,75, 3,25 e 3,75 g de calcário dolomítico por quilograma de solo. No segundo ensaio, os tratamentos constituíram um fatorial 2x6, ou seja: duas fontes de N (sulfato de amônio e nitrato de sódio e seis doses de N (0, 11, 16, 21, 26 e 31 mg kg-1 de solo. A acidez do material de solo usado no segundo ensaio foi corrigida com 1,75 g de calcário por quilograma de solo. Foram colocados 16 g de grãos de arroz infestados por R. solani em cada vaso com 1 kg de material de solo. Utilizou-se, em ambos os ensaios, o delineamento inteiramente casualizado, com cinco repetições. A severidade da PRR foi avaliada 25 dias após a emergência das plantas, atribuindo-se nota para cada planta de acordo com o tamanho das lesões formadas no hipocótilo. Os dados obtidos foram usados para calcular o índice de doença (ID, %. Foram obtidas equações lineares significativas que permitiram descrever as relações entre a calagem e fontes de N com a severidade da PRR. Houve um acréscimo de 32% no ID, em virtude das doses crescentes de calcário. Após a calagem, a aplicação de sulfato de amônio reduziu em 22% o ID, enquanto o nitrato de sódio o aumentou em 18%, com relação ao controle.The objective of this study was to determine the effects of liming, nitrogen sources and rates on the severity of Rhizoctonia root rot (RRR in beans under controlled conditions. In the first experiment, the soil was amended with 0, 1.75, 2.25, 2.75, 3.25 and 3.75 g of dolomitic lime per kilogram of soil. In the second experiment, the soil was fertilized with 0, 11, 16, 21, 26 and 31 mg N kg-1 of soil, using ammonium sulfate and sodium nitrate as N sources. For the second experiment, soil acidity was adjusted by applying 1.75 g of dolomitic lime per kilogram of soil. Both experiments were arranged in a completely randomized design, with five replications. Soil was infested before sowing with 16 g of rice grains infested by Rhizoctonia solani per kilogram of soil. Twenty-five days after seed germination, the severity of RRR was evaluated based on lesion development on the hypocotyls, by using a scale ranging from 0 to 5. Data obtained were used to calculate the disease index (DI, %. Linear equations significantly described liming and N source-severity of RRR relationships. Liming increased DI by 32% over the control. After liming, application of ammonium sulfate reduced DI by 22%, while sodium nitrate increased DI by 18%, over the control.

  7. Genetic diversity among isolates of stemphylium solani from cotton

    Directory of Open Access Journals (Sweden)

    MEHTA Y.R.

    2001-01-01

    Full Text Available The fungus Stemphylium solani causes leaf blight of tomato (Lycopersicon esculentum in Brazil. In recent years, severe epidemics of a new leaf blight of cotton (Gossipium hyrsutum caused by S. solani occurred in three major cotton-growing Brazilian states (PR, MT and GO. Molecular analysis was performed to assess the genetic diversity among the S. solani isolates from cotton, and to verify their relationship with representative S. solani isolates from tomato. Random amplified polymorphic DNA (RAPD markers and internal transcribed spacers of ribosomal DNA (rDNA were used to compare 33 monosporic isolates of S. solani (28 from cotton and five from tomato. An isolate of Alternaria macrospora from cotton was also used for comparison. RAPD analysis showed the presence of polymorphism between the genera and the species. The A. macrospora and the S. solani isolates from cotton and tomato were distinct from each other, and fell into separate groups. Variation by geographic region was observed for the tomato isolates but not for the cotton isolates. Amplifications of the ITS region using the primer pair ITS4/ITS5 resulted in a single PCR product of approximately 600 bp for all the isolates. Similarly, when amplified fragments were digested with eight restriction enzymes, identical banding patterns were observed for all the isolates. Hence, rDNA analysis revealed no inter-generic or intra-specific variation. The genetic difference observed between the cotton and the tomato isolates provides evidence that S. solani attacking cotton in Brazil belongs to a distinct genotype.

  8. 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.

  9. 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.

  10. Controle de alternaria solani com fungicidas na cultura do tomateiro.

    OpenAIRE

    Silva Coelho, Fabrício; Rezende Alvarenga, Marco Antônio; Bezerra Leão, Armindo; Rodrigues, Leandro

    2012-01-01

    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...

  11. Production of paclitaxel by Fusarium solani isolated from Taxus celebica

    Indian Academy of Sciences (India)

    B V S K Chakravarthi; Prasanta Das; Kalpana Surendranath; Anjali A Karande; Chelliah Jayabaskaran

    2008-06-01

    A fungus was isolated from the stem cuttings of Taxus celebica, which produced paclitaxel in liquid-grown cultures. The fungus was identified as Fusarium solani based on colony characteristics, morphology of conidia and the 26S rDNA sequence. Paclitaxel was identified by chromatographic and spectroscopic comparison with authentic paclitaxel and its cytotoxic activity towards Jurkat cells in vitro.

  12. BANDED LEAF AND SHEATH BLIGHT OF MAIZE INCITED BY Rhizoctonia solanif.spsasakii AND ITS MANAGEMENT. A REVIEW

    Directory of Open Access Journals (Sweden)

    V. Divya Rani

    2015-12-01

    Full Text Available Globally maize (Zea mays L. is the first and most important cereal crop grown under diverse environments unmatched by any other crop, as expansion of maize to new areas and environment still continues due to its range of plasticity.Maize has a wide adaptability to diverse agro-climatic conditions around the world. Maize was introduced to India in the beginning of 17th century. It is now one of the important crops in India occupying fifth place in area and third place in production. In India, maize is cultivated in an area of about 8.26 m.ha with the production of 19.73 million tonnes and productivity of 2295 kg ha-1 (Centre for monitoring Indian economy report, 2009. Maize crop is attacked by number of fungal, bacterial and viral diseases out of which banded leaf and sheath blight (BLSB caused by Rhizoctonia solani f. spsasakii(Thanatephoruscucumeris is considered as one of the most important disease and major constraint for low yields. In India the disease was first recorded in the Tarai (foot hill plain areas region of Uttar Pradesh (Payak and Renfro, 1966. In early sixties, the disease was considered only as a disease of minor importance till it appeared in the epidemic form in the foot hill regions of Himalayas especially in the district of Mandi in Himachal Pradesh. Now banded leaf and sheath blight is considered as one of the major diseases of Maize (Payak and Sharma, 1985. In India it is known to be present in the states of Himachal Pradesh, Uttar Pradesh, Bihar, Haryana, Punjab, Madhya Pradesh, Rajasthan, West Bengal, Meghalaya, Assam, Nagaland, Andhra Pradesh and Orissa. Yield losses vary from 11 to 40 per cent (Singh and Sharma, 1976.

  13. Ag doped hollow TiO2 nanoparticles as an effective green fungicide against Fusarium solani and Venturia inaequalis phytopathogens.

    Science.gov (United States)

    Boxi, Siddhartha Sankar; Mukherjee, Khushi; Paria, Santanu

    2016-02-26

    Chemical-based pesticides are widely used in agriculture to protect crops from insect infestation and diseases. However, the excessive use of highly toxic pesticides causes several human health (neurological, tumor, cancer) and environmental problems. Therefore nanoparticle-based green pesticides have become of special importance in recent years. The antifungal activities of pure and Ag doped (solid and hollow) TiO2 nanoparticles are studied against two potent phytopathogens, Fusarium solani (which causes Fusarium wilt disease in potato, tomato, etc) and Venturia inaequalis (which causes apple scab disease) and it is found that hollow nanoparticles are more effective than the other two. The antifungal activities of the nanoparticles were further enhanced against these two phytopathogens under visible light exposure. The fungicidal effect of the nanoparticles depends on different parameters, such as particle concentration and the intensity of visible light. The minimum inhibitory dose of the nanoparticles for V. inaequalis and F. solani are 0.75 and 0.43 mg/plate. The presence of Ag as a dopant helps in the formation of stable Ag-S and disulfide bonds (R-S-S-R) in cellular protein, which leads to cell damage. During photocatalysis generated ()OH radicals loosen the cell wall structure and this finally leads to cell death. The mechanisms of the fungicidal effect of nanoparticles against these two phytopathogens are supported by biuret and triphenyl tetrazolium chloride analyses and field emission electron microscopy. Apart from the fungicidal effect, at a very low dose (0.015 mg/plate) the nanoparticles are successful in arresting production of toxic napthoquinone pigment for F. solani which is related to the fungal pathogenecity. The nanoparticles are found to be effective in protecting potatoes affected by F. solani or other fungi from spoiling. PMID:26808118

  14. Ag doped hollow TiO2 nanoparticles as an effective green fungicide against Fusarium solani and Venturia inaequalis phytopathogens

    Science.gov (United States)

    Sankar Boxi, Siddhartha; Mukherjee, Khushi; Paria, Santanu

    2016-02-01

    Chemical-based pesticides are widely used in agriculture to protect crops from insect infestation and diseases. However, the excessive use of highly toxic pesticides causes several human health (neurological, tumor, cancer) and environmental problems. Therefore nanoparticle-based green pesticides have become of special importance in recent years. The antifungal activities of pure and Ag doped (solid and hollow) TiO2 nanoparticles are studied against two potent phytopathogens, Fusarium solani (which causes Fusarium wilt disease in potato, tomato, etc) and Venturia inaequalis (which causes apple scab disease) and it is found that hollow nanoparticles are more effective than the other two. The antifungal activities of the nanoparticles were further enhanced against these two phytopathogens under visible light exposure. The fungicidal effect of the nanoparticles depends on different parameters, such as particle concentration and the intensity of visible light. The minimum inhibitory dose of the nanoparticles for V. inaequalis and F. solani are 0.75 and 0.43 mg/plate. The presence of Ag as a dopant helps in the formation of stable Ag-S and disulfide bonds (R-S-S-R) in cellular protein, which leads to cell damage. During photocatalysis generated •OH radicals loosen the cell wall structure and this finally leads to cell death. The mechanisms of the fungicidal effect of nanoparticles against these two phytopathogens are supported by biuret and triphenyl tetrazolium chloride analyses and field emission electron microscopy. Apart from the fungicidal effect, at a very low dose (0.015 mg/plate) the nanoparticles are successful in arresting production of toxic napthoquinone pigment for F. solani which is related to the fungal pathogenecity. The nanoparticles are found to be effective in protecting potatoes affected by F. solani or other fungi from spoiling.

  15. 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)

  16. Phylogenetic relationships of Rhizoctonia fungi within the Cantharellales.

    Science.gov (United States)

    Gónzalez, Dolores; Rodriguez-Carres, Marianela; Boekhout, Teun; Stalpers, Joost; Kuramae, Eiko E; Nakatani, Andreia K; Vilgalys, Rytas; Cubeta, Marc A

    2016-04-01

    Phylogenetic relationships of Rhizoctonia fungi within the order Cantharellales were studied using sequence data from portions of the ribosomal DNA cluster regions ITS-LSU, rpb2, tef1, and atp6 for 50 taxa, and public sequence data from the rpb2 locus for 165 taxa. Data sets were analysed individually and combined using Maximum Parsimony, Maximum Likelihood, and Bayesian Phylogenetic Inference methods. All analyses supported the monophyly of the family Ceratobasidiaceae, which comprises the genera Ceratobasidium and Thanatephorus. Multi-locus analysis revealed 10 well-supported monophyletic groups that were consistent with previous separation into anastomosis groups based on hyphal fusion criteria. This analysis coupled with analyses of a larger sample of 165 rpb2 sequences of fungi in the Cantharellales supported a sister relationship between the Botryobasidiaceae and Ceratobasidiaceae and a sister relationship of the Tulasnellaceae with the rest of the Cantharellales. The inclusion of additional sequence data did not clarify incongruences observed in previous studies of Rhizoctonia fungi in the Cantharellales based on analyses of a single or multiple genes. The diversity of ecological and morphological characters associated with these fungi requires further investigation on character evolution for re-evaluating homologous and homoplasious characters. PMID:27020160

  17. Resistance induction in the pathosystem tomato - Alternaria solani

    OpenAIRE

    Fritz, Maendy

    2005-01-01

    The objective of this work was to study the pathosystem tomato – Alternaria solani with regard to several new plant protection strategies. Agents and symbionts were tested alone and in combinations to find environmentally friendly but effective methods of early blight control. The included agents and symbionts were: (i) systemic acquired resistance, induced by ASM; (ii) plant restorative Spirulina platensis; (iii) growth-promoting fungus Piriformospora indica; (iv) symbiotic arbuscular mycorr...

  18. THE EFFECT OF MEDIA AND LIGHT ON IN VITRO SPORULATION OF ALTERNARIA SOLANI

    OpenAIRE

    P. Kishore Varma; C. Yamuna; U. N. Mangala

    2015-01-01

    Early blight of tomato incited by Alternaria solani is an economically significant disease especially in commercial tomato cultivation under greenhouse and field conditions. Since, A. solani is a shy sporulator, the present investigation was taken to assess the optimum in vitro conditons for growth and sporulation of early blight pathogen. Ten A. solani isolates obtained from diseased leaf samples collected different crop growing areas of India were used in the present study. The effect of di...

  19. Biochemical Evaluation of Resistance Responses of Potato to Different Isolates of Alternaria Solani

    Science.gov (United States)

    The resistance phenotypes of nine potato cultivars to five isolates of Alternaria solani, causal agent of early blight, were studied after inoculation and growth under greenhouse conditions. We identified potato cultivars with both susceptible and resistant phenotypes as well as A. solani isolates ...

  20. 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...

  1. Fusarium solani causing quasi-invasive infection of the foot in an immunocompetent middle-aged man from South India

    Directory of Open Access Journals (Sweden)

    Mohan H Kudur

    2013-01-01

    Full Text Available Fusarium solani is commonly found in soil, and it is associated with infections in immunocompromised individuals. Fusaroium solani causing infection in immunocompetent adult male is rare and usually overlooked. We report a case of mycetoma caused by Fusariom solani in an immunocompetent adult male from South India.

  2. 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.

  3. 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.

  4. Overexpression of GhWRKY27a reduces tolerance to drought stress and resistance to Rhizoctonia solani infection in transgenic Nicotiana benthamiana

    OpenAIRE

    Yan, Yan; Jia, Haihong; Wang, Fang; Wang, Chen; Liu, Shuchang; Guo, Xingqi

    2015-01-01

    WRKY proteins constitute transcriptional regulators involved in various biological processes, especially in coping with diverse biotic and abiotic stresses. However, in contrast to other well-characterized WRKY groups, the functions of group III WRKY transcription factors are poorly understood in the economically important crop cotton (Gossypium hirsutum). In this study, a group III WRKY gene from cotton, GhWRKY27a, was isolated and characterized. Our data indicated that GhWRKY27a localized t...

  5. Impact of Rhizophagus sp. (syn. Glomus sp.) and Trichoderma harzianum on the potato resistance against Rhizoctonia solani and Phytophthora infestans, two major potato pathogens

    OpenAIRE

    Gallou, Adrien

    2011-01-01

    Potato is the fourth largest food crop cultivated in the world. This crop is susceptible to numerous pests and diseases, which control requires large quantities of pesticides in conventional agriculture. In the last decade, several studies have suggested the use of beneficial microorganisms as promising alternatives to reduce/replace chemicals. Among these microorganisms, the arbuscular mycorrhizal (AM) fungi and the fungal antagonist, Trichoderma spp. are the most frequently cited in the lit...

  6. Estudio del antagonismo de algunas especies de trichoderma aisladas de suelos colombianos en el control de fusarium oxysporum y rhizoctonia solani

    OpenAIRE

    Elías Ricardo; Arcos Omar; Arbeláez Germán

    2011-01-01

    El estudio de las relaciones existentes entre los organismos del suelo ha permitido modificar ciertos factores para controlar la actividad de algunos patógenos que ocasionan enfermedades de importancia económica en diversos cultivos. El control biológico de algunos patógenos es un fenómeno natural, común en los suelos; prácticamente, todos éstos contienen organismos con potencial para suprimir el desarrollo de las enfermedades de las plantas (Linderman et al, 1983). Los diversos organismos re...

  7. Diversidad de pseudomonas fluorescentes en cultivos de papa de la region cundiboyacense y su actividad antagonista in vitro sobre rhizoctonia solani

    OpenAIRE

    D. Uribe; Ortiz, E.; Portillo, M.; Bautista, G.; Cerón, J

    2011-01-01

    Las pseudomonas fluorescentes son unas de las bacterias benéficas más importantes a nivel de la rizosfera gracias a que pueden controlar algunos fitopatógenos habituales del suelo como resultado de su capacidad antagonista. Hay muy pocos trabajos realizados para conocer la composición y diversidad de pseudomonas fluorescentes en países tropicales. En este trabajo se determinó la composición de pseudomonas fluorescentes provenientes de dife-rentes cultivos de papa ubicados en la región Cundibo...

  8. Allelopathic Effect of Some Cruciferous Seeds on Rhizoctonia solani kuhn and Gossypium barbadense L.

    OpenAIRE

    I.M. El-Refai; S.M.I. Moustafa

    2004-01-01

    Phenolic substances, lipoidal matters and fatty acid contents of some cruciferous powdered seeds, Raphanus sativus L., Brassica oleracea L. var capitata, Sinapis alba L., Brassica nigra Koch, Eruca sativa Mill, Brassica napus L. and Lipidium sativum L., were determined. The results indicated that R. sativus L., B. napus L. and B. oleracea L. var capitata contained higher percentage of phenolic compounds, lipoidal matters and unsaturated fatty acids, respectively, compared to other tested pla...

  9. Ribosome Inactivating Protein of barley enhanced resistance to Rhizoctonia solani in transgenic potato cultivar 'Desirée' in greenhouse conditions

    OpenAIRE

    M'hamdi, M.; Chikh-Rouhou, H.; N. Boughalleb; Ruiz de Galarreta, JI.

    2013-01-01

    In the present study, the potato cultivar 'Desirée' was transformed via Agrobacterium tumefaciens strain LBA4404 containing the plasmid pBIN19 which harbors the Ribosome Inactivating Protein (rip30). The potato leaf discs were used as an explant for transformation. The in vitro regeneration parameters (percentage of callus regenerated, number of shoots per callus, percentage of regenerated roots and percentage of the transgenic plants) were evaluated. The PCR technique was used for identifica...

  10. 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 Fusarium species tested

  11. 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...

  12. Seasonal prevalence of species of binculeate Rhizoctonia fungi in growing medium, leaf litter, and stems of container-grown azalea

    Science.gov (United States)

    Rhizoctonia web blight is an annual problem on container-grown azalea in the southern and eastern U.S., but little is documented about the distribution or persistence of Rhizoctonia in container-grown azalea. Sixty azalea plants (cv. >Gumpo White=) with greater than 35% web blight severity were coll...

  13. 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 μm and the conidia are 35-75 μm in length and 10-20 μm 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.

  14. Bilateral endogenous Fusarium solani endophthalmitis in a liver-transplanted patient

    DEFF Research Database (Denmark)

    Jørgensen, Jesper Skovlund; Prause, Jan Ulrik; Kiilgaard, Jens Folke

    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.......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....

  15. 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)

  16. Supressão da atividade saprofítica de Rhizoctonia spp. em solos de jardim clonal de Eucalyptus Suppression of Rhizoctonia spp. saprophytic activity in Eucalyptus clonal hedge soils

    Directory of Open Access Journals (Sweden)

    EUGENIO A. SANFUENTES

    2002-09-01

    Full Text Available Avaliou-se a eficiência de Trichoderma longibranchiatum (UFV-1, de T. inhamatum (UFV-2 e UFV-3, compostos de casca e folhas de eucalipto contra Rhizoctonia spp., aplicados em solo de jardim clonal de eucalipto (Eucalyptus sp.. Em solos artificialmente infestados com Rhizoctonia spp., sob condições controladas, os antagonistas UFV-2 e UFV-3 apresentaram níveis elevados de supressividade, quando se aumentou a fonte alimentar na formulação, de 5 a 50 g de farelo de trigo por litro. No campo, o antagonista UFV-3 não teve efeito significativo na redução do inóculo de Rhizoctonia spp. Compostos de casca de eucalipto apresentaram diferentes graus de supressão a Rhizoctonia spp., dependendo da origem e do lote do composto. A incorporação de folhas de eucalipto ao solo favoreceu o aumento do inóculo de Rhizoctonia spp.The effectiveness of Trichoderma longibranchiatum (UFV-1, T. inhamatum (UFV-2 and UFV-3, eucalyptus bark compost and leaves of eucalyptus was tested for the suppression of Rhizoctonia spp. in the soil of a clonal hedge of eucalyptus under controlled conditions. Soils artificially infested with Rhizoctonia spp., the antagonists UFV-2 and UFV-3 showed high levels of suppression of the pathogen when the feeding formulation rose from 5 to 50 g wheat bran per liter. However, in the field, the antagonist UFV-3 did not show a significant effect in reducing the inoculum of Rhizoctonia spp. Eucalypt us bark compost resulted in different levels of suppression of the pathogen depending on the compost pile and source. Adding eucalyptus leaves to the soil favored the inoculum of Rhizoctonia spp.

  17. Morphological and Physiological Characterization of Alternaria solani Isolated from Tomato in Jordan Valley

    OpenAIRE

    Khalaf M. Alhussaen

    2012-01-01

    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...

  18. Spread potential of binucleate Rhizoctonia from propagation floors to trays containing stem cuttings

    Science.gov (United States)

    Binucelate Rhizoctonia spp. (BNR), the cause of web blight, are present all year on container-grown azaleas in the southern U.S. BNR can be eliminated during vegetative propagation by submerging stem cuttings in 50°C water for 21 minutes. The objective was to evaluate risk of rooting trays bein...

  19. Rhizoctonia crown and root rot resistance evaluation of Beta PIs in Fort Collins, CO, 2014

    Science.gov (United States)

    Thirty-six sugar beet (Beta vulgaris subsp. vulgaris) germplasm from the USDA-Agricultural Research Service pre-breeding program at Fort Collins, Colorado were screened for resistance to Rhizoctonia crown and root rot (RCRR) at the Colorado State University ARDEC facility in Fort Collins, CO. There...

  20. Effect of Plant Spacing on Microclimate and Rhizoctonia Web Blight Development in Container Grown Azalea

    Science.gov (United States)

    Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 ‘Gumpo’ azalea plants. Plant ...

  1. 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.

  2. The galactolipase activity of Fusarium solani (phospho)lipase.

    Science.gov (United States)

    Jallouli, Raida; Othman, Houcemeddine; Amara, Sawsan; Parsiegla, Goetz; Carriere, Frédéric; Srairi-Abid, Najet; Gargouri, Youssef; Bezzine, Sofiane

    2015-03-01

    The purified (phospho)lipase of Fusarium solani (FSL), was known to be active on both triglycerides and phospholipids. This study aimed at assessing the potential of this enzyme in hydrolyzing galactolipids. FSL was found to hydrolyze at high rates of synthetic medium chains monogalactosyldiacylglycerol (4658±146U/mg on DiC8-MGDG) and digalactosyldiacylglycerol (3785±83U/mg on DiC8-DGDG) and natural long chain monogalactosyldiacylglycerol extracted from leek leaves (991±85U/mg). It is the microbial enzyme with the highest activity on galactolipids identified so far with a level of activity comparable to that of pancreatic lipase-related protein 2. FSL maximum activity on galactolipids was measured at pH8. The analysis of the hydrolysis product of natural MGDG from leek showed that FSL hydrolyzes preferentially the ester bond at the sn-1 position of galactolipids. To investigate the structure-activity relationships of FSL, a 3D model of this enzyme was built. In silico docking of medium chains MGDG and DGDG and phospholipid in the active site of FSL reveals structural solutions which are in concordance with in vitro tests. PMID:25529980

  3. 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

  4. THE EFFECT OF MEDIA AND LIGHT ON IN VITRO SPORULATION OF ALTERNARIA SOLANI

    Directory of Open Access Journals (Sweden)

    P. Kishore Varma

    2015-03-01

    Full Text Available Early blight of tomato incited by Alternaria solani is an economically significant disease especially in commercial tomato cultivation under greenhouse and field conditions. Since, A. solani is a shy sporulator, the present investigation was taken to assess the optimum in vitro conditons for growth and sporulation of early blight pathogen. Ten A. solani isolates obtained from diseased leaf samples collected different crop growing areas of India were used in the present study. The effect of different incubation periods, fluorescent light, cold-water treatment and media were evaluated. Our results revealed maximum sporulation of A. solani on tomato fruit extract agar medium (TFEA under continuous light for 7 days at 250C, followed by cold-water treatment and further incubated in darkness at 200C for 48 h. The sporulation of test pathogen was however sparse on V-8 juice agar. Further, the A. solani isolates on V-8 juice agar did not respond to the treatments imposed. Among the isolates, JAS (Jhajjar isolate, that is more versatile in its ability to produce spores recorded irregular margin with abundant aerial mycelium.

  5. Metabolites change in Jatropha plants due to seed treatment with rhizobacteria and Rhizoctonia bataticola

    OpenAIRE

    Surender Kumar; Sushil Sharma

    2013-01-01

    An experiment on the metabolite [salicylic acid (SA), jasmonic acid (JA), hydrocyanic acid (HCN) and chitinase activity] changes owing to seed treatn1ent with pathogen, plant growth pron1oting 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 ...

  6. 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)

    OpenAIRE

    PL. Santana-Neto; CMR. Albuquerque; APP. Silva; VM. Svedese; EALA. Lima

    2010-01-01

    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 interseg...

  7. Effect of Alternaria solani exudates on resistant and susceptible potato cultivars from two different pathogen isolates

    Science.gov (United States)

    The resistance phenotypes of two potato cultivars to two isolates of Alternaria solani, causal agent of early blight, were studied under greenhouse conditions. The two isolates contain varying degrees of aggressiveness on both susceptible and resistant phenotypes of potatoes. A bioassay was used to ...

  8. 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...

  9. EARLY INFECTION OF SOYBEAN ROOTS BY FUSARIUM SOLANI F. SP. GLYCINES

    Science.gov (United States)

    Fusarium solani f. sp. glycines, the causal organism of soybean sudden death syndrome (SDS), is a major pathogen of soybean in the United States. SDS is known as a late season disease although it is known that the fungus infects soybean early in the season; however, it is not known how early infecti...

  10. 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 30C at 3% substrate concentration for free cells and 5.0 and 30C 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.

  11. Atividades amiloltica e pectinoltica de Alternaria solani e a relao com a agressividade em tomateiro / Amilolytic and pectinolytic activities of Alternaria solani and aggressiveness in tomato plants

    Scientific Electronic Library Online (English)

    Carlos Eduardo, Marchi; Mirian de Freitas, Borges; Eduardo Seiti Gomide, Mizubuti.

    2006-09-01

    Full Text Available As atividades amiloltica e pectinoltica de 45 isolados de Alternaria solani, provenientes de diferentes hospedeiros, foram estimadas por meio da difuso enzimtica em meio slido especfico e mensurao do halo de degradao do substrato. Todos os isolados degradaram pectina. Apenas 17 isolados ap [...] resentaram atividade amiloltica, sendo nove isolados provenientes de batateira. Somente o isolado AS18 se destacou como bom produtor de ambas as enzimas. Uma vez que a atividade pectinoltica foi mais evidente, avaliou-se a influncia de pectinases na agressividade de A. solani ao tomateiro. Para isso, cinco isolados (2 de berinjela, 2 de tomateiro e 1 de batateira) contrastantes quanto produo de pectinases foram selecionados para testes em fololos destacados e plantas inteiras. Quatro isolados foram utilizados no teste em fololos destacados (AS6, AS7, AS12 e AS26), e constatou-se haver variabilidade patognica. A correlao obtida entre o tamanho das leses e a atividade pectinoltica foi de r = 0,963 (P = 0,087). Cinco isolados (AS6, AS7, AS12, AS25 e AS26) foram inoculados em plantas inteiras de tomate. Os isolados no diferiram quanto ao nmero de leses/cm de rea foliar, porm variaram em agressividade. Houve correlao (r = 0,916; P = 0,042) entre a atividade de pectinases e o ndice de doena, sugerindo possvel papel para as enzimas pcticas durante a infeco de A. solani em tomateiro. provvel que as diferenas no perfil enzimtico dos isolados estejam associadas ao hospedeiro original de onde os mesmos foram obtidos. Os resultados reforaram evidncias de especificidade por hospedeiro em populaes de A. solani. Abstract in english Amilolytic and pectinolytic activities of 45 isolates of Alternaria solani from distinct hosts were investigated. Enzyme secretion was evaluated in glucose-free medium amended with pectin or starch as carbon source. All isolates degraded pectin. Only 17 isolates had amilolytic activity, and nine of [...] these isolates were isolated from potato. Only AS18 had good amilolytic and pectinolytic activities. The role of pectinases produced by A. solani in its aggressiveness on tomato was examined. Five isolates showing substantial differences regarding the ability to produce pectic enzymes were selected, two from eggplant, two from tomato plants, and one from potato plant. Four isolates (AS6, AS7, AS12, and AS26) were inoculated on detached leaflets of tomato and pectinolytic activity was correlated with lesion size (r = 0.963; P = 0.087). Pathogenicity test with five isolates (AS6, AS7, AS12, AS25, and AS26) was conducted in tomato plants. Variation in the number of lesions per cm of leaf area was not detected, but isolates varied in aggressiveness. Pectinolytic activity and aggressiveness were correlated (r = 0.916; P = 0.042). In general, pectinases-producing isolates caused larger lesions on tomato plants. It is possible that enzymatic profile differences are associated with the host origin. The results contribute to cumulative evidences of host specificity in populations of A. solani.

  12. Relationships between M. enterolobii and F. solani: spatial and temporal dynamics in the occurrence of guava decline

    OpenAIRE

    Vicente Martins Gomes; Ricardo Moreira de Souza; Alexandre Macedo Almeida; Claudia Dolinski

    2014-01-01

    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 effe...

  13. In vitro Susceptibility of Alternaria solani to Several Iranian Soil Actinomycetes

    Directory of Open Access Journals (Sweden)

    F. Sharifi

    2006-01-01

    Full Text Available Streptomyces sp. are of the most attractive sources of biologically active compounds. In the recent decades, they have attracted high interests as biocontrol agents. In search of finding such principles, in vitro suppression of Alternaria solani was studied by use of Streptomyces antagonists. A. solani was sensitive to several species mainly Streptomyces plicatus, S. olivaceus and two unidentified actinomycetes. Activity versus time was monitored in S. olivaceus in solid and shaked cultures. Ongoing goals of this research include isolation, characterization and identification of the active metabolites. Future goals include identification of active genes for use in development of recombinant DNAs in transgenic hosts bearing elevated resistance to infections by Alternaria sp.

  14. 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...

  15. Assessment of early blight (Alternaria solani) resistance in tomato using a droplet inoculation method

    OpenAIRE

    Chaerani, R.; Groenwold, R.; Stam, P.; Voorrips, R. E.

    2006-01-01

    A droplet inoculation method was used for evaluation of tomato resistance to early blight, a destructive foliar disease of tomato caused by Alternaria solani (Ellis and Martin) Sorauer. In this test method, leaflets are inoculated with small droplets of a spore suspension in either water or a 0.1% agar solution. Early blight resistance was evaluated based on lesion size. The droplet method better discriminated the level of resistance (P <0.001) for a range of spore densities in comparison ...

  16. QTL identification for early blight resistance (Alternaria solani) in a Solanum lycopersicum x S. arcanum cross.

    OpenAIRE

    Chaerani, R.; Smulders, M.J.M.; Linden, van der, B.J.J.J.; Vosman, B.; Stam, P.; Voorrips, R. E.

    2007-01-01

    Alternaria solani (Ellis and Martin) Sorauer, the causal agent of early blight (EB) disease, infects aerial parts of tomato at both seedling and adult plant stages. Resistant cultivars would facilitate a sustainable EB management. EB resistance is a quantitatively expressed character, a fact that has hampered effective breeding. In order to identify and estimate the effect of genes conditioning resistance to EB, a quantitative trait loci (QTL) mapping study was performed in F2 and F3 populati...

  17. Root Rot of Balloon Flower (Platycodon grandiflorum) Caused by Fusarium solani and Fusarium oxysporum.

    Science.gov (United States)

    Jeon, Chi Sung; Kim, Gyoung Hee; Son, Kyeong In; Hur, Jae-Seoun; Jeon, Kwon-Seok; Yoon, Jun-Hyuck; Koh, Young Jin

    2013-12-01

    Balloon flower (Platycodon grandiflorum) is a kind of mountain herbs whose roots have restorative properties and the cultivating acreage of balloon flower has been steadily increasing in Korea. More frequent rain and high amount of rainfalls as a result of climate changes predisposed balloon flower to the outbreaks of root rot at high-density cultivation area in recent years. Root crowns were usually discolored into brown to blackish brown at first and the infected plants showed slight wilting symptom at early infection stage. Severely infected roots were entirely rotted and whole plants eventually died at late infection stage. The overall disease severities of root rot of balloon flower were quite variable according to the surveyed fields in Jeonnam, Gyeongnam and Jeju Provinces, which ranged from 0.1% to 40%. The root rot occurred more severely at the paddy or clay soils than the sandy soils and their severities were much higher at lowland than upland in the same localty. The disease increased with aging of the balloon flower. The causal fungi were identified as Fusarium solani and F. oxysporum on the basis of their mycological characteristics. The optimum temperature ranges of their mycelial growths was found to be 24°C. The pathogenic characters of F. solani and F. oxysporum treated by artificial wounding inoculation on healthy roots of balloon flower revealed that F. solani was more virulent than F. oxysporum. This study identified the causal agents of root rot of balloon flower as Fusarium solani and F. oxysporum, probably for the first time. PMID:25288973

  18. 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...

  19. 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.

  20. RESISTANCE OF TOMATO (Lycopersicon esculentum Mill. TO THE Stemphylium solani Weber RESISTÊNCIA DE TOMATEIRO (Lycopersicon esculentum Mill. A Stemphylium solani Weber

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    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 genótipos Ohio 4013 e o 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; Stemphylium solani.

  1. Characterization of fungi (Fusarium and Rhizoctonia) and oomycetes (Phytophthora and Pythium) associated with apple orchards in South Africa.

    Science.gov (United States)

    Several species of fungi and oomycetes including Fusarium, Rhizoctonia, Phytophthora and Pythium have been reported as root pathogens of apple where they contribute to a phenomenon known as apple replant disease. In South Africa, very little is known about the specific species in these genera and th...

  2. USDA-ARS germplasm evaluated for resistance to Rhizoctonia crown and root rot in Fort Collins, CO, 2014

    Science.gov (United States)

    Thirty-six sugar beet (Beta vulgaris subsp. vulgaris) germplasm from the USDA-Agricultural Research Service pre-breeding program at Fort Collins, Colorado were screened for resistance to Rhizoctonia crown and root rot (RCRR) at the Colorado State University ARDEC facility in Fort Collins, CO. There...

  3. 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.

  4. Characterization and colonization of endomycorrhizal Rhizoctonia fungi in the medicinal herb Anoectochilus formosanus (Orchidaceae).

    Science.gov (United States)

    Jiang, Jr-Hau; Lee, Yung-I; Cubeta, Marc A; Chen, Lung-Chung

    2015-08-01

    The medicinal effects and techniques for cultivating Anoectochilus formosanus are well-documented, but little is known about the mycorrhizal fungi associated with A. formosanus. Rhizoctonia (Thanatephorus) anastomosis group 6 (AG-6) was the most common species isolated from fungal pelotons in native A. formosanus and represented 67% of the sample. Rhizoctonia (Ceratobasidium) AG-G, P, and R were also isolated and represent the first occurrence in the Orchidaceae. Isolates of AG-6, AG-R, and AG-P in clade I increased seed germination 44-91% and promoted protocorm growth from phases III to VI compared to asymbiotic treatments and isolates of AG-G in clade II and Tulasnella species in clade III. All isolates in clades I to III formed fungal pelotons in tissue-cultured seedlings of A. formosanus, which exhibited significantly greater growth than nonmycorrhizal seedlings. An analysis of the relative effect of treatment ([Formula: see text]) showed that the low level of colonization ([Formula: see text]) by isolates in clade I resulted in a significant increase in seedling growth compared to isolates in clades II (0.63-0.82) and III (0.63-0.75). There was also a negative correlation (r = -0.8801) with fresh plant weight and fungal colonization. Our results suggest that isolates in clade I may represent an important group associated with native populations of A. formosanus and can vary in their ability to establish a symbiotic association with A. formosanus. The results presented here are potentially useful for advancing research on the medicinal properties, production, and conservation of A. formosanus in diverse ecosystems. PMID:25575732

  5. Cyanide Degradation under Alkaline Conditions by a Strain of Fusarium solani Isolated from Contaminated Soils

    OpenAIRE

    Dumestre, A.; Chone, T.; Portal, J.; M. GERARD; Berthelin, J.

    1997-01-01

    Several cyanide-tolerant microorganisms have been selected from alkaline wastes and soils contaminated with cyanide. Among them, a fungus identified as Fusarium solani IHEM 8026 shows a good potential for cyanide biodegradation under alkaline conditions (pH 9.2 to 10.7). Results of K(sup14)CN biodegradation studies show that fungal metabolism seems to proceed by a two-step hydrolytic mechanism: (i) the first reaction involves the conversion of cyanide to formamide by a cyanide-hydrolyzing enz...

  6. In vitro Control of Alternaria solani, the Cause of Early Blight of Tomato

    Directory of Open Access Journals (Sweden)

    Ashraf Saber Hawamdeh

    2001-01-01

    Full Text Available In vitro control of Alternaria solani was studied with different fungicides. Using Poison Food Technique (PFT, seven fungicides, Antracol, Benlate, Copper oxychloride, Dithane M-45, Ridomil, Topas, and Topsin were evaluated at four different concentrations (250, 500, 750, and 1000 ppm to control colony growth of fungi . The lowest colony growth was recorded in Dithane M-45 treatment at 1000 ppm, and the highest in treatment where no fungicide was used, indicating the significance of using fungicides in controlling early blight disease in tomato

  7. '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

  8. 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

  9. Biochemical Response of Glycine Max after Inoculation of Different Concentrations of Fusarium Solani

    Directory of Open Access Journals (Sweden)

    N. Hamid

    2014-06-01

    Full Text Available Diseases of agricultural crops are old as agriculture itself. It has been estimated that fungal diseases are responsible for an annual reduction for more than 20% of total potential world food production from crop plants. Randomized complete block design experiments were conducted to study the effect of different colonies of Fusarium solani on some biochemical and physiological parameters of Glycine max. Sterilized seeds of Glycine max (L. Merr was artificially inoculated with conidia of 3 different concentrations (10,000, 100,000 and 1000, 000 cfu. Seedlings of Glycine max was grown in 350g acid washed sand. Complete Nutrient Hoagland solution was regularly used to irrigate the plants. Leaves samples were weekly collected for analysis of biochemical tests. It was observed that inoculation of Fusarium solani significantly increase the concentration of total soluble carbohydrate and reducing sugar in inoculated plants over healthy tissues. Protein analysis revealed a significant reduction with the development of disease. Activity of invertase illustrate a variable change initially it was increased than afterward declined.

  10. Synthesis of N-substituted phthalimides and their antifungal activity against Alternaria solani and Botrytis cinerea.

    Science.gov (United States)

    Pan, Le; Li, Xiuzhuang; Gong, Chengwen; Jin, Hui; Qin, Bo

    2016-06-01

    As organosulfur and organophosphorus agents, phaltane and phosmet are facing great challenges for the environmental contamination, mammalian toxicity and increasing resistance with long term use. It is efficient and meaningful to develop phthalimide-based alternatives with non-sulfur and non-phosphorus groups. A series of N-substituted phthalimides were synthesized and their antifungal activity against two disastrous phytopathogenic fungi, Alternaria solani and Botrytis cinerea was evaluated in vitro. Most of them showed significant antifungal activity against both of fungi, or either of them selectively. N-vinylphthalimide (4) and 8-[4-(phthalimide-2-yl) butyloxy] quinoline (13) were identified as the most promising candidates against B. cinerea and A. solani with the IC50 values of 7.92 μg/mL and 10.85 μg/mL respectively. The brief structure-activity relationships have revealed that vinyl, quinolyl, bromide alkyl and benzyl substitutions were appropriate substituents and coupling functional moieties indirectly with optimum alkyl chain was efficient to prepare phthalimides related fungicides. PMID:27079471

  11. Rhizopus arrhizus and Fusarium solani Concomitant Infection in an Immunocompromised Host.

    Science.gov (United States)

    de Almeida Júnior, João N; Ibrahim, Karim Y; Del Negro, Gilda M B; Bezerra, Evandro D; Duarte Neto, Amaro N; Batista, Marjorie V; Siciliano, Rinaldo F; Giudice, Mauro C; Motta, Adriana L; Rossi, Flávia; Pierrotti, Ligia C; Freire, Maristela P; Bellesso, Marcelo; Pereira, Juliana; Abdala, Edson; Benard, Gil

    2016-02-01

    Neutropenic patients are at risk of the development of hyalohyphomycosis and mucormycosis. Correct identification is essential for the initiation of the specific treatment, but concomitant mold infections are rarely reported. We report one unprecedented case of concomitant mucormycosis and fusariosis in a neutropenic patient with acute myeloid leukemia. The patient developed rhino-orbital infection by Rhizopus arrhizus and disseminated infection by Fusarium solani. The first culture from a sinus biopsy grew Rhizopus, which was consistent with the histopathology report of mucormycosis. A second sinus biopsy collected later during the patient's clinical deterioration was reported as hyalohyphomycosis, and the culture yielded F. solani. Due to the discordant reports, the second biopsy was reviewed and two hyphae types suggestive of both hyalohyphomycetes and mucormycetes were found. The dual mold infection was confirmed by PCR assays from paraffinized tissue sections. Increased awareness of the existence of dual mold infections in at-risk patients is necessary. PCR methods in tissue sections may increase the diagnosis of dual mold infections. In case of sequential biopsies showing discrepant results, mixed infections have to be suspected. PMID:26346377

  12. Resistance to Alternaria solani in hybrids between a Solanum tuberosum haploid and S. raphanifolium.

    Science.gov (United States)

    Weber, B N; Jansky, S H

    2012-02-01

    Early blight of potato (Solanum tuberosum), 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 blight resistant clone of the diploid wild species S. raphanifolium was crossed as a male to a haploid (2n=2x) of cultivated potato. Hybrids were backcrossed to both parents. Eight families were created and evaluated for early blight resistance in the field. Families created by backcrossing to the wild species parent exhibited significantly lower relative area under the disease progress curve means than those from backcrossing to the cultivated parent, leading to the conclusion that S. raphanifolium contributes genes for early blight resistance. The mechanism of resistance in S. raphanifolium is unique because A. solani could not be recovered from lesions. Clones were identified with high levels of resistance and adaptation to the photoperiod of a temperate production region. PMID:22007613

  13. Atividade alelopática do filtrado de cultura produzido por Fusarium solani Allelopathic activity of culture filtrate produced by Fusarium solani

    Directory of Open Access Journals (Sweden)

    A.P.S. Souza Filho

    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 dos 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.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.

  14. Molecular characterization and detection of mutations associated with resistance to succinate dehydrogenase inhibiting (SDHI) fungicides in Alternaria solani

    Science.gov (United States)

    Early blight, caused by Alternaria solani, is an economically important foliar disease of potato in several production areas of the United States. Few potato cultivars possess resistance to early blight, therefore, the application of fungicides is a primary means of achieving disease control. Previo...

  15. Nonhost-specific phytotoxicity of the polyketide-derived toxin solanapyrone A produced by Ascochyta rabiei and Alternaria solani

    Science.gov (United States)

    Solanapyrone A is a polyketide-derived metabolite produced by Ascochyta rabiei and Alternaria solani, which are the most destructive necrotrophic pathogens of chickpea and potato/tomato, respectively. They belong to the Order Pleosporales within the Class Dothideomycetes, but are phylogenetically di...

  16. Antifungal efficiency of a lipopeptide biosurfactant derived from Bacillus subtilis SPB1 versus the phytopathogenic fungus, Fusarium solani.

    Science.gov (United States)

    Mnif, Ines; Hammami, Ines; Triki, Mohamed Ali; Azabou, Manel Cheffi; Ellouze-Chaabouni, Semia; Ghribi, Dhouha

    2015-11-01

    Bacillus subtilis SPB1 lipopeptides were evaluated as a natural antifungal agent against Fusarium solani infestation. In vitro antifungal assay showed a minimal inhibitory concentration of about 3 mg/ml with a fungicidal mode of action. In fact, treatment of F. solani by SPB1 lipopeptides generated excessive lyses of the mycelium and caused polynucleation and destruction of the related spores together with a total inhibition of spore production. Furthermore, an inhibition of germination potency accompanied with a high spore blowing was observed. Moreover, in order to be applied in agricultural field, in vivo antifungal activity was proved against the dry rot potato tubers caused by F. solani. Preventive treatment appeared as the most promising as after 20 days of fungi inoculation, rot invasion was reduced by almost 78%, in comparison to that of non-treated one. When treating infected tomato plants, disease symptoms were reduced by almost 100% when applying the curative method. Results of this study are very promising as it enables the use of the crude lipopeptide preparation of B. subtilis SPB1 as a potent natural fungicide that could effectively control the infection of F. solani in tomato and potato tubers at a concentration similar to the commercial fungicide hymexazol and therefore prevent the damage of olive tree. PMID:26178831

  17. Systematics and Population Genetics of a Phylogenetic Species Within the Fusarium solani Species Complex Associated with Human Infections

    Science.gov (United States)

    The Fusarium solani species complex (FSSC) is a monophyletic group comprising dozens of phylogenetic and biological species, and represents the most common species complex associated with fusarial infections of mammals, particularly mycotic keratitis. Previous work found that approximately 75% of k...

  18. Molecular phylogenetic diversity, multilocus haplotype nomenclature, and in vitro antifungal resistance within the Fusarium solani species complex

    Science.gov (United States)

    Members of the species-rich Fusarium solani species complex (FSSC) are responsible for approximately two-thirds all fusarioses of humans and other animals. In addition, many economically important phytopathogenic species are nested within this complex. Due to their increasing clinical relevance an...

  19. Production of extracellular lipase by the phytopathogenic fungus Fusarium solani FS1 Produo de lipase extracelular pelo fungo fitopatognico 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.

  20. 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 μg g-1 over control (24 μg g-1 was noticed for P. fluorescens followed by co-seed inoculation with P. fluorescens + pathogen (43 μg 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.

  1. 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)

  2. Effect of biotherapic of Alternaria solani on the early blight of tomato-plant and the in vitro development of the fungus

    OpenAIRE

    Marcus Zulian Teixeira; Maria Elizabeth da Costa Vasconcelos; José Carlos Gomes; Erika Pignoni; Euclides Davidson Bueno Romano; Solange Monteiro de Toledo Piza Gomes Carneiro

    2010-01-01

    Background: homeopathy is a means permitted in organic agriculture to control disease and plagues; biotherapics are a practical means for farmers to intervene on the health of plants in agro-ecological systems of production. Tomato-plants can be affected by several diseases, one of the most significant ones in Brazil is early blight, caused by fungus Alternaria solani, due to the damage it causes and its wide distribution in the country. Aims: to establish whether a biotherapic of A. solani m...

  3. Identification of Fusarium solani f. sp cucurbitae race 1 and race 2 with PCR and production of disease-free pumpkin seeds

    OpenAIRE

    Mehl, H. L.; Epstein, L.

    2007-01-01

    Fusarium solani f. sp. cucurbitae causes a fruit rot of cucurbits and is classified into two races that are actually distinct species: F solani f. sp. cucurbitae race 1 (Fsc1) and race 2 (Fsc2). Because Fsc1 and Fsc2 are not easily distinguished morphologically, we developed a polymerase chain reaction (PCR) assay for rapid identification. Taxon-specific primers were designed from translation elongation factor 1-alpha sequences. Because clean seed is critical for disease control, we conducted...

  4. 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.

  5. Kahalalide F analogues from the mucous secretion of Indian sacoglossan mollusc Elysia ornata

    Digital Repository Service at National Institute of Oceanography (India)

    Ciavatta, M.L.; PrabhaDevi; Carbone, M.; Mathieu, V.; Kiss, R.; Casapullo, A.; Gavagnin, M.

    (Mangifera indica) Black mold rot +++ ++ - ++ Trichoderma koningii Oudemans (M. indica) Fruit rot +++ ++ ++ ++ Trichoderma atroviride (Anacardium occidentale) Rot disease - ++ ++ + Rhizoctonia solani (Amaranthus) Leaf blight - ++ + - Colletotrichum...

  6. Histopathological features of infections caused by Fusarium oxysporum and F. solani in purple passionfruit plants (Passiflora edulis Sims) / Caractersticas hispatologicas da infeco causada por Fusarium oxysporum e F. solani em maracuj-roxo (Passiflora edulis Sims). Summa Phytopathologica

    Scientific Electronic Library Online (English)

    Emiro, Ortiz; Marisol, Cruz; Luz Marina, Melgarejo; Xavier, Marqunez; Lilliana, Hoyos-Carvajal.

    2014-06-01

    Full Text Available O maracuj roxo Passiflora edulis Sims., destaca-se posicionado em segundo lugar na exportao de frutas da Colmbia, cujo mercado europeu o principal destino. No entanto, a produo afetada por vrias doenas, incluindo a presena de fusariose. Este trabalho apresenta as caractersticas histopa [...] tolgicas de diferentes tecidos afetados elos patgenos Fusarium oxysporum e Fusarium solani. Ambos os organismos produzem efeitos semelhantes sobre a planta: colonizao dos vasos do xilema por hifas e microcondios, hipertrofia e hiperplasia do cmbio, xilema e floema; destruio de fibras do xilema e amiloplastos em clulas parenquimatosas, tambm a produo de gis pela planta. No entanto, existem diferenas no mecanismo de colonizao, F. solani entra e se concentra principalmente na rea do colo enquanto F. oxysporum penetra nas razes e move-se atravs 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.

  7. PATHOGENICITY TESTS AND EVALUATION OF EFFICACY OF FUNGICIDES AGAINST RHIZOCTONIA BATATICOLA, THE CAUSAL AGENT OF DRY ROOT ROT OF CHICKPEA

    Directory of Open Access Journals (Sweden)

    G Amrutha Veena

    2014-03-01

    Full Text Available The pathogen was identified based on its mycelial and sclerotial characters and pathogenicity test was proved by soil inoculation method. Efficacy of two non systemic fungicides (copper oxychloride and captan, two systemic fungicides (hexaconazole and tebuconazole and one antifungal antibiotic validamycin each at different concentrations were tested against Rhizoctonia bataticola, incitant of dry root rot of chickpea under in vitro conditions. The fungicides copper oxychloride, captan, hexaconazole and tebuconazole were found to be highly effective (100% in inhibiting the mycelial growth of the highly virulent pathogen at all the concentrations tested.

  8. In vitro sensitivity of Alternaria solani to conventional fungicides and a biofungicide based on tea tree essential oil

    Directory of Open Access Journals (Sweden)

    Miloš Stepanović

    2015-01-01

    Full Text Available A study of in vitro sensitivity of five Alternaria solani isolates to cooper-oxychloride, chlorothalonil, difenoconazole, pyraclostrobin and a biofungicide based on tea tree essential oil was carried out. The isolates were obtained from infected tomato leaves collected from five different locations in Serbia. The tested isolates showed the highest sensitivity to pyraclostrobin with EC50 values ranging from 0.0014 to 0.0041 μg ml-1. The EC50 values of difenoconazole were 0.018-0.037 μg ml-1, chlorothalonil 2.99-4.54 μg ml-1, and cooper-oxychloride 13.27-15.63 μg ml-1. All tested A. solani isolates were the least sensitive to tea tree oil (1323.97-3307.08 μg l-1.

  9. In vitro sensitivity of Alternaria solani to conventional fungicides and a biofungicide based on tea tree essential oil

    OpenAIRE

    Miloš Stepanović; Stojan Jevremović; Emil Rekanović; MIlica MIhajlović; Svetlana Milijašević-Marčić; Ivana Potočnik; Biljana Todorović

    2015-01-01

    A study of in vitro sensitivity of five Alternaria solani isolates to cooper-oxychloride, chlorothalonil, difenoconazole, pyraclostrobin and a biofungicide based on tea tree essential oil was carried out. The isolates were obtained from infected tomato leaves collected from five different locations in Serbia. The tested isolates showed the highest sensitivity to pyraclostrobin with EC50 values ranging from 0.0014 to 0.0041 μg ml-1. The EC50 values of difeno...

  10. 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...

  11. Efficacy and Safety of Some Plant Extracts against Tomato Early Blight Disease Caused by Alternaria solani

    OpenAIRE

    El-Sayed, A. B.; 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...

  12. 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...

  13. Antagonismo in vitro de Trichoderma harzianum Rifai sobre Fusarium solani (Mart. Sacc., asociado a la marchitez en maracuy

    Directory of Open Access Journals (Sweden)

    Carol Libeth Surez Meza

    2009-01-01

    Full Text Available Cultivos de maracuy de la regin Caribe colombiana presentan problemas de marchitez y el hongo Fusarium solani (Mart. Sacc., est asociado a esta patologa. Plantas de maracuy de la Estacin Experimental (E.E Caribia de Corpoica poseen este problema y por tal razn se determin el antagonismo in vitro de aislamientos de Trichoderma harzianum Rifai, frente a F. solani, aislado de plantas enfermas de maracuy (Passiflora edulis. Utilizando la tcnica de cultivo dual en platos Petri con Agar Sabouraud, se evaluaron competencia por nutrientes y espacio, micoparasitismo y porcentaje de inhibicin del crecimiento radial (PICR, empleando un diseo estadstico 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 ms competentes por nutrientes y espacio, con el mayor radio de crecimiento de 7,50 y 7,32 cm el da 10, comparado a FSM-011 en el cual solo fue de 2,30 cm. Aunque, TCN-014 mostr micoparasitismo grado 4 con ambos aislamientos de F. solani y TCC-005 nicamente con FSM-012, el cual fue ms susceptible a ser micoparasitado. En cuanto al PICR, los tratamientos con mejores porcentajes de inhibicin fueron TA-9, TA-12 y TA-6 con valores de 70,56, 68,52 y 65,32% respectivamente. El aislamiento del patgeno 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, inhibicin, antagonismo.

  14. 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.

  15. Oxidative burst and the activity of defense-related enzymes in compatible and incompatible tomato-Alternaria solani interactions

    Directory of Open Access Journals (Sweden)

    Maria Isabel Balbi-Peña

    2014-10-01

    Full Text Available The production of reactive oxygen species (ROS, hypersensitive response (HR, and the activity of the enzymes guaiacol peroxidase, catalase, polyphenol oxidase, B-1,3-glucanase and chitinase, were studied in leaves of resistant [CNPH 1287 (Solanum habrochaites syn. Lycopersicon hirsutum] and susceptible [Santa Cruz Kada (S. lycopersicum syn. L. esculentum] tomato genotypes inoculated with Alternaria solani. Leaves were collected at the time of inoculation and at 4, 8, 12, 24, 48, 72, 96 and 120 hours post inoculation. Conidia germination occurred equally onto the leaf surface in both genotypes and germination tubes grew without apparent orientation. Lesion frequency was lower in CNPH 1287, and it was the consequence of a lower number of appressoria formed in that genotype. ROS were observed in low frequency in both genotypes. HR was observed in penetrated epidermal host cells also in both genotypes. It seems that ROS and HR would not contribute to the resistance of S. habrochaites to A. solani in this study. The activity of guaiacol peroxidase, polyphenol oxidase, B-1,3-glucanase and chitinase was significantly increased in the resistant genotype. These results suggest that defense-related enzymes but no oxidative burst play a role in the defense response of S. habrochaites to A. solani.

  16. Effect of Neem (Azardirachta indica A. Juss) Seeds and Leaves Extract on Some Plant Pathogenic Fungi

    OpenAIRE

    M. A. Moslem; E.M. El-Kholie

    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...

  17. Atividades amilolítica e pectinolítica de Alternaria solani e a relação com a agressividade em tomateiro Amilolytic and pectinolytic activities of Alternaria solani and aggressiveness in tomato plants

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Marchi

    2006-09-01

    Full Text Available As atividades amilolítica e pectinolítica de 45 isolados de Alternaria solani, provenientes de diferentes hospedeiros, foram estimadas por meio da difusão enzimática em meio sólido específico e mensuração do halo de degradação do substrato. Todos os isolados degradaram pectina. Apenas 17 isolados apresentaram atividade amilolítica, sendo nove isolados provenientes de batateira. Somente o isolado AS18 se destacou como bom produtor de ambas as enzimas. Uma vez que a atividade pectinolítica foi mais evidente, avaliou-se a influência de pectinases na agressividade de A. solani ao tomateiro. Para isso, cinco isolados (2 de berinjela, 2 de tomateiro e 1 de batateira contrastantes quanto à produção de pectinases foram selecionados para testes em folíolos destacados e plantas inteiras. Quatro isolados foram utilizados no teste em folíolos destacados (AS6, AS7, AS12 e AS26, e constatou-se haver variabilidade patogênica. A correlação obtida entre o tamanho das lesões e a atividade pectinolítica foi de r = 0,963 (P = 0,087. Cinco isolados (AS6, AS7, AS12, AS25 e AS26 foram inoculados em plantas inteiras de tomate. Os isolados não diferiram quanto ao número de lesões/cm² de área foliar, porém variaram em agressividade. Houve correlação (r = 0,916; P = 0,042 entre a atividade de pectinases e o índice de doença, sugerindo possível papel para as enzimas pécticas durante a infecção de A. solani em tomateiro. É provável que as diferenças no perfil enzimático dos isolados estejam associadas ao hospedeiro original de onde os mesmos foram obtidos. Os resultados reforçaram evidências de especificidade por hospedeiro em populações de A. solani.Amilolytic and pectinolytic activities of 45 isolates of Alternaria solani from distinct hosts were investigated. Enzyme secretion was evaluated in glucose-free medium amended with pectin or starch as carbon source. All isolates degraded pectin. Only 17 isolates had amilolytic activity, and nine of these isolates were isolated from potato. Only AS18 had good amilolytic and pectinolytic activities. The role of pectinases produced by A. solani in its aggressiveness on tomato was examined. Five isolates showing substantial differences regarding the ability to produce pectic enzymes were selected, two from eggplant, two from tomato plants, and one from potato plant. Four isolates (AS6, AS7, AS12, and AS26 were inoculated on detached leaflets of tomato and pectinolytic activity was correlated with lesion size (r = 0.963; P = 0.087. Pathogenicity test with five isolates (AS6, AS7, AS12, AS25, and AS26 was conducted in tomato plants. Variation in the number of lesions per cm² of leaf area was not detected, but isolates varied in aggressiveness. Pectinolytic activity and aggressiveness were correlated (r = 0.916; P = 0.042. In general, pectinases-producing isolates caused larger lesions on tomato plants. It is possible that enzymatic profile differences are associated with the host origin. The results contribute to cumulative evidences of host specificity in populations of A. solani.

  18. Effect of cropping system on composition of the Rhizoctonia populations recovered from canola and lupin in a winter rainfall region of South Africa

    Science.gov (United States)

    Rhizoctonia spp. are important pathogens of a broad range of crop plants that are economically important to the farm economy of the Western Cape region of South Africa. However, there is little information concerning the identity and relative importance of these fungal pathogens, and the effect of ...

  19. Efficacy of fungicides to manage onion stunting caused by Rhizoctonia spp. in the Columbia Basin of Oregon and Washington, 2011-2012

    Science.gov (United States)

    Onion stunting, caused by Rhizoctonia spp., has become a significant soilborne problem of onion bulb crops planted in sandy soils in the semi-arid Columbia Basin of Oregon and Washington following winter cereal cover crops. Research on the epidemiology and management of this disease is in progress. ...

  20. Molecular characterization and detection of mutations associated with resistance to succinate dehydrogenase-inhibiting fungicides in Alternaria solani.

    Science.gov (United States)

    Mallik, I; Arabiat, S; Pasche, J S; Bolton, M D; Patel, J S; Gudmestad, N C

    2014-01-01

    Early blight, caused by Alternaria solani, is an economically important foliar disease of potato in several production areas of the United States. Few potato cultivars possess resistance to early blight; therefore, the application of fungicides is the primary means of achieving disease control. Previous work in our laboratory reported resistance to the succinate dehydrogenase-inhibiting (SDHI) fungicide boscalid in this plant pathogen with a concomitant loss of disease control. Two phenotypes were detected, one in which A. solani isolates were moderately resistant to boscalid, the other in which isolates were highly resistant to the fungicide. Resistance in other fungal plant pathogens to SDHI fungicides is known to occur due to amino acid exchanges in the soluble subunit succinate dehydrogenase B (SdhB), C (SdhC), and D (SdhD) proteins. In this study, the AsSdhB, AsSdhC, and AsSdhD genes were analyzed and compared in sensitive (50% effective concentration [EC50] 100 μg ml(-1)) A. solani isolates. In total, five mutations were detected, two in each of the AsSdhB and AsSdhD genes and one in the AsSdhC gene. The sequencing of AsSdhB elucidated point mutations cytosine (C) to thymine (T) at nucleotide 990 and adenine (A) to guanine (G) at nucleotide 991, leading to an exchange from histidine to tyrosine (H278Y) or arginine (H278R), respectively, at codon 278. The H278R exchange was detected in 4 of 10 A. solani isolates moderately resistant to boscalid, exhibiting EC50 values of 6 to 8 μg ml(-1). Further genetic analysis also confirmed this mutation in isolates with high and very high EC50 values for boscalid of 28 to 500 μg ml(-1). Subsequent sequencing of AsSdhC and AsSdhD genes confirmed the presence of additional mutations from A to G at nucleotide position 490 in AsSdhC and at nucleotide position 398 in the AsSdhD, conferring H134R and H133R exchanges in AsSdhC and AsSdhD, respectively. The H134R exchange in AsSdhC was observed in A. solani isolates with sensitive, moderate, highly resistant, and very highly resistant boscalid phenotypes, and the AsSdhD H133R exchange was observed in isolates with both moderate and very high EC50 value boscalid phenotypes. Detection and differentiation of point mutations in AsSdhB resulting in H278R and H278Y exchanges in the AsSdhB subunit were facilitated by the development of a mismatch amplification mutation assay. Detection of these two mutations in boscalid-resistant isolates, in addition to mutations in AsSdhC and AsSdhD resulting in an H134R and H133R exchange, respectively, was achieved by the development of a multiplex polymerase chain reaction to detect and differentiate the sensitive and resistant isolates based on the single-nucleotide polymorphisms present in all three genes. A single A. solani isolate with resistance to boscalid did not contain any of the above-mentioned exchanges but did contain a substitution of aspartate to glutamic acid at amino acid position 123 (D123E) in the AsSdhD subunit. Among A. solani isolates possessing resistance to boscalid, point mutations in AsSdhB were more frequently detected than mutations in genes coding for any other subunit. PMID:23901829

  1. Geostatistical analysis of soil moisture distribution in a part of Solani River catchment

    Science.gov (United States)

    Kumar, Kamal; Arora, M. K.; Hariprasad, K. S.

    2016-03-01

    The aim of this paper is to estimate soil moisture at spatial level by applying geostatistical techniques on the point observations of soil moisture in parts of Solani River catchment in Haridwar district of India. Undisturbed soil samples were collected at 69 locations with soil core sampler at a depth of 0-10 cm from the soil surface. Out of these, discrete soil moisture observations at 49 locations were used to generate a spatial soil moisture distribution map of the region. Two geostatistical techniques, namely, moving average and kriging, were adopted. Root mean square error (RMSE) between observed and estimated soil moisture at remaining 20 locations was determined to assess the accuracy of the estimated soil moisture. Both techniques resulted in low RMSE at small limiting distance, which increased with the increase in the limiting distance. The root mean square error varied from 7.42 to 9.77 in moving average method, while in case of kriging it varied from 7.33 to 9.99 indicating similar performance of the two techniques.

  2. 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.

  3. CHITOSAN EXTRACTION FROM F.solani sps, STUDY OF ITS ANTIBACTERIAL AND DYE DEGRADATION ABILITY

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    Senthil Kumar V

    2015-07-01

    Full Text Available Recent advances in fermentation technology have led to new innovative techniques to obtain useful by-products from various soil microbes. F.solani CBNR KRRR, isolated from the marine soils of Pichavaram, Tamil Nadu was used for the economic production of Chitosan using Hesseltine and Anderson medium. The polysaccharides were extracted by alkali-acid treatment, and characterized by infrared spectroscopy. The highest growth rate was with Henderson and Anderson medium with a mycelial dry weight of 14 g/L. The best yield of the chitosan so obtained is (33.57 mg/g or 3.3%. The antimicrobial activity of Chitosan was tested against E.coli and S.aureus using Growth kinetics. It was found that the Extracted Chitosan have antimicrobial activity comparable to the Commercial Chitosan as well as the standard antibiotic used. Subsequently the extracted Chitosan was also tested for its photocatalytic ability to degrade dye-methylene blue and was found to exhibit 94.5% inhibition in 72 hours.

  4. Effect of fermentation parameters, elicitors and precursors on camptothecin production from the endophyte Fusarium solani.

    Science.gov (United States)

    Venugopalan, Aarthi; Potunuru, Uma Rani; Dixit, Madhulika; Srivastava, Smita

    2016-04-01

    Volumetric productivity of camptothecin from the suspension culture of the endophyte Fusarium solani was enhanced up to ∼152 fold (from 0.19μgl(-1)d(-1) to 28.9μgl(-1)d(-1)) under optimized fermentation conditions including initial pH (6.0), temperature (32°C) and agitation speed (80rpm) with (5% (v/v)) ethanol as medium component. Among various elicitors and precursors studied, tryptamine (0.5mM) as precursor and bovine serum albumin (BSA) (0.075mM) as an elicitor added on day 6 of the cultivation period resulted in maximum enhancement of camptothecin concentration (up to 4.5 and 3.4-fold, respectively). These leads provide immense scope for further enhancement in camptothecin productivity at bioreactor level. The cytotoxicity analysis of the crude camptothecin extract from the fungal biomass revealed its high effectiveness against colon and mammary gland cancer cell lines. PMID:26851893

  5. 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...

  6. 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.

  7. 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, Vsquez Covarrubias; Roberto, Montes Belmont; Alfredo, Jimnez Prez; Hilda Elizabet, Flores Moctezuma.

    Full Text Available El uso de fungicidas sintticos favorece la aparicin de hongos fitopatgenos 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 esporulacin de Fusarium oxysporum f. sp. lycopersici (FOL) y F. solani. Se encontr 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 esporulacin en ambas especies de Fusarium. De los EA probados, el de Beta vulgaris ejerci la mayor reduccin del crecimiento micelial (38 %) y esporulacin (61 %). Los EA al 5 %, de las cinco especies evaluadas, mostraron una estimulacin 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.

  8. Cultural, Morphological and Pathogenic Variability of Alternaria solani Causing Early Blight in Tomato

    Directory of Open Access Journals (Sweden)

    Abhishek Singh

    2014-01-01

    Full Text Available Experiment was conducted at BHU in the year 2012-13. Radial growth was not significantly different for most of the isolates. Seven DAI (days after inoculation highest radial growth has obtained in isolate RF-1 (35.50 mm, Ten DAI maximum growth was observed in isolate EC-1 (52.00 mm and Thirteen DAI maximum radial growth was same observed in two isolates IIVR and BHU-1 (88.75 mm. The maximum mean mycelial growth was observed in isolate IIVR (57.83 mm followed by MF-4 (57.66 mm and BHU-1 (56.83 mm. Isolates of A. solani depicted high variability in pigment production on PDA medium. Mycelial growth patterns were observed on PDA where BG RF-1 SF-1 MF-4 BHU-1 grew with circular margin with smooth surfaced colony and AF-2, PN-4, EC-1, BX-2 and IIVR isolates grew with irregular margin and rough surface. Five varieties of tomato were screened with 10 different isolates. The variety Selection-7 and H-86 were highly susceptible and susceptible, respectively with all the isolates tested. The variety Feb-2 was resistant while, the variety Flora Dade and Swarna Naveen were highly resistant with all the isolates. There was no significant difference between Flora Dade and Swarna Naveen. Out of 10 isolates, only three major groups were recorded on the basis of SAS analysis likewise Group-A isolates were highly virulent (MF-4 and PN-4, Group-C isolates indicate virulent (BG, AF-2, EC-1 and RF-1 and Group- E isolates were less virulent (BHU-1, IIVR, SF-1 and BX-2 with all the five varieties.

  9. Response Surface Optimization for Decaffeination and Theophylline Production by Fusarium solani.

    Science.gov (United States)

    Nanjundaiah, Shwetha; Bhatt, Praveena; Rastogi, Navin Kumar; Thakur, Munna Singh

    2016-01-01

    Coffee processing industries generate caffeine-containing waste that needs to be treated and decaffeinated before being disposed. Five fungal isolates obtained on caffeine-containing mineral media were tested for their ability to utilize caffeine at high concentrations. An isolate identified as Fusarium solani could utilize caffeine as a sole source of carbon and nitrogen up to 5 g/l and could degrade it to an extent of 30-53 % in 120 h. Sucrose that was added as an auxiliary substrate (5 g/l) enhanced the biodecaffeination of caffeine to 88 % in 96 h. The addition of co- substrate (sucrose) not only resulted in higher biodecaffeination efficiency, but also reduced the incubation period from the initial 120 to 96 h. Theophylline and 3-methyl xanthine were obtained as the major metabolites of decaffeination at 96 and 120 h, respectively. Response surface methodology used to optimize the process parameters for maximum biodecaffeination as well as theophylline production showed that a pH of 5.8, temperature of 24 °C and inoculum size of 4.8 × 10(5) spores/ml have resulted in a complete biodecaffeination of caffeine as well as the production of theophylline with a yield of 33 % (w/w). Results thus show that a viable and sustainable process can be developed for the detoxification of caffeine along with the recovery of theophylline, a commercially important chemical. PMID:26419659

  10. 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

  11. An abundant 'Candidatus Phytoplasma solani' tuf b strain is associated with grapevine, stinging nettle and Hyalesthes obsoletus.

    Science.gov (United States)

    Aryan, A; Brader, G; Mörtel, J; Pastar, M; Riedle-Bauer, M

    2014-10-01

    Bois noir (BN) associated with 'Candidatus Phytoplasma solani' (Stolbur) is regularly found in Austrian vine growing regions. Investigations between 2003 and 2008 indicated sporadic presence of the confirmed disease vector Hyalesthes obsoletus and frequent infections of bindweed and grapevine. Infections of nettles were rare. In contrast present investigations revealed a mass occurrence of H. obsoletus almost exclusively on stinging nettle. The high population densities of H. obsoletus on Urtica dioica were accompanied by frequent occurrence of 'Ca. P. solani' in nettles and planthoppers. Sequence analysis of the molecular markers secY, stamp, tuf and vmp1 of stolbur revealed a single genotype named CPsM4_At1 in stinging nettles and more than 64 and 90 % abundance in grapevine and H. obsoletus, respectively. Interestingly, this genotype showed tuf b type restriction pattern previously attributed to bindweed associated 'Ca. P. solani' strains, but a different sequence assigned as tuf b2 compared to reference tuf b strains. All other marker genes of CPsM4_At1 clustered with tuf a and nettle derived genotypes verifying distinct nettle phytoplasma genotypes. Transmission experiments with H. obsoletus and Anaceratagallia ribauti resulted in successful transmission of five different strains including the major genotype to Catharanthus roseus and in transmission of the major genotype to U. dioica. Altogether, five nettle and nine bindweed associated genotypes were described. Bindweed types were verified in 34 % of grapevine samples, in few positive Reptalus panzeri, rarely in bindweeds and occasionally in Catharanthus roseus infected by H. obsoletus or A. ribauti. 'Candidatus Phytoplasma convolvuli' (bindweed yellows) was ascertained in nettle and bindweed samples. PMID:25309042

  12. 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 μl ml-1.

  13. Identification of differentially expressed genes from Trichoderma harzianum during growth on cell wall of Fusarium solani as a tool for biotechnological application

    OpenAIRE

    Vieira, Pabline Marinho; Coelho, Alexandre Siqueira Guedes; Steindorff, Andrei Stecca; de Siqueira, Saulo José Linhares; Silva, Roberto do Nascimento; Ulhoa, Cirano José

    2013-01-01

    Background The species of T. harzianum are well known for their biocontrol activity against many plant pathogens. However, there is a lack of studies concerning its use as a biological control agent against F. solani, a pathogen involved in several crop diseases. In this study, we have used subtractive library hybridization (SSH) and quantitative real-time PCR (RT-qPCR) techniques in order to explore changes in T. harzianum genes expression during growth on cell wall of F. solani (FSCW) or gl...

  14. 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...

  15. Evaluacin de la capacidad biocontroladora de cepas nativas de Trichoderma spp sobre Rhizoctonia sp y Fusarium sp en caf (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 agroqumicos, en la agricultura convencional, se esta provocando problemas de contaminacin del medio ambiente (suelo, aire y agua), de ah que, la bsqueda de alternativas que contribuyan a una produccin agrcola libre de agroqumicos haciendo sostenible la produccin. [...] En este trabajo se estudia el control biolgico del damping off en caf (Coffea arabica) aplicando el hongo antagnico Trichoderma sp., en condiciones experimentales a escala de laboratorio, en instalaciones de la Unidad Acadmica Campesina Carmen Pampa, comunidad de Carmen Pampa, municipio de Coroico. El objetivo de este trabajo fue controlar biolgicamente el damping off, se encontraron dos gneros causantes del damping off en almacigo de caf: Rhizoctonia sp. y Fusarium sp. Para determinar el porcentaje de crecimiento y control en el medio de cultivo, se utiliz el mtodo de conteo de cuadrantes, donde se obtuvieron los porcentajes del crecimiento micelial del hongo antagnico Trichoderma sp.,y de los hongos fitopatgenos Rhizoctonia sp. y Fusarium sp. Estadsticamente existi una diferencia altamente significativa en la variable porcentaje de crecimiento de Trichoderma sp. sobre los hongos patgenos Rhizoctonia sp. y Fusarium sp. a los 3, 6 y 9 das esto da a conocer que el factor tiempo y los tratamientos son dependientes entre s. La variable de control mostr una diferencia altamente significativa en el factor tiempo y tratamiento, pero en la interaccin 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, as mostrando su poder inhibidor a Rhizoctonia sp. y Fusarium sp.. Esta prueba da referencias de que existe control del hongo antagnico sobre los hongos fitopatgenos 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.

  16. Expression of ß-1,3-glucanase and ß-1,4-glucanase in two potato cultivars following challenge by the fungal pathogen Alternaria solani

    Science.gov (United States)

    Early blight of potato, caused by Alternaria solani, is a ubiquitous disease in many countries around the world. We have previously found that variation in resistance phenotypes exist between two different Iranian cultivars of potato. Cultivar ‘Diamond’ is more resistant to multiple isolates of A. s...

  17. 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)

    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 incuding solanapyrones A, B, and C. Although both the phytotoxicity of solanopyrones and the...

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Expression of a radish defensin in transgenic wheat confers increased resistance to Fusarium graminearum and Rhizoctonia cerealis.

    Science.gov (United States)

    Li, Zhao; Zhou, Miaoping; Zhang, Zengyan; Ren, Lijuan; Du, Lipu; Zhang, Boqiao; Xu, Huijun; Xin, Zhiyong

    2011-03-01

    Fusarium head blight (scab), primarily caused by Fusarium graminearum, is a devastating disease of wheat (Triticum aestivum L.) worldwide. Wheat sharp eyespot, mainly caused by Rhizoctonia cerealis, is one of the major diseases of wheat in China. The defensin RsAFP2, a small cyteine-rich antifungal protein from radish (Raphanus sativus), was shown to inhibit growth in vitro of agronomically important fungal pathogens, such as F. graminearum and R. cerealis. The RsAFP2 gene was transformed into Chinese wheat variety Yangmai 12 via biolistic bombardment to assess the effectiveness of the defensin in protecting wheat from the fungal pathogens in multiple locations and years. The genomic PCR and Southern blot analyses indicated that RsAFP2 was integrated into the genomes of the transgenic wheat lines and heritable. RT-PCR and Western blot proved that the RsAFP2 was expressed in these transgenic wheat lines. Disease tests showed that four RsAFP2 transgenic lines (RA1-RA4) displayed enhanced resistance to F. graminearum compared to the untransformed Yangmai 12 and the null-segregated plants. Assays on Q-RT-PCR and disease severity showed that the express level of RsAFP2 was associated with the enhanced resistance degree. Two of these transgenic lines (RA1 and RA2) also exhibited enhanced resistance to R. cerealis. These results indicated that the expression of RsAFP2 conferred increased resistance to F. graminearum and R. cerealis in transgenic wheat. PMID:21279533

  3. 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 μg/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 μg/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 μg/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 μg/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.

  4. Hexacyclopeptides secreted by an endophytic fungus Fusarium solani N06 act as crosstalk molecules in Narcissus tazetta.

    Science.gov (United States)

    Wang, Wen-Xuan; Kusari, Souvik; Sezgin, Selahaddin; Lamshft, Marc; Kusari, Parijat; Kayser, Oliver; Spiteller, Michael

    2015-09-01

    The basis of chemical crosstalk in plants and associated endophytes lies in certain so-called communication molecules that are responsible for plant-microbe and microbe-microbe interactions. Consequently, elucidating the factors that affect the nature, distribution, and amount of these molecules and how they impact the interaction among endophytes and associated organisms is essential to understand the true potential of endophytes. In the present study, we report the discovery of nine hexacyclopeptides from an endophytic fungus, Fusarium solani, isolated from the bulb of Narcissus tazetta, and their selective accumulation by an endophytic bacterium, Achromobacter xylosoxidans isolated from the same tissue. We used matrix-assisted laser desorption ionization imaging high-resolution mass spectrometry (MALDI-imaging-HRMS) to firstly identify and visualize the spatial distribution of the hexacyclopeptides produced by endophytic F. solani. After culture condition optimization, their sequence was identified to be cyclo((Hyp or Dhp)-Xle-Xle-(Ala or Val)-Thr-Xle) (Dhp: dehydroproline) by the characteristic a, b, or y ions using liquid chromatography tandem mass spectrometry (LC-HRMS(n)). These hexacyclopeptides were confirmed to be fungal biosynthetic products by deuterium labeling experiments. Finally, in order to understand the plausible ecological relevance of one or more of the discovered hexacyclopeptides within the contexts of microbial "neighbor communication," we devised a dual-culture setup to visualize using MALDI-imaging-HRMS how the hexacyclopeptides released by the endophytic fungus are accumulated by another endophytic bacterium, A. xylosoxidans, isolated from the same bulb tissue. This work exemplifies the relevance of cyclopeptides in endophyte-endophyte interspecies neighbor communication occurring in nature. Such communication strategies are evolved by coexisting endophytes to survive and function in their distinct ecological niches. PMID:25958995

  5. Fungal Peritonitis Due to Fusarium solani Species Complex Sequential Isolates Identified with DNA Sequencing in a Kidney Transplant Recipient in Brazil.

    Science.gov (United States)

    da Silva-Rocha, Walicyranison Plinio; Zuza-Alves, Diana Luzia; Melo, Analy Salles de Azevedo; Chaves, Guilherme Maranho

    2015-12-01

    Fungal peritonitis is a rare serious complication most commonly observed in immunocompromised patients under peritoneal dialysis. Nevertheless, this clinical condition is more difficult to treat than bacterial peritonitis. Bacterial peritonitis followed by the use of antibiotics is the main risk factor for developing fungal peritonitis. Candida spp. are more frequently isolated, and the isolation of filamentous fungi is only occasional. Here we describe a case of Fusarium solani species complex peritonitis associated with bacterial peritonitis in a female kidney transplant recipient with previous history of nephrotic syndrome. The patient has had Enterobacter sp. endocarditis and was hypertensive and diabetic. Two sequential isolates of F. solani were recovered from cultures and identified with different molecular techniques. She was successfully treated with 50 mg daily amphotericin B for 4 weeks. PMID:26296944

  6. 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.

  7. Mtodos de inoculao para quantificao de resistncia em soja a Fusarium solani f. sp. glycines, em casa-de-vegetao 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 sndrome da morte sbita (SMS, causada por Fusarium solani f. sp. glycines, tem se mostrado uma das mais importantes doenas da soja, devido aos prejuzos provocados e dificuldade de controle. Este trabalho teve como objetivo selecionar os mtodos de inoculao mais eficientes para a avaliao de resistncia gentica de gentipos de soja SMS. Foram realizados dois experimentos em delineamento de blocos casualizados, sendo seis tratamentos e 12 repeties, no primeiro experimento, e seis tratamentos e 16 repeties, no segundo. Cada parcela foi constituda por um vaso contendo uma planta de soja da cultivar FT Estrela, altamente suscetvel SMS e outra planta de "Conquista", moderadamente resistente. As plantas foram avaliadas quanto incidncia e severidade da SMS a cada trs dias e durante 15 dias, com incio no 15 dia aps a emergncia. A partir dos resultados, foi estimada a rea abaixo da curva de progresso da doena (AACPD para os tratamentos. As inoculaes com gros de sorgo e milho colonizados pelo patgeno foram mais eficientes em causar doena, no primeiro experimento, e com gros de milho, no segundo. Entretanto, nos dois experimentos, apenas a inoculao com gros de milho foi capaz de separar a reao das cultivares quanto resistncia SMS, de acordo com o teste de Tukey (PSudden death syndrome (SDS caused by Fusarium solani f. sp. glycines has become one of the most important diseases in soybean due to significant yield losses and limitations for control. Control has been possible by means of genetic resistance. This work aimed to identify efficient methods of inoculation to assess the soybean genotypes genetically resistant to SDS. Two experiments were arranged in a randomized block design (RBD. The former consisted of six treatments and 12 replicates, and the latter of six treatments and 16 replicates. Each plot contained a pot with one plant of the cultivar FT Estrela, highly susceptible to SDS, and another plant of the moderately resistant cultivar Conquista. The plants were assessed in relation to incidence and severity of SDS, every three days, for fifteen days, starting from the fifteenth day of emergence. From the data obtained, the area under the disease progress curve (AUDPC was estimated for the treatments. Inoculations with grains of sorghum and corn were the most effective in causing the appearance of the disease in the first experiment. Inoculations with corn kernels were the most effective method in causing the disease in the second experiment. However, only inoculation with corn kernels permitted the separation between genotypes in relation to SDS resistance, according to Tukey test (P<0.05 in both experiments. Thus, inoculation with corn kernels can be recommended for assessing soybean genotype reactions to SDS under greenhouse conditions.

  8. Ocorrência de Fusarium solani f. sp. piperis em Piper nigrum no estado de Alagoas Report of Fusariom solani f. sp. piperis in Piper nigrum in the state of Alagoas

    Directory of Open Access Journals (Sweden)

    Juliana Paiva Carnaúba

    2007-03-01

    Full Text Available A pimenta-do-reino (Piper nigrum L. é uma planta trepadeira, pertencente à família Piperaceae. Ela é originária do Sudeste Asiático, sendo a mais comum e importante das especiarias. A fusariose, também conhecida por podridão do pé e podridão das raízes é a principal doença da cultura, de ocorrência restrita ao Brasil. Um isolado de Fusarium sp., encontrado infectando plantas de pimenta-do-reino cv. bragantina no município de União dos Palmares em Alagoas, foi caracterizado morfologicamente e teve sua patogenicidade confirmada em mudas deste hospedeiro. Os macroconídios apresentaram-se falcados, hialinos com três a cinco septos, com dimensões de 30,5 - 26,5 x 6,3 - 4,9 ìm, enquanto os microconídios apresentaram-se hialinos, unicelulares, elípticos ou alantóides medindo 16,6 - 4,9 x 6,5 - 3,3 ìm. Os clamidósporos foram abundantes em meio batata-dextrose-ágar. O isolado foi identificado como Fusarium solani f. sp. piperis Alb. tratando-se do primeiro relato deste patógeno em pimenta-do-reino no estado de Alagoas.The pepper-of the-kingdom (Piper nigrum L. it is a climbing plant, pertaining plant to the Piperaceae family. It is originary the southeastern Asian, being most common and important of the spices. Seedling death, also known for rottenness of the foot and rottenness of the root is the main illness of the culture, restricted occurrence to Brazil. Isolated of Fusarium sp., found contamined plants of bragantina pepper-do-kingdom cv. in the city of União dos Palmares in Alagoas, was characterized morphologycament and had its pathogenicity confirmed in changes of this host. The macroconidia slightly curved, typically canoe-shaped, hyaline with three the five septate, measuring 30,5 - 26,5 x 6,3 - 4,9 ìm. Microconidia hyaline, unicellulars, ellipticals or allantoises measuring 16,6 - 4,9 x 6,5 - 3,3 ìm. The chlamydospores had been abundant in half potato-dextrose-agar. The isolated one was identified as to Fusarium solani f. sp. piperis being about the first story of this parasitic on plants in pepper-of the-kingdom in the state of Alagoas.

  9. In vitro Control of Alternaria solani, the Cause of Early Blight of Tomato

    OpenAIRE

    Ashraf Saber Hawamdeh; Shabeer Ahmad

    2001-01-01

    In vitro control of Alternaria solani was studied with different fungicides. Using Poison Food Technique (PFT), seven fungicides, Antracol, Benlate, Copper oxychloride, Dithane M-45, Ridomil, Topas, and Topsin were evaluated at four different concentrations (250, 500, 750, and 1000 ppm) to control colony growth of fungi . The lowest colony growth was recorded in Dithane M-45 treatment at 1000 ppm, and the highest in treatment where no fungicide was used, indicating the significance of using f...

  10. 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

  11. Serine protease identification (in vitro) and molecular structure predictions (in silico) from a phytopathogenic fungus, Alternaria solani.

    Science.gov (United States)

    Chandrasekaran, Murugesan; Chandrasekar, Raman; Sa, Tongmin; Sathiyabama, Muthukrishnan

    2014-07-01

    Serine proteases are involved in an enormous number of biological processes. The present study aims at characterizing three-dimensional (3D) molecular architecture of serine proteases from early blight pathogen, Alternaria solani that are hypothesized to be markers of phytopathogenicity. A serine protease was purified to homogeneity and MALDI-TOF-MS/MS analysis revealed that protease produced by A. solani belongs to alkaline serine proteases (AsP). AsP is made up of 403 amino acid residues with molecular weight of 42.1 kDa (Isoelectric point - 6.51) and its molecular formula was C1859 H2930 N516 O595 S4 . AsP structure model was built based on its comparative homology with serine protease using the program, MODELER. AsP had 16 β-sheets and 10 α-helices, with Ser(350) (G347-G357), Asp(158) (D158-H169), and His(193) (H193-G203) in separate turn/coil structures. Biological metal binding region situated near 6th-helix and His(193) residue is responsible for metal binding site. Also, calcium ion (Ca(2+)) is coordinated by the carboxyl groups of Lys(84), Ile(85), Lys(86), Asp(87), Phe(88), Ala(89), Ala(90) (K84-A90) for first Ca(2+) binding site and carbonyl oxygen atom of Lys(244), Gly(245), Arg(246), Thr(247), Lys(248), Lys(249), and Ala(250) (K244-A250), for second Ca(2+) binding site. Moreover, Ramachandran plot analysis of protein residues falling into most favored secondary structures were determined (83.3%). The predicted molecular 3D structural model was further verified using PROCHECK, ERRAT, and VADAR servers to confirm the geometry and stereo-chemical parameters of the molecular structural design. The functional analysis of AsP 3D molecular structure predictions familiar in the current study may provide a new perspective in the understanding and identification of antifungal protease inhibitor designing. PMID:24122785

  12. Effect of timing of glyphosate application to a winter wheat cover crop on stunting of spring-sown onions caused by Rhizoctonia spp. in the Columbia Basin of Washington, 2012.

    Science.gov (United States)

    The development of patches of stunted onion plants caused by Rhizoctonia spp. is an emerging problem in onion bulb crops planted in the semi-arid Columbia Basin of Oregon and Washington following winter cereal cover crops. Cereals such as winter wheat are used as cover crops to protect onion seedlin...

  13. Fusarium paranaense sp. nov., a member of the Fusarium solani species complex causes root rot on soybean in Brazil.

    Science.gov (United States)

    Costa, Sarah S; Matos, Kedma S; Tessmann, Dauri J; Seixas, Claudine D S; Pfenning, Ludwig H

    2016-01-01

    Isolates of Fusarium obtained from soybean plants showing symptoms of root rot collected in subtropical southern and tropical central Brazil were characterized based on phylogenetic analyses, sexual crossing, morphology, and pathogenicity tests. A novel species within the Fusarium solani species complex (FSSC) causing soybean root rot is formally described herein as Fusarium paranaense. This species can be distinguished from the other soybean root rot pathogens in the FSSC, which are commonly associated with soybean sudden death syndrome (SDS) based on analyses of the combined DNA sequences of translation elongation factor 1-? and the second largest subunit of RNA polymerase II and on interspecies mating compatibility. Bayesian and maximum parsimony phylogenetic analyses showed that isolates of F. paranaense formed a distinct group in clade 3 of the FSSC in contrast to the pathogens currently known to cause SDS, which are in clade 2. Female fertile tester strains were developed that can be used for the identification of this new species in the FSSC based on sexual crosses. All isolates were heterothallic and belonged to a distinct mating population. Fusarium tucumaniae, a known SDS pathogen, was found in the subtropical southern region of the country. PMID:26693684

  14. 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.

  15. EVALUACIN DE LA CAPACIDAD BIOCONTROLADORA DE TRICHODERMA HARZIANUM RIFAI CONTRA FUSARIUM SOLANI (MART.) SACC. ASOCIADO AL COMPLEJO SECADERA EN MARACUY, BAJO CONDICIONES DE INVERNADERO / EVALUATION OF THE BIOCONTROL CAPACITY OF TRICHODERMA HARZIANUM RIFAI AGAINST FUSARIUM SOLANI (MART.) SACC. ASSOCIATED TO THE COMPLEX DRYER IN PASSION FRUIT UNDER GREENHOUSE CONDITIONS

    Scientific Electronic Library Online (English)

    Juan Guillermo, Cubillos Hinojosa; Alberto, Pez Redondo; Lauris, Meja Doria.

    2011-06-01

    Full Text Available En la zona bananera del Magdalena en Colombia se ha reportado una disminucin del 30% en la produccin del cultivo de maracuy (Passiflora edulis var. flavicarpa) como consecuencia de la muerte de unidades productivas causadas por la enfermedad secadera o marchitez vascular, a la cual est asociada [...] el hongo Fusarium solani. Con el objeto de contribuir al manejo del problema sanitario, se evalu bajo condiciones de invernadero el efecto biocontrolador de la cepa nativa TCN-014 y la cepa comercial TCC-005 de Trichoderma harzianum contra F. solani. Para el estudio se utilizaron plantas de dos meses de edad, establecidas en invernadero. Se ensayaron dos tiempos de aplicacin del antagonista: 1. inoculando las plantas con el patgeno y cinco das despus el antagonista. 2. inoculando primero el antagonista y cinco das despus el patgeno. El experimento se estableci bajo un diseo experimental de bloques completos al azar con arreglo factorial 2x3, y los resultados fueron sometidos al anlisis de varianza (ANOVA) y comparacin de promedios mediante la prueba de rangos mltiples de Duncan, obtenindose que al inocular primero el antagonista se presenta un mejor efecto biocontrolador de F. solani utilizando concentraciones de 106 y 108 conidias/mL tanto de la cepa nativa como comercial. Los resultados sugieren una accin efectiva de T. harzianum como biocontrolador de F. solani, mostrando que se pueden realizar estudios en campo que permitan desarrollar un bioproducto para el manejo ecolgico de la marchitez en el cultivo de maracuy. Abstract in english In the banana zone of Magdalena in Colombia has been reported a 30% decrease in crop production of passion fruit (Passiflora edulis var. Flavicarpa) due to the death of plants caused by the Dryer or vascular wilt disease, which is associated with the fungus Fusarium solani. In order to help manage o [...] f the disease was evaluated under greenhouse conditions the effect of the biocontrol strain native TCN-014 and CCL-005 commercial strain of Trichoderma harzianum against F. solani. For the evaluation were used plants with two months of age, set in the greenhouse; were tested two times of application of the antagonist: (1) inoculating the antagonist five days after of pathogen agent, and (2) inoculating the antagonist five days before the pathogen. The experiment was established under an experimental design of randomized blocks with 2x3 factorial arrangement, and data were submitted to analysis of variance (ANOVA) and comparison of averages using the multiple range test of Duncan. Results indicated that to inoculate the antagonist before the pathogen is obtained a better biocontrol effect of F. solani using concentrations of 106 and 108 conidia/ mL of both native and commercial strains. The results suggest an effective action of T. harzianum as a biocontrol of F. solani, showing that it can perform field studies in order to develop a byproduct for ecological management of wilt in cultivation of passion fruit.

  16. Efeito inibitório do extrato hexânico dos folíolos de Caesalpinia spinosa em Fusarium solani e Phoma tarda - DOI: 10.4025/actascibiolsci.v27i2.1329 Inhibitory effect of Caesalpinia spinosa leaflets crude extract on Fusarium solani and Phoma tarda - DOI: 10.4025/actascibiolsci.v27i2.1329

    Directory of Open Access Journals (Sweden)

    Júlio César Miranda

    2005-03-01

    Full Text Available Extrato hexânico foi obtido dos folíolos do falso pau-brasil (Caesalpinia spinosa e incorporado em BDA (batata-dextrose-ágar, obtendo-se as concentrações de 2204 mg L-1, 4460 mg L-1, 6370 mg L-1, 7644 mg L-1 e 16179 mg L-1. Foi avaliado o crescimento micelial de Fusarium solani e Phoma tarda. Os resultados mostraram o efeito inibitório do extrato em porcentagens variáveis de 3,95% a 32,20% para P. tarda e de 7,29% a 33,83% para F. solani, conforme as doses crescentes do extrato, cuja fungitoxidade evidencia seu potencial alternativo aos métodos físicos e químicos de controle da fusariose em vários cultivos e mancha de Phoma no cafeeiroIn order to evaluate the plant extract effect on the in vitro growth of Fusarium solani and Phoma tarda, hexane crude extract from spiny holdback (Caesalpinia spinosa leaflets was obtained and incorporated into potato-dextrose-agar (PDA at 2204 mg L-1, 4460 mg L-1, 6370 mg L-1, 7644 mg L-1 and 16179 mg L-1 concentrations. The hexane crude extract inhibited mycelial growth at the range of 3,95% to 32,20% of P. tarda and 7,29% to 33,83% of F. solani, according to the extract concentration. It was demonstrated that the extract has antifungal activity and might be an alternative to physical or chemical control methods of fusariosis disease in several cultivations and of Phoma spot on coffee plant leaf

  17. Hyperspectral remote sensing for advanced detection of early blight (Alternaria solani) disease in potato (Solanum tuberosum) plants

    Science.gov (United States)

    Atherton, Daniel

    Early detection of disease and insect infestation within crops and precise application of pesticides can help reduce potential production losses, reduce environmental risk, and reduce the cost of farming. The goal of this study was the advanced detection of early blight (Alternaria solani) in potato (Solanum tuberosum) plants using hyperspectral remote sensing data captured with a handheld spectroradiometer. Hyperspectral reflectance spectra were captured 10 times over five weeks from plants grown to the vegetative and tuber bulking growth stages. The spectra were analyzed using principal component analysis (PCA), spectral change (ratio) analysis, partial least squares (PLS), cluster analysis, and vegetative indices. PCA successfully distinguished more heavily diseased plants from healthy and minimally diseased plants using two principal components. Spectral change (ratio) analysis provided wavelengths (490-510, 640, 665-670, 690, 740-750, and 935 nm) most sensitive to early blight infection followed by ANOVA results indicating a highly significant difference (p < 0.0001) between disease rating group means. In the majority of the experiments, comparisons of diseased plants with healthy plants using Fisher's LSD revealed more heavily diseased plants were significantly different from healthy plants. PLS analysis demonstrated the feasibility of detecting early blight infected plants, finding four optimal factors for raw spectra with the predictor variation explained ranging from 93.4% to 94.6% and the response variation explained ranging from 42.7% to 64.7%. Cluster analysis successfully distinguished healthy plants from all diseased plants except for the most mildly diseased plants, showing clustering analysis was an effective method for detection of early blight. Analysis of the reflectance spectra using the simple ratio (SR) and the normalized difference vegetative index (NDVI) was effective at differentiating all diseased plants from healthy plants, except for the most mildly diseased plants. Of the analysis methods attempted, cluster analysis and vegetative indices were the most promising. The results show the potential of hyperspectral remote sensing for the detection of early blight in potato plants.

  18. Phylogenetic relationships among members of the Fusarium solani species complex in human infections and the descriptions of F. keratoplasticum sp. nov. and F. petroliphilum stat. nov

    DEFF Research Database (Denmark)

    Short, Dylan P.G.; O’Donnell, Kerry; Thrane, Ulf; Nielsen, Kristian Fog; Zhang, Ning; Juba, Jean H.; Geiser, David M.

    2013-01-01

    dozens of strongly supported phylogenetic species within this important evolutionary clade, though little work has been done to improve the taxonomy and understanding of the reproductive mode and phenotypes of the predominant clinically relevant species. Here we described Fusarium keratoplasticum sp. nov...... characteristics typical for most classical concepts of ‘F. solani.’ Many isolates failed to produce sporodochia and macroconidia. Although most attempts to sexually cross F. keratoplasticum isolates failed, a heterothallic sexual stage typical for the FSSC was discovered by pairing isolates of opposite mating...

  19. Genome Sequence of Dickeya solani, a New soft Rot Pathogen of Potato, Suggests its Emergence May Be Related to a Novel Combination of Non-Ribosomal Peptide/Polyketide Synthetase Clusters

    OpenAIRE

    Linda Garlant; Patrik Koskinen; Leo Rouhiainen; Pia Laine; Lars Paulin; Petri Auvinen; Liisa Holm; Minna Pirhonen

    2013-01-01

    Soft rot Enterobacteria in the genera Pectobacterium and Dickeya cause rotting of many crop plants. A new Dickeya isolate has been suggested to form a separate species, given the name Dickeya solani. This bacterium is spreading fast and replacing the closely related, but less virulent, potato pathogens. The genome of D. solani isolate D s0432-1 shows highest similarity at the nucleotide level and in synteny to D. dadantii strain 3937, but it also contains three large polyketide/fatty acid/n...

  20. Biodégradation des cyanures libres par le champignon Fusarium solani: relation avec le pH et la distribution des espèces cyanurées en solution

    Science.gov (United States)

    Dumestre, Alain; Bousserrhine, Noureddine; Berthelin, Jacques

    1997-07-01

    Free cyanide biodégradation by Fusarium solani, a fungi isolated from cyanide-contaminated soils. involves a cyanide hydrolyzing enzyme. cyanide hydratase (EC 4.2.1.66). This enzyme specifically seems to convert cyanhydric acid (HCN) to formamide but not the cyanide ion (CN -). Hence. the rate of free cyanide biodégradation is a function of the equilibrium HCN/CN - in solution. A better understanding of cyanide hydratase properties allows the definition of optimal conditions of F.solani biodégradation activity. and the proposition of a biological treatment of cyanide-contaminated alkaline soils and effluents.

  1. Genome Sequence of Dickeya solani, a New soft Rot Pathogen of Potato, Suggests its Emergence May Be Related to a Novel Combination of Non-Ribosomal Peptide/Polyketide Synthetase Clusters

    OpenAIRE

    Garlant, Linda; Koskinen, Patrik; Rouhiainen, Leo; Laine, Pia; Paulin, Lars; Auvinen, Petri; Holm, Liisa; Pirhonen, Minna

    2013-01-01

    Soft rot Enterobacteria in the genera Pectobacterium and Dickeya cause rotting of many crop plants. A new Dickeya isolate has been suggested to form a separate species, given the name Dickeya solani. This bacterium is spreading fast and replacing the closely related, but less virulent, potato pathogens. The genome of D. solani isolate D s0432-1 shows highest similarity at the nucleotide level and in synteny to D. dadantii strain 3937, but it also contains three large polyketide/fatty acid/non...

  2. Genetic Diversity in the Fungus Fusarium solani f.sp. cucurbitae Race 1, the Casual Agent of Root and Crown Rot of Cucurbits in Iran, using Molecular Markers

    Directory of Open Access Journals (Sweden)

    M.R. Alymanesh

    2009-01-01

    Full Text Available Fusarium solani f.sp. cucurbitae race 1 is a pathogen on cucurbit plants. In this study genetic diversity among 26 isolates of Fusarium solani f.sp. cucurbitae race 1 was studied using Restriction Fragment Length Polymorphism (RFLP of ITS (Interal Transcribed Spacer regions and Random Amplified Polymorphic DNAs (RAPD markers. Outcome of digestion with six restriction enzymes including EcoR I, Rsa I, Bme 18I, Msp I, Hae III and Hind III, together with the patterns of restriction fragment length polymorphism of ITS regions divided the isolates into two groups. Deoxy Ribonuckin Acid DNA pattern was obtained for the isolates using 12 random primers and genetic distance between them was calculated and relationships (by cluster analysis determined. Among the primers used, seven primers showed polymorphism. Genetic distance between isolate pairs ranged from 0.03 to 0.48. Genetic diversity was high (e.g., the isolates were distributed into 10 genetic groups at a similarity percentage of 75. The lowest distance was observed between isolates 50 and 73 and the highest distance observed between isolates 50 and 73 with isolate 102. Restriction fragment length polymorphism results show diversity in ITS regions, without any correlation to geographic origin and RAPD. However, this genomic regions usually have high constancy in species, but in this study diversity was shown in ITS regions even for race 1. The data suggest that taxonomical situation of Foc race 1 probably needs revision.

  3. Preliminary evidence of the role of hydrogen peroxide in the degradation of benzo[a]pyrene by a non-white rot fungus Fusarium solani

    International Nuclear Information System (INIS)

    In order to study the enzymatic mechanisms involved in the successive steps of BaP degradation by a Deuteromycete fungus Fusarium solani, we developed an indirect approach by using inhibitors of enzymes. We used either specific inhibitors of peroxidases (i.e. salicylhydroxamic acid) and of cytochrome P-450 (i.e. piperonyl butoxyde) or inhibitors of both enzymes (i.e. potassium cyanide). Surprisingly, no expected decrease of BaP degradation was observed with most inhibitors tested. On the contrary, more BaP was degraded. Only butylated hydroxytoluene, which acts as a free radical scavenger, inhibited BaP degradation. The inhibition of these enzymes, which use H2O2 as a cosubstrat, might have resulted in an increase of hydrogen peroxide availability in the fungal cultures. This enhancement could induce formation of reactive oxygen species (ROS) which might be the agents that initiate benzo[a]pyrene oxidation. This study proposed a hypothetic alternative metabolic pathway involved in PAH metabolism by Fusarium solani. - An alternative metabolic pathway was demonstrated

  4. Preliminary evidence of the role of hydrogen peroxide in the degradation of benzo[a]pyrene by a non-white rot fungus Fusarium solani

    Energy Technology Data Exchange (ETDEWEB)

    Veignie, Etienne; Rafin, Catherine; Woisel, Patrice; Cazier, Fabrice

    2004-05-01

    In order to study the enzymatic mechanisms involved in the successive steps of BaP degradation by a Deuteromycete fungus Fusarium solani, we developed an indirect approach by using inhibitors of enzymes. We used either specific inhibitors of peroxidases (i.e. salicylhydroxamic acid) and of cytochrome P-450 (i.e. piperonyl butoxyde) or inhibitors of both enzymes (i.e. potassium cyanide). Surprisingly, no expected decrease of BaP degradation was observed with most inhibitors tested. On the contrary, more BaP was degraded. Only butylated hydroxytoluene, which acts as a free radical scavenger, inhibited BaP degradation. The inhibition of these enzymes, which use H{sub 2}O{sub 2} as a cosubstrat, might have resulted in an increase of hydrogen peroxide availability in the fungal cultures. This enhancement could induce formation of reactive oxygen species (ROS) which might be the agents that initiate benzo[a]pyrene oxidation. This study proposed a hypothetic alternative metabolic pathway involved in PAH metabolism by Fusarium solani. - An alternative metabolic pathway was demonstrated.

  5. Suppression of phytopathogenic fungi by hexane extract of Nepenthes ventricosa x maxima leaf.

    Science.gov (United States)

    Shin, Kwang-Soo; Lee, Samkeun; Cha, Byeong Jin

    2007-12-01

    The hexane extract of Nepenthes ventricosa x maxima leaf exhibited antifungal activity against Alternaria alternata, Aspergillus niger, Bipolaris oryzae, Fusarium oxysporum, Phytophthora capsici, Rhizoctonia solani, Rhizopus stolonifer var. stolonifer and Sclerotinia sclerotiorum. PMID:17573203

  6. Population performance of collembolans feeding on soil fungi from different ecological niches

    DEFF Research Database (Denmark)

    Larsen, J.; Johansen, A.; Larsen, S.E.; Heckmann, L.H.; Jakobsen, Iver; Krogh, P.H.

    2008-01-01

    The potential reproductive value of arbuscular mycorrhizal fungi (Gloinus intraradices and Glomus invermaium), root pathogenic fungi (Rhizoctonia solani and Fusarium culmorum) and saprotrophic fungi (Penicillium hordei and Trichoderma harzianum) were examined for the collembolans Folsomia candida...

  7. Genome Sequence of Dickeya solani, a New soft Rot Pathogen of Potato, Suggests its Emergence May Be Related to a Novel Combination of Non-Ribosomal Peptide/Polyketide Synthetase Clusters

    Directory of Open Access Journals (Sweden)

    Linda Garlant

    2013-12-01

    Full Text Available Soft rot Enterobacteria in the genera Pectobacterium and Dickeya cause rotting of many crop plants. A new Dickeya isolate has been suggested to form a separate species, given the name Dickeya solani. This bacterium is spreading fast and replacing the closely related, but less virulent, potato pathogens. The genome of D. solani isolate D s0432-1 shows highest similarity at the nucleotide level and in synteny to D. dadantii strain 3937, but it also contains three large polyketide/fatty acid/non-ribosomal peptide synthetase clusters that are not present in D. dadantii 3937. These gene clusters may be involved in the production of toxic secondary metabolites, such as oocydin and zeamine. Furthermore, the D. solani genome harbors several specific genes that are not present in other Dickeya and Pectobacterium species and that may confer advantages for adaptation to new environments. In conclusion, the fast spreading of D. solani may be related to the acquisition of new properties that affect its interaction with plants and other microbes in the potato ecosystem.

  8. Effect of topical 0.5% povidone-iodine compared to 5% natamycin in fungal keratitis caused by Fusarium solani in a rabbit model: a pilot study Efeito tópico de iodo-povidona 0,5% comparado com natamicina 5% em ceratites fúngicas causadas por Fusarium solani em um modelo animal de coelhos: estudo piloto

    Directory of Open Access Journals (Sweden)

    Lauro Augusto de Oliveira

    2008-12-01

    Full Text Available PURPOSE: To evaluate the efficacy of topical administration of 0.5% povidone-iodine in experimental Fusarium solani keratitis in rabbits. METHODS: Fungal keratitis caused by Fusarium solani was induced in the right eye of 24 New Zealand rabbits. The rabbits were randomly divided into 3 different treatment groups: Group I (povidone-iodine - treated with topical 0.5% povidone-iodine; Group II (natamycin - treated with topical 5% natamycin; and Group III (control - treated with topical saline solution. In all groups the rabbits were treated for three days and then sacrificed. The corneas were excised, macerated and immersed in 10 mL BHI. Culture samples were plated daily on Sabouraud's agar for 7 days, and the number of colony-forming units (CFU was counted. The rabbits were clinically evaluated during the treatment period. RESULTS: The povidone-iodine and natamycin groups demonstrated better efficacy than the control group based on the number of rabbits with no colonies growing. However, there were no statistically significant differences between the three groups when the number of CFU was analyzed (p>0.05. CONCLUSIONS: Our study demonstrates important methodological considerations in the use of in vivo animal models for the testing of antifungal agents. Using this sample size and methodology of counting CFU, topical 0.5% povidone-iodine demonstrated no benefit in the treatment of experimental Fusarium solani when compared with topical 5% natamycin.OBJETIVO: Avaliar a eficácia do uso tópico de iodo-povidona 0,5% em ceratite experimental por Fusarium solani em coelhos. MÉTODOS: Ceratite fúngica por Fusarium solani foi induzida no olho direito de 24 coelhos da raça New Zealand. Os coelhos foram divididos aleatoriamente em 3 diferentes grupos de tratamento: Grupo I (iodo-povidona - tratados com iodo-povidona 0,5%; Grupo II (natamicina - tratados com natamicina 5%; Grupo III (controle - tratados com solução salina. Os coelhos dos 3 grupos foram tratados por 3 dias e sacrificados em seguida. As córneas foram removidas cirurgicamente, maceradas e incubadas em meio BHI. Semeou-se culturas em placas de ágar Sabouraud, diariamente, durante 7 dias, e contou-se o número de unidades formadoras de colônias (UFC. Os coelhos foram avaliados clinicamente durante o período de tratamento. RESULTADOS: Os grupos iodo-povidona e natamicina demonstraram melhor eficácia do que o grupo controle considerando-se o número de coelhos nos quais não houve crescimento de colônias. Entretanto, não houve diferença estatística significante entre os 3 grupos quando se analizou o número de UFC (p>0,05. CONCLUSÃO: Este estudo demonstrou considerações metodológicas importantes na utilização de modelos animais para o teste de agentes antifúngicos. Usando a metodologia de contar UFC e com este tamanho amostral, administração tópica de iodo-povidona 0,5% não demonstrou benefício do tratamento de ceratite fúngica experimental causada por Fusarium solani quando comparado com a administração tópica de natamicina 5%.

  9. 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; Boiteux, Leonardo S.; 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 genótipos culti...

  10. EFECTO DE DIFERENTES NIVELES DE HUMEDAD EN EL SUELO SOBRE EL DESARROLLO DEL CARBÓN DE LA PAPA (Angiosorus solani) EN DOS VARIEDADES DE PAPA (Solanum tuberosum) BAJO CONDICIONES DE INVERNADERO Effect of different soil humidity on the development of potato smut (Angiosorus solani) in two potato varieties (Solanum tuberosum) under greenhouse conditions

    OpenAIRE

    Paulina Sepúlveda R.; Horacio López T.; Diego Nuñez L.

    2000-01-01

    El experimento tuvo como objetivo estudiar bajo condiciones de invernadero, el efecto de dos niveles de humedad en el suelo (20-25% y 50-55%), en el desarrollo del hongo Angiosorus solani inoculado artificialmente al suelo, donde se plantaron dos variedades de papa (Solanum tuberosum) Mirka y Cardinal, consideradas como resistente y susceptible a la enfermedad, respectivamente. Los porcentajes de humedad en el suelo se mantuvieron durante todo el período que duró el ensayo y la reposición de ...

  11. Changes in chemical composition of potato tubers caused by dry rot (Fusarium solani (Mart. Sacc. var. coeruleum (Sacc. Booth, Fusarium sulphureum Schlecht.

    Directory of Open Access Journals (Sweden)

    Zdzisław Przeździecki

    2013-12-01

    Full Text Available Investigations on effect of dry root (F. solani var. coeruleum and F. sulphureum pathogens on three potato cultivares Azalia, Pola, Odra chemical composition were carried out. Content of total nitrogen and protein, total saccharides, reducting and bisaccharides and vit. C was investigated. Significant decrease of total and protein nitrogen content in potatoes affected by Fusarium in relation to intact tubers was found. Moreover increase of reducting saccharides and bisaccharides in potatoes infected by Fusarium compared with controls was observed. Level of vit. C was decreased in tubers affected by Fusarium in all potato cultivars. In this experiment changes in chemical composition content in potato tubers were connected with a kind of dry rot patogen.

  12. Identification of the non-ribosomal peptide synthetase responsible for biosynthesis of the potential anti-cancer drug sansalvamide in Fusarium solani

    DEFF Research Database (Denmark)

    Romans Fuertes, Patricia; Søndergaard, Teis Esben; Sandmann, Manuela Ilse Helga; Wallenberg, Rasmus Dam; Nielsen, Kristian Fog; Hansen, Frederik Teilfeldt; Giese, Henriette; Brodersen, Ditlev Egeskov; Sørensen, Jens Laurids

    2016-01-01

    Sansalvamide is a cyclic pentadepsipeptide produced by Fusarium solani and has shown promising results as potential anti-cancer drug. The biosynthetic pathway has until now remained unidentified, but here we used an Agrobacterium tumefaciens- mediated transformation (ATMT) approach to generate...... knock-out mutants of two candidate non-ribosomal peptide synthetases (NRPS29 and NRPS30). Comparative studies of secondary metabolites in the two deletion mutants and wild type confirmed the absence of sansalvamide in the NRPS30 deletion mutant, implicating this synthetase in the biosynthetic pathway...... for sansalvamide. Sansalvamide is structurally related to the cyclic hexadepsipeptide destruxin, which both contain an α-hydroxyisocaproic acid (HICA) unit. A gene cluster responsible for destruxin production has previously been identified in Metarhizium robertsii together with a hypothetical...

  13. "A PCR-RFLP Method to Identification of the Important Opportunistic Fungi: Candida Species, Cryptococcus neoformans, Aspergillus famigatus and Fusarium solani"

    Directory of Open Access Journals (Sweden)

    SH Mirhendi

    2001-09-01

    Full Text Available Deep-seated fungal infection present with non specific symptoms and involove a large number of different organisms. DNA-based technology offers for eariler detection of fungal pathogens and then earlier initiation of antifungal therapy. In this study universal primers common to almost all fungi were used to amplification of internal transcribe spacer 1 and 2 region. Subsequent restriction enzyme analysis of PCR products, using HpaII allows us to identify the most medically opportunistic important fungi: Candida albicans, C. glabrata, C. tropicalis, C. kruzei, C. guilliermondi, Cryptococcus neoformans, Aspergillus fumigatus and Fusarium solani, according to sizely different bands in polyacrilamid gel electrophoresis. It seems that this panel of PCR-RFLP could be a rapid and useful molecular approach in diagnostic studies of invasive opportunistic fungal infections.

  14. Salicylic and jasmonic acid pathways are necessary for defence against Dickeya solani as revealed by a novel method for Blackleg disease screening of in vitro grown potato.

    Science.gov (United States)

    Burra, D D; Mühlenbock, P; Andreasson, E

    2015-09-01

    Potato is major crop ensuring food security in Europe, and blackleg disease is increasingly causing losses in yield and during storage. Recently, one blackleg pathogen, Dickeya solani has been shown to be spreading in Northern Europe that causes aggressive disease development. Currently, identification of tolerant commercial potato varieties has been unsuccessful; this is confounded by the complicated etiology of the disease and a strong environmental influence on disease development. There is currently a lack of efficient testing systems. Here, we describe a system for quantification of blackleg symptoms on shoots of sterile in vitro potato plants, which saves time and space compared to greenhouse and existing field assays. We found no evidence for differences in infection between the described in vitro-based screening method and existing greenhouse assays. This system facilitates efficient screening of blackleg disease response of potato plants independent of other microorganisms and variable environmental conditions. We therefore used the in vitro screening method to increase understanding of plant mechanisms involved in blackleg disease development by analysing disease response of hormone- related (salicylic and jasmonic acid) transgenic potato plants. We show that both jasmonic (JA) and salicylic (SA) acid pathways regulate tolerance to blackleg disease in potato, a result unlike previous findings in Arabidopsis defence response to necrotrophic bacteria. We confirm this by showing induction of a SA marker, pathogenesis-related protein 1 (StPR1), and a JA marker, lipoxygenase (StLOX), in Dickeya solani infected in vitro potato plants. We also observed that tubers of transgenic potato plants were more susceptible to soft rot compared to wild type, suggesting a role for SA and JA pathways in general tolerance to Dickeya. PMID:25903921

  15. Efecto de hongos endófitos de orquídeas del grupo Rhizoctonia y otros endófitos cultivables sobre el desarrollo de plantas de Vanilla planifolia Jacks.

    OpenAIRE

    Ordoñez Castillo, Nancy Fiorela

    2012-01-01

    Los hongos endófitos y formadores de micorriza se encuentran muy ligados entre sí, y a veces es imposible discutir estas asociaciones por separado. Muchos trabajos han centrado la atención sobre la relación entre las orquídeas y el género-forma Rhizoctonia, hongo generalmente reportado como formador de micorriza orquideoide y también como patógeno de una variedad de cultivos. Sin embargo, recientemente, los hongos endófitos no formadores de micorriza han ganado atención, pero con la limitante...

  16. Screening of Potato Lines Including Department Genetic & National Plant Gene Bank of Iran for Resistance to Early Blight (Alternaria. solani) Using Culture Filtrate Produced by the Fungus

    OpenAIRE

    Hamid Reza Mirkarimi; Ahmad Abasi Moghadam; Javad Mozafari

    2013-01-01

    Potato is a plant that can be influenced by early blight disease. Early blight is one of the most destructive plant diseases, especially in the members of solanaceae family. This disease can reduce yield. Experiment design was a factorial randomized complete design to evaluate the isolate pathogenic Alternaria solani in National Plant Gene Bank of Iran, during 2008-2009. This experiment was conducted with three replications, and the factors include test methods and thre...

  17. Antifungal Activity of Medicinal Plants from Jordan Environment

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    Amjad B. Khalil

    2005-01-01

    Full Text Available Medicinal plants collected from different locations in Jordan were tested for their antifungal activities against 5 plant pathogenic fungi: Phytophthora infestans, Fuusarium oxysporum, Rhizoctonia solani, Stemphylium solani and Mucor sp. Data of this study showed that the highest growth inhibition of all fungi was observed with Salvia indica, which gave (66.3%, of inhibitions for Stemphylium, followed by Mucor (60.5%, R. solani (51.7%, F. oxysporum (48% and P. infestans (28.8%.

  18. Antifungal Activity of Medicinal Plants from Jordan Environment

    OpenAIRE

    Khalil, Amjad B.; Basem F. Dabaneh; Ghandi H. Anfoka

    2005-01-01

    Medicinal plants collected from different locations in Jordan were tested for their antifungal activities against 5 plant pathogenic fungi: Phytophthora infestans, Fuusarium oxysporum, Rhizoctonia solani, Stemphylium solani and Mucor sp. Data of this study showed that the highest growth inhibition of all fungi was observed with Salvia indica, which gave (66.3%), of inhibitions for Stemphylium, followed by Mucor (60.5%), R. solani (51.7%), F. oxysporum (48%) and P. infestans (28.8%).

  19. In vitro Antifungal Activity of Some Plant Essential Oils

    OpenAIRE

    Abdallah M. Elgorban; Bahkali, Ali H.; Mohamed A. El- Metwally; Mohamed Elsheshtawi; Mohamed A. Abdel- Wahab

    2015-01-01

    In the present study the antimicrobial activity of essential oils of allium bulb (Allium cepa L.), black cumin seeds (Nigella sativa L.) and eucalyptus (Eucalyptus globulus Labill) were evaluated against five fungi (Fusarium oxysporum f.sp. melonis, Fusarium solani, Fusarium verticillioides, Sclerotinia sclerotiorum and Rhizoctonia solani). Allium cepa oils completely inhibited the mycelial growth of Fusarium oxysporum f.sp. melonis, Fusarium solani and Sclerotinia sclerotiorum at 500 ppm con...

  20. Reduction of Soybean Root and Stalk Rots by Growth Substances Under Salt Stress Conditions

    OpenAIRE

    M.A. EL-Metwally; K.M. Abd El-Hai; S.M. El-Baz

    2010-01-01

    The causal pathogens of root rot and stalk rot of soybean were isolated from infected plants. Fusarium oxysporum, F. solani, Macrophomina phaseolina and Rhizoctonia solani were the main causal pathogens of pre- and post-emergence damping-off. The isolated fungi especially R. solani caused anatomically deformation in the basal portion of infected stem including complete disruption in epidermal cells and degradation of primary cell wall in cortical cells. The growth substances; Ethrel, Indole B...

  1. CD45-mediated signaling pathway is involved in Rhizoctonia bataticola lectin (RBL)-induced proliferation and Th1/Th2 cytokine secretion in human PBMC

    Energy Technology Data Exchange (ETDEWEB)

    Pujari, Radha [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India); Eligar, Sachin M. [Department of Biochemistry, Karnatak University, Dharwad, 580003 Karnataka (India); Kumar, Natesh [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India); Nagre, Nagaraja N.; Inamdar, Shashikala R.; Swamy, Bale M. [Department of Biochemistry, Karnatak University, Dharwad, 580003 Karnataka (India); Shastry, Padma, E-mail: padma@nccs.res.in [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer RBL, a potent mitogenic and complex N-glycan specific lectin binds to CD45 on PBMC. Black-Right-Pointing-Pointer RBL triggers CD45-mediated signaling involved in activation of p38MAPK and STAT-5. Black-Right-Pointing-Pointer Inhibition of CD45 PTPase signaling blocks RBL-induced ZAP70 phosphorylation. Black-Right-Pointing-Pointer RBL-CD45 mediated signaling is crucial for RBL-induced immunodulatory activities. -- Abstract: We earlier reported the mitogenic and immunostimulatory activities of Rhizoctonia bataticola lectin (RBL), purified from phytopathogenic fungus R. bataticola in human PBMC. The lectin demonstrates specificity towards glycoproteins containing complex N-glycans. Since CD45-protein tyrosine phosphatase that abundantly expresses N-glycans is important in T-cell signaling, the study aimed to investigate the involvement of CD45 in the immunomodulatory activities of RBL. Flowcytometry and confocal microscopy studies revealed that RBL exhibited binding to PBMC and colocalized with CD45. The binding was comparable in cells expressing different CD45 isoforms-RA, -RB and -RO. CD45 blocking antibody reduced the binding and proliferation of PBMC induced by RBL. CD45-PTPase inhibitor dephostatin inhibited RBL-induced proliferation, expression of CD25 and pZAP-70. RBL-induced secretion of Th1/Th2 cytokines were significantly inhibited in presence of dephostatin. Also, dephostatin blocked phosphorylation of p38MAPK and STAT-5 that was crucial for the biological functions of RBL. The study demonstrates the involvement of CD45-mediated signaling in RBL-induced PBMC proliferation and Th1/Th2 cytokine secretion through activation of p38MAPK and STAT-5.

  2. Effect of biotherapic of Alternaria solani on the early blight of tomato-plant and the in vitro development of the fungus

    Directory of Open Access Journals (Sweden)

    Marcus Zulian Teixeira

    2010-12-01

    Full Text Available Background: homeopathy is a means permitted in organic agriculture to control disease and plagues; biotherapics are a practical means for farmers to intervene on the health of plants in agro-ecological systems of production. Tomato-plants can be affected by several diseases, one of the most significant ones in Brazil is early blight, caused by fungus Alternaria solani, due to the damage it causes and its wide distribution in the country. Aims: to establish whether a biotherapic of A. solani may interfere on the in vitro development of the fungus and whether it affects the severity of early blight on tomato-plants in greenhouse. Methods: the effect of the biotherapic on the fungus was evaluated through the percentage of germinated spores under microscope and the growth of colonies in a culture medium. Treatments used were: biotherapic 26cH, 27cH, 28cH, 29cH and 30cH; sterilized distilled water; and diluted and agitated hydroalcoholic solution. The effect of the biotherapic on the development of disease was evaluated in 4 experiments in greenhouse. Plants were kept in vases and subjected to artificial inoculation of the fungus after the application of treatments. Evaluation of disease was carried out through diagrammatic scale. Results: no treatment affected the germination of spores or the development of fungus colonies in the culture medium. In the first test, treatment 26cH differed from water in Tukey’s test at 5% but did not differed from diluted and agitated hydroalcoholic solution. In the second test, treatments 27cH and 28cH showed significant difference from both water and hydroalcoholic solution with an average control of disease of 57% and 62% respectively. The other 2 tests did nor exhibit any significant effect. Conclusions: there was no direct effect of the biotherapic on the fungus, but there was an effect on the severity of the disease. Factors affecting the efficiency of the biotherapic must be better understood before it can be recommended to farmers for the management of early blight in tomato-plants.

  3. 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

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    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.

  4. Lethal synergy of solar UV-radiation and H(2)O(2) on wild Fusarium solani spores in distilled and natural well water.

    Science.gov (United States)

    Sichel, C; Fernández-Ibáñez, P; de Cara, M; Tello, J

    2009-04-01

    Environmentally-friendly disinfection methods are needed in many industrial applications. As a natural metabolite of many organisms, hydrogen peroxide (H(2)O(2))-based disinfection may be such a method as long as H(2)O(2) is used in non-toxic concentrations. Nevertheless, when applied alone as a disinfectant, H(2)O(2) concentrations need to be high enough to achieve significant pathogen reduction, and this may lead to phytotoxicity. This paper shows how H(2)O(2) disinfection concentrations could be significantly reduced by using the synergic lethality of H(2)O(2) and sunlight the first time for fungi and disinfection. Experiments were performed on spores of Fusarium solani, the ubiquitous, pytho- and human pathogenic fungus. Laboratory (250-mL bottles) and pilot plant solar reactors (2 x 14 L compound parabolic collectors, CPCs) were employed with distilled water and real well water under natural sunlight. This opens the way to applications for agricultural water resources, seed disinfection, curing of fungal skin infections, etc. PMID:19217637

  5. Fatal Fusarium solani species complex infections in elasmobranchs: the first case report for black spotted stingray (Taeniura melanopsila) and a literature review.

    Science.gov (United States)

    Fernando, Nimal; Hui, Suk-Wai; Tsang, Chi-Ching; Leung, Shui-Yee; Ngan, Antonio H Y; Leung, Raymond W W; Groff, Joseph M; Lau, Susanna K P; Woo, Patrick C Y

    2015-07-01

    Fusarium species are environmental saprophytic fungi. Among the many Fusarium species, members of the Fusarium solani species complex (FSSC) are the most prevalent and virulent in causing human and animal infections. In this study, we describe the first case of fatal FSSC infection in a black spotted stingray and three concomitant infections in scalloped hammerhead sharks. In the stingray, cutaneous lesions were characterised by ulcers and haemorrhage of the ventral pectoral fin, or 'ray', especially around the head; while cutaneous lesions in the sharks were characterised by ulcers, haemorrhage, as well as white and purulent exudates at the cephalic canals of the cephalofoil and lateral line. Histological sections of the cutaneous lesions revealed slender (1-4 μm in diameter), branching, septate fungal hyphae. Internal transcribed spacer region and 28S nrDNA sequencing of the fungal isolates from the fish showed two isolates were F. keratoplasticum (FSSC 2) and the other two were FSSC 12. Environmental investigation revealed the FSSC strains isolated from water and biofilms in tanks that housed the elasmobranchs were also F. keratoplasticum and FSSC 12. Fusarium is associated with major infections in elasmobranchs and FSSC 12 is an emerging cause of infections in marine animals. DNA sequencing is so far the most reliable method for accurate identification of Fusarium species. PMID:26095191

  6. Heterologous overexpression and biochemical characterization of the (galactophospho)lipase from Fusarium solani in Pichia pastoris that is expressed in planta.

    Science.gov (United States)

    Jallouli, Raida; Ali, Madiha Bou; Charfeddine, Mariam; Gargouri-Bouzid, Radhia; Gargouri, Youssef; Bezzine, Sofiane

    2016-03-01

    High-level extracellular production of Fusarium solani (galactophospho)lipase, named FSL, was achieved using a Pichia pastoris X33 expression system. The (galactophospho) lipase encoding gene was cloned into pGAPZ?A with the Saccharomyces cerevisiae ?-factor signal sequence by two different ways. The two constructs consist of an additional sequence of a (His)6-tag of the vector fused to the N-terminus of this enzyme (tFSL) while the other expression vector was constructed without any additional sequence (rFSL). Compared to the native enzyme (nFSL) (18.75mg/L), a high level secretion of rFSL (310mg/L) and tFSL (240mg/L) was achieved providing an important improvement in enzyme production. Biochemical characterization showed that pure recombinant proteins (rFSL and tFSL) presented similar behaviour towards triglycerides, phospholipid and galactolipid. Like the nFSL, rFSL and tFSL are active at high concentration of bile salts (4mM) and calcium ions enhanced lipase activity. During plant infection, transcripts of this fungal lipase gene were detected 3, 7 and 10 days post infection. PMID:26675137

  7. 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

    Directory of Open Access Journals (Sweden)

    Bruno Eduardo C de Miranda

    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.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 in 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 management systems of the disease.

  8. Effect of Neem (Azardirachta indica A. Juss Seeds and Leaves Extract on Some Plant Pathogenic Fungi

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    M.A. Moslem

    2009-01-01

    Full Text Available 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 extracts could cause growth inhibition of tested fungi, although the rate of inhibition of tested fungi varied with different extracts and concentrations. But all these extracts and concentrations of extract inhibited the growth of pathogenic fungi at a significant level. Azadirachtin, nimonol and expoxyazdirodione were detected from neem extract by using High Performance Liquid Chromatography (HPLC. We can conclude that neem leave and seed extracts were effective as antifungal against all tested fungi but F. oxysporum and R. solani were the most sensitive fungi.

  9. Screening of fungi implicated in the dieback of olive trees (Olea europea in Chebika’s area

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    Boughalleb-M’Hamdi N

    2011-10-01

    Full Text Available Several surveys were conducted during spring 2008 in Chebika’s area in Tunisia.Samples were collected from infected plants showed different types of symptoms andthey have been the subject of mycological analysis. The morphological identification offungal colonies isolated from roots, crown and stems of two olive varieties Koroneiki andChemlali Sfax, revealed the presence of a fungi complex including Fusarium oxysporum,Fusarium solani, Rhizoctonia solani, Verticillium dahliae, Cladosporium fulvum,Alternaria solani, Alternaria tenuis, Bispora punctata. and Cylindrocarpon.sp; Although,those fungi Fusarium oxysporum, Fusarium solani, Rhizoctonia solani and Verticilliumdahliae are ubiquitous and the predominant one. Pathogenicity results revealed that thefungi isolated from olive trees exhibited typical symptoms on Koroneiki variety incontrolled conditions.

  10. Genotyping of Fusarium Isolates from Onychomycoses in Colombia: Detection of Two New Species Within the Fusarium solani Species Complex and In Vitro Antifungal Susceptibility Testing.

    Science.gov (United States)

    Guevara-Suarez, Marcela; Cano-Lira, José Francisco; Cepero de García, María Caridad; Sopo, Leticia; De Bedout, Catalina; Cano, Luz Elena; García, Ana María; Motta, Adriana; Amézquita, Adolfo; Cárdenas, Martha; Espinel-Ingroff, Ana; Guarro, Josep; Restrepo, Silvia; Celis, Adriana

    2016-04-01

    Fusariosis have been increasing in Colombia in recent years, but its epidemiology is poorly known. We have morphologically and molecularly characterized 89 isolates of Fusarium obtained between 2010 and 2012 in the cities of Bogotá and Medellín. Using a multi-locus sequence analysis of rDNA internal transcribed spacer, a fragment of the translation elongation factor 1-alpha (Tef-1α) and of the RNA-dependent polymerase subunit II (Rpb2) genes, we identified the phylogenetic species and circulating haplotypes. Since most of the isolates studied were from onychomycoses (nearly 90 %), we carried out an epidemiological study to determine the risk factors associated with such infections. Five phylogenetic species of the Fusarium solani species complex (FSSC), i.e., F. falciforme, F. keratoplasticum, F. lichenicola, F. petroliphilum, and FSSC 6 as well as two of the Fusarium oxysporum species complex (FOSC), i.e., FOSC 3 and FOSC 4, were identified. The most prevalent species were FOSC 3 (38.2 %) followed by F. keratoplasticum (33.7 %). In addition, our isolates were distributed into 23 haplotypes (14 into FOSC and nine into FSSC). Two of the FSSC phylogenetic species and two haplotypes of FSSC were not described before. Our results demonstrate that recipients of pedicure treatments have a lower probability of acquiring onychomycosis than those not receiving such treatments. The antifungal susceptibility of all the isolates to five clinically available agents showed that amphotericin B was the most active drug, while the azoles exhibited lower in vitro activity. PMID:26943726

  11. Secretome analysis of the mycoparasitic fungus Trichoderma harzianum ALL 42 cultivated in different media supplemented with Fusarium solani cell wall or glucose.

    Science.gov (United States)

    Ramada, Marcelo Henrique Soller; Steindorff, Andrei Stecca; Bloch, Carlos; Ulhoa, Cirano José

    2016-02-01

    Trichoderma harzianum is a fungus well known for its potential as a biocontrol agent against many fungal phytopathogens. The aim of this study was to characterize the proteins secreted by T. harzianum ALL42 when its spores were inoculated and incubated for 48 h in culture media supplemented with glucose (GLU) or with cell walls from Fusarium solani (FSCW), a phytopathogen that causes severe losses in common bean and soy crops in Brazil, as well as other crop diseases around the world. Trichoderma harzianum was able to grow in Trichoderma Liquid Enzyme Production medium (TLE) and Minimal medium (MM) supplemented with FSCW and in TLE+GLU, but was unable to grow in MM+GLU medium. Protein quantification showed that TLE+FSCW and MM+FSCW had 45- and 30- fold, respectively, higher protein concentration on supernatant when compared to TLE+GLU, and this difference was observable on 2D gel electrophoresis (2DE). A total of 94 out of 105 proteins excised from 2DE maps were identified. The only protein observed in all three conditions was epl1. In the media supplemented with FSCW, different hydrolases such as chitinases, β-1,3-glucanases, glucoamylases, α-1,3-glucanases and proteases were identified, along with other proteins with no known functions in mycoparasitism, such as npp1 and cys. Trichoderma harzianum showed a complex and diverse arsenal of proteins that are secreted in response to the presence of FSCW, with novel proteins not previously described in mycoparasitic-related studies. PMID:26631988

  12. Evaluación de la capacidad biocontroladora de trichoderma harzianum rifai contra fusarium solani (mart.) sacc. asociado al complejo “secadera” en maracuyá, bajo condiciones de invernadero.

    OpenAIRE

    Cubillos Hinojosa, Juan Guillermo; Páez Redondo, Alberto; Mejía Doria, Lauris

    2012-01-01

    En la zona bananera del Magdalena en Colombia se ha reportado una disminución del 30% en la producción del cultivo de maracuyá (Passiflora edulis var. flavicarpa) como consecuencia de la muerte de unidades productivas causadas por la enfermedad secadera o marchitez vascular, a la cual está asociada el hongo Fusarium solani. Con el objeto de contribuir al manejo del problema sanitario, se evaluó bajo condiciones de invernadero el efecto biocontrolador de la cepa nativa TCN-014 y la cepa comerc...

  13. Isolation and molecular characterization of Rhizoctonia-like fungi associated with orchid roots in the Quadrilátero Ferrífero and Zona da Mata regions of the state of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Ricardo Eustáquio Nogueira

    2014-06-01

    Full Text Available Mycorrhizal associations can be considered required for orchids, which depend on the fungi for germination and establishment in natural conditions. Knowledge of the mycorrhizal fungi is important for programs aimed at the reintroduction, conservation and management of orchid species. The objective of this study was the molecular characterization of Rhizoctonia-like fungi from orchids in the Quadrilátero Ferrífero ("Iron Quadrangle" and Zona da Mata ("Forest Zone" regions of the state of Minas Gerais, Brazil. The affinities of these fungi were studied by comparing the rRNA internal transcribed spacer region with that of other isolates and sequences in GenBank. Three isolates had an affinity for Epulorhiza repens, and one was the holotypeof E. epiphytica.

  14. IMPROVMENT BIOCONTROL OF DAMPING-OFF AND ROOT ROT/WILT OF FABA BEAN BY SALICYLIC ACID AND HYDROGEN PEROXIDE

    OpenAIRE

    Montaser F. Abdel-Monaim

    2013-01-01

    Rhizoctonia solani, Fusarium solani, F. oxysporum and Macrophomina phaseolina were found to be associated with root rot and wilt symptoms of faba bean plants collected from different fields in New Valley governorate, Egypt. All the obtained isolates were able to attack faba bean plants (cv. Giza 40) causing damping-off and root rot/wilt diseases. R. solani isolates 2 and 5, F. solani isolate 8, F. oxysporum isolate 12 and M. phaseolina isolate 14 were the more virulent ones in the pathogenici...

  15. Improvement of Biocontrol of Damping-off and Root Rot/Wilt of Faba Bean by Salicylic Acid and Hydrogen Peroxide

    OpenAIRE

    Montaser Fawzy ABDEL-MONAIM

    2013-01-01

    Rhizoctonia solani, Fusarium solani, F. oxysporum, and Macrophomina phaseolina were found to be associated with root rott and wilt symptoms of faba bean plants collected from different fieldes in New Valley governorate, Egypt. All the obtained isolates were able to attack faba bean plants (cv. Giza 40) causing damping-off and root rot/wilt diseases. R. solani isolates 2 and 5, F. solani isolate 8, F. oxysporum isolate 12 and M. phaseolina isolate 14 were the more virulent ones in the pathogen...

  16. Endophytic bacteria from Piper tuberculatum Jacq.: isolation, molecular characterization, and in vitro screening for the control of Fusarium solani f. sp piperis, the causal agent of root rot disease in black pepper (Piper nigrum L.).

    Science.gov (United States)

    Nascimento, S B; Lima, A M; Borges, B N; de Souza, C R B

    2015-01-01

    Endophytic bacteria have been found to colonize internal tissues in many different plants, where they can have several beneficial effects, including defense against pathogens. In this study, we aimed to identify endophytic bacteria associated with roots of the tropical piperaceae Piper tuberculatum, which is known for its resistance to infection by Fusarium solani f. sp piperis, the causal agent of black pepper (Piper nigrum) root rot disease in the Amazon region. Based on 16S rRNA gene sequence analysis, we isolated endophytes belonging to 13 genera: Bacillus, Paenibacillus, Pseudomonas, Enterobacter, Rhizobium, Sinorhizobium, Agrobacterium, Ralstonia, Serratia, Cupriavidus, Mitsuaria, Pantoea, and Staphylococcus. The results showed that 56.52% of isolates were associated with the phylum Proteobacteria, which comprised α, β, and γ classes. Other bacteria were related to the phylum Firmicutes, including Bacillus, which was the most abundant genus among all isolates. Antagonistic assays revealed that Pt12 and Pt13 isolates, identified as Pseudomonas putida and Pseudomonas sp, respectively, were able to inhibit F. solani f. sp piperis growth in vitro. We describe, for the first time, the molecular identification of 23 endophytic bacteria from P. tuberculatum, among which two Pseudomonas species have the potential to control the pathogen responsible for root rot disease in black pepper in the Amazon region. PMID:26214435

  17. Electronics and electronic systems

    CERN Document Server

    Olsen, George H

    1987-01-01

    Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

  18. Fungi isolated from Stewartia pseudocamellia Max. seeds and their pathogenesis

    Directory of Open Access Journals (Sweden)

    Halina Kurzawińska

    2012-12-01

    Full Text Available The aim of studies was to determine typical composition of fungi occurring on seeds of Stewartia pseudocamellia.The studies conducted on 100 disinfected and 100 nondisinfected seeds of these plants.Isolates of Alternaria alternata, Fusarium oxysporum, Cylindrocarpon radicicola and Rhizoctonia solani were characterized by pathogenicity towards the investigated Stewartia pseudocamellia. In the laboratory experiment, 204 isolations of microorganisms were obtained that belonged to 20 species and form of fungi and bacteria. Among fungi there were both of parasite (Alternaria alternata, Botrytis cinerea, Fusarium spp., Rhizoctonia solani and typical saprophytic (Cladosporium spp., Penicillium spp., Aspergillus spp., Epicoccum spp., Mucor spp.. The dominant fungus on seeds was Alternaria alternata. Among the investigated isolates only one isolate (R4 Rhizoctonia solani, was strongly pathogenic, isolates (A1 Alternaria alternata were weakly pathogenic to seedlings of Stewartia pseudocamellia.

  19. Efeito de meios de cultura e fatores físicos no crescimento e esporulação de Alternaria dauci e A. solani Effect of culture media and physical factors on growth and sporulation of Alternaria dauci and A. solani

    Directory of Open Access Journals (Sweden)

    Pablo Pulz

    2009-06-01

    Full Text Available Alternaria dauci e Alternaria solani são espécies / 24 h. O método desenvolvido neste trabalho foi comparado ao reconhecidamente difíceis de esporular em meios de cultura. Este tradicionalmente utilizado (BDA, 25 ºC, 12 h luz branca / 12 h trabalho teve o objetivo de verificar a influência de alguns meios escuro e raspagem da colônia. O meio V8-ágar, temperatura de 25 de cultura e fatores fisicos sobre o crescimento micelial e a ºC, luz NUV e raspagem das colônias exerceram influência mais esporulação dessas espécies. Testaram-se os meios de cultura BDA, marcante no crescimento e esporulação. O fotoperíodo 12 h luz NUV Aveia e V8; temperaturas (15ºC, 20ºC, 25ºC, 30ºC e 35ºC / 12 h escuro foi o que mais estimulou a esporulação. Observou-se que, comprimentos de onda da luz durante a incubação (amarelo, azul, de modo geral, períodos de escuro maiores que os períodos de luz, branco, NUV, verde e vermelho; tipos de injúria aplicados à aplicados após injúria da colônia, favoreceram a esporulação. O colônia (raspagem, UV, irradiação de microondas, e temperatura método desenvolvido mostrou-se nitidamente superior ao de 100 ºC e fotoperíodos (luz / escuro, respectivamente, de 24 h tradicionalmente utilizado, para crescimento e esporulação de ambas / 0 h, 22 h / 2 h, 17 h / 7 h, 12 h / 12 h, 7 h / 17 h, 2 h / 22 e 0 h as espécies.Alternaria dauci and A. solani are fungal species known for h and 0 h / 24 h were tested. The method developed in this study was difficult sporulation in culture media. This study had the objective of compared to the traditional procedure (BDA, 25 ºC, 12 h white / 12 verifying the influence of some physical factors on mycelia growth h dark light and scratching of the colony. V8-agar medium, and sporulation of these two species. Culture media (BDA, oat and temperature of 25 ºC, NUV light and scratching of the colonies had a V8, temperature (15ºC, 20ºC, 25ºC, 30ºC and 35ºC, light wavelengths marked effect on growth and sporulation. The 12 h light / 12 h dark during incubation (yellow, blue, white, NUV, green, and red, injury photoperiod stimulated sporulation most. In general, longer dark types applied to the colony (scratching, UV, microwave irradiation, than light periods after the injury of the colony favored sporulation. and temperature of 100 ºC and photoperiods (light / dark, respectively, The developed procedure is clearly superior to the traditional method of 24 h / 0 h, 22 h / 2 h, 17 h / 7 h, 12 h / 12 h, 7 h / 17 h, 2 h / 22 for growth and sporulation of both species.

  20. Diversity and activity of Lysobacter species from disease suppressive soils

    OpenAIRE

    Gmez Expsito, Ruth; Postma, Joeke; Raaijmakers, Jos M.; de Bruijn, Irene

    2015-01-01

    The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani, but their actual role in disease suppression is still unclear. Here, the antifungal and plant growth-promoting activities of 18 Lysobacter strains, including 11 strains from Rhizoctonia-suppressi...

  1. Effects of Fungal Root Pathogens on the Population Dynamics of Biocontrol Strains of Fluorescent Pseudomonads in the Wheat Rhizosphere

    OpenAIRE

    Mazzola, Mark; Cook, R. James

    1991-01-01

    The influences of Gaeumannomyces graminis var. tritici (which causes take-all of wheat), Rhizoctonia solani AG-8 (which causes rhizoctonia root rot of wheat), Pythium irregulare, P. aristosporum, and P. ultimum var. sporangiiferum (which cause pythium root rot of wheat) on the population dynamics of Pseudomonas fluorescens 2-79 and Q72a-80 (bicontrol strains active against take-all and pythium root rot of wheat, respectively) in the wheat rhizosphere were examined. Root infection by either G....

  2. Enhanced quantitative resistance against fungal disease by combinatorial expression of different barley antifungal proteins in transgenic tobacco

    DEFF Research Database (Denmark)

    Jach, G; Görnhardt, B; Mundy, J; Logemann, J; Pinsdorf, E; Leah, R; Schell, J; Maas, C

    1995-01-01

    original cytosolic form or fused to a plant secretion peptide (spRIP). Fungal infection assays revealed that expression of the individual genes in each case resulted in an increased protection against the soilborne fungal pathogen Rhizoctonia solani, which infects a range of plant species including tobacco....... Transgenic tobacco lines were generated with tandemly arranged genes coding for RIP and CHI as well as GLU and CHI. The performance of tobacco plants co-expressing the barley transgenes GLU/CHI or CHI/RIP in a Rhizoctonia solani infection assay revealed significantly enhanced protection against fungal attack...

  3. Biological Control of Tomato Seedling Damping off with Streptomyces sp.

    Directory of Open Access Journals (Sweden)

    D. Dhanasekaran

    2005-01-01

    Full Text Available Twenty six antibiotic producing Streptomyces were isolated from soils of Cuddalore Tamil Nadu, India and were evaluated for their ability to inhibit plant pathogenic Rhizoctonia solani in vitro. It was found that the isolates having pathogenic inhibitory ability and also controls Rhizoctonia solani damping off in tomato in interested field soils. The Streptomyces isolates tested significantly reduced damping off severity in tomato. A variation in their effect on plant disease severity, percentage dead plants and plant biomass in the presence of the pathogen, was observed among the isolates.

  4. Effect of Avicennia Marina and Paecilomyces lilacinus on Root Rot - Root Knot Diseases of Tomato

    Directory of Open Access Journals (Sweden)

    Fatima S. Mehdi

    1999-01-01

    Full Text Available Potential of Avicennia marina (mangrove with Paecilomyces lilacinus for the control of root infecting fungi viz., Macrophomina phaseolina, Fusarium solani, Rhizoctonia solani and Meloidogyne javanica root knot nematode was evaluated invitro and under green house conditions. Soil amendment with A. marina alone or in combination with P. lilacinus significantly controlled root rot-root knot diseases in tomato with enhancement in plant growth. Organic amendment enhanced biocontrol efficacy of P. lilacinus in the control of root pathogens.

  5. Using Commercial Compost as Control Measures against Cucumber Root-Rot Disease

    OpenAIRE

    Kamel Kamal Sabet; Magdy Mohamed Saber; Mohamed Adel-Aziz El-Naggar; Nehal Samy El-Mougy; Hatem Mohamed El-Deeb; Ibrahim El-Saied El-Shahawy

    2013-01-01

    Five commercial composts were evaluated to suppress the root-rot pathogens (Fusarium solani (Mart.) App. and Wr, Pythium ultimum Trow, Rhizoctonia solani Kuhn, and Sclerotium rolfsii Sacc.) of cucumber plants under in vitro and greenhouse conditions. In vitro tests showed that all tested unautoclaved and unfiltrated composts water extracts (CWEs) had inhibitor effect against pathogenic fungi, compared to autoclaved and filtrated ones. Also, the inhibitor effects of 40 bacteria and 15 fungi is...

  6. Anlise microscpica da resistncia do arroz queima das bainhas mediada pelo silcio

    OpenAIRE

    Daniel Augusto Schurt; Ricardo Dutra Reis; Leonardo Araujo; Vivian Carr- Missio; Fabrcio de vila Rodrigues

    2015-01-01

    A queima das bainhas, causada pelo fungo Rhizoctonia solani Khn, uma das mais importantes e destrutivas doenas que afetam a produo de arroz no mundo. Embora o silcio (Si) seja capaz de reduzir a intensidade da queima das bainhas, os mecanismos de resistncia mediados por esse elemento permanecem desconhecidos. Assim, este trabalho teve como objetivo investigar a nvel microscpico o efeito do Si na resistncia do arroz infeco por R. solani. Plantas de arroz das cultivares BR-Irga-4...

  7. Interaction of Rotylenchulus reniformis with Seedling Disease Pathogens of Cotton

    OpenAIRE

    Palmateer, A. J.; Lawrence, K. S.; van Santen, E.; Morgan-Jones, G.

    2004-01-01

    The impact of 10 Fusarium species in concomitant association with Rotylenchulus reniformis on cotton seedling disease was examined under greenhouse conditions. In experiment 1, fungal treatments consisted of Fusarium chlamydosporum, F. equiseti, F. lateritium, F. moniliforme, F. oxysporum, F. oxysporum f.sp. vasinfectum, F. proliferatum, F. semitectum, F. solani, and F. sporotrichioides; Rhizoctonia solani; and Thielaviopsis basicola. The experimental design was a 2 × 14 factorial consisting ...

  8. Isolation, Identification and antimicrobial activity of pseudomonads isolated from the rhiszosphere of popatoes growing in Algeria

    OpenAIRE

    Guechi, Abla; Nicklin, Jane; Drider, Djamel; Prévost, Hervé; Strange, Richard N.

    2012-01-01

    Fourteen bacterial isolates from the rhizosphere of potato plants growing near Sétif, (Algeria) were characterised as fluorescent Pseudomonads by phenotypical methods and one was identified as Pseudomonas chlororaphis by sequencing ribosomal DNA. In dual culture, this isolate inhibited the growth of the phytopathogenic fungi Fusarium oxysporum f. sp. lycopersici, F. oxysporum f. sp. albedinis, F. solani and Rhizoctonia solani and the oomycete Pythium ultimum. Extracts of supernatants from liq...

  9. Utilization of solar collector for treatment of plant growth substrates; Desinfestacao de substratos com a utilizacao de coletor solar

    Energy Technology Data Exchange (ETDEWEB)

    Ghini, Raquel; Bettiol, Wagner [EMBRAPA, Jaquariuna, SP (Brazil). Centro Nacional de Pesquisa de Defesa da Agricultura; Geraldo Armond; Carlos Augusto da Silva Braga [IAC, Jundiai, SP (Brazil). Div. de Engenharia Agricola; Inomoto, Mario M. [ESALQ, Piracicaba, SP (Brazil). Departamento de Zoologia

    1992-12-31

    Flat solar collectors were tested for the control of Sclerotium rolfsii, Rhizoctonia solani, Verticillium sp., Meloidogyne arenaria and Cyperus rotundus (nut sedge). The equipment developed comprises, basically, gutters of aluminium with thermic liner of glass wool and transparent plastic cover. the results showed that, depending upon the solar radiation, one day is required for the disinfestation of substrate infested with S. rolfsii and nut sedge, and two days for R. solani, Verticillium sp. and M. arenaria. (author) 12 refs., 1 fig., 11 tabs.

  10. Screening of fungi implicated in the dieback of olive trees (Olea europea) in Chebika’s area

    OpenAIRE

    Boughalleb-M’Hamdi N; Souli M; Ben Salem I; Selmi S; M. E. Romdhani

    2011-01-01

    Several surveys were conducted during spring 2008 in Chebika’s area in Tunisia.Samples were collected from infected plants showed different types of symptoms andthey have been the subject of mycological analysis. The morphological identification offungal colonies isolated from roots, crown and stems of two olive varieties Koroneiki andChemlali Sfax, revealed the presence of a fungi complex including Fusarium oxysporum,Fusarium solani, Rhizoctonia solani, Verticillium dahliae, Cladosporium ful...

  11. In vitro effect of Bacillus thuringiensis strains and Cry proteins in phytopathogenic fungi of paddy rice-field Efeito in vitro de cepas e proteínas Cry de Bacillus thuringiensis em fungos fitopatogênicos da cultura do arroz irrigado

    OpenAIRE

    Neiva Knaak; Angelise Ana Rohr; Lidia Mariana Fiuza

    2007-01-01

    Cry1Ab and Cry1Ac strains and proteins synthesized by Bacillus thuringiensis thuringiensis and B. thuringiensis kurstaki were assessed in the following phytopathogens: Rhizoctonia solani,Pyricularia grisea,Fusarium oxysporum and F. solani, which had their micelial growth decreased after incubation in the presence of the bacterial strains. As to Cry proteins, there were no inhibition halo development in the assessed concentrations.As cepas e proteínas Cry1Ab e Cry1Ac sintetizadas por Bacillus ...

  12. Efficacy of Pseudomonas aeruginosa and other biocontrol agents in the control of root rot infection in cotton

    Directory of Open Access Journals (Sweden)

    Shamama Shamim

    2013-12-01

    Full Text Available Seed dressing with Pseudomonas aeruginosa, Paecilomyces lilacinus and Trichoderma koningii significantly (pMacrophomina phaseolina, Rhizoctonia solani and Fusarium solani on cotton roots in pot experiments and in field. Combined use of P.aeruginosa strain CMG63 with T.koningii produced greater plant height and fresh weight of shoot in field as compared to CMG52 which showed better results in pot experiments.

  13. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    In the fields of power conversion devices and broadcasting/communication amplifiers, high power, high frequency and low losses are desirable. Further, for electronic elements in aerospace/aeronautical/geothermal surveys, etc., heat resistance to 500degC is required. Devices which respond to such hard specifications are called hard electronic devices. However, with Si which is at the core of the present electronics, the specifications cannot fully be fulfilled because of the restrictions arising from physical values. Accordingly, taking up new device materials/structures necessary to construct hard electronics, technologies to develop these to a level of IC were examined and studied. They are a technology to make devices/IC of new semiconductors such as SiC, diamond, etc. which can handle higher temperature, higher power and higher frequency than Si and also is possible of reducing losses, a technology to make devices of hard semiconducter materials such as a vacuum microelectronics technology using ultra-micro/high-luminance electronic emitter using negative electron affinity which diamond, etc. have, a technology to make devices of oxides which have various electric properties, etc. 321 refs., 194 figs., 8 tabs.

  14. Electronic technology

    International Nuclear Information System (INIS)

    This book is composed of five chapters, which introduces electronic technology about understanding of electronic, electronic component, radio, electronic application, communication technology, semiconductor on its basic, free electron and hole, intrinsic semiconductor and semiconductor element, Diode such as PN junction diode, characteristic of junction diode, rectifier circuit and smoothing circuit, transistor on structure of transistor, characteristic of transistor and common emitter circuit, electronic application about electronic equipment, communication technology and education, robot technology and high electronic technology.

  15. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

  16. The Electron

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, George

    1972-01-01

    Electrons are elementary particles of atoms that revolve around and outside the nucleus and have a negative charge. This booklet discusses how electrons relate to electricity, some applications of electrons, electrons as waves, electrons in atoms and solids, the electron microscope, among other things.

  17. In Vitro antifungal potency of plant extracts against five phytopathogens

    Directory of Open Access Journals (Sweden)

    Ashwani Tapwal

    2011-12-01

    Full Text Available The antifungal activity of aqueous extract of Cannabis sativa, Parthenium hysterophorus, Urtica dioeca, Polystichum squarrosum and Adiantum venustum was investigated against Alternaria solani, Alternaria zinniae, Curvularia lunata, Rhizoctonia solani and Fusarium oxysporum at different concentrations (5, 10, 15 and 20%. At 20%, maximum antifungal potential was observed with the extracts of C. sativa, which recorded excellent inhibitory activity against C. lunata (100%, A. zinniae (59.68%, followed by leaf extract of P. hysterophorus (50% against A. solani. The application of botanical extracts for disease management could be less expensive, easily available, non-polluting and eco-friendly.

  18. Biological activity of some bacterial isolates against soil borne pathogenic fungi

    International Nuclear Information System (INIS)

    The antagonistic activity of three bacterial isolates namely Micro bacterium terregens, Cellulosimicrobium cellulans and Bacillus amyloliquefaciens was evaluated through direct confrontation method and filtrates culture against the growth of Fusarium solani, Fusarium oxysporum, Rhizoctonia solani and Phytophthra cactorum. All bacterial isolates showed the inhibition of the mycelia growth of the isolated fungi as resulting to confrontation methods except R. solani with C. cellulans that showed no inhibitory effect and energized the low activity with B. amyloliquefaciens. Culture filtrate of different bacterial isolates after different incubation periods revealed that the highest antifungal activity between 3-10 days

  19. Electronic Prescribing

    Science.gov (United States)

    ... Do you prescribe electronically? For more information about electronic prescribing, call 1-800-MEDICARE (1-800-633- ... to the pharmacy, and my prescription was ready. Electronic eRx Prescribing CMS Product No. 11382 Revised July ...

  20. Electronic Prescribing

    Science.gov (United States)

    ... Do you prescribe electronically?” For more information about electronic prescribing, call 1-800-MEDICARE (1-800-633- ... to the pharmacy, and my prescription was ready. Electronic eRx Prescribing CMS Product No. 11382 Revised July ...

  1. Multilocus phylogeny reveals an association of agriculturally important Fusarium solani species complex (FSSC) 11, and clinically important FSSC 5 and FSSC 3 + 4 with soybean roots in the north central United States.

    Science.gov (United States)

    Chitrampalam, P; Nelson, B

    2016-02-01

    The Fusarium solani species complex (FSSC) includes important root pathogens of soybean in the United States, but the evolutionary lineages associated with soybean root rot are unknown. A multilocus phylogeny based on 93 isolates from soybean and pea roots from North Dakota and Minnesota revealed that root rot was associated with three known phylogenetic species, FSSC 3 + 4 (=Fusarium falciforme) (3 % of isolates), FSSC 5 (60 %), FSSC 11 (34 %), and one unknown species, FSSC X (2 %). Of these species FSSC 5 and FSSC 3 + 4 are clinically important while FSSC 11 is a plant pathogen. Isolates from FSSC 11 were pathogenic on soybean, dry bean, pea and lentil, and did not grow at 37 °C. However, isolates from FSSC 5 were weakly to non-pathogenic, but grew at 37 °C. Isolates from both FSSC 5 and FSSC 11 were highly resistant to fludioxonil in vitro. This is the first study revealing the pathogenic robustness of FSSC 11 in causing root rot among Fabaceae crops and also the association of clinically important members of the FSSC with roots of a widely grown field crop in the United States. PMID:26671414

  2. Evaluation of the USDA Rice Core Collection for sheath blight disease using micro-chamber

    Science.gov (United States)

    The USDA rice core collection, including 1,794 accessions from 114 countries, was developed using a stratified random sampling method to represent the entire NSGC collection including over 18,000 accessions. Sheath blight (Rhizoctonia solani) is one of the most important and widely distributed disea...

  3. The effect of Pseudomonas fluorescens strain q2-87 in pathogen inhibition and growth promotion of slash pine seedlings

    Science.gov (United States)

    Pseudomonas fluorescens strain Q2-87 showed significant antagonistic activity against the damping-off pathogens of slash pine (Pinus elliottii), including Rhizoctonia solani, Alternaria alternata and Fusarium oxysporum. In vitro assays showed that strain Q2-87, which has an inhibition index higher t...

  4. Use of biocontrol organisms and compost amendments for improved control of soilborne diseases and increased potato production

    Science.gov (United States)

    Soilborne potato diseases are persistent problems in potato production and alternative management practices are needed. In this research, biocontrol agents (Bacillus subtilis GB03 and Rhizoctonia solani hypovirulent isolate Rhs1A1) and compost amendments (from different source material), were evalua...

  5. Evaluation of Nostoc Strain ATCC 53789 as a Potential Source of Natural Pesticides

    OpenAIRE

    Biondi, Natascia; Piccardi, Raffaella; Margheri, M. Cristina; Rodolfi, Liliana; Smith, Geoffrey D.; Tredici, Mario R.

    2004-01-01

    The cyanobacterium Nostoc strain ATCC 53789, a known cryptophycin producer, was tested for its potential as a source of natural pesticides. The antibacterial, antifungal, insecticidal, nematocidal, and cytotoxic activities of methanolic extracts of the cyanobacterium were evaluated. Among the target organisms, nine fungi (Armillaria sp., Fusarium oxysporum f. sp. melonis, Penicillium expansum, Phytophthora cambivora, P. cinnamomi, Rhizoctonia solani, Rosellinia, sp., Sclerotinia sclerotiorum,...

  6. Construction of recombinant fluorescent Pseudomonas spp. for suppression of soilborne pathogens

    Science.gov (United States)

    Take-all, caused by Gaeumannomyces graminis var. tritici, and Rhizoctonia root rot, caused by R. solani AG-8, are among the most important soilborne diseases of wheat in the Pacific Northwest. Because of the lack of resistance to these and many other soilborne diseases, wheat roots rely on antagonis...

  7. Molecular dynamics of interactions of rice with rice blast and sheath blight pathogens

    Science.gov (United States)

    In an effort to develop the molecular strategies to control rice (Oryzae sativa) diseases, molecular interactions of rice with rice blast [Magnaporthe oryzae, formerly (Magnaporthe grisea] and sheath blight (Rhizoctonia solani) fungi were analyzed. The interaction of rice with M. oryzae follows a b...

  8. Genome Sequence of the Plant Growth-Promoting Rhizobacterium Bacillus sp. Strain 916

    OpenAIRE

    Wang, Xiaoyu; Luo, Chuping; Chen, Zhiyi

    2012-01-01

    Bacillus sp. strain 916, isolated from the soil, showed strong activity against Rhizoctonia solani. Here, we present the high-quality draft genome sequence of Bacillus sp. strain 916. Its 3.9-Mb genome reveals a number of genes whose products are possibly involved in promotion of plant growth or antibiosis.

  9. Antifungal effect of some spice hydrosols.

    Science.gov (United States)

    Boyraz, Nuh; Ozcan, Musa

    2005-12-01

    The antifungal effects of rosemary, cumin, sater (savory), basil and pickling herb hydrosols were investigated against Rhizoctonia solani, Fusarium oxysporum f. sp tulipae, Botrytis cinerea and Alternaria citri. Hydrosols of sater and pickling herb showed the most relevant fungicidal activity. PMID:16243447

  10. Novel, Pseudomonas-derived Antifungal Lipopeptides From A Disease Suppressive Soil In Greenlandic Potato Fields

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Michelsen, Charlotte F.; Glaring, Mikkel A.; Phippen, Christopher; Nielsen, Kristian Fog; Olsson, Stefan; Stougaard, Peter

    the two non-ribosomal peptides nunapeptin and nunamycin, which are key components of the antifungal activity of In5. Bacterial-fungal interaction studies uncovered a complex interaction whereby nunamycin appears most active against Rhizoctonia solani with no antimicrobial effect against the oomycete...

  11. Fungistatic Activity Of Essential Oils Extracted from Peumus boldus Mol., Laureliopsis philippiana (Looser) Schodde and Laurelia sempervirens (Ruiz & Pav.) Tul. (Chilean Monimiaceae) Actividad Fungisttica de Extractos de Aceites Asenciales de Peumus boldus Mol., Laureliopsis philippiana (Looser) Schodde y Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae chilenas)

    OpenAIRE

    Magalis Bittner; MILENKO A AGUILERA; Vctor Hernndez; Cecilia Arbert; Jos Becerra; Mara E. Casanueva

    2009-01-01

    Components of essential oils from the Chilean Monimiaceae, boldo (Peumus boldus Mol.), tepa (Laureliopsis philippiana (Looser) Schodde), and laurel (Laurelia sempervirens (Ruiz & Pav.) Tul.) were determined using Gas Chromatography- Mass Spectrometry (GCMS) and fungistatic activity of the essential oils was tested against Rhizoctonia solani Khn (Donk), Pythium irregulare Buisman, Ceratocystis pilifera (Fr.) C. Moreau, Phragmidium violaceum (Schultz) G. Winter, and Fusarium oxysporum Schltdl....

  12. Optimalisering van de biologisch-dynamische en ecologische pootgoedteelt : eindrapport over de onderzoeksjaren 1992 tot en met 1995 = Optimization of bio-dynamic and ecological cultivation of seed potatoes : final report on research carried out between 1992 and 1995

    OpenAIRE

    Hospers, M.

    1996-01-01

    In a broad based study, various aspects of the control of the diseases Rhizoctonia solani and Phytophthora infestans were studied in a biological cultivation system. Experiments were carried out on organic farms. In addition a farm study was carried out in which the cultivation of seed potatoes was followed and recorded for a period of three years on 15 organic farms

  13. Promises and challenges of genomics for rice pathology

    Science.gov (United States)

    Publically available genome sequences of Magnaporthe oryzae, Rhizoctonia solani, and Oryza sativa are being used to study host-pathogen interactions. Comparative genomic analyses on natural alleles of major resistance (R) genes and the corresponding avirulence (AVR) genes have provided new clues for...

  14. BIOLOGICAL CONTROL OF SUGAR BEET DAMPING-OFF WITH TRICHODERMA SPP.

    Science.gov (United States)

    Biological control of damping-off in sugar beet seedlings with Trichoderma species. Isolates of Trichoderma virens and other Trichoderma species are effective biocontrol agents for diseases of several crops. Control of damping-off caused by Rhizoctonia solani has been observed in a number of c...

  15. Rapeseed rotation, compost and biocontrol amendments reduce soilborne diseases and increase tuber yield in conventional and organic potato production systems

    Science.gov (United States)

    Three different potential disease-suppressive management practices, including a Brassica napus (rapeseed) green manure rotation crop, a conifer-based compost amendment, and three biological control organisms (Trichoderma virens, Bacillus subtilis, and Rhizoctonia solani hypovirulent isolate Rhs1A1)...

  16. Soil suppressiveness and functional diversity of soil microflora in organic farming systems

    OpenAIRE

    Postma, J; Schilder, M.T.; Speksnijder, A.G.C.L.

    2008-01-01

    Arable fields of 10 organic farms from different locations within the Netherlands were sampled in four subsequent years. The soil samples were analysed for disease suppressiveness against Rhizoctonia solani, Streptomyces scabies and Verticillium dahliae. Furthermore, a variety of microbial characteristics and chemical and physical soil properties were assessed. All these characteristics and different environmental factors were correlated by multivariate analyses. Significant differences in so...

  17. Cultivar Selection for Sugar Beet Root Rot Resistance

    Science.gov (United States)

    Fungal and bacterial root rots in sugar beet caused by Rhizoctonia solani (Rs) and Leuconostoc mesenteroides subsp. dextranicum (Lm) can lead to root yield losses greater than 50%. To reduce the impact of these root rots on sucrose loss in the field, storage, and factories, studies were conducted t...

  18. Electrons, Electronic Publishing, and Electronic Display.

    Science.gov (United States)

    Brownrigg, Edwin B.; Lynch, Clifford A.

    1985-01-01

    Provides a perspective on electronic publishing by distinguishing between "Newtonian" publishing and "quantum-mechanical" publishing. Highlights include media and publishing, works delivered through electronic media, electronic publishing and the printed word, management of intellectual property, and recent copyright-law issues and their…

  19. Electron detector

    International Nuclear Information System (INIS)

    A device for measuring electron densities at a given energy level in an electron beam or the like having strong background noise, for example, in the detection of Auger electric energy spectrums is described. An electron analyzer passes electrons at the given energy level and at the same time electrons of at least one adjacent energy level. Detecting means associated therewith produce signals indicative of the densities of the electrons at each energy level and combine these signals to produce a signal indicative of the density of the electrons of the given energy level absent background noise

  20. Inhibition of in vitro growth of soil-borne pathogens by compost-inhabiting indigenous bacteria and fungi

    International Nuclear Information System (INIS)

    During the present studies, compost-inhabiting microorganisms including 44 fungi and 15 bacteria isolated from different compost samples were evaluated for their in vitro efficacy against soil-borne pathogens viz., Fusarium solani, Macrophomina phaseolina, Pythium aphanidermatum, Rhizoctonia solani, and Sclerotium rolfsii. Compost inhabiting microbes like Trichoderma harzianum, T. virens, Bacillus cereus, B. pumilus, B. subtilis, Micrococcus varians and Pseudomonas fluorescens were found to inhibit all the test pathogens. Acrophialophora fusispora and Penicillium citrinum reduced the mycelial growth of all the test pathogens except Sclerotium rolfsii. Bacillus licheniformis and Bacillus megaterium showed biocontrol activity against all the pathogens except Rhizoctonia solani. Trichoderma harzianum parasitized mycelia of all the tested pathogens and produced coiling around the mycelium. (author)

  1. Competition in artifical plant growth media by Trichoderma spp

    DEFF Research Database (Denmark)

    Sarocco, Sabrina; Lübeck, Mette; Vannacci, Giovanni

    isolates in a natural pot mix in order to select potential fungal antagonists to be employed in the biocontrol of Rhizoctonia solani damping-off of radish, and 2) to verify the hypothesis that competition for a food base plays a role in reducing pathogen activity. Fifteen Trichoderma spp., selected among...... 150 isolates according to their growth rate, were evaluated as potential biocontrol agents against the soil-borne plant pathogen Rhizoctonia solani on radish in vivo in a natural peat based growth medium usually employed in commercial production. Two different temporal antagonist-pathogen soil......, but even after R. solani was able to re-colonize haulm fragments, the positive effects on damping off were still evident, demonstrating a “residual” effect of antagonists. On the whole, competition for the food base explains a large part of the recorded effects....

  2. Electronic emission and electron guns

    International Nuclear Information System (INIS)

    This paper reviews the process of electron emission from metal surface. Although electrons move freely in conductors like metals, they normally do not leave the metal without some manipulation. In fact, heating and bombardment are the two primary ways in which electrons are emitted through the use of a heating element behind the cathode (termed thermionic emission) or as a result of bombardment with a beam of electrons, ions, or metastable atoms (termed secondary emission). Another important emission mechanism called Explosive Electron Emission (EEE) is also often used in various High Voltage Pulse Power Systems to generate very high current (few hundreds of kA) pulsed electron beams. The electron gun is the device in that it shoots off a continuous (or pulsed) stream of electrons. A brief idea about the evolution of the electron gun components and their basis of functioning are also discussed. (author)

  3. Vacuum electronics

    CERN Document Server

    Eichmeier, Joseph A

    2008-01-01

    Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. ""Vacuum Electronics"" covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

  4. Electronic components

    CERN Document Server

    Colwell, Morris A

    1976-01-01

    Electronic Components provides a basic grounding in the practical aspects of using and selecting electronics components. The book describes the basic requirements needed to start practical work on electronic equipment, resistors and potentiometers, capacitance, and inductors and transformers. The text discusses semiconductor devices such as diodes, thyristors and triacs, transistors and heat sinks, logic and linear integrated circuits (I.C.s) and electromechanical devices. Common abbreviations applied to components are provided. Constructors and electronics engineers will find the book useful

  5. Understand electronics

    CERN Document Server

    Bishop, Owen

    2013-01-01

    Understand Electronics provides a readable introduction to the exciting world of electronics for the student or enthusiast with little previous knowledge. The subject is treated with the minimum of mathematics and the book is extensively illustrated.This is an essential guide for the newcomer to electronics, and replaces the author's best-selling Beginner's Guide to Electronics.The step-by-step approach makes this book ideal for introductory courses such as the Intermediate GNVQ.

  6. Electronic archive

    OpenAIRE

    Šafhalter, Simon

    2010-01-01

    This diploma thesis leads us through the main points of making a coherent legal electronic archive: from law, by means of various information technologies, to the final service of electronic archiving. In the introduction we will briefly explain the reason for the emergence of electronic archives and the law that is related to it. In the second chapter we will introduce to the basic archiving functions, applicable to both classical and electronic archiving. We will answer to questions...

  7. Polarized electrons

    International Nuclear Information System (INIS)

    This article reviews all the possible uses of polarized electrons: as lepton probes, for polarization measurement in electron-nucleus scattering; in polarized electron sources; in beams with all the related problems of polarized beams; in reaction for parity violation measurement; in scattering for nucleon physics study

  8. Basic electronics

    CERN Document Server

    Holbrook, Harold D

    1971-01-01

    Basic Electronics is an elementary text designed for basic instruction in electricity and electronics. It gives emphasis on electronic emission and the vacuum tube and shows transistor circuits in parallel with electron tube circuits. This book also demonstrates how the transistor merely replaces the tube, with proper change of circuit constants as required. Many problems are presented at the end of each chapter. This book is comprised of 17 chapters and opens with an overview of electron theory, followed by a discussion on resistance, inductance, and capacitance, along with their effects on t

  9. Electron Tree

    DEFF Research Database (Denmark)

    Appelt, Ane L; Rønde, Heidi S

    2013-01-01

    The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

  10. Electronic Elections

    DEFF Research Database (Denmark)

    Schrmann, Carsten

    2010-01-01

    Electronic voting technology is a two edged sword. It comes with many risks but brings also many benefits. Instead of flat out rejecting the technology as uncontrollably dangerous, we advocate in this paper a different technological angle that renders electronic elections trustworthy beyond the...... posteriori validation on an acceptably small trusted computing base. Our technology enables us to prove that an electronic elections preserves the voters intent, assuming that the voting machine and the trace verifier are independent....

  11. Electronic Elections

    DEFF Research Database (Denmark)

    Schürmann, Carsten

    2010-01-01

    Electronic voting technology is a two edged sword. It comes with many risks but brings also many benefits. Instead of flat out rejecting the technology as uncontrollably dangerous, we advocate in this paper a different technological angle that renders electronic elections trustworthy beyond the...... posteriori validation on an acceptably small trusted computing base. Our technology enables us to prove that an electronic elections preserves the voter’s intent, assuming that the voting machine and the trace verifier are independent....

  12. Micropower electronics

    CERN Document Server

    Keonjian, Edward

    1964-01-01

    Micropower Electronics deals with the operation of modern electronic equipment at micropower levels and the problems associated with micropower electronics. Topics covered include the relations between minimum required power density and frequency response for semiconductor triode amplifiers; physical realization of digital logic circuits; micropower microelectronic subsystems; and metal-oxide-semiconductor field-effect devices for micropower logic circuitry. This book is comprised of 10 chapters and begins with an analysis of fundamental relationships and basic requirements pertinent to the ph

  13. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  14. Electron Bifurcation

    Energy Technology Data Exchange (ETDEWEB)

    Peters, John W.; Miller, Anne-Frances; Jones, Anne K.; King, Paul W.; Adams, Michael W. W.

    2016-04-01

    Electron bifurcation is the recently recognized third mechanism of biological energy conservation. It simultaneously couples exergonic and endergonic oxidation-reduction reactions to circumvent thermodynamic barriers and minimize free energy loss. Little is known about the details of how electron bifurcating enzymes function, but specifics are beginning to emerge for several bifurcating enzymes. To date, those characterized contain a collection of redox cofactors including flavins and iron-sulfur clusters. Here we discuss the current understanding of bifurcating enzymes and the mechanistic features required to reversibly partition multiple electrons from a single redox site into exergonic and endergonic electron transfer paths.

  15. Isolated electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ekstrom, Ph.; Winwland, D.

    1981-08-01

    The problem of electron g-factor measurement by means of an isolated electron is considered. The technique of the experiment performed at the Washington university is described. A single electron is enclosed in a homogeneous magnetic field which is superimposed by an electric field. The electric field configuration represents a Penning trap. The trap together with the enclosed electron forms an ''atom'' of macroscopic dimensions. The electron trajectory in the trap consists of three components. The electron quickly rotates over small loops (cyclotron motion), the centre of these loops slowly moves over a large circle (magistron motion). Meanwhile the electron oscillates back and forth along the trap axis. The electron motion in the atom field is quantized and the transitions between various types of motions correspond to definite radiation frequencies. At the anomal frequency the transition with spin flip is registered and the electron g-factor is measured. The value g=2.0023193044 is obtained with a probable error less than a unit of the last decimal digit.

  16. Electronic money

    OpenAIRE

    Denisenko, Y.; Chuchilina, L.M.

    2009-01-01

    Modern, quickly developing world impossible to present without electronic money. Quite soon they will become integral part of our life. Electronic money is really incredible invention of humanity. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/17048

  17. Printed Electronics

    Science.gov (United States)

    Crain, John M. (Inventor); Lettow, John S. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

    2015-01-01

    Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

  18. Electronic Government and Electronic Participation:

    OpenAIRE

    Tambouris, E; Scholl, H.J.; Janssen, M.F.W.H.A.; M.A. Wimmer; Tarabanis, K.; Gascó, M.; Klievink, A.J.; Lindgren, I.; Milano, M.; Panagiotopoulos, P; Pardo, T.A.; Parycek, P.; Sæbø, O.

    2015-01-01

    Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies. This book presents papers from the 14th International Federation for Information Processing’s EGOV conference (IFIP EGOV 2015), and its sister conference, the 7th Electronic Participation (ePart) conference, held in Thessaloniki, Greece, from 30 August to 2 September 2015, wi...

  19. Kicking electrons

    CERN Document Server

    Gerlach, Martin; Rost, Jan M

    2011-01-01

    The concept of dominant interaction hamiltonians is introduced and applied to classical planar electron-atom scattering. Each trajectory is governed in different time intervals by two variants of a separable approximate hamiltonian. Switching between them results in exchange of energy between the two electrons. A second mechanism condenses the electron-electron interaction to instants in time and leads to an exchange of energy and angular momentum among the two electrons in form of kicks. We calculate the approximate and full classical deflection functions and show that the latter can be interpreted in terms of the switching sequences of the approximate one. Finally, we demonstrate that the quantum results agree better with the approximate classical dynamical results than with the full ones.

  20. Biological and Chemical Control of Soil-borne Fungi and Effect of These on Growth of Mungbean

    Directory of Open Access Journals (Sweden)

    S. Shahid Shaukat

    2001-01-01

    Full Text Available Efficacy of soil amendment with Lantana camara and various concentrations of three phenolics (caffeic acid, p-hydroxybenzoic acid and (p-coumaric acid were tested against the soil-borne root-infecting fungi (Fusarium solani and Rhizoctonia solani in unsterilized sandy-loam soil. The potential impact of L. camara amendment on the rhizosphere population of Pseudomonas aeruginosa and consequent biocontrol potential was also evaluated. Powdered L. camara and its aqueous extract caused substantial suppression of F. solani and R. solani infection in mungbean roots. At high concentration of L. camara (1% w/w, population of P. aeruginosa in the rhizosphere declined but not to a degree that could reduce biological control and growth promoting potential of the bacterium. L. camara and P. aeruginosa used together caused greater suppression of the root-infecting fungi as compared to their individual application. P. aeruginosa mixed with L. camara also resulted in enhanced plant growth. Soil application of caffeic acid at the rate of 10-?g/g soil caused complete inhibition in germination of mungbean. With an increase in phenol concentration, plant growth was progressively reduced and root infection caused by F. solani and R. solani was suppressed. Caffeic acid at 5-?g/g soil caused greater suppression of F. solani whereas p -hydroxybenzoic acid at 10 ? g/g resulted in the maximum inhibition of R. solani.

  1. Electronic diagrams

    CERN Document Server

    Colwell, Morris A

    1976-01-01

    Electronic Diagrams is a ready reference and general guide to systems and circuit planning and in the preparation of diagrams for both newcomers and the more experienced. This book presents guidelines and logical procedures that the reader can follow and then be equipped to tackle large complex diagrams by recognition of characteristic 'building blocks' or 'black boxes'. The goal is to break down many of the barriers that often seem to deter students and laymen in learning the art of electronics, especially when they take up electronics as a spare time occupation. This text is comprised of nin

  2. Stretchable electronics

    CERN Document Server

    Someya, Takao

    2012-01-01

    With its comprehensive coverage this handbook and ready reference brings together some of the most outstanding scientists in the field to lay down the undisputed knowledge on how to make electronics stretchable.As such, it focuses on gathering and evaluating the materials, designs, models and technologies that enable the fabrication of fully elastic electronic devices which can sustain high strain. Furthermore, it provides a review of those specific applications that directly benefit from highly compliant electronics, including transistors, photonic devices and sensors. In addition to stre

  3. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  4. Digital electronics

    CERN Document Server

    Morris, John

    2013-01-01

    An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

  5. Electron optics

    CERN Document Server

    Grivet, Pierre; Bertein, F; Castaing, R; Gauzit, M; Septier, Albert L

    1972-01-01

    Electron Optics, Second English Edition, Part I: Optics is a 10-chapter book that begins by elucidating the fundamental features and basic techniques of electron optics, as well as the distribution of potential and field in electrostatic lenses. This book then explains the field distribution in magnetic lenses; the optical properties of electrostatic and magnetic lenses; and the similarities and differences between glass optics and electron optics. Subsequent chapters focus on lens defects; some electrostatic lenses and triode guns; and magnetic lens models. The strong focusing lenses and pris

  6. Electronic identity

    CERN Document Server

    de Andrade, Norberto Nuno Gomes; Argles, David

    2014-01-01

    With the increasing availability of electronic services, security and a reliable means by which identity is verified is essential.Written by Norberto Andrade the first chapter of this book provides an overview of the main legal and regulatory aspects regarding electronic identity in Europe and assesses the importance of electronic identity for administration (public), business (private) and, above all, citizens. It also highlights the role of eID as a key enabler of the economy.In the second chapter Lisha Chen-Wilson, David Argles, Michele Schiano di Zenise and Gary Wills discuss the user-cent

  7. Anti-fungal activity of some medicinal plants on different pathogenic fungi

    International Nuclear Information System (INIS)

    The antifungal activity of different medicinal and locally available plants extracts (leaves, fruit, seeds) which are usually found in the surrounding of fields or in the fields on some fungi were tested in lab conditions. Six different plants were selected for testing these plants were Acacia nilotica (Lamk.) Willd. Azadirachta indica (A.) Juss. Crotalaria juncea L. Eucalyptus camaldulensis Dehnh. Ocimum basilicum L. and Prosopis juliflora (Sw.) Dc. These plants showed antifungal activity against the Aspergillus flavus, A. niger, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani. These plants crude extracts of leaves showed inhibition activity against the fungi and suppressed the myclial growth. Over all selected plants exhibited moderate type of inhibition against these above mentioned pathogens. Among these plants, Azadirachta indica, Ocimum basilicum and Crotalaria juncea showed the most effective results against the Aspergillus, Fusarium and Rhizoctonia sp. of fungal pathogens. Whereas, Acacia nilotica, Eucalyptus camaldulensis and Prosopis juliflora showed least potential of inhibition against all above mentioned fungal pathogens. It is investigated in present studies that Azadirachta indica, Ocimum basilicum and Crotalaria juncea can be utilized against the management of fungal diseases particularly Aspergillus flavus, A. niger, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani. (author)

  8. Nuclear electronics

    International Nuclear Information System (INIS)

    A short survey is given on nuclear radiation detectors and nuclear electronics. It is written for newcomers and those, who are not very familiar with this technique. Some additional information is given on typical failures in nuclear measurement systems. (orig.)

  9. Electronic filaments

    OpenAIRE

    Kouropoulos, C. P.

    2005-01-01

    In the one-dimensional world of a flux line beyond Bce, paired evanescent low momentum 0-Landau electron states condense into magnetized bosons of vanishing momentum. I use the results of Rojas et al. within a Coulomb potential and show that magnetic intensities and electron densities sufficient to initiate condensation can be achieved in the shockwaves of cathode hot spots; from unipolar pulses on the surface of a discontinuous micro conductor or cathode tip as a discharge suddenly self-inte...

  10. Electronic plants

    OpenAIRE

    Stavrinidou, Eleni; Gabrielsson, Roger; Gomez, Eliot; Crispin, Xavier; Nilsson, Ove; Simon, Daniel T.; Berggren, Magnus

    2015-01-01

    The roots, stems, leaves, and vascular circuitry of higher plants are responsible for conveying the chemical signals that regulate growth and functions. From a certain perspective, these features are analogous to the contacts, interconnections, devices, and wires of discrete and integrated electronic circuits. Although many attempts have been made to augment plant function with electroactive materials, plants’ “circuitry” has never been directly merged with electronics. We report analog and d...

  11. Electronic spectroscopies

    OpenAIRE

    Weckhuysen, B. M.; Schoonheydt, R. A.

    2000-01-01

    Diffuse reflectance spectroscopy (DRS) in the ultraviolet, visible and near-infrared region is a versatile spectroscopic technique, as both d-d and charge transfer transitions of supported TMI can be probed. One of the advantages of electronic spectroscopy is that the obtained information is directly chemical since the outer shell electrons of the TMI are probed and provide information about the oxidation state and coordination environment of TMI on surfaces. Furthermore, the D...

  12. The application of Bacillus globisporus strain isolated from composts of fat wastes in plant protection

    Directory of Open Access Journals (Sweden)

    Agnieszka Piotrowska-Cyplik

    2011-06-01

    Full Text Available The study investigated the effect of a Bacillus globisporus strain and produced supernatants on growth of selected plant pathogens, i.e. Alternaria alternata, Botrytis cinerea, Cladosporium spp., Trichothecium roseum, Fusarium oxysporum, F. solani, Trichoderma viride, Rhizoctonia solani, Sclerotinia sclerotiorum, Verticillium dahliae. The highest fungistatic activity of bacterial cultures was found against R. solani, S. sclerotiorum, B. cinerea and T. roseum, whereas in case of the supernatant, it was found against R. solani and S. sclerotiorum. At identical concentrations, the fungistatic activity of B. globisporus culture appeared stronger than that of the supernatant. No significant effect of bacterial culture concentration in the medium was observed. Growth of Cladosporium spp., V. dahliae, T. viride, and A. alternata was found both after seven and 10 days of the experiment. In case of the supernatant, this situation was observed only for F. oxysporum, after seven days.

  13. Electronic Commerce

    Energy Technology Data Exchange (ETDEWEB)

    Laird, N. [NRG Information Services Inc., Calgary, AB (Canada)

    1995-11-01

    The concept of electronic commerce in the gas industry was discussed. It was defined as the integration of communication technology, advanced information processing capability and business standards, to improve effectiveness of the business process. Examples of electronic data interchange from the automotive, airline, and banking industry were given. The objective of using this technology in the gas industry was described as the provision of one electronic facility to make seamless contractual and operational arrangements for moving natural gas across participating pipelines. The benefit of seamless integration - one readily available standard system used by several companies - was highlighted. A list of value-added services such as the free movement of bulletins, directories, nominations,and other documents was provided.

  14. Spin electronics

    CERN Document Server

    Buhrman, Robert; Daughton, James; Molnár, Stephan; Roukes, Michael

    2004-01-01

    This report is a comparative review of spin electronics ("spintronics") research and development activities in the United States, Japan, and Western Europe conducted by a panel of leading U.S. experts in the field. It covers materials, fabrication and characterization of magnetic nanostructures, magnetism and spin control in magnetic nanostructures, magneto-optical properties of semiconductors, and magnetoelectronics and devices. The panel's conclusions are based on a literature review and a series of site visits to leading spin electronics research centers in Japan and Western Europe. The panel found that Japan is clearly the world leader in new material synthesis and characterization; it is also a leader in magneto-optical properties of semiconductor devices. Europe is strong in theory pertaining to spin electronics, including injection device structures such as tunneling devices, and band structure predictions of materials properties, and in development of magnetic semiconductors and semiconductor heterost...

  15. Electron tube

    Science.gov (United States)

    Suyama, Motohiro (Hamamatsu, JP); Fukasawa, Atsuhito (Hamamatsu, JP); Arisaka, Katsushi (Los Angeles, CA); Wang, Hanguo (North Hills, CA)

    2011-12-20

    An electron tube of the present invention includes: a vacuum vessel including a face plate portion made of synthetic silica and having a surface on which a photoelectric surface is provided, a stem portion arranged facing the photoelectric surface and made of synthetic silica, and a side tube portion having one end connected to the face plate portion and the other end connected to the stem portion and made of synthetic silica; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the photoelectric surface, and made of synthetic silica; and an electron detector arranged on the projection portion, for detecting electrons from the photoelectric surface, and made of silicon.

  16. Isolamento e identificação de fungos micorrízicos rizoctonióides associados a três espécies de orquídeas epífitas neotropicais no Brasil Isolation and identification of rhizoctonia-like mycorrhizal fungi associated to three neotropical epiphytic orchid species in Brazil

    Directory of Open Access Journals (Sweden)

    Olinto Liparini Pereira

    2005-04-01

    Full Text Available Distúrbios causados pelo homem têm resultado no aumento do risco de extinção de diversos táxons de orquídeas nativas da Mata Atlântica no Brasil. Na natureza, orquídeas utilizam obrigatoriamente fungos endomicorrízicos para a germinação de sementes e desenvolvimento da plântula, ao menos nos primeiros estádios do seu ciclo de vida. Assim, fungos micorrízicos associados ao sistema radicular de orquídeas nativas vêm sendo isolados, caracterizados e armazenados para uso em futuros programas de conservação de espécies de orquídeas, por meio da germinação simbiótica. Três isolados de fungos micorrízicos rizoctonióides foram obtidos do sistema radicular de três espécies de orquídeas neotropicais, Gomesa crispa, Campylocentrum organense e Bulbophyllum sp., de três diferentes fragmentos de Mata Atlântica no Brasil. Estudos taxonômicos, baseados na condição nuclear, morfologia da hifa vegetativa e ultra-estrutura do septo dolipórico, revelaram que os isolados pertencem aos gêneros Ceratorhiza e Rhizoctonia. Esse é o primeiro relato do isolamento de fungos micorrízicos associados ao sistema radicular dessas espécies de orquídeas neotropicais. Aspectos relativos à taxonomia e ao uso desses isolados no contexto de um programa de conservação de orquídeas nativas são discutidos.Anthropogenic disturbances have resulted in an increased threat of extinction of many native orchid taxa in Brazil's Atlantic rain forest. In nature, orchids utilize mycorrhizal fungi to initiate seed germination and seedling development, at least in the early stages of their life cycle. Mycorrhizal fungi associated with the roots of orchids have thus been isolated, characterized and stored as important resources for a future conservation program of orchid species through symbiotic seed germination. Three mycorrhizal Rhizoctonia-like fungi were isolated from roots of three neotropical orchid species Gomesa crispa, Campylocentrum organense and Bulbophyllum sp. from three different Atlantic rain forest fragments in Brazil. Taxonomic studies based on the nuclear condition, vegetative hyphal morphology and septal pore ultrastructure revealed that the isolates belong to the genera Ceratorhiza and Rhizoctonia. This is the first report on the isolation of mycorrhizal fungal species associated to the referred neotropical orchid species. Aspects concerning their taxonomy and use in the context of a native orchid conservation programs are discussed.

  17. Fungitoxic and phytotoxic action of organic mercurials in the soil

    Energy Technology Data Exchange (ETDEWEB)

    Welvaert, W.; Vermeire, A.

    1962-01-01

    Some organic mercurials were tested for the duration of their activity after sterile (laboratory test) and on sterile conservation (cold-test) by means of their effect on Rhizoctonia solani Kuehn and Fusarium oxysporum f. mel. The phytotoxicity for cuttings of Coleus, Begonia gracilius and Saintpaulia and for seedlings of lettuce var. attractie, Lepidium and melon has been examined. It appears that the phytotoxicity for seedlings can still be demonstrated when there is no longer any fungitoxic action against Rhizoctonia. In propagation beds the orgnaic mercurials, used in normal concentration, were inactivated in 14 days. 4 references, 5 figures.

  18. Computational electronics

    CERN Document Server

    Vasileska, Dragica

    2006-01-01

    Computational Electronics is devoted to state of the art numerical techniques and physical models used in the simulation of semiconductor devices from a semi-classical perspective. Computational electronics, as a part of the general Technology Computer Aided Design (TCAD) field, has become increasingly important as the cost of semiconductor manufacturing has grown exponentially, with a concurrent need to reduce the time from design to manufacture. The motivation for this volume is the need within the modeling and simulation community for a comprehensive text which spans basic drift-diffusion m

  19. Graded electron affinity electron source

    International Nuclear Information System (INIS)

    We describe a new electron source using electric field and low electron affinity semiconductor materials to bring charge to potential energy levels near the vacuum level while still in the solid. The basic idea involves moving some of the potential barrier from the surface to the bulk, and distributing the barrier over a thin layer below the surface. In so doing, the emission physics is changed fundamentally from a quantum mechanical tunneling process largely controlled by surface properties to a classical transport process largely controlled by the band structure of a wide bandgap semiconductor. The composition of the thin layer below the surface would be graded such that the conduction band minimum changes from an energy close to the substrate Fermi level to an energy significantly closer to the vacuum level. Electrons from the substrate would be drawn into the graded composition layer with an electric field produced by a pointed emitter structure and extraction gate similar to that used in field emitter arrays. Relative to a conventional field emitter array, the new source is expected to require lower extraction fields and exhibit improved emission uniformity, stability, and noise. The I endash V characteristics are not Fowler endash Nordheim and may include a saturation effect at high current densities that could be engineered to improve reliability and uniformity. The group III nitrides can be grown with a continuous range of composition that provides the range of electron affinity needed to produce the proposed electronic structure. copyright 1996 American Vacuum Society

  20. Graded electron affinity electron source

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, J.L.; Gray, H.F.; Jensen, K.L.; Jung, T.M. [Naval Research Laboratory, Washington, DC 20375 (United States)

    1996-05-01

    We describe a new electron source using electric field and low electron affinity semiconductor materials to bring charge to potential energy levels near the vacuum level while still in the solid. The basic idea involves moving some of the potential barrier from the surface to the bulk, and distributing the barrier over a thin layer below the surface. In so doing, the emission physics is changed fundamentally from a quantum mechanical tunneling process largely controlled by surface properties to a classical transport process largely controlled by the band structure of a wide bandgap semiconductor. The composition of the thin layer below the surface would be graded such that the conduction band minimum changes from an energy close to the substrate Fermi level to an energy significantly closer to the vacuum level. Electrons from the substrate would be drawn into the graded composition layer with an electric field produced by a pointed emitter structure and extraction gate similar to that used in field emitter arrays. Relative to a conventional field emitter array, the new source is expected to require lower extraction fields and exhibit improved emission uniformity, stability, and noise. The {ital I}{endash}{ital V} characteristics are not Fowler{endash}Nordheim and may include a saturation effect at high current densities that could be engineered to improve reliability and uniformity. The group III nitrides can be grown with a continuous range of composition that provides the range of electron affinity needed to produce the proposed electronic structure. {copyright} {ital 1996 American Vacuum Society}

  1. Electronics department

    International Nuclear Information System (INIS)

    This report summarizes the activities in 1978 of some of the groups within the Electronics Department. The work covered includes plant protection and operator studies, reliability techniques, application of nuclear techniques to mineral exploration, applied laser physics, computing and, lastly, research instrumentation. (author)

  2. Electronic Government

    DEFF Research Database (Denmark)

    Wimmer, Maria A.; Traunmüller, Roland; Grönlund, Åke; Viborg Andersen, Kim

    This book constitutes the refereed proceedings of the 4th International Conference on Electronic Government, EGOV 2005, held in Copenhagen, Denmark, in August 2005. The 30 revised papers presented were carefully reviewed and selected from numerous submissions, and assess the state-of-the-art in e...

  3. Electronic Engineering

    International Nuclear Information System (INIS)

    During the past year the Electronics Division has worked on various projects needed for the development and improvement of the cyclotron facility. These included a target position controller for the spectrometer, completion of the isotope production target transport system, and installation of power supplies and cables. 1 fig

  4. Electronic Enlightenment

    OpenAIRE

    Dekker, Jennifer

    2010-01-01

    This article reviews Electronic Enlightenment (EE), a subscription-based, full text database containing critical editions of eighteenth century letters from Oxford University Press. It offers an overview of the content and functionality of the database with an assessment of potential use in a research library.

  5. Greening Electronics

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Søes Kokborg, Morten; Thomsen, Marianne

    Based on a literature review with focus on hazardous substances in waste electric and electronic equipment (WEEE) and numbers from a Danish treatment facility a flow analysis for specific substances has been conducted. Further, the accessible knowledge on human and environmental effects due to po...

  6. Electron linacs

    International Nuclear Information System (INIS)

    To study the present status of the thousand or so electron linacs in the world, and future trends in the field, we have classified these machines according to their use: medical, industrial, and nuclear physics. In the medical category, two types of electron linacs are discussed: the conventional ones which are used for X-ray and electron therapy, and those which may in the future be used for negative pion therapy. The section on industrial machines includes linacs for radiographic and other specialized applications. In the nuclear physics category, the status of conventional low- and medium-energy as well as high duty cycle linacs is reviewed. The question of how one might obtain a C.W., 1 GeV, 100 μA electron linac is raised and various options using recirculation and stretchers are examined. In this connection, the status of RF superconductivity is summarized. Following, there is a review of linacs for injectors into synchrotrons and e+- storage rings. The paper ends with a description of recent work done to upgrade the only multi-GeV linac, namely SLAC. (author)

  7. Automotive electronics

    Energy Technology Data Exchange (ETDEWEB)

    Basshuysen, R. van (ed.)

    2004-03-01

    Electronic systems in motor cars are getting increasingly innovative and complex. The consumption of resources of electronic systems increased from about 1 MB to about 90 MB per vehicle during the past decade. This is due to increasing demands on software, which is a key element of electronic systems in motor cars. Electronic systems provide higher safety without being noticed by the driver. Software reliability and quality must remain a point of focus as well as further cost reduction and ever shorter developing times. One option for achieving this is the automatic generation of program codes from the functional models developed. Code generation is accompanied by standardization of modular software architectures. The BCE project (Bertrand Competence Electronic, a universal control platform for individualized use with customer-specific applications), which was first presented at the IAA 2003, showed how development times can be shortened without impairing the software quality. (orig.) [German] Die Elektronik hat sich als Innovationstreiber im Automobil etabliert. Damit einher geht eine zunehmende Komplexitaet. So hat sich beispielsweise der Ressourcenbedarf elektronischer Systeme in den letzten zehn Jahren von rund 1 MB auf 90 MB pro Fahrzeug erhoeht. Dieser Entwicklung liegen steigende Anforderungen an die Aufgaben der Software zugrunde, die als wesentlicher Teil der Elektronik eine entscheidende Schluesselrolle einnimmt. Verdeutlichen laesst sich dies zum Beispiel am Bereich Fahrzeugsicherheit. Elektronische Assistenzsysteme bieten dem Fahrer in vielen Situationen ein Plus an Sicherheit. Diese Funktionalitaeten nimmt er in der Regel nicht aktiv wahr, da er auf sie vertraut. Um diesem Vertrauen gerecht zu werden, muss die Zuverlaessigkeit und Qualitaet der Software bei gleichzeitiger Reduzierung von Kosten und einer Verkuerzung der Entwicklungszeiten weiterhin im Fokus bleiben. Eine Moeglichkeit zur Verkuerzung der Entwicklungszeiten bietet die automatische Erzeugung von Programmcodes aus den entwickelten Funktionsmodellen. Die Codegenerierung geht einher mit der Standardisierung modular aufgebauter Software-Architekturen. Die Erfahrungen im Zusammenhang mit dem auf der Internationalen Automobil-Austellung 2003 vorgestellten BCE-Projekt (Bertrandt Competence Electronic: universelle Steuergeraete-Plattform, die individuell mit kundenspezifischen Applikationen bestueckt werden kann) zeigen, wie sich Entwicklungszeiten bei gleichzeitiger Absicherung der geforderten Qualitaet sinnvoll verkuerzen lassen. (orig.)

  8. Molecular Electronics

    DEFF Research Database (Denmark)

    Jennum, Karsten Stein

    This thesis includes the synthesis and characterisation of organic compounds designed for molecular electronics. The synthesised organic molecules are mainly based on two motifs, the obigo(phenyleneethynylenes) (OPE)s and tetrathiafulvalene (TTF) as shown below. These two scaffolds (OPE and TTF......) are chemically merged together to form cruciform-like structures that are an essential part of the thesis. The cruciform molecules were subjected to molecular conductance measurements to explore their capability towards single-crystal field-effect transistors (Part 1), molecular wires, and single...... electron transistors (Part 2). The synthetic protocols rely on stepwise Sonogashira coupling reactions. Conductivity studies on various OPE-based molecular wires reveal that mere OPE compounds have a higher electrical resistance compared to the cruciform based wires (up to 9 times higher). The most...

  9. Automotive electronics

    Energy Technology Data Exchange (ETDEWEB)

    Basshuysen, R. van [ed.; Baun, R. [comp.

    2000-10-01

    Electronic equipment is indispensable in modern motor cars for active and passive safety, exhaust and consumption monitoring or comfort. Electric and electronic systems today account for nearly 20 percent of the production cost of a normal passenger car, with an upward trend. Infotainment equipment is a growing market, which gets center stage in this issue. Further subjects discussed are current electronic and mechatronic applications as well as new developments in data transmission, development tools and constructional elements. [German] Ohne Elektronik sind moderne Automobile nicht mehr vorstellbar. Ob aktive oder passive Sicherheit, Abgas, Verbrauch oder Komfort - der Fortschritt im Autombil ist eng verknuepft mit der Einfuehrung neuer elektronischer Systeme und Komponenten. Obwohl meist nicht sehr auffaellig in einer Black-box verpackt, liegen die anteiligen Herstellungskosten fuer die Elektrik und Elektronik bei einem Mittelklassefahrzeug schon bei knapp 20 Prozent. Tendenz: Weiter steigend. Waehrend die Segnungen von ABS, ESP oder Motormanagement fuer den Kunden unsichtbar bleiben, tritt die Elektronik mit den Infotainment-Systemen ins Rampenlicht. Hochwertige Audio-Anlagen im Doppel-DIN-Format und grosse Farbbildschirme sitzen an prominenter Stelle im Armaturenbrett. Elektronische Systeme werden damit fuer den Kunden sichtbar, greifbar und erlebbar. Doch je mehr Funktionen integriert werden, desto wichtiger wird eine einfache Bedienung, die den Fahrer moeglichst wenig vom Verkehrsgeschehen ablenkt. Das ist leider keine Selbstverstaendlichkeit: Eine klare, einfache Bedienung wurde in der Vergangenheit schon bei so manchem simplen Cassetten-Radio schmerzlich vermisst. Infotainment im Automobil ist ein Wachstumsmarkt - und das Schwerpunkt-Thema der vorliegenden zweiten Ausgabe von 'Automotive Electronics'. Darueber hinaus beschaeftigt sich auch diese Ausgabe mit aktuellen Elektronik- und Mechatronik-Anwendungen und berichtet ueber neue Entwicklungen bei der Datenuebertragung, den Entwicklungswerkzeugen und den Baulementen. (orig.)

  10. Electronic engineering

    International Nuclear Information System (INIS)

    During the past year the Electronics group has worked on various projects such as an isotope target transport system, short-circuit plate control system for SPC1 and the SSC, a single board micro-controller, a tuning capacitor control system, installation of power supplies and cables as well as numerous smaller projects. A description of some of the larger projects are given. 6 figs

  11. Electronic Aggression

    Centers for Disease Control (CDC) Podcasts

    2007-11-20

    Aggression is no longer limited to the school yard. New forms of electronic media, such as blogs, instant messaging, chat rooms, email, text messaging, and the internet are providing new arenas for youth violence to occur.  Created: 11/20/2007 by National Center for Injury Prevention and Control, Division of Violence Prevention.   Date Released: 11/28/2007.

  12. Electronic tourism

    OpenAIRE

    Georgeta SOAVA; Amelia BADICA

    2008-01-01

    The constant development in technology, communication and particularly the Internet, has revolutionized the entire tourism industry, by generating new business models, restructuring the distribution channels, reshaping the production process involved in tourism industry and last but not least has influenced the suppliers of touristic services as well as the stakeholders. In this work I have tried to enhance the implications of electronic tourism for the visitors, the tourism operators, highli...

  13. Electronic mail.

    OpenAIRE

    Lau, Günter

    1995-01-01

    Electronic mail (email) has many advantages over other forms of communication: it is easy to use, free of charge, fast, and delivers information in a digital format. As a text only medium, email is usually less formal in style than conventional correspondence and may contain acronyms and other features, such as smileys, that are peculiar to the Internet. Email client programs that run on your own microcomputer render email powerful and easy to use. With suitable encoding methods, email can be...

  14. Advance in the biological handling of pathogen forming sclerocios

    International Nuclear Information System (INIS)

    Field rehearsals in the Center of Investigations Tibaitata allowed to determine that the mushrooms Trichoderma sp., Trichogramma search. Konigui No.1, Trichoderma search Konigui No.2 and Gliocladium sp. They have antagonistic effects against Rhizoctonia solani, that which showed in low percentages of tubers affected by R. solani, when the soil was treated with the mentioned mushrooms. In the control of Sclerotinia sclerotiorum, it was determined that Trichoderma barzianum should be applied in the moment in that it is presented more than 3 days of continuous humidity in the soil; lower these conditions 14.3 percent of plants it was only observed affected by the pathogen

  15. Role of Bradyrhizobium japonicum and Trichoderma spp. in the control of root rot disease of soybean

    Directory of Open Access Journals (Sweden)

    Syed Ehteshamul-Haque

    2014-08-01

    Full Text Available Seed treatment of soybean with Bndyrhizobium japonicum, Trichoderma harzianum, T. viride, T. hamatum, T. koningii and T. pseudokoningii significantly controlled the infection of 30-day-old seedlingsby Maerophomina phaseolina, Rhizoctonia solani and Fusarium spp. In 60-day-old plants Trichoderma spp.. and B. japonicum inhibited the grouth of R. solani and Fusarium spp., whereas the use of B. japonicum (TAL-102 with T. harzianum. T. viride, T. koningii and T. pseudokoningii controlled the infection by M. phaseolina. Greater grain yield was recorded when B. japonium (TAI-102 was used with T. hamatum.

  16. Beneficial rhizobacteria

    DEFF Research Database (Denmark)

    Michelsen, Charlotte Frydenlund

    , a number of beneficial fungal-inhibiting bacteria were isolated from a Rhizoctonia solani suppressive potato soil in Inneruulalik, South Greenland. Especially one bacterium, Pseudomonas fluorescens In5, showed high antifungal activity against ascomycetes, basidiomycetes, and oomycetes, and it was...... able to protect tomato seedlings against R. solani infection. Various molecular and biochemical methods, such as PCR and sequence analysis, genome mining, gene knock-out, heterologous recombination, TLC and HPLC analyses were used in order to assess the antifungal mechanisms of P. fluorescens In5. In...

  17. Fungicidal property of active component derived from Acorus gramineus rhizome against phytopathogenic fungi.

    Science.gov (United States)

    Lee, H S

    2007-04-01

    The fungicidal property of Acorus gramineus rhizome-derived materials against Botrytis cineria, Erysiphe graminis, Phytophthora infestans, Puccinia recondita, Pyricularia grisea, and Rhizoctonia solani was tested using a whole plant method in vivo, and was compared with a synthetic fungicide and seven commercially available A. gramineus rhizome-derived components. The responses varied according to the plant pathogen tested. At 2000 mg/l, the hexane fraction of A. gramineus rhizomes showed strong fungicidal activities against R. solani and P. infestans. The results indicated at least one of the fungicidal actions of alpha-asarone and asaronaldehyde derived from A. gramineus rhizomes. PMID:16806912

  18. ELECTRON GUN

    Science.gov (United States)

    Christofilos, N.C.; Ehlers, K.W.

    1960-04-01

    A pulsed electron gun capable of delivering pulses at voltages of the order of 1 mv and currents of the order of 100 amperes is described. The principal novelty resides in a transformer construction which is disposed in the same vacuum housing as the electron source and accelerating electrode structure of the gun to supply the accelerating potential thereto. The transformer is provided by a plurality of magnetic cores disposed in circumferentially spaced relation and having a plurality of primary windings each inductively coupled to a different one of the cores, and a helical secondary winding which is disposed coaxially of the cores and passes therethrough in circumferential succession. Additional novelty resides in the disposition of the electron source cathode filament input leads interiorly of the transformer secondary winding which is hollow, as well as in the employment of a half-wave filament supply which is synchronously operated with the transformer supply such that the transformer is pulsed during the zero current portions of the half-wave cycle.

  19. In vitro Antifungal Activity of Some Plant Essential Oils

    Directory of Open Access Journals (Sweden)

    Abdallah M. Elgorban

    2015-01-01

    Full Text Available In the present study the antimicrobial activity of essential oils of allium bulb (Allium cepa L., black cumin seeds (Nigella sativa L. and eucalyptus (Eucalyptus globulus Labill were evaluated against five fungi (Fusarium oxysporum f.sp. melonis, Fusarium solani, Fusarium verticillioides, Sclerotinia sclerotiorum and Rhizoctonia solani. Allium cepa oils completely inhibited the mycelial growth of Fusarium oxysporum f.sp. melonis, Fusarium solani and Sclerotinia sclerotiorum at 500 ppm concentration. While, E. globulus oil completely inhibited the radial growth of F. solani, S. sclerotiorum R. solani. On the other hand, the percentage inhibition varied in case of Nigella sativa oil is 28.6-73.9% from (F. oxysporum f.sp. melonis, F. verticillioides at 500 ppm concentration. Whereas, the spore germination of F. oxysporum f.sp. melonis and F. solani were completely inhibited by the application of A. cepa oil, while the oil of eucalyptus completely inhibited the spore germination of F. solani and highly effective against spore germination of F. oxysporum f.sp. melonis, F. verticillioides with 98 and 93%, respectively at 500 ppm concentration. Considering the inhibition in the growth and spore germination, it concluded that allium and eucalyptus essential oils could be used as possible bio-fungicides alternative to synthetic fungicides against phytopathogenic fungi.

  20. Basic electronics

    CERN Document Server

    Tayal, DC

    2010-01-01

    The second edition of this book incorporates the comments and suggestions of my friends and students who have critically studied the first edition. In this edition the changes and additions have been made and subject matter has been rearranged at some places. The purpose of this text is to provide a comprehensive and up-to-date study of the principles of operation of solid state devices, their basic circuits and application of these circuits to various electronic systems, so that it can serve as a standard text not only for universities and colleges but also for technical institutes. This book

  1. Nuclear electronics

    International Nuclear Information System (INIS)

    The rapid technical development of Colombia over the past years, resulted among others, a considerable increase in the number of measuring instrumentation and testing laboratories, scientific research and metrology centers, in industry, agriculture, public health, education on the nuclear field, etc. IAN is a well organized institution with qualified management, trained staff and reasonably equipped laboratories to carry out tasks as: Metrology, standardization, quality control and maintenance and repair of nuclear instruments. The government of Colombia has adopted a policy to establish and operate through the country maintenance and repair facilities for nuclear instrumentation. This policy is reflected in the organization of electronic laboratories in Bogota-IAN

  2. Electronic materials

    CERN Document Server

    Kwok, H L

    2010-01-01

    The electronic properties of solids have become of increasing importance in the age of information technology. The study of solids and materials, while having originated from the disciplines of physics and chemistry, has evolved independently over the past few decades. The classical treatment of solid-state physics, which emphasized classifications, theories and fundamental physical principles, is no longer able to bridge the gap between materials advances and applications. In particular, the more recent developments in device physics and technology have not necessarily been driven by new conc

  3. Electronic Router

    Science.gov (United States)

    Crusan, Jason

    2005-01-01

    Electronic Router (E-Router) is an application program for routing documents among the cognizant individuals in a government agency or other organization. E-Router supplants a prior 14 NASA Tech Briefs, May 2005 system in which paper documents were routed physically in packages by use of paper slips, packages could be lost, routing times were unacceptably long, tracking of packages was difficult, and there was a need for much photocopying. E-Router enables a user to create a digital package to be routed. Input accepted by E-Router includes the title of the package, the person(s) to whom the package is to be routed, attached files, and comments to reviewers. Electronic mail is used to notify reviewers of needed actions. The creator of the package can, at any time, see the status of the package in the routing structure. At the end of the routing process, E-Router keeps a record of the package and of approvals and/or concurrences of the reviewers. There are commercial programs that perform the general functions of E-Router, but they are more complicated. E-Router is Web-based, easy to use, and does not require the installation or use of client software.

  4. Effect of Seed Treatments and Root Pathogens on Seedling Establishment and Yield of Alfalfa, Birdsfoot Trefoil and Sweetclover

    Directory of Open Access Journals (Sweden)

    Sheau-Fang Hwang

    2006-01-01

    Full Text Available Soil-borne fungal pathogens can reduce stand density in alfalfa (Medicago sativa, birdsfoot trefoil (Lotus corniculatus and yellow sweetclover (Melilotus officinalis by reducing seedling establishment and subsequent stand longevity. Fungicide seed treatments containing metalaxyl and fludioxonil were examined in inoculated greenhouse and field tests to determine their efficacy against seedling blight and root rot caused by Fusarium avenaceum and Rhizoctonia solani. Inoculation increased disease severity and reduced establishment, especially in field trials inoculated with Rhizoctonia solani. Under controlled conditions, fludioxonil (alone or in a formulation with metalaxyl was effective against either pathogen in inoculated trials-seed treatment consistently increased seedling survival and reduced root rot on all three forage species. However, seed treatment had little impact on subsequent forage yield under field conditions. Metalaxyl alone was not efficacious. In fields with high pathogen populations, application of fludioxonil seed treatment on forage legume species could improve seedling establishment substantially.

  5. Epidermal Electronics

    Science.gov (United States)

    Kim, Dae-Hyeong; Lu, Nanshu; Ma, Rui; Kim, Yun-Soung; Kim, Rak-Hwan; Wang, Shuodao; Wu, Jian; Won, Sang Min; Tao, Hu; Islam, Ahmad; Yu, Ki Jun; Kim, Tae-il; Chowdhury, Raeed; Ying, Ming; Xu, Lizhi; Li, Ming; Chung, Hyun-Joong; Keum, Hohyun; McCormick, Martin; Liu, Ping; Zhang, Yong-Wei; Omenetto, Fiorenzo G.; Huang, Yonggang; Coleman, Todd; Rogers, John A.

    2011-08-01

    We report classes of electronic systems that achieve thicknesses, effective elastic moduli, bending stiffnesses, and areal mass densities matched to the epidermis. Unlike traditional wafer-based technologies, laminating such devices onto the skin leads to conformal contact and adequate adhesion based on van der Waals interactions alone, in a manner that is mechanically invisible to the user. We describe systems incorporating electrophysiological, temperature, and strain sensors, as well as transistors, light-emitting diodes, photodetectors, radio frequency inductors, capacitors, oscillators, and rectifying diodes. Solar cells and wireless coils provide options for power supply. We used this type of technology to measure electrical activity produced by the heart, brain, and skeletal muscles and show that the resulting data contain sufficient information for an unusual type of computer game controller.

  6. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede; Cutululis, Nicolaos A.

    2008-01-01

    The global electrical energy consumption is still rising and there is an urgent demand to increase the power capacity. It is expected that the power capacity has to be doubled within 20 years. The production, distribution and use of energy should be as efficient as possible and incentives to save...... energy at the end-user should also be set up. Deregulation of energy has in the past lowered the investment in larger power plants, which means the need for new electrical power sources will be high in the near future. Two major technologies will play important roles to solve the future problems. One is...... to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss...

  7. Epidermal electronics.

    Science.gov (United States)

    Kim, Dae-Hyeong; Lu, Nanshu; Ma, Rui; Kim, Yun-Soung; Kim, Rak-Hwan; Wang, Shuodao; Wu, Jian; Won, Sang Min; Tao, Hu; Islam, Ahmad; Yu, Ki Jun; Kim, Tae-il; Chowdhury, Raeed; Ying, Ming; Xu, Lizhi; Li, Ming; Chung, Hyun-Joong; Keum, Hohyun; McCormick, Martin; Liu, Ping; Zhang, Yong-Wei; Omenetto, Fiorenzo G; Huang, Yonggang; Coleman, Todd; Rogers, John A

    2011-08-12

    We report classes of electronic systems that achieve thicknesses, effective elastic moduli, bending stiffnesses, and areal mass densities matched to the epidermis. Unlike traditional wafer-based technologies, laminating such devices onto the skin leads to conformal contact and adequate adhesion based on van der Waals interactions alone, in a manner that is mechanically invisible to the user. We describe systems incorporating electrophysiological, temperature, and strain sensors, as well as transistors, light-emitting diodes, photodetectors, radio frequency inductors, capacitors, oscillators, and rectifying diodes. Solar cells and wireless coils provide options for power supply. We used this type of technology to measure electrical activity produced by the heart, brain, and skeletal muscles and show that the resulting data contain sufficient information for an unusual type of computer game controller. PMID:21836009

  8. Le Malattie crittogamiche del carciofo e relativi metodi di lotta

    OpenAIRE

    Fiori, Mario; Murgia, Giancarlo

    2003-01-01

    Vengono descritte le malattie fungine (oidio da Leveillula taurica f. sp. cynarae; peronospora da Bremia lactucae; marciume dei capolini da Botrytis cinerea; “marciumi del colletto” da Rhizoctonia solani, Sclerotinia sclerotiorum e Sclerotium rolfsii) e batteriche (marciume radicale batterico da Erwinia carotovora subsp. carotovora) del carciofo. Condizioni climatiche tipiche dell’Isola e tecnica colturale adottata (forzatura e sistemi di irrigazione) rivestono ruolo fondamentale e rappresent...

  9. Soybean diseases in Poland

    OpenAIRE

    J. Marcinkowska; J. W. Tomala-Bednarek; Schollenberger, M

    2013-01-01

    Field observations on the occurrence of soybean diseases were undertaken in the southern and central regions of Poland in the period 1976-1980. Most prevalent were foliage diseases caused by Peronospora manshurica, Pseudomonas syrinqae pv. glycinea and soybean mosaic virus (SMV). Sclerotinia sclerotiorum and Ascochyta sojaecola were reported as pathogens of local importance. The following pathogenic fungi: Botrytis cinerea, Fusarium culmorum, F. oxysporum and Rhizoctonia solani were also isol...

  10. Synthesis and Biological Activities of Some Novel (E)-Alpha-(methoxyimino)benzeneacetate Derivatives with Modified 1,2,4-Triazole Moiety

    OpenAIRE

    Xianyou Wang; Hua Wang; Peiyun Chen; Yanping Pang; Zhilei Zhao; Guangchen Wu

    2014-01-01

    To find new strobilurin analogues with high activity against resistant pathogens, a series of (E)-α-(methoxyimino)benzeneacetate derivatives containing 1,2,4-triazole Schiff base side chain were designed and synthesized. Their structures were confirmed by IR, 1H NMR, and 13C NMR, ESI-HRMS, or elemental analyses. Bioassays indicated that most of the target compounds showed moderate to good fungicidal activities against Rhizoctonia solani, Botrytis cinerea Pers., Fusarium graminearum, Cotton rh...

  11. Antifungal Activity of Some Extracts Against Some Plant Pathogenic Fungi

    OpenAIRE

    Abdulrahman A. Aba AlKhail

    2005-01-01

    In vitro studies were carried out to determine the antifungal activity of five plant extracts viz., Allium sativum, Cymogopogon proxims, Carum carvi, Azadirchia indica and Eugenia caryophyllus extracted with either Cold Distilled Water (CDW), Boiling Distilled Water (BDW) or Cold Ethanol (CET) as well two culture filtrates of Trichoderma antagonistic fungi against Fusarium oxysporum f. sp. lycopersici, Botrytis cinerea and Rhizoctonia solani. The results revealed that plant extracts especiall...

  12. Investıgatıons on the fungal dıseases of vıne nurserıes ın Aegean Regıon.

    OpenAIRE

    Arı, M.; Kapkın, A.; Öz, S.

    2009-01-01

    Studies have been carried out in 27 vine nurseries in İzmir, Manisa, Uşak, Denizli and Çanakkale provinces. Disease incidence and prevalence have been determined in the sandboxes, callus chambers, greenhouses (stocks growing in pots), and fields of these nurseries. Determined pathogens are given below: a) In the sandboxes : Armillaria mellea the agent of Armillaria root-rot disease on the buried cane cluster. b) In the callus chambers : Rhizoctonia solani and Phythium sp. which...

  13. Molecular and Functional Characterization of a Polygalacturonase-Inhibiting Protein from Cynanchum komarovii That Confers Fungal Resistance in Arabidopsis

    OpenAIRE

    Liu, Nana; Ma, Xiaowen; Zhou, Sihong; Wang, Ping; Sun, Yun; Li, Xiancai; Hou, Yuxia

    2016-01-01

    Compliance with ethical standards: This study did not involve human participants and animals, and the plant of interest is not an endangered species. Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat proteins that plants produce against polygalacturonase, a key virulence agent in pathogens. In this paper, we cloned and purified CkPGIP1, a gene product from Cynanchum komarovii that effectively inhibits polygalacturonases from Botrytis cinerea and Rhizoctonia solani. We foun...

  14. Enhanced Antifungal Bioactivity of Coptis Rhizome Prepared by Ultrafining Technology

    OpenAIRE

    Ping-Chung Kuo; Yao-Tung Lin; Mei-Lin Yang; Ming-Yuan Liao; Guo-Feng Chen; Po-Hsun Chen; Lin-Fu Wong; Jenn-Wen Huang

    2014-01-01

    The aim of this study was to identify and quantify the bioactive constituents in the methanol extracts of Coptis Rhizome prepared by ultrafining technology. The indicator compound was identified by spectroscopic method and its purity was determined by HPLC. Moreover, the crude extracts and indicator compound were examined for their ability to inhibit the growth of Rhizoctonia solani Kühn AG-4 on potato dextrose agar plates. The indicator compound is a potential candidate as a new plant derive...

  15. Biological Control Activities of Rice-Associated Bacillus sp. Strains against Sheath Blight and Bacterial Panicle Blight of Rice

    OpenAIRE

    Shrestha, Bishnu K.; Karki, Hari Sharan; Groth, Donald E.; Jungkhun, Nootjarin; Ham, Jong Hyun

    2016-01-01

    Potential biological control agents for two major rice diseases, sheath blight and bacterial panicle blight, were isolated from rice plants in this study. Rice-associated bacteria (RABs) isolated from rice plants grown in the field were tested for their antagonistic activities against the rice pathogens, Rhizoctonia solani and Burkholderia glumae, which cause sheath blight and bacterial panicle blight, respectively. Twenty-nine RABs were initially screened based on their antagonistic activiti...

  16. Biological control of potato black scurf by rhizosphere associated bacteria

    OpenAIRE

    Mohsin Tariq; Sumera Yasmin; Hafeez, Fauzia Y.

    2010-01-01

    The present work was carried out to study the potential of plant rhizosphere associated bacteria for the biocontrol of potato black scurf disease caused by Rhizoctonia solani Khun AG-3. A total of twenty-eight bacteria isolated from diseased and healthy potato plants grown in the soil of Naran and Faisalabad, Pakistan were evaluated for their antagonistic potential. Nine bacterial strains were found to be antagonistic in vitro, reduced the fungal growth and caused the lysis of sclerotia of R....

  17. Exploring Western Ghats microbial diversity for antagonistic microorganisms against fungal phytopathogens of pepper and chickpea

    OpenAIRE

    B.N. RAMKUMAR; K.M. NAMPOOTHIRI; U. SHEEBA; P. JAYACHANDRAN; N.S. SREESHMA; S.M. SNEHA; K.S. Meenakumari; P. SivaPrasad

    2015-01-01

    Newly isolated microbial cultures from Western Ghat soil samples of Kerala region in India were screened for antagonistic activity by well diffusion and dual culture plating against Phytophthora capsici and Rhizoctonia solani, infecting pepper and chickpea, respectively. Bioactive samples were made by varying solvent extraction of the culture broths of the potent isolates belongs to Actinomycetes, Pseudomonas, Bacillus and Trichoderma. The efficacy of the isolates to produce other potent anti...

  18. Effect Of Sugar Beet Seed Treatments With Some Growth Regulators On Damping Off Incidence, Total Soluble Sugars And Yield

    OpenAIRE

    El Nasr, H. I. Shif [???? ??????? ??? ?????

    1989-01-01

    Seven seed borne fungi were isolated from sugar beet seeds viz. Alternaria alternata, Helminthosponum sp., Rhizopus stolonifer, Epicoccum sp., Rhizoctonia solani, Phoma betae and Fusarium oxysporium f. sp. befae. The last three fungi were found internal, while the others were external on seed surface. The internal fungi caused root-rot disease to sugar beet plants. Treatment of seeds with each of gibh-rellic acid (GA3), indole acetic acid (IAA) and Q -naphthol ( ff -N) as 50 and 100 ppm gave ...

  19. Soybean diseases in Poland

    Directory of Open Access Journals (Sweden)

    J. Marcinkowska

    2013-12-01

    Full Text Available Field observations on the occurrence of soybean diseases were undertaken in the southern and central regions of Poland in the period 1976-1980. Most prevalent were foliage diseases caused by Peronospora manshurica, Pseudomonas syrinqae pv. glycinea and soybean mosaic virus (SMV. Sclerotinia sclerotiorum and Ascochyta sojaecola were reported as pathogens of local importance. The following pathogenic fungi: Botrytis cinerea, Fusarium culmorum, F. oxysporum and Rhizoctonia solani were also isolated from soybean.

  20. Trichoderma harzianum transformant has high extracellular alkaline proteinase expression during specific mycoparasitic interactions

    Directory of Open Access Journals (Sweden)

    Goldman Maria Helena S.

    1998-01-01

    Full Text Available The mycoparasite Trichoderma harzianum produces an alkaline proteinase that may be specifically involved in mycoparasitism. We have constructed transformant strains of this fungus that overexpress this alkaline proteinase. Some of the transformants were assessed for alkaline proteinase activity, and those with higher activity than the wild type were selected for further studies. One of these transformant strains produced an elevated and constitutive pbr1 mRNA level during mycoparasitic interactions with Rhizoctonia solani.