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Sample records for antibiosis

  1. Resistance of maize to the maize weevil: I. Antibiosis | Derera ...

    African Journals Online (AJOL)

    Resistance to damage by maize weevil (Sitophilus zeamais Motsch.) is critically important to subsistence farmers who typically store maize grain on-farm. To evaluate grain's antibiosis effects to weevil, 18 inbred lines, six each from Southern Africa, Mexico and CIMMYT-Zimbabwe were mated in sets, according to a North ...

  2. Antibiosis in Ascia monuste orseis Godart (Lepidoptera: Pieridae ...

    African Journals Online (AJOL)

    Ascia monuste orseis (Lepidoptera: Pieridae) is one of the main insect pests of kale. The study was done to identify kale varieties resistant to A. monuste orseis by the antibiosis resistance mechanism. Kale genotypes (26) were evaluated in experiments performed at the Laboratory of Agricultural Entomology of Goiano ...

  3. MEKANISME ANTIBIOSIS BACILLUS SUBTILIS B315 UNTUK PENGENDALIAN PENYAKIT LAYU BAKTERI KENTANG

    Directory of Open Access Journals (Sweden)

    Nur Prihatiningsih

    2015-03-01

    Full Text Available Antibiosis mechanism of Bacillus subtilis B315 for controlling potato bacterial wilt disease. Bacillus subtilis B315 isolated from rhizospheric potato has antibiosis mechanism against Ralstonia solanacearum in vitro and become potentially used as controlling method of bacterial wilt in the field. The objectives of this research were to study the mechanism of B.subtilis B315 in controlling bacterial wilt disease, to study of B. subtilis B315 potency as both biocontrol and plant growth promoter, and to evaluate the mechanism as biocontrol agent. This green house experiment used CRD (Completely Randomized Design with 5 treatments and 6 replicates. The treatments were control (without B. subtilis B315, B. subtilis B315 wild type, antibiosis mutant M16, antibiosis mutant M4, and antibiosis mutant M14. Variables observed were incubation period, disease index, infection rate, effectiveness of control, and growth components (i.e number of bud, plant height, leaf area, plant fresh and dry weight. The result of this research showed that B. subtilis B315 could delay incubation period, suppressed the disease index up to 64,9% and could promote the plant growth (leaf area. B. subtilis B315 had the antibiosis and other mechanisms that induced sistemic resistance. The implication of this research was that B. subtilis B315 could be used for biocontrol the bacterial wilt and promoted the potato growth.

  4. Competition and antibiosis in the biological control of potato scab.

    Science.gov (United States)

    Neeno-Eckwall, E C; Kinkel, L L; Schottel, J L

    2001-04-01

    Nonpathogenic, antibiotic-producing streptomycetes have been shown to reduce potato scab when added to disease-conducive soil. Spontaneous mutants of the pathogenic Streptomyces scabies RB4 that are resistant to at least one antibiotic activity produced by the nonpathogenic suppressive isolates Streptomyces diastatochromogenes strain PonSSII and S. scabies PonR have been isolated. To determine the importance of antibiosis in this biocontrol system, these mutants were investigated for their ability to cause disease in the presence of the two pathogen antagonists in a greenhouse assay. Disease caused by one of the mutant strains was reduced in the presence of both suppressive isolates, whereas disease caused by the other five mutants was not significantly reduced by either suppressive strain. In addition, a nonpathogenic mutant of S. scabies RB4 was isolated, which produced no detectable in vitro antibiotic activity and reduced disease caused by its pathogenic parent strain when the pathogen and mutant were coinoculated into soil. Population densities of the pathogen were consistently lower than those of the suppressive strains when individual strains were inoculated into soil. When a pathogen was coinoculated with a suppressive strain, the total streptomycete population density in the pot was always less than that observed when the suppressive isolate was inoculated alone. When the pathogens were inoculated individually into soil, a positive correlation was seen between population density and disease severity. In coinoculation experiments with pathogen and suppressive strains, higher total streptomycete population densities were correlated with lower amounts of disease.

  5. Antibiosis activity of Pantoea agglomerans biocontrol strain E325 against Erwinia amylovora on apple flower stigmas.

    Science.gov (United States)

    Pusey, P L; Stockwell, V O; Reardon, C L; Smits, T H M; Duffy, B

    2011-10-01

    Pantoea agglomerans E325, the active ingredient in a commercial product for fire blight control, was previously shown in vitro to produce a unique alkaline- and phosphate-sensitive antibiotic specific to Erwinia amylovora. Antibiosis was evaluated as a mode of antagonism on flower stigmas using two antibiosis-deficient mutants. On King's medium B, mutants E325ad1 and E325ad2 have stable smooth-butyrous or hypermucoid colony morphologies, respectively, and the parental strain E325 exhibits phenotypic plasticity with predominantly hypermucoid colonies accompanied by slower-growing, smooth-butyrous colonies. Mutants were tested against E. amylovora on stigmas of detached flowers of crab apple (Malus mandshurica) in growth chambers and apple (Malus domestica) in the orchard. Epiphytic fitness of the antibiosis-negative mutants was similar or greater than the parental strain as determined by relative area under the population curve (RAUPC). In laboratory and orchard trials, both mutants had significantly lower inhibitory activity against the pathogen (i.e., less reduction of E. amylovora RAUPC) compared with the parental strain. E325 and the mutants caused similar decreases in pH in a broth medium, indicating that acidification, which was previously reported as a possible mechanism of pathogen inhibition on stigmas, is not directly related to antibiosis. In this study we provide the first evidence for E325 antibiosis involved in E. amylovora growth suppression on apple flower stigmas.

  6. Antibiosis by Pantoea agglomerans biocontrol strain E325 against Erwinia amylovora on apple blossom stigmas

    Science.gov (United States)

    Pantoea agglomerans E325, the active ingredient in a commercial product for fire blight control, was previously shown in vitro to produce a unique alkaline- and phosphate-sensitive antibiotic specific to Erwinia amylovora. Antibiosis was evaluated as a mode of antagonism on blossom stigmas using two...

  7. Role and prevalence of antibiosis and the related resistance genes in the environment

    DEFF Research Database (Denmark)

    Nazaret, Sylvie; Aminov, Rustam

    2014-01-01

    It becomes increasingly clear that the basis of antibiotic resistance problem among bacterial pathogens is not confined to the borders of clinical microbiology but has broader ecological and evolutionary associations. This Research Topic “Role and prevalence of antibiosis and the related resistance...... genes in the environment” in Frontiers in Microbiology: Antimicrobials, Resistance, and Chemotherapy presents the examples of occurrence and diversity of antibiotic resistance genes (ARGs) in the wide range of environments, from the grasslands of the Colombian Andes, to the dairy farms and small animal...... approach to access the probability of rare horizontal gene transfer (HGT) events in bacterial populations....

  8. Synergism among volatile organic compounds resulting in increased antibiosis in Oidium sp.

    Science.gov (United States)

    Strobel, Gary A; Spang, Shanney; Kluck, Katreena; Hess, W M; Sears, Joe; Livinghouse, Tom

    2008-06-01

    Oidium sp. has been recovered as an endophyte in Terminalia catappa (tropical chestnut) in Costa Rica. The volatile organic compounds (VOCs) of this organism uniquely and primarily consist of esters of propanoic acid, 2-methyl-, butanoic acid, 2-methyl-, and butanoic acid, 3-methyl-. The VOCs of Oidium sp. are slightly inhibitory to many plant pathogenic fungi. Previous work on the VOCs of Muscodor albus demonstrated that besides esters of small organic acids, a small organic acid and a naphthalene derivative were needed to obtain maximum antibiotic activity. Thus, the addition of exogenous volatile compounds such as isobutyric acid and naphthalene, 1,1'-oxybis caused a dramatic synergistic increase in the antibiotic activity of the VOCs of Oidium sp. against Pythium ultimum. In fact, at elevated concentrations, there was not only 100% inhibition of P. ultimum but killing as well. In addition, a coculture of Muscodor vitigenus (making only naphthalene) and Oidium sp. plus isobutyric acid produced an additive antibiosis effect against P. ultimum. The biological implications of multiple volatile compounds acting to bring about antibiosis in nature are discussed.

  9. Role and prevalence of antibiosis and the related resistance genes in the environment

    DEFF Research Database (Denmark)

    It becomes increasingly clear that the basis of antibiotic resistance problem among bacterial pathogens is not confined to the borders of clinical microbiology but has broader ecological and evolutionary associations. This Research Topic “Role and prevalence of antibiosis and the related resistance...... genes in the environment” in Frontiers in Microbiology, section Antimicrobials, Resistance and Chemotherapy, presents the examples of occurrence and diversity of antibiotic resistance genes in the wide range of environments, from the grasslands of the Colombian Andes, to the dairy farms and small animal...... veterinary hospitals in the United Stated, and to the various environments of Continental Europe and Indochina. Besides, various genetic mechanisms and selection/co-selection factors contributing to the dissemination and maintenance of antibiotic resistance genes are presented. The topic is finalized...

  10. Wheat Antixenosis, Antibiosis, and Tolerance to Infestation by Delphacodes kuscheli (Hemiptera: Delphacidae), a Vector of "Mal de Rio Cuarto" in Argentina

    Czech Academy of Sciences Publication Activity Database

    Brentassi, M.E.; Corrales, C.; Snape, J.W.; Dixon, Anthony F. G.; Castro, A.M.

    2009-01-01

    Roč. 102, - (2009), s. 1801-1807 ISSN 0022-0493 Institutional research plan: CEZ:AV0Z60870520 Keywords : Delphaeodes kuscheli * wheat * antibiosis * antixenosis * tolerance Subject RIV: EG - Zoology Impact factor: 1.296, year: 2009

  11. Feeding behavior of Russian wheat aphid (Hemiptera: Aphididae) biotype 2 in response to wheat genotypes exhibiting antibiosis and tolerance resistance.

    Science.gov (United States)

    Lazzari, Sonia; Starkey, Sharon; Reese, John; Ray-Chandler, Andrea; McCubrey, Raymond; Smith, C Michael

    2009-06-01

    In this study, wheat, Triticum aestivum L. (em Thell), genotypes containing the Dnx, Dn7, Dn6, and Dn4 genes for resistance to the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), along with Dn0, a susceptible control, were assessed to determine the categories of D. noxia biotype 2 (RWA2) resistance in each genotype and RWA2 feeding behaviors on Dnx and Dn0 plants by using the electronic penetration graph technique. At 14 d postinfestation, Dn0 plants exhibited intense chlorosis and leaf rolling, and all test genotypes expressed some degree of chlorosis and leaf rolling, except Dn7, which was not damaged. Both Dn7 and Dnx expressed antibiosis effects, significantly reducing the numbers of aphids on plants and the intrinsic rate of aphid increase. Dn6 plants seemed to contain tolerance, exhibiting tolerance index measurements for leaf and root dry weight and plant height that were significantly lower than those of the susceptible Dn0 plants. Principal component analyses indicated that antibiosis and leaf rolling data explained 80% of the variance among genotypes. Electronic penetration graph analysis demonstrated contrasting results between RWA1 and RWA2 phloem sieve element phase feeding events, but results indicated that Dnx resistance factors are present in the sieve element cells or phloem sap. Plants containing Dnx exhibit antibiosis resistance to D. noxia RWA2 similar to that in plants containing the Secale cereale L. (rye)-based Dn7 gene without the negative baking quality traits associated with Dn7.

  12. Antibiosis and antixenosis to Aphis gossypii (Homoptera: Aphididac) in Colocasia esculenta.

    Science.gov (United States)

    Coleson, Jenifer L; Miller, Ross H

    2005-06-01

    Fifty cultivars of taro, Colocasia esculenta (L.) Schott (Araceae), collected from islands in Micronesia and Polynesia, eight cultivars from the University of Hawaii's taro germplasm collection, and a closely related aroid, Xanthosorna sagittifolium (L.) (Araceae), were screened for antibiosis and antixenosis to Aphis gossypii Clover. Life history data for A. gossypii were collected by assessing survivorship and fecundity of aphids caged on taro leaves in the field. Significant differences in aphid reproductive rate and longevity were observed among the taro cultivars, and cultivars were ranked from most resistant to most susceptible. Antixenosis was assayed in the laboratory in a multiround choice test where A. gossypii were offered four leaf discs excised from different taro cultivars. Additionally, field observations of aphid abundance on taro cultivars were made to corroborate clip cage studies and laboratory experiments. 'Iliuaua','Rumung Mary','Maria', 'Ketan 36', and'Agaga' were the most resistant in terms of reducing aphid fecundity and survivorship, whereas the Iliuana,'Purple', 'TC-83001', and 'Putih 24' were least preferred in aphid choice tests. X. sagittifolium consistently exhibited strong aphid resistance. Resistant cultivars identified in this study may form the basis of breeding programs seeking to combine aphid resistance with other desirable agronomic traits in taro.

  13. Assesing Bemisia tabaci (Genn. biotype B resistance in soybean genotypes: Antixenosis and antibiosis Evaluación de la resistencia de genotipos de soya a Bemisia tabaci (Genn. biotipo B: Antixenosis y antibiosis

    Directory of Open Access Journals (Sweden)

    José Paulo Gonçalves Franco da Silva

    2012-12-01

    Full Text Available Since it was first reported in Brazil in the 1990s, the B biotype of silverleaf whitefly (Bemisia tabaci Genn., Hemiptera: Aleyrodidae has been recognized as an important pest in soybeans (Glycine max L., reducing the productivity of this legume species in some areas of the country. As an alternative to chemical control, the use of resistant genotypes represents an important tool for integrated pest management (IPM. This study evaluated the performance of 10 soybean genotypes prior to whitefly infestation, by testing attractiveness and preference for oviposition in the greenhouse and antibiosis in the laboratory. In a multiple-choice test, 'IAC-17' was the least attractive to insects. In a no-choice test, 'IAC-17' was the least attractive for egg deposition, indicating the occurrence of non-preference for oviposition on this genotype. Trichome density was positively correlated with the oviposition site and may be associated with the resistance of 'IAC-17' to infestation. The genotypes 'IAC-PL1', 'IAC-19', 'Conquista', 'IAC-24' and 'IAC-17' extended the insect's life cycle, indicating the occurrence of a small degree of antibiosis and/or non-preference for feeding.Desde que se registró por primera vez en Brasil en la década de 1990, el biotipo B de la mosca-blanca (Bemisia tabaci Genn., Hemiptera: Aleyrodidae, se reconoce como una importante plaga de la soya (Glycine max L. y es lo que reduce la productividad de estas especies de leguminosas en algunas zonas del pais. Como una alternativa al control químico, el uso de genotipos resistentes representa una herramienta importante para la gestión integrada de plagas (MIP. Este trabajo evaluó el comportamiento de 10 genotipos de soya frente al ataque de la mosca-blanca, por medio de ensayos de atractividad y preferencia para ovipostura en invernaderos y antibiosis en laboratorio. En una prueba de elección multiple, 'IAC-17' fue el menos atractivo para los insectos. En una prueba sin elecci

  14. Characterization of Antibiosis to Diabrotica speciosa (Coleoptera: Chrysomelidae) in Brazilian Maize Landraces.

    Science.gov (United States)

    Costa, Eduardo Neves; Nogueira, Luciano; de Souza, Bruno Henrique Sardinha; Ribeiro, Zulene Antônio; Louvandini, Helder; Zukoff, Sarah Natalie; Júnior, Arlindo Leal Boiça

    2018-02-09

    Resistance to insect pests can be found in several native, landrace plants and can be an important alternative to conventional control methods. Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) larvae are important maize (Zea mays L.) (Cyperales: Poaceae) root pests and finding native resistance in landraces would greatly contribute to maize-breeding programs aimed at controlling this pest. This study investigated whether the growth, survival, oviposition rhythm, fecundity, and fertility of D. speciosa are negatively influenced by specific maize landraces, and the existence of any morphological barriers in the roots that may correlate with plant resistance to the larval attack. Nineteen genotypes (17 landraces and 2 cultivars) were screened for antibiosis in assays that were conducted in the laboratory using seedling maize plants where the development time, longevity, weight, total survival, and sex ratio of adults were evaluated. Out of nineteen genotypes, eight were selected according to their resistance levels for an additional rearing study evaluating oviposition and fecundity. Landrace Pérola and cultivar SCS 154-Fortuna were classified as resistant because they increased the maturation period from larva to adult and decreased survivorship; and the landrace Palha Roxa was also classified as resistant for showing a lower fertility rate than other landraces. Resistant landraces that were infested by D. speciosa larvae showed greater amounts of some morphological barriers comparing with uninfested plants. The landraces classified as resistant may be considered in future plant-breeding programs, aiming to develop resistant maize cultivars to D. speciosa larval attack. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. In vitro growth inhibition of intra root canal pathogenic microorganisms by Lactic Acid Bacteria, an Antibiosis method

    Directory of Open Access Journals (Sweden)

    A. Nakhjavani F.

    2008-12-01

    Full Text Available "nBackground and Aim: Elimination of microorganisms and their byproducts from root canal system is one of important aims of root canal therapy. This object is gained by using of many chemomechanical techniques but with noncertain success. A new method is used of nonpathogenic bacteria for growth inhibition of pathogenic bacteria, Antibiosis, in root canal therapy.The aim of this study was in vitro evaluation of antimicrobial effect of probiotics, such as Lactic Acid Bacteria (LAB on the infected root canal bacteria. "nMaterials and Methods: Isolated bacteria from infected root canal were grown and then scattered onto the muller Hinton agar plates which contain wells, LAB, extracted from dairy products, were added into these wells, Inhibition effected of LAB was determined. Furthermore the sample taken from the inhibition zone and possible resistant monoclonal bacteria also were identified, then 6 sensitive and 14 resistant samples were selected and E. faecalis species were added to them; Then antimicrobial effects of LAB on these samples was reevaluated. "nResults: The results showed that 66.7% of the samples were sensitive at least to one type of LAB, and 33% were resistant to all kind of LAB. Meanwhile the outgrowing anaerobic bacteria inside the inhibition zone were from the low frequency oral bacterial flora. Furthermore, adding E. faecalis to the samples caused more sensitivity of them to LAB. Mc-Neamar test recognized the difference significant. "nConclusion: This study showed that the LAB inhibit growth of the pathogenic root canal bacteriae. Furthermore, presence of E. faecalis reinforces the antimicrobial effect of LAB. It seemed that LAB maybe have potential to use in endodontic practice for elimination of root canal infections.

  16. An Interspecies Signaling System Mediated by Fusaric Acid Has Parallel Effects on Antifungal Metabolite Production by Pseudomonas protegens Strain Pf-5 and Antibiosis of Fusarium spp.

    Science.gov (United States)

    Quecine, Maria Carolina; Kidarsa, Teresa A; Goebel, Neal C; Shaffer, Brenda T; Henkels, Marcella D; Zabriskie, T Mark; Loper, Joyce E

    2015-12-11

    Pseudomonas protegens strain Pf-5 is a rhizosphere bacterium that suppresses soilborne plant diseases and produces at least seven different secondary metabolites with antifungal properties. We derived mutants of Pf-5 with single and multiple mutations in biosynthesis genes for seven antifungal metabolites: 2,4-diacetylphoroglucinol (DAPG), pyrrolnitrin, pyoluteorin, hydrogen cyanide, rhizoxin, orfamide A, and toxoflavin. These mutants were tested for inhibition of the pathogens Fusarium verticillioides and Fusarium oxysporum f. sp. pisi. Rhizoxin, pyrrolnitrin, and DAPG were found to be primarily responsible for fungal antagonism by Pf-5. Previously, other workers showed that the mycotoxin fusaric acid, which is produced by many Fusarium species, including F. verticillioides, inhibited the production of DAPG by Pseudomonas spp. In this study, amendment of culture media with fusaric acid decreased DAPG production, increased pyoluteorin production, and had no consistent influence on pyrrolnitrin or orfamide A production by Pf-5. Fusaric acid also altered the transcription of biosynthetic genes, indicating that the mycotoxin influenced antibiotic production by Pf-5 at the transcriptional level. Addition of fusaric acid to the culture medium reduced antibiosis of F. verticillioides by Pf-5 and derivative strains that produce DAPG but had no effect on antibiosis by Pf-5 derivatives that suppressed F. verticillioides due to pyrrolnitrin or rhizoxin production. Our results demonstrated the importance of three compounds, rhizoxin, pyrrolnitrin, and DAPG, in suppression of Fusarium spp. by Pf-5 and confirmed that an interspecies signaling system mediated by fusaric acid had parallel effects on antifungal metabolite production and antibiosis by the bacterial biological control organism. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  17. Folliculitis et perifolliculitis capitis abscedens et suffodiens controlled with a combination therapy: Systemic antibiosis (Metronidazole Plus Clindamycin, dermatosurgical approach, and high-dose isotretinoin

    Directory of Open Access Journals (Sweden)

    Georgi Tchernev

    2011-01-01

    Full Text Available Folliculitis et perifolliculitis capitis abscedens et suffodiens is a rare disease of unknown etiology. It is a suppurative process that involves the scalp, eventually resulting in extensive scarring and irreversible alopecia. The condition is also known as ′acne necrotica miliaris′ or ′Proprionibacterium′ folliculitis. Most often the disease affects men of African-American or African-Caribbean descent between 20 and 40 years of age. The clinical picture is determined by fluctuating painful fistule-forming conglomerates of abscesses in the region of the occipital scalp. The cause of scalp folliculitis is not well understood. It is generally considered to be an inflammatory reaction to components of the hair follicle, particularly the micro-organisms. These include: bacteria (especially Propionibacterium acnes, but in severe cases, also Staphylococcus aureus, Yeasts (Malassezia species and mites (Demodex folliculorum. The initial histopathologic finding is an exclusively neutrophilic infiltration followed by a granulomatous infiltrate. The treatment of the disease is usually difficult and often disappointing. Successful treatment with isotretinoin 1 mg/kg body mass could be achieved only after regular systematic administration in the course of 3-4 months. Here we describe a patient with eruptive purulent form of the disease, which has been controlled with combination therapy: systemic antibiosis with metronidazole and clindamycin, dermatosurgical removal of single nodular formations, and isotretinoin 1 mg/kg body mass for 3-5 months.

  18. Resistência por antibiose de Lycopersicon peruvianum à traça do tomateiro Antibiosis resistance of Lycopersicon peruvianum to tomato leafminer

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    Fábio Akiyoshi Suinaga

    2004-06-01

    Full Text Available Este trabalho foi realizado em casa de vegetação na Universidade Federal de Viçosa e objetivou estudar a resistência por antibiose do acesso CNPH 101 de Lycopersicon peruvianum a traça do tomateiro Tuta absoluta (Meyrick (Lepidoptera: Gelechiidae e as possíveis causas químicas desta resistência. Os tratamentos foram as espécies de tomateiro Lycopersicon esculentum (cvs. IPA-5 e Santa Clara: padrões de suscetibilidade e o acesso de L. peruvianum. As características avaliadas foram: mortalidade larval, peso de pupas e proporção sexual, duração das fases larval e pupal e números de ovos/fêmea de T. absoluta. Realizou-se extração hexânica nas folhas e os extratos obtidos foram submetidos a cromatografia gasosa associada a espectrômetro de massa. O acesso CNPH 101 de L. peruvianum apresentou resistência a T. absoluta afetando a mortalidade larval e duração da fase pupal. Duas substâncias (provavelmente o 4-metil-2,6-di-tert-butilfenol e outra com tempo de retenção 18,8 min. no cromatograma estiveram associadas ao fato de que L. esculentum é mais suscetível a T. absoluta do que L. peruvianum. Foram detectadas duas substâncias associadas a plantas da cultivar Santa Clara (provavelmente o transcarofileno e de L. peruvianum (provavelmente o hexadecano mais suscetíveis a T. absoluta. Foi detectada uma substância (com tempo de retenção 22,796 min. no cromatograma associada a plantas de L. peruvianum mais resistentes a T. absoluta.This work was carried out in a greenhouse in the Federal University of Viçosa, to evaluate the antibiosis of Lycopersicon peruvianum (CNPH 101 to tomato leafminer Tuta absoluta (Meyrick (Lepidoptera: Gelechiidae and its possible chemical causes. The treatments were represented by the species of tomato Lycopersicon esculentum (cv. Santa Clara and IPA-5: susceptibility patterns to T. absoluta and the introduction CNPH 101 of L. peruvianum. The characteristics assessed were: larval mortality, pupal

  19. Antibiosis in Ascia monuste orseis Godart (Lepidoptera: Pieridae ...

    African Journals Online (AJOL)

    Flávio Gonçalves

    (Sinapis arvensis), wild radish (Raphanus raphanistrum), cabbage (Brassica oleracea var. capitata), cauliflower. (Brassica oleracea var. botrytis) and Chinese ..... seeds: Phytochemical characterization and antioxidant potential. Food Chem. 101: 549-558. Filgueira FAR (2008). Novo manual de olericultura: Agrotecnologia.

  20. Role of antibiosis on suppression of bacterial common blight ...

    African Journals Online (AJOL)

    Paenibacillus polymyxa strain HKA-15, a soybean bacterial endophyte showed strong antagonism against bacterial common blight pathogen Xanthomonas campestris pv. phaseoli strains M-5 and CP-1-1. In agar diffusion assay, the antibacterial metabolite from P. polymyxa HKA-15 showed a clear zone of inhibition ...

  1. Role of antibiosis on suppression of bacterial common blight ...

    African Journals Online (AJOL)

    Magesh

    2012-07-26

    Jul 26, 2012 ... Paenibacillus polymyxa strain HKA-15, a soybean bacterial endophyte showed strong antagonism against bacterial common ... with positive chemical control in suppression of bacterial common blight disease in French bean plants. ... known to induce systemic resistance in host plant and competing out the ...

  2. Role of antibiosis on suppression of bacterial common blight ...

    African Journals Online (AJOL)

    Magesh

    2012-07-26

    Jul 26, 2012 ... legumes and is a pathogen hard to control (Zanatta et al.,. 2007). Increasing resistance of pathogen and detrimental effect of chemicals force us to search an alternative for better disease management.Of the different management strategies, biocontrol of the pathogens by plant growth promoting bacteria ...

  3. ASSESSING Bemisia tabaci (GENN.) BIOTYPE B RESISTANCE IN SOYBEAN GENOTYPES: ANTIXENOSIS AND ANTIBIOSIS

    OpenAIRE

    Goncalves Franco da Silva, Jose Paulo; Lopes Baldin, Edson Luiz; de Souza, Efrain Santana; Lourencao, Andre Luiz

    2012-01-01

    Since it was first reported in Brazil in the 1990s, the B biotype of silverleaf whitefly (Bemisia tabaci [Genn.], Hemiptera: Aleyrodidae) has been recognized as an important pest in soybeans (Glycine max L.), reducing the productivity of this legume species in some areas of the country. As an alternative to chemical control, the use of resistant genotypes represents an important tool for integrated pest management (IPM). This study evaluated the performance of 10 soybean genotypes prior to wh...

  4. Our Contributions in Nanochemistry for Antibiosis, Electrocatalyst and Energy Storage Materials.

    Science.gov (United States)

    Zhang, Jian; Xu, Jing; Wang, Yan; Xue, Huaiguo; Pang, Huan

    2018-01-01

    This account mainly introduces and reviews our recent progress in three projects: antibacterial nanomaterial, electrocatalyst for detecting and electrode nanomaterial of energy storage device, especially the supercapacitor. Besides, our thought and idea about the design, fabrication and application of corresponding nanomaterials are sketched throughout the whole article in order to reveal the structure-function relationship and corresponding mechanism. In the end, we tend to attach importance to the bottleneck of nanomaterial's development and put forward our understanding in this field. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Assesing Bemisia tabaci (Genn.) biotype B resistance in soybean genotypes: Antixenosis and antibiosis Evaluación de la resistencia de genotipos de soya a Bemisia tabaci (Genn.) biotipo B: Antixenosis y antibiosis

    OpenAIRE

    José Paulo Gonçalves Franco da Silva; Edson Luiz Lopes Baldin; Efrain Santana de Souza; André Luiz Lourenção

    2012-01-01

    Since it was first reported in Brazil in the 1990s, the B biotype of silverleaf whitefly (Bemisia tabaci Genn., Hemiptera: Aleyrodidae) has been recognized as an important pest in soybeans (Glycine max L.), reducing the productivity of this legume species in some areas of the country. As an alternative to chemical control, the use of resistant genotypes represents an important tool for integrated pest management (IPM). This study evaluated the performance of 10 soybean genotypes prior to whit...

  6. Antibiosis and tolerance discovered in USDA-ARS sorghums resistant to the sugarcane aphid Melanaphis sacchari (Hemiptera: Aphididae)

    Science.gov (United States)

    The sugarcane aphid, Melanaphis sacchari, was discovered infesting grain sorghum near Beaumont, TX, close to the Texas and Louisiana state line a few miles inland from the Gulf coast in the late summer of 2013, and has been a perennial pest of sorghum through 2016. Our research was aimed at identif...

  7. Discovery of three woolly apple aphid Eriosoma lanigerum (Hemiptera: Aphididae) biotypes in Australia: the role of antixenosis and antibiosis in apple tree resistance

    Czech Academy of Sciences Publication Activity Database

    Costa, Arnaud; Williams, D. G.; Powell, K. S.

    2014-01-01

    Roč. 53, č. 3 (2014), s. 280-287 ISSN 2052-1758 Institutional support: RVO:60077344 Keywords : aphid * apple * biotype Subject RIV: EH - Ecology, Behaviour http://onlinelibrary.wiley.com/doi/10.1111/aen.12074/pdf

  8. An inter-species signaling system mediated by fusaric acid has parallel effects on antifungal metabolite production by Pseudomonas protegens Pf-5 and antibiosis of Fusarium spp.

    Science.gov (United States)

    Pseudomonas protegens strain Pf-5 is a rhizosphere bacterium that acts as a biocontrol agent of soilborne plant diseases, and produces at least seven different secondary metabolites with antifungal properties. We derived site-directed mutants of Pf-5 with single and multiple mutations in the biosynt...

  9. Antibiosis and dark-pigments secretion by the phytopathogenic and environmental fungal species after interaction in vitro with a Bacillus subtilis isolate

    Directory of Open Access Journals (Sweden)

    Alexandre Paulo Machado

    2010-10-01

    Full Text Available In this work, different reactions in vitro between an environmental bacterial isolate and fungal species were related. The Gram-positive bacteria had terminal and subterminal endospores, presented metabolic characteristics of mesophilic and acidophilic growth, halotolerance, positive to nitrate reduction and enzyme production, as caseinase and catalase. The analysis of partial sequences containing 400 to 700 bases of the 16S ribosomal RNA gene showed identity with the genus Bacillus. However, its identity as B. subtilis was confirmed after analyses of the rpoB, gyrA, and 16S rRNA near-full-length sequences. Strong inhibitory activity of environmental microorganisms, such as Penicillium sp, Aspergillus flavus, A. niger, and phytopathogens, such as Colletotrichum sp, Alternaria alternata, Fusarium solani and F. oxysporum f.sp vasinfectum, was shown on co-cultures with B. subtilis strain, particularly on Sabouraud dextrose agar (SDA and DNase media. Red and red-ochre color pigments, probably phaeomelanins, were secreted by A. alternata and A. niger respectively after seven days of co-culture.Na presente investigação, nosso objetivo principal foi relatar diferentes interações in vitro de um isolado bacteriano ambiental com espécies fúngicas. Através da identificação clássica, nós verificamos que o bacilo ambiental apresentava endósporos terminais e subterminais, características metabólicas de mesofilia, acidofilia, halotolerância, redução de nitrato e produção de enzimas, como caseinase e catalase. Análise de seqüências parciais do gene 16S RNAr contendo de 400 a 700 bases revelou identidade com gênero Bacillus. No entanto, a espécie Bacillus subtilis foi confirmada somente depois da análise de seqüências dos genes rpoB, gyrA, and 16S RNAr. Intensa atividade inibitória aos fungos ambientais, como Penicillium sp, Aspergillus flavus, A. niger, e fitopatogênicos, como Colletotrichum sp, Alternaria alternata, Fusarium solani e F. oxysporum f.sp vasinfectum, foi observada em coculturas com a cepa bacteriana (B. subtilis, particularmente em ágar Sabouraud dextrose e ágar DNase. Pigmentos de cor avermelhada e vermelho-amarronzado, provavelmente feomelaninas, foram secretados respectivamente por colônias de A. alternata e A. niger depois de sete dias de co-cultivo.

  10. Antibiosis and bmyB Gene Presence As Prevalent Traits for the Selection of Efficient Bacillus Biocontrol Agents against Crown Gall Disease

    Directory of Open Access Journals (Sweden)

    Olfa Frikha-Gargouri

    2017-08-01

    Full Text Available This study aimed to improve the screening method for the selection of Bacillus biocontrol agents against crown gall disease. The relationship between the strain biocontrol ability and their in vitro studied traits was investigated to identify the most important factors to be considered for the selection of effective biocontrol agents. In fact, previous selection procedure relying only on in vitro antibacterial activity was shown to be not suitable in some cases. A direct plant-protection strategy was performed to screen the 32 Bacillus biocontrol agent candidates. Moreover, potential in vitro biocontrol traits were investigated including biofilm formation, motility, hemolytic activity, detection of lipopeptide biosynthetic genes (sfp, ituC and bmyB and production of antibacterial compounds. The obtained results indicated high correlations of the efficiency of the biocontrol with the reduction of gall weight (p = 0.000 and the antibacterial activity in vitro (p = 0.000. Moreover, there was strong correlations of the efficiency of the biocontrol (p = 0.004 and the reduction in gall weight (p = 0.000 with the presence of the bmyB gene. This gene directs the synthesis of the lipopeptide bacillomycin belonging to the iturinic family of lipopeptides. These results were also confirmed by the two-way hierarchical cluster analysis and the correspondence analysis showing the relatedness of these four variables. According to the obtained results a new screening procedure of Bacillus biocontrol agents against crown gall disease could be advanced consisting on two step selection procedure. The first consists on selecting strains with high antibacterial activity in vitro or those harbouring the bmyB gene. Further selection has to be performed on tomato plants in vivo. Moreover, based on the results of the biocontrol assay, five potent strains exhibiting high biocontrol abilities were selected. They were identified as Bacillus subtilis or Bacillus amyloliquefaciens. These strains were found to produce either surfactin or surfactin and iturin lipopeptides. In conclusion, our study presented a new and effective method to evaluate the biocontrol ability of antagonistic Bacillus strains against crown gall disease that could increase the efficiency of screening method of biocontrol agents. Besides, the selected strains could be used as novel biocontrol agents against pathogenic Agrobacterium tumefaciens strains.

  11. Influência da antibiose exercida por actinomicetos às estirpes de Bradyrhizobium SPP., na nodulação da soja Influence of antibiosis produced by actinomycetes on strains of Bradyrhizobium SPP. on soybean nodulation

    Directory of Open Access Journals (Sweden)

    João Carlos Pereira

    1999-01-01

    Full Text Available Este trabalho teve por objetivo avaliar o espectro antibiótico de actinomicetos provenientes de solos de Cerrados e a sua influência na nodulação da soja. As estirpes BR 29, BR 33, BR 40, BR 85, BR 86, BR 96, 47/587, 3B-7 e 4A-5 de Bradyrhizobium spp. apresentaram comportamento diferenciado em relação à resistência natural aos antibióticos produzidos por 204 actinomicetos. As estirpes BR 29 e BR 96 foram sensíveis a 5,2 e 9,9% dos antibióticos produzidos, respectivamente, enquanto a BR 33 apresentou sensibilidade a 20,3%. O antagonismo exercido pelos actinomicetos exclusivamente à BR 29 e BR 33 foi de 1,6 e 5,7%, respectivamente. Esse efeito não foi observado nas estirpes BR 40 e BR 96. Inoculações simples e em mistura das estirpes na presença de actinomicetos influenciaram a nodulação da soja. A co-inoculação da BR 33 e BR 29 com o isolado 370 reduziu o percentual de ocorrência média, nos nódulos, da BR 29, de 94,1% para 83,7%, com conseqüente aumento da BR 33 de 6,7% para 17,2%. Os resultados evidenciam a importância de estudos ecológicos desses microrganismos, visando avaliar o seu papel no estabelecimento de uma nodulação eficiente.The aim of this work was to evaluate the antibiotic spectrum of actinomycetes from Cerrado soils and their influence on soybean nodulation. Strains BR 29, BR 33, BR 40, BR 85, BR 86, BR 96, 47/587, 3B-7 and 4A-5 of Bradyrhizobium spp. were characterized by their natural resistence to antibiotics produced by 204 actinomycete isolates. The strains BR 29 and BR 96 of B. elkanii were sensitive to 5.2% and 9.9% the products of actinomycete isolates, respectively, while BR 33 was sensitive up to 20.3%. The antagonistic effects caused by actinomycete exclusively to BR 29 and BR 33 were 1.6% and 5.7% respectively. This effect was not observed for strains BR 40 and BR 96. Single and multistrains inoculations in the presence or absence of actinomycetes affected soybean nodulation. On double strain inoculations, with BR 33 and BR 29 mixed with actinomycete 370 there was a decrease in nodule occupancy by BR 29 from 94.1% to 83.7% with concomitant increase in the occupying of BR 33 from 6.7% to 17.2%. The results indicate the importance of ecological studies on actinomycetes population in order to access their role in the establishment of efficient nodulation.

  12. Xylem Resin in the Resistance of the Pinaceae to Bark Beetles

    Science.gov (United States)

    Richard H. Smith

    1972-01-01

    Xylem resin of Pinaceae is closely linked with their resistance and suseptibility to tree-killing bark beetles. This review of the literature on attacking adults suggests that all three resistance mechanisms proposed by Painter -- preference, antibiosis, and tolerance -- are active in this relationship: preference by attraction, repellency, and synergism; antibiosis...

  13. Antibiotic Conditioned Growth Medium of Pseudomonas Aeruginosa

    Science.gov (United States)

    Benathen, Isaiah A.; Cazeau, Barbara; Joseph, Njeri

    2004-01-01

    A simple method to study the consequences of bacterial antibiosis after interspecific competition between microorganisms is presented. Common microorganisms are used as the test organisms and Pseudomonas aeruginosa are used as the source of the inhibitor agents.

  14. Antifungal metabolites from antagonistic fungi used to control tomato ...

    African Journals Online (AJOL)

    Yomi

    2011-12-28

    Dec 28, 2011 ... exhibit cytotoxicity against a human breast cancer cell line. It should be noted that Ch. elatum ChE01 can also ... cancer cell lines (Moosophon et al., 2009). Another species of Emericella (Emericella nidulans) ..... destroy the pathogen cells implies antibiosis. As pre- viously reported by Soytong et al. (2001) ...

  15. Induction of soybean resistance to the Mexican bean beetle (Coleoptera: Coccinellidae)

    Science.gov (United States)

    A.L. Iverson; R.B. Hammond; L.R. Iverson

    2001-01-01

    We tested chemical and insect feeding-induced insect resistance on soybean plants.The chemical induction effects of jasmonic acid (JA) and salicylic acid (SA) were investigated. We also evaluated the effects of plants stressed with previous insect herbivory. A larval antibiosis screening technique (LAST) and a preference test were performed in petri dishes using...

  16. Characterization and genetic dissection of resistance to spotted alfalfa aphid (Therioaphis trifolii) in Medicago truncatula

    Science.gov (United States)

    Kamphuis, Lars G.; Lichtenzveig, Judith; Peng, Kefan; Guo, Su-Min; Klingler, John P.

    2013-01-01

    Aphids cause significant yield losses in agricultural crops worldwide. Medicago truncatula, a model legume, cultivated pasture species in Australia and close relative of alfalfa (Medicago sativa), was used to study the defence response against Therioaphis trifolii f. maculate [spotted alfalfa aphid (SAA)]. Aphid performance and plant damage were compared among three accessions. A20 is highly susceptible, A17 has moderate resistance, and Jester is strongly resistant. Subsequent analyses using A17 and A20, reciprocal F1s and an A17×A20 recombinant inbred line (RIL) population revealed that this moderate resistance is phloem mediated and involves antibiosis and tolerance but not antixenosis. Electrical penetration graph analysis also identified a novel waveform termed extended potential drop, which occurred following SAA infestation of M. truncatula. Genetic dissection using the RIL population revealed three quantitative trait loci on chromosomes 3, 6, and 7 involved in distinct modes of aphid defence including antibiosis and tolerance. An antibiosis locus resides on linkage group 3 (LG3) and is derived from A17, whereas a plant tolerance and antibiosis locus resides on LG6 and is derived from A20, which exhibits strong temporary tolerance. The loci identified reside in regions harbouring classical resistance genes, and introgression of these loci in current medic cultivars may help provide durable resistance to SAA, while elucidation of their molecular mechanisms may provide valuable insight into other aphid–plant interactions. PMID:24058162

  17. Biochemical factors associated with cassava resistance to whitefly ...

    African Journals Online (AJOL)

    Cassava (Manihot esculenta Crantz) an important food security crop, is inflicted by whitefly (Bemisia tabaci) worldwide, causing direct damage of up to 80% of yield loss. Although resistance to the pest has been associated with antibiosis, changes that occur in metabolite activity, and their effect on the pest have not been ...

  18. Biochemical factors associated with cassava resistance to whitefly

    African Journals Online (AJOL)

    ACSS

    2017-08-17

    Aug 17, 2017 ... Cassava (Manihot esculenta Crantz) an important food security crop, is inflicted by whitefly (Bemisia tabaci) worldwide, causing direct damage of up to 80% of yield loss. Although resistance to the pest has been associated with antibiosis, changes that occur in metabolite activity, and their effect on the pest ...

  19. Arabidopsis thaliana resistance to insects, mediated by an earthworm-produced organic soil amendment.

    Science.gov (United States)

    Cardoza, Yasmin J

    2011-02-01

    Vermicompost is an organic soil amendment produced by earthworm digestion of organic waste. Studies show that plants grown in soil amended with vermicompost grow faster, are more productive and are less susceptible to a number of arthropod pests. In light of these studies, the present study was designed to determine the type of insect resistance (antixenosis or antibiosis) present in plants grown in vermicompost-amended potting soil. Additionally, the potential role of microarthropods, entomopathogenic organisms and non-pathogenic microbial flora found in vermicompost on insect resistance induction was investigated. Findings show that vermicompost from two different sources (Raleigh, North Carolina, and Portland, Oregon) were both effective in causing Arabidopsis plants to be resistant to the generalist herbivore Helicoverpa zea (Boddie). However, while the Raleigh (Ral) vermicompost plant resistance was expressed as both non-preference (antixenosis) and milder (lower weight and slower development) toxic effect (antibiosis) resistance, Oregon (OSC) vermicompost plant resistance was expressed as acute antibiosis, resulting in lower weights and higher mortality rates. Vermicompost causes plants to have non-preference (antixenosis) and toxic (antibiosis) effects on insects. This resistance affects insect development and survival on plants grown in vermicompost-amended soil. Microarthropods and entomopathogens do not appear to have a role in the resistance, but it is likely that resistance is due to interactions between the microbial communities in vermicompost with plant roots, as is evident from vermicompost sterilization assays conducted in this study. Copyright © 2010 Society of Chemical Industry.

  20. Isolement et caractérisation morphologique de moisissures ...

    African Journals Online (AJOL)

    Bacterial resistance to the actual antibiotic is mostly in dangerous progress, why we have interest in isolation and characterization of fungi strains producing antibiotics using local food in Burkina Faso. Fifty (50) isolated strains were used in the antibiosis trial which revealed twenty (20) strains producing antimicrobial ...

  1. Induced systemic resistance by fluorescent Pseudomonas spp.

    NARCIS (Netherlands)

    Bakker, P.A.H.M.; Pieterse, C.M.J.; Loon, L.C. van

    2007-01-01

    Fluorescent Pseudomonas spp. have been studied for decades for their plant growth-promoting effects through effective suppression of soilborne plant diseases. The modes of action that play a role in disease suppression by these bacteria include siderophore-mediated competition for iron, antibiosis,

  2. Characterization and genetic dissection of resistance to spotted alfalfa aphid (Therioaphis trifolii) in Medicago truncatula

    KAUST Repository

    Kamphuis, L. G.

    2013-09-21

    Aphids cause significant yield losses in agricultural crops worldwide. Medicago truncatula, a model legume, cultivated pasture species in Australia and close relative of alfalfa (Medicago sativa), was used to study the defence response against Therioaphis trifolii f. maculate [spotted alfalfa aphid (SAA)]. Aphid performance and plant damage were compared among three accessions. A20 is highly susceptible, A17 has moderate resistance, and Jester is strongly resistant. Subsequent analyses using A17 and A20, reciprocal F1s and an A17×A20 recombinant inbred line (RIL) population revealed that this moderate resistance is phloem mediated and involves antibiosis and tolerance but not antixenosis. Electrical penetration graph analysis also identified a novel waveform termed extended potential drop, which occurred following SAA infestation of M. truncatula. Genetic dissection using the RIL population revealed three quantitative trait loci on chromosomes 3, 6, and 7 involved in distinct modes of aphid defence including antibiosis and tolerance. An antibiosis locus resides on linkage group 3 (LG3) and is derived from A17, whereas a plant tolerance and antibiosis locus resides on LG6 and is derived from A20, which exhibits strong temporary tolerance. The loci identified reside in regions harbouring classical resistance genes, and introgression of these loci in current medic cultivars may help provide durable resistance to SAA, while elucidation of their molecular mechanisms may provide valuable insight into other aphid–plant interactions.

  3. Evidence that antibiotic of Pantoea agglomerans E325 is produced and active against Erwinia amylovora on stigmas of pomaceous blossoms

    Science.gov (United States)

    Pantoea agglomerans strain E325, the active ingredient in a commercial product for fire blight, previously was shown to produce a unique pH-sensitive inhibitor in vitro that is specific to E. amylovora. To evaluate antibiosis as a mode of antagonism of E325, Tn5 mutagenesis was used to generate...

  4. Nutritional environment influences transcription of a pantocin A biosynthesis gene in Pantoea vagans strain C9-1

    Science.gov (United States)

    The histidine-reversible antibiotic pantocin A is produced by Pantoea vagans strain C9-1 and Pantoea agglomerans strains Eh252, EH318 and P10c and contributes significantly to efficacy of biological control of fire blight of pear and apple flowers caused by Erwinia amylovora. Antibiosis by pantocin ...

  5. Formation of rod-like nanostructure by aggregation of TiO2 ...

    Indian Academy of Sciences (India)

    as antibiosis3,4 to renewable energy development as photo- voltaic cells.5,6 The nanostructured TiO2 has been proven to be a kind of excellent photocatalysis materials to break down most organic compounds with highly efficient degra- dation and no secondary pollution. TiO2 nanomaterials, one of the most studied ...

  6. Hevea brasiliensis Muell. Arg.

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... Syncephalastrum sp. showed different levels of zones of inhibition with the pathogen. Metabolites produced by Gonatorrhodiella sp. and Syncephalastrum sp. affected the pathogen by antibiosis. This finding showed that Trichocladium sp. and Trichophyton sp. exhibited the highest antagonistic effects.

  7. Author Details

    African Journals Online (AJOL)

    Ribeiro, ZA. Vol 14, No 41 (2015) - Articles Antibiosis in Ascia monuste orseis Godart (Lepidoptera: Pieridae) caused by kale genotypes. Abstract PDF. ISSN: 1684-5315. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

  8. Author Details

    African Journals Online (AJOL)

    de Jesus, FG. Vol 14, No 41 (2015) - Articles Antibiosis in Ascia monuste orseis Godart (Lepidoptera: Pieridae) caused by kale genotypes. Abstract PDF · Vol 13, No 50 (2014) - Articles Chrysodeixis includens (Lepidoptera: Noctuidae) on soybean treated with resistance inducers. Abstract PDF. ISSN: 1684-5315.

  9. Mechanisms of Oryza sativa (Poaceae resistance to Tagosodes orizicolus (Homoptera: Delphacidae under greenhouse condition in Venezuela

    Directory of Open Access Journals (Sweden)

    Alex González

    2012-03-01

    Full Text Available Tagosodes orizicolus is one of the main plagues of rice in tropical America causing two types of damages, the direct one, feeding and oviposition effect, and an indirect one, by the transmission of the “Rice hoja blanca virus”. During 2006-2007 we carried out research under greenhouse conditions at Fundación Danac, Venezuela, in order to determine the mechanisms of antixenosis, antibiosis and tolerance to T. orizicolus, which could be acting in commercial varieties and advanced lines of the rice genetic breeding programs of INIA and Fundación Danac. The method of free feeding was used for the antixenosis evaluation, whereas the method of forced feeding was used for antibiosis evaluation (effect on survival and oviposition. Additionally, we used the indirect method based on biomass depression to estimate the tolerance. Some of the evaluated traits included: grade of damage, number of insects settling on rice plants, percentage of sogata mortality at the mature state, number of eggs in the leaf midrib and an index of tolerance. The results showed that rice genotypes possess different combinations of resistance mechanisms, as well as different grades of reactions. The susceptible control ‘Bluebonnet 50’ was consistently susceptible across experiments and the resistant control ‘Makalioka’ had high antixenosis and high antibiosis based on survival and oviposition. The rest of the genotypes presented lower or higher degrees of antixenosis and antibiosis for survival and viposition. The genotype ‘FD0241-M-17-6-1-1-1-1’ was identified with possible tolerance to the direct damage of sogata.Tagosodes orizicolus es una de las principales plagas del cultivo del arroz en América tropical causando dos tipos de daños a la planta, el directo, por efecto de la alimentación y oviposición; el indirecto, por la transmisión del virus de la hoja blanca del arroz. Durante el período 2006-2007 se llevó a cabo una investigación bajo condiciones

  10. Search for endophytic diazotrophs in barley seeds

    Directory of Open Access Journals (Sweden)

    Myriam S. Zawoznik

    2014-06-01

    Full Text Available Eight endophytic isolates assigned to Pseudomonas, Azospirillum, and Bacillus genera according to pheno-genotypic features were retrieved from barley seeds under selective pressure for nitrogen-fixers. Genetic relationships among related isolates were investigated through RAPD. Six isolates displayed nitrogen-fixing ability, while all could biosynthesize indolacetic acid in vitro and showed no antibiosis effects against Azospirillum brasilense Az39, a recognized PGPR.

  11. Induced systemic resistance by fluorescent Pseudomonas spp.

    OpenAIRE

    Bakker, P.A.H.M.; Pieterse, C.M.J.; Loon, L.C. van

    2007-01-01

    Fluorescent Pseudomonas spp. have been studied for decades for their plant growth-promoting effects through effective suppression of soilborne plant diseases. The modes of action that play a role in disease suppression by these bacteria include siderophore-mediated competition for iron, antibiosis, production of lytic enzymes, and induced systemic resistance (ISR). The involvement of ISR is typically studied in systems in which the Pseudomonas bacteria and the pathogen are inoculated and rema...

  12. Bacterial elicitors and plant signaling in induced systemic resistance

    OpenAIRE

    Bakker, P.A.H.M.; Pelt, J.A. van; Sluis, I. van der; Pieterse, C.M.J.

    2008-01-01

    Plant root colonizing, fluorescent Pseudomonas spp. have been studied for decades for their plant growth promoting properties and their effective suppression of soil borne plant diseases. The modes of action that play a role in disease suppression by these bacteria include siderophore-mediated competition for iron, antibiosis, and induced systemic resistance (ISR). The involvement of ISR is typically studied in systems in which the Pseudomonas bacteria and the pathogen are inoculated and rema...

  13. Some structures of marine natural products

    Energy Technology Data Exchange (ETDEWEB)

    Finer-Moore, J.S.

    1979-07-01

    Applications of x-ray crystallographic methods to marine chemistry are discussed. Results of research on a biosynthetic problem: diterpenes from Dictyotaceae are discussed under the following section headings: history of the problem; dictyoxepin; dictyodial; and dictyolactone. Studies on marine ecology are reported under the following headings: symbiosis and antibiosis; metabolites from opisthobranch molluscs, including, dolabelladiene, 9-isocyanopupukeanane and 2-isocyanopupukeanane, and crispatone; metabolites of goronians and soft corals, including zooxanthellae and the metabolism of coelenterates, ophirin, sinularene, and erectene. (JGB)

  14. Proceedings of Workshop on Algal Management and Control Held on 9-12 march 1980 at Pacific Grove, Calif.

    Science.gov (United States)

    1981-05-01

    loading to the lake from domestic, agricultural, and industrial ( dairy wastes) discharges. In May, 1970, 10.2 metric tons of liquid aluminum sulfate were...of both positive and negative ( probiotic and antibiotic) plant-to- plant effects. The terms antibiosis and probiosis are more suitable in the present...antibiotic, or probiotic effects was evidenced in Akehurst’s (1931) writings, but the intuitive nature of his theories instigated experimental efforts

  15. Natural resistance of soybean cultivars to the soybean looper larva Chrysodeixis includens (Lepidoptera: Noctuidae)

    OpenAIRE

    Wille, Paulo Eduardo; Pereira, Bruna Angelina; Wille, Cleiton Luiz; Restelatto, Samanta Souza; Boff, Mari Inês Carissimi; Franco, Cláudio Roberto

    2017-01-01

    Abstract: The objective of this work was to evaluate the natural resistance of soybean cultivars to Chrysodeixis includens. For this, four commercial soybean cultivars recommended for the Southern region of Brazil were used: BR 36, NA 5909 RG, BMX Turbo RR, and Benso 1RR. In the laboratory, larvae were subjected to the antixenosis feeding assay, in which they were free or not to choose among old leaves, new leaves, and pods. Neonate larvae were subjected to two antibiosis tests: in the first ...

  16. Gamma (60CO) radiation effects on arcelin protein and evaluation of bean lineages against Acanthoscelides obtectus (Say) and Zabrotes subfasciatus (Boh.) (Col.: Bruchidae)

    International Nuclear Information System (INIS)

    Botelho, Ana Claudia Girardo

    2006-01-01

    The resistance of arcelin carrying seeds of bean lineages (Phaseolus vulgaris L.) against the bean weevils Acanthoscelides obtectus (Say, 1831) and Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae), and the influence of gamma radiation ( 60 CO) on the manifestation of arcelin resistance to Z. subfasciatus were verified. Laboratorial tests, in choice and non-choice tests, with wild specimens carrying Arc-1, Arc-2, Arc-3, Arc-4, Raz-56 and Raz-59 (with Arc-5 alleles) and commercial lineages as control IAC - Carioca and IAC - Arua were conducted. Statistical design was completely randomized, with five repetitions, with 10 g of grains from each lineage samples by portion. Attractiveness, oviposition, emergence, mortality, adults' weigh and longevity, developing period, sexual rate, seeds' weigh loss, infestation and fecundity (Z. subfasciatus) were observed. Gamma radiation doses irradiations, in general, haven't affected the resistance manifestation of lineages carrying arcelin protein variants against the Z. subfasciatus bean weevil, thus, joint application use of both control methods can be recommended. Raz-56 lineage showed high resistance of the antibiosis types and non-preference for oviposition and feeding to Z. subfasciatus, while Raz-59 showed antibiosis and non-preference for feeding, and both (Raz-56 and Raz-59) showed intermediate resistance to A. obtectus, against which lineage Arc-2 was the most harmful to its development, expressing non-preference to feeding and/or antibiosis. (author)

  17. Polyphasic characterization of bacteria obtained from upland rice cultivated in Cerrado soil

    Directory of Open Access Journals (Sweden)

    Lívia Fabiana Braga

    Full Text Available ABSTRACT This work aimed to characterize 20 isolates obtained from upland rice plants, based on phenotypic (morphology, enzymatic activity, inorganic phosphate solubilization, carbon source use, antagonism, genotypic assays (16S rRNA sequencing and plant growth promotion. Results showed a great morphological, metabolic and genetic variability among bacterial isolates. All isolates showed positive activity for catalase and protease enzymes and, 90% of the isolates showed positive activity for amylase, catalase and, nitrogenase. All isolates were able to metabolize sucrose and malic acid in contrast with mannitol, which was metabolized only by one isolate. For the other carbon sources, we observed a great variability in its use by the isolates. Most isolates showed antibiosis against Rhizoctonia solani (75% and Sclerotinia sclerotiorum (55% and, 50% of them showed antibiosis against both pathogens. Six isolates showed simultaneous ability of antibiosis, inorganic phosphate solubilization and protease activity. Based on phylogenetic analysis of the 16S rRNA gene all the isolates belong to Bacillus genus. Under greenhouse conditions, two isolates (S4 and S22 improved to about 24%, 25%, 30% and 31% the Total N, leaf area, shoot dry weight and root dry weight, respectively, of rice plants, indicating that they should be tested for this ability under field conditions.

  18. Gamma ({sup 60}CO) radiation effects on arcelin protein and evaluation of bean lineages against Acanthoscelides obtectus (Say) and Zabrotes subfasciatus (Boh.) (Col.: Bruchidae);Efeito da radiacao gama ({sup 60}CO) sobre a proteina arcelina e avaliacao de linhagens de feijoeiro a Acanthoscelides obtectus (Say) and Zabrotes subfasciatus (Boh.) (Col.: Bruchidae)

    Energy Technology Data Exchange (ETDEWEB)

    Botelho, Ana Claudia Girardo

    2006-07-01

    The resistance of arcelin carrying seeds of bean lineages (Phaseolus vulgaris L.) against the bean weevils Acanthoscelides obtectus (Say, 1831) and Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae), and the influence of gamma radiation ({sup 60}CO) on the manifestation of arcelin resistance to Z. subfasciatus were verified. Laboratorial tests, in choice and non-choice tests, with wild specimens carrying Arc-1, Arc-2, Arc-3, Arc-4, Raz-56 and Raz-59 (with Arc-5 alleles) and commercial lineages as control IAC - Carioca and IAC - Arua were conducted. Statistical design was completely randomized, with five repetitions, with 10 g of grains from each lineage samples by portion. Attractiveness, oviposition, emergence, mortality, adults' weigh and longevity, developing period, sexual rate, seeds' weigh loss, infestation and fecundity (Z. subfasciatus) were observed. Gamma radiation doses irradiations, in general, haven't affected the resistance manifestation of lineages carrying arcelin protein variants against the Z. subfasciatus bean weevil, thus, joint application use of both control methods can be recommended. Raz-56 lineage showed high resistance of the antibiosis types and non-preference for oviposition and feeding to Z. subfasciatus, while Raz-59 showed antibiosis and non-preference for feeding, and both (Raz-56 and Raz-59) showed intermediate resistance to A. obtectus, against which lineage Arc-2 was the most harmful to its development, expressing non-preference to feeding and/or antibiosis. (author)

  19. Artificial Agrobacterium tumefaciens strains exhibit diverse mechanisms to repress Xanthomonas oryzae pv. oryzae-induced hypersensitive response and non-host resistance in Nicotiana benthamiana.

    Science.gov (United States)

    Li, Wen; Cao, Jia-Yi; Xu, You-Ping; Cai, Xin-Zhong

    2017-05-01

    Xanthomonas oryzae pv. oryzae (Xoo) rapidly triggers a hypersensitive response (HR) and non-host resistance in its non-host plant Nicotiana benthamiana. Here, we report that Agrobacterium tumefaciens strain GV3101 blocks Xoo-induced HR in N. benthamiana when pre-infiltrated or co-infiltrated, but not when post-infiltrated at 4 h after Xoo inoculation. This suppression by A. tumefaciens is local and highly efficient to Xoo. The HR-inhibiting efficiency of A. tumefaciens is strain dependent. Strain C58C1 has almost no effect on Xoo-induced HR, whereas strains GV3101, EHA105 and LBA4404 nearly completely block HR formation. Intriguingly, these three HR-inhibiting strains employ different strategies to repress HR. Strain GV3101 displays strong antibiotic activity and thus suppresses Xoo growth. Comparison of the genotype and Xoo antibiosis activity of wild-type A. tumefaciens strain C58 and a set of C58-derived strains reveals that this Xoo antibiosis activity of A. tumefaciens is negatively, but not solely, regulated by the transferred-DNA (T-DNA) of the Ti plasmid pTiC58. Unlike GV3101, strains LBA4404 and EHA105 exhibit no significant antibiotic effect on Xoo, but rather abolish hydrogen peroxide accumulation. In addition, expression assays indicate that strains LBA4404 and EHA105 may inhibit Xoo-induced HR by suppression of the expression of Xoo type III secretion system (T3SS) effector genes hpa1 and hrpD6. Collectively, our results unveil the multiple levels of effects of A. tumefaciens on Xoo in N. benthamiana and provide insights into the molecular mechanisms underlying the bacterial antibiosis of A. tumefaciens and the non-host resistance induced by Xoo. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  20. Resistance of Wheat Accessions to the English Grain Aphid Sitobion avenae

    Science.gov (United States)

    Hu, Xiang-Shun; Liu, Ying-Jie; Wang, Yu-Han; Wang, Zhe; Yu, Xin-lin; Wang, Bo; Zhang, Gai-Sheng; Liu, Xiao-Feng; Hu, Zu-Qing; Zhao, Hui-Yan; Liu, Tong-Xian

    2016-01-01

    The English grain aphid, Sitobion avenae, is a major pest species of wheat crops; however, certain varieties may have stronger resistance to infestation than others. Here, we investigated 3 classical resistance mechanisms (antixenosis, antibiosis, and tolerance) by 14 wheat varieties/lines to S. avenae under laboratory and field conditions. Under laboratory conditions, alatae given the choice between 2 wheat varieties, strongly discriminated against certain varieties. Specifically, the ‘Amigo’ variety had the lowest palatability to S. avenae alatae of all varieties. ‘Tm’ (Triticum monococcum), ‘Astron,’ ‘Xanthus,’ ‘Ww2730,’ and ‘Batis’ varieties also had lower palatability than other varieties. Thus, these accessions may use antibiosis as the resistant mechanism. In contrast, under field conditions, there were no significant differences in the number of alatae detected on the 14 wheat varieties. One synthetic line (98-10-30, a cross between of Triticum aestivum (var. Chris) and Triticum turgidum (var. durum) hybridization) had low aphid numbers but high yield loss, indicating that it has high antibiosis, but poor tolerance. In comparison, ‘Amigo,’ ‘Xiaoyan22,’ and some ‘186Tm’ samples had high aphid numbers but low yield loss rates, indicating they have low antibiosis, but good tolerance. Aphid population size and wheat yield loss rates greatly varied in different fields and years for ‘98-10-35,’ ‘Xiaoyan22,’ ‘Tp,’ ‘Tam200,’ ‘PI high,’ and other ‘186Tm’ samples, which were hybrid offspring of T. aestivum and wheat related species. Thus, these germplasm should be considered for use in future studies. Overall, S. avenae is best adapted to ‘Xinong1376,’ because it was the most palatable variety, with the greatest yield loss rates of all 14 wheat varieties. However, individual varieties/lines influenced aphid populations differently in different years. Therefore, we strongly recommend a combination of

  1. [Advances in study on anti-tumor mechanism of andrographolide].

    Science.gov (United States)

    Qi, Cui-Ling; Wang, Li-Jing; Zhou, Xin-Lei

    2007-10-01

    In recent years, more and more attention was payed to the study of andrographolide. Andrographolide has the extensive pharmacological actions, such as anti-tumor, dephlogisticate and antibiosis and anti-virus. It was dected that andrographolide had the action of anti-tumor in gastric cancer, liver cancer, lung cancer and breast cancer. The anti-tumor mechanism of andrographolide was versatile, for instance, andrographolide can induce the apoptosis of cancer cell, inhibit the cell cycle, and increase the antitumor activity of lymphocyte. The following review was about the recent progress of study on the anti-tumor mechanism of andrographolide.

  2. CAPTURA, ACTIVIDAD BIOLÓGICA E IDENTIFICACION DE VOLÁTILES DE LA INTERACCIÓN Trichoderma asperellum - Sclerotium rolfsii.

    OpenAIRE

    Ruiz Rosales, Arely

    2015-01-01

    Trichoderma asperellum presenta mecanismos de acción de micoparasitismo y antibiosis con compuestos no volátiles, para competir por espacio y nutrientes, pero se desconoce si produce compuestos volátiles (CV) que presenten actividad antifúngica sobre Sclerotium rolfsii. Los objetivos de este trabajo fueron: a) capturar los CV producidos durante la interacción de T. asperellum-S. rolfsii, b) determinar el efecto de CV generados en la interacción T. asperellum-S. rolfsii, sobre la producción de...

  3. Development of Sparganothis sulfureana (Lepidoptera: Tortricidae) on Cranberry Cultivars

    Science.gov (United States)

    McMahan, Erin E.; Guédot, Christelle

    2018-01-01

    Sparganothis fruitworm (Sparganothis sulfureana Clemens) (Lepidoptera: Tortricidae) is a serious pest of cranberry (Vaccinium macrocarpon Aiton), a native North American fruit cultivated in northern regions of the United States and southeastern Canada. This study assessed antibiosis in several cranberry cultivars commonly grown in Wisconsin. Five cultivars previously shown to host different levels of populations of S. sulfureana in commercial cranberry were assessed in this study to evaluate the performance of S. sulfureana amongst these cultivars. We measured growth and time to developmental stages of newly emerged larvae to adulthood on selected cranberry cultivars in the laboratory. There was no difference in the rates of survival to pupation and to adult emergence among any of the cultivars tested. Mid-instar larvae that fed on the cultivar ‘Ben Lear’ were heavier than those feeding on ‘GH-1’, ‘Stevens’, or ‘HyRed’, and larvae that fed on ‘Mullica Queen’ were heavier than those feeding on ‘HyRed’. However, there were no significant differences in pupal weights or in the number of days from neonate to adult emergence among varieties. Therefore, this study did not provide evidence of antibiosis among the cultivars tested, and found that larval weight was not correlated with other measurements of performance. PMID:29301287

  4. Reevaluating the conceptual framework for applied research on host-plant resistance.

    Science.gov (United States)

    Stout, Michael J

    2013-06-01

    Applied research on host-plant resistance to arthropod pests has been guided over the past 60 years by a framework originally developed by Reginald Painter in his 1951 book, Insect Resistance in Crop Plants. Painter divided the "phenomena" of resistance into three "mechanisms," nonpreference (later renamed antixenosis), antibiosis, and tolerance. The weaknesses of this framework are discussed. In particular, this trichotomous framework does not encompass all known mechanisms of resistance, and the antixenosis and antibiosis categories are ambiguous and inseparable in practice. These features have perhaps led to a simplistic approach to understanding arthropod resistance in crop plants. A dichotomous scheme is proposed as a replacement, with a major division between resistance (plant traits that limit injury to the plant) and tolerance (plant traits that reduce amount of yield loss per unit injury), and the resistance category subdivided into constitutive/inducible and direct/indirect subcategories. The most important benefits of adopting this dichotomous scheme are to more closely align the basic and applied literatures on plant resistance and to encourage a more mechanistic approach to studying plant resistance in crop plants. A more mechanistic approach will be needed to develop novel approaches for integrating plant resistance into pest management programs. © 2012 Institute of Zoology, Chinese Academy of Sciences.

  5. Induction of resistance by silicon in wheat plants to alate and apterous morphs of Sitobion avenae (Hemiptera: Aphididae).

    Science.gov (United States)

    Dias, P A S; Sampaio, M V; Rodrigues, M P; Korndörfer, A P; Oliveira, R S; Ferreira, S E; Korndörfer, G H

    2014-08-01

    Despite the knowledge about the effects of silicon augmenting antibiosis and nonpreference of plants by apterous aphids, few studies exist on such effects with alate aphids. This study evaluated the effects of silicon fertilization on the biology of alate and apterous morphs of Sitobion avenae (F.) (Hemiptera: Aphididae), and the effect on nonpreference by S. avenae alates for wheat plants with or without silicon fertilization. A method for rearing aphids on detached leaves was evaluated comparing the biology of apterous aphids reared on wheat leaf sections and on whole plants with and without silicon fertilization. Because the use of detached leaves was a reliable method, the effect of silicon fertilization on the biology of apterous and alate S. avenae was assessed using wheat leaf sections. Biological data of aphids were used to calculate a fertility life table. Finally, the effect of silicon fertilization on the nonpreference of alate aphids was carried out for both vegetative and reproductive phases of wheat. Thirty alate aphids were released in the center of a cage, and the number of aphids per whole plant with or without silicon fertilization was observed. Silicon fertilization induced antibiosis resistance in wheat plants to apterous morphs as shown by reduced fecundity, reproductive period, longevity, intrinsic rate of increase, and net reproductive rate; however, alates were unaffected. Plants that received silicon fertilization had fewer alate aphids in both the vegetative and reproductive phases. Thus, silicon fertilization can reduce colonization by alates, enhancing nonpreference resistance, and population growth of apterous S. avenae in wheat plants.

  6. Biological control of the cucurbit powdery mildew pathogen Podosphaera xanthii by means of the epiphytic fungus Pseudozyma aphidis and parasitism as a mode of action

    Directory of Open Access Journals (Sweden)

    Aviva eGafni

    2015-03-01

    Full Text Available Epiphytic yeasts, which colonize plant surfaces, may possess activity that can be harnessed to help plants defend themselves against various pathogens. Due to their unique characteristics, epiphytic yeasts belonging to the genus Pseudozyma hold great potential for use as biocontrol agents. We identified a unique, biologically active isolate of the epiphytic yeast Pseudozyma aphidis that is capable of inhibiting Botrytis cinerea via a dual mode of action, namely induced resistance and antibiosis. Here, we show that strain L12 of P. aphidis can reduce the severity of powdery mildew caused by Podosphaera xanthii on cucumber plants with an efficacy of 75%. Confocal and scanning electron microscopy analyses demonstrated P. aphidis proliferation on infected tissue and its production of long hyphae that parasitize the powdery mildew hyphae and spores as an ectoparasite. We also show that crude extract of P. aphidis metabolites can inhibit P. xanthii spore germination in planta. Our results suggest that in addition to its antibiosis mode of action, P. aphidis may also act as an ectoparasite on P. xanthii. These results indicate that P. aphidis strain L12 has the potential to control powdery mildew.

  7. Near-isogenic lines of Triticum aestivum with distinct modes of resistance exhibit dissimilar transcriptional regulation during Diuraphis noxia feeding

    Directory of Open Access Journals (Sweden)

    Anna-Maria Botha

    2014-10-01

    Full Text Available Russian wheat aphid (Diuraphis noxia, Kurdjumov feeding on susceptible Triticum aestivum L. leads to leaf rolling, chlorosis and plant death – symptoms not present in resistant lines. Although the effects of several D. noxia (Dn resistance genes are known, none have been isolated or characterized. Wheat varieties expressing different Dn genes exhibit distinct modes of D. noxia resistance, such as antibiosis (Dn1, tolerance (Dn2, and antixenosis (Dn5. However, the mechanism whereby feeding aphids are perceived, and how subsequent transcriptional responses are partitioned into resistance categories, remains unclear. Here we report on downstream events in near-isogenic wheat lines containing different Dn genes after D. noxia biotype SA1 feeding. Transcripts involved in stress, signal transduction, photosynthesis, metabolism and gene regulation were differentially regulated during D. noxia feeding. Expression analyses using RT-qPCR and RNA hybridization, as well as enzyme activity profiling, provide evidence that the timing and intensity of pathways induced are critical in the development of particular modes of resistance. Pathways involved include the generation of kinase signalling cascades that lead to a sustained oxidative burst, and a hypersensitive response that is active during antibiosis. Tolerance is a passive resistance mechanism that acts through repair or de novo synthesis of photosystem proteins. Results further suggest that ethylene-mediated pathways are possibly involved in generating volatile compounds and cell wall fortification during the antixenosic response.

  8. Suitability of Soybean Meal from Insect-Resistant Soybeans for Broiler Chickens.

    Science.gov (United States)

    Ortega, María A; Davis, Adam J; Boerma, H Roger; Parrott, Wayne A

    2016-03-23

    Benning(M) and Benning(MGH) are near-isogenic lines (NILs) of the soybean cultivar Benning, which contain insect-resistance quantitative trait loci (QTLs) from the soybean accession PI 229358. Benning(M) contains QTL-M, which confers antibiosis and antixenosis. In addition to QTL-M, Benning(MGH) contains QTL-G, which confers antibiosis, and QTL-H, which confers antixenosis. Soybean meal was produced from Benning and the NILs. Nutritional composition, digestible amino acid content, and nitrogen-corrected true metabolizable energy (TMEN) were equivalent among soybean meals. A 21-day broiler feeding trial was carried out to determine if the QTLs affect soybean meal quality. Weight gain and feed-to-gain ratio were evaluated. No biologically significant differences were detected for broilers fed Benning, Benning(M), and Benning(MGH). This demonstrates that soybean meal produced from the insect-resistant NILs is equivalent to soybean meal produced from their non-insect-resistant parent cultivar for broiler weight gain.

  9. Evaluation of hybrids of So/anum po/yadenium Greenm for white worm resistance in potatoe (Premmotripes voraxHustoche. Evaluación de híbridos de Solanum polyadenium Greenm. Para resistencia al gusano blanco de la papa (Premnotrypes vorax Hustache

    Directory of Open Access Journals (Sweden)

    Trillos G. Ofelia

    1993-12-01

    Full Text Available Four Solanum polyadenlum crossed with Solanum berthanltil, Solanum chacoense and Solanum phureja were evaluated for resistance to the Andean potato weevil (Premnotrypes vorax Hustache. From the set of 397 hybrids avaluated six (1,52%
    were selected for resistance. For other agronomical and biochemical characteristics the most promising hybrids were the 12 th, the 14 th and the 15 th from the second family (498096.1-Solanum polyadenlium x Solanum phureja. The type of resistance found was antibiosis which affects both the development and the reproduction of the insect.Enel presente trabajo se evaluó el grado de resistencia
    al gusano blanco de la Papa (Premnotrypes voraxHustache de los hibrldos obtenidos mediante el cruzamiento de la especie Solanum polyadenium con las especies Solanum berthanltil, Solanum chacoense y Solanum phureja. De un total de 397 hibridos evaluados, se seleccionaron seis (1.5% por su alto nivel de resistencia al gusano blanco. Porotras caracteristicas agronómicas y bioquimicas, se consideraron como losmás importantesen un programa de mejoramiento a los hibridos 12; 14 y 15 de la Familia 2 (498096.1 - hibrido de Solanum polyadenlum x Amarilla Perú - Solanum phureja. El mecanismo de resistencia observado es del tipo antibiosis, el cual afecta la supervivencia, desarrollo y reproducción del insecto.

  10. Empiric systemic antibiotics for hospitalized patients with severe odontogenic infections.

    Science.gov (United States)

    Zirk, Matthias; Buller, Johannes; Goeddertz, Peter; Rothamel, Daniel; Dreiseidler, Timo; Zöller, Joachim E; Kreppel, Matthias

    2016-08-01

    Odontogenic infections may lead to severe head and neck infections with potentially great health risk. Age, location of purulent affected sites and beta-lactam allergy are some mentionable factors regarding patients' in-hospital stay and course of disease. Are there new challenges regarding bacteria' antibiotic resistance for empiric treatment and what influences do they have on patients' clinical course? We analyzed in a 4-year retrospective study the medical records of 294 in-hospital patients with severe odontogenic infections. On a routine base bacteria were identified and susceptibility testing was performed. Length of stay in-hospital was evaluated regarding patients' age, beta-lactam allergy profile, affected sites and bacteria susceptibility to empiric antibiotics. Length of stay in-hospital was detected to be associated with affected space and penicillin allergy as well (p odontogenic neck infections. Cephalosporins seem to be a considerable option as well. If beta-lactam allergy is diagnosed co-trimoxazol and moxifloxacin represent relevant alternatives. Age, allergic profile and bacteria' resistance patterns for empiric antibiotics have an influence on patients in-hospital stay. Ampicillin/sulbactam proves itself to be good for empiric antibiosis in severe odontogenic infections. Furthermore cephalosporins could be considered as another option in treatment. However moxifloxacin and co-trimoxazol deserves further investigation as empiric antibiosis in odontogenic infections if beta-lactam allergy is diagnosed. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  11. Susceptibility and possible resistance mechanisms in the palm species Phoenix dactylifera, Chamaerops humilis and Washingtonia filifera against Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera: Curculionidae).

    Science.gov (United States)

    Cangelosi, B; Clematis, F; Curir, P; Monroy, F

    2016-06-01

    Rhynchophorus ferrugineus, known as the Red Palm Weevil (RPW), is reported as a pest of up to 40 palm species. However, the susceptibility degree and the defense mechanisms of these species against this weevil are still poorly known. In Europe, the RPW is a major pest of Phoenix canariensis while other palm species, including the congeneric Phoenix dactylifera, seem to be less suitable hosts for this insect. The aim of our study was to compare the defensive response of P. dactylifera, Chamaerops humilis and Washingtonia filifera against R. ferrugineus and try to define the mechanisms of resistance that characterize these species. Bioassays were carried out to evaluate the mortality induced on RPW larvae by extracts from the leaf rachis of the studied palm species. Tests at semi-field scale were also conducted, based either on forced palm infestation, with larvae of RPW, or on natural infestation, with adult females. Rachis extracts from C. humilis and W. filifera caused 100% larval mortality after 2 days of exposure, while extracts of P. dactylifera did not impair larval survival. Independently of the effect of the leaf extracts, the weevils were unable to naturally infest the three palm species, although larval survival was high after forced infestation of the plants. We concluded that the observed lack of infestation of P. dactylifera by RPW is due to factors other than antibiosis. In W. filifera and C. humilis, although the presence of antixenosis mechanisms cannot be excluded, resistance to R. ferrugineus seems to rely on the presence of antibiosis compounds.

  12. Evaluación de la resistencia a Schizaphis graminum (Hemiptera: Aphididae en cebada Assessment of resistance against Schizaphis graminum (Hemiptera: Aphididae in barley

    Directory of Open Access Journals (Sweden)

    Erica F. Tocho

    2012-06-01

    Full Text Available El pulgón verde de los cereales, Schizaphis graminum (Rondani, es una de las principales plagas de estos cultivos en el mundo y también presente en Argentina. Si bien el control químico es la práctica más utilizada, el uso de variedades resistentes (uno de los componentes principales del MIP es la estrategia más efectiva y ambientalmente más amigable para el control de plagas. Dado que las plantas presentan distintos mecanismos que les permiten defenderse de los insectos, el objetivo de este trabajo fue caracterizar la resistencia a Schizaphis graminum en una población de líneas recombinantes de cebada, e identificar aquellas con mejores características, portadoras de genes de resistencia a este insecto. La antixenosis fue analizada por la prueba de libre selección de hospederos. La antibiosis se evaluó por los parámetros del ciclo y el desarrollo del áfido y la tolerancia por características de crecimiento de las plantas bajo infestación. Al menos ocho líneas antibióticas fueron más tolerantes que sus testigos, presentando similares pesos secos, área foliar y contenido de clorofila bajo infestación. Estas líneas portadoras de genes de resistencia pueden ser de utilidad en los planes de mejora de la cebada.Greenbug, Schizaphis graminum (Rondani is one of the major pests of cereals around the world that is present in Argentina. Chemical control is the most widely used practice; however, the use of resistant varieties, one of the main components in IPM, is the most effective and environmentally sustainable strategy of control. Since plants have different types of insect resistance that allow them to defend against pests, the aim of the current study was to characterize the resistance to Schizaphis graminum in a population of recombinant inbred lines of barley and to identify lines with improved characteristics that enable the development of commercial cultivars. Antixenosis was studied by the host free choice test. Antibiosis

  13. Strains of the genus Serratia as beneficial rhizobacteria of oilseed rape with antifungal properties.

    Science.gov (United States)

    Kalbe, C; Marten, P; Berg, G

    1996-12-01

    Isolates of Serratia have been isolated from the rhizosphere of oilseed rape. The percentage of Serratia in this microenvironment was determined as 12.4% of the total antifungal bacteria. Serratia liquefaciens, S. plymuthica and S. rubidaea were found. All of the isolates showed an antifungal activity against different phytopathogenic fungi in vitro but the efficiency of strains was different. The antifungal mechanisms of 18 selected strains were investigated. Direct antifungal effect may be based on antibiosis (production of prodigiosin and pyrrolnitrin) and production of lytic enzymes (chitinases and beta-1,3-glucanases). Potent siderophores were secreted by the strains to improve the availability of iron. No strain was able to produce cyanide. Most of the strains secrete the plant growth hormone indole-acetic-acid which can directly promote the growth of roots. The mechanisms were specific for each isolate.

  14. Acute Forefoot Phlegmon - A Complication of Intravenous Heroin-Addiction.

    Science.gov (United States)

    Wollina, Uwe; Lotti, Torello; Tchernev, Georgi

    2018-01-25

    Infections of the skin and soft tissues (SSTI) are clinical entities with variable presentations, causes, and levels of clinical severity. They are frequent in emergency departments. The most common pathogen in the Western World is Staphylococcus aureus . SSTI may provide a hint to underlying pathologies such as diabetes and other states of immune compromise. Here we present a 41-year-old non-diabetic male patient with pain and swelling of the left forefoot but not any recent trauma. Microbiology identified streptococci. The medical history was positive for intravenous heroin abuse. The diagnosis of forefoot phlegm due to drug addition was confirmed. Treatment was realised by a combination of intravenous antibiosis and drainage. Intravenous drug addiction is a significant risk factor for SSTI.

  15. Acute Forefoot Phlegmon – A Complication of Intravenous Heroin-Addiction

    Directory of Open Access Journals (Sweden)

    Uwe Wollina

    2018-01-01

    Full Text Available Infections of the skin and soft tissues (SSTI are clinical entities with variable presentations, causes, and levels of clinical severity. They are frequent in emergency departments. The most common pathogen in the Western World is Staphylococcus aureus. SSTI may provide a hint to underlying pathologies such as diabetes and other states of immune compromise. Here we present a 41-year-old non-diabetic male patient with pain and swelling of the left forefoot but not any recent trauma. Microbiology identified streptococci. The medical history was positive for intravenous heroin abuse. The diagnosis of forefoot phlegm due to drug addition was confirmed. Treatment was realised by a combination of intravenous antibiosis and drainage. Intravenous drug addiction is a significant risk factor for SSTI.

  16. Talisia esculenta lectin and larval development of Callosobruchus maculatus and Zabrotes subfasciatus (Coleoptera: Bruchidae).

    Science.gov (United States)

    Macedo, Maria Ligia R; das Graças Machado Freire, Maria; Novello, José Camillo; Marangoni, Sérgio

    2002-06-06

    Bruchid larvae cause major losses in grain legume crops throughout the world. Some bruchid species, such as the cowpea weevil and the Mexican bean weevil, are pests that damage stored seeds. Plant lectins have been implicated as antibiosis factors against insects, particularly the cowpea weevil, Callosobruchus maculatus. Talisia esculenta lectin (TEL) was tested for anti-insect activity against C. maculatus and Zabrotes subfasciatus larvae. TEL produced ca. 90% mortality to these bruchids when incorporated in an artificial diet at a level of 2% (w/w). The LD(50) and ED(50) for TEL was ca. 1% (w/w) for both insects. TEL was not digested by midgut preparations of C. maculatus and Z. subfasciatus. The transformation of the genes coding for this lectin could be useful in the development of insect resistance in important agricultural crops.

  17. Characterization of cowpea genotype resistance to Callosobruchus maculatus

    Directory of Open Access Journals (Sweden)

    Maria de Jesus Passos de Castro

    2013-09-01

    Full Text Available The objective of this work was to characterize the resistance of 50 cowpea (Vigna unguiculata genotypes to Callosobruchus maculatus. A completely randomized design with five replicates per treatment (genotype was used. No-choice tests were performed using the 50 cowpea genotypes to evaluate the preference for oviposition and the development of the weevil. The genotypes IT85 F-2687, MN05-841 B-49, MNC99-508-1, MNC99-510-8, TVu 1593, Canapuzinho-1-2, and Sanzi Sambili show non-preference-type resistance (oviposition and feeding. IT81 D-1045 Ereto and IT81 D-1045 Enramador exhibit antibiosis against C. maculatus and descend from resistant genitors, which grants them potential to be used in future crossings to obtain cowpea varieties with higher levels of resistance.

  18. Acute pulmonary edema following liposuction due to heart failure and atypical pneumonia.

    Science.gov (United States)

    Wollina, Uwe; Graf, Andreas; Hanisch, Volkmar

    2015-05-01

    Microcannular liposuction in tumescent anesthesia is the most effective treatment for painful lipedema. Tumescent anesthesia is an established and safe procedure in local analgesia when performed according to guidelines. Major adverse effects are rare. In patients with advanced lipedema, however, the commonly presented comorbidities bear additional risks.We report on post-surgical acute pulmonary edema after tumescent liposuction according to guidelines in a 52-year-old female patient with lipedema of the legs. We discuss in detail possible scenarios that might be involved in such emergency. In the present case the most likely was a retarded community acquired atypical pneumonia with aggravation of pre-existent comorbidities.A combined treatment with intravenous b-lactam antibiosis, positive pressure ventilation, and continuous venovenous hemodialysis and filtration resulted in complete remission in a couple of days. In conclusion, tumescent liposuction of advanced lipedema patients should only be performed in well-trained centers with sufficient infrastructure.

  19. Painful, slow developing abscesses. Furuncular miyasis due to double skin infestation by Dermatobia hominis.

    Science.gov (United States)

    Krönert, Claudia; Wollina, Uwe

    2009-08-24

    Myiasis is defined as invasion of tissues by Diptera flies. The condition is endemic in the forested areas of Mexico, Central and South America. A 61-year-old woman presented with two boil-like inflammatory and painful lesions on her back. She had been travelling in Central America. Biopsies revealed a myiasis with mature third instar larvae of Dermatobia hominis, a diptera fly endemic in this region. Complete surgical excision and systemic antibiosis led to a delayed but complete healing. We presented a patient with a double infestation by Dermatobia hominis. Dermatologists should be aware of this disease, which has become increasingly common in travellers and is seen now also in unusual regions, other than Central and South America.

  20. Potencial de pseudomonas spp. fluorescentes para biocontrole de alternaria ricini em mamoneira Potential of fluorescent pseudomonas spp. For biological control of alternaria ricini on castorbean

    Directory of Open Access Journals (Sweden)

    Francisco de A.G. da Silva

    1998-06-01

    Full Text Available The potential of fluorescent Pseudomonas spp. to control Alternaria leaf spot on castorbean, caused by Alternaria ricini, was studied under greenhouse conditions. Two periods for antagonist applications were tested: 48h before and simultaneously to the pathogen inoculation. Among the antagonists tested JA4 and BJ22 were the most effectives showing disease severity reduction of 20.9% and 17.8% respectively, when applied simultaneously. The effect of Pseudomonas spp. on the micelial growth and sporulation was also studied throughout three different methods (funel, streak and celophane. Inhibition of micelial growth and sporulation was observed. There was no correlation between in vitro and in vivo data. Antibiosis was showed as a mode of action for Pseudomonas spp. in relation to Alternaria ricini. Ultrastructural studies confirmed the inhibition of spore germination by the bacteria.

  1. Controlled synthesis and photocatalysis of sea urchin-like Fe3O4@TiO2@Ag nanocomposites

    Science.gov (United States)

    Zhao, Yilin; Tao, Chengran; Xiao, Gang; Wei, Guipeng; Li, Linghui; Liu, Changxia; Su, Haijia

    2016-02-01

    Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the core and nanofiber TiO2/Fe3O4/Ag nanoheterojunctions as the shell; and Ag nanoparticles with diameter of approximately 4 nm are loaded both on TiO2 nanofibers and inside the cavities of sea urchin-like Fe3O4@TiO2 nanocomposites uniformly. Ag nanoparticles lead to the production of more photogenerated charges in the TiO2/Fe3O4/Ag heterojunction via LSPR absorption, and enhance the band-gap absorption of TiO2, while the Fe3O4 cocatalyst provides the active sites for oxygen reduction by the effective transfer of photogenerated electrons to oxygen. So the photocatalytic performance is improved due to the synergistic effect of TiO2/Fe3O4/Ag nanoheterojunctions. As photocatalysts under UV and visible irradiation, the as-synthesized nanocomposites display enhanced photocatalytic and recycling properties for the degradation of ampicillin. Moreover, they present better broad-spectrum antibiosis under visible irradiation. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, makes this multifunctional nanostructure a promising candidate for antibiosis and remediation in aquatic environmental contamination in the future.Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the

  2. Antagonistic action of Lactobacillus spp. against Staphylococcus aureus in cheese from Mompox - Colombia

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    Piedad M. Montero Castillo

    2015-06-01

    Full Text Available In the food industry, food preservation techniquesthat do not use chemical products are becoming more common.Therefore, the aim of this research was to evaluate the antagonisticactivity (antibiosis of lactic-acid bacterial strains againstpathogenic microorganisms. Lactic-acid bacterial strains wereisolated from layered cheese and a commercial product (yogurt;and the same was done with pathogenic bacteria solely fromlayered cheese. The lactic-acid bacterial strains were identified asspecies from the Lactobacilli family, while the pathogenic bacteriafrom layered cheese were identified as Micrococcaceae familyspecies (Staphylococcus aureus. Subsequently, in the sameculture medium, bacteria of each species were sowed in order todetermine the inhibitory activity ability of the Lactic Acid Bacteria(BAL As a result, the highly antagonistic activity of the Lactobacilli(inhibition halos were larger than 0.5 centimeters in diameteragainst isolated pathogenic microorganisms was demonstrated.

  3. Genetic and biochemical basis of Gall Midge resistance in some cultivars of Indica Rice. Final report for the period 1 October 1980 - 30 November 1986

    International Nuclear Information System (INIS)

    Reddy, G.M.

    1986-01-01

    The stability of high productivity of modern rice varieties is greatly affected by insect pests. Rice gall midge is a serious insect pest of rice that is prevalent in several south eastern asian countries. Gall midge resistance has been mainly attributed to antibiosis. No progress has so far been made in identifying the exact biochemical nature of resistance. In Indica subspecies the understanding of chemical nature of disease would be helpful in the control of the disease and also in breeding programme aimed at developing resistance varieties. Studies were undertaken to establish the biochemical basis of resistance. Biochemical characterization of resistant and susceptible varieties were carried out. The parameters considered were: total sugar and reducing sugar content, total phenol content, amino acid profile, post infectional changes in sugar and phenol, isozyme studies. 2 figs, 6 tabs

  4. Genetic divergence of bean genotypes to infestation of Zabrotes subfasciatus (Bohemann (Coleoptera: Bruchidae

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    Eduardo Neves Costa

    2013-12-01

    Full Text Available The aim of this work was to evaluate the genetics divergence of bean genotypes in relation to the oviposition, feeding and development of Zabrotes subfasciatus, determining the degrees of resistance to the weevil. The genotypes used were: IAC Carioca-Tybatã, IAC Fortaleza, IAPAR 81, IAC Carioca-Eté, IAC Galante, IAC Harmonia, IAC Una, IAC Diplomata, BRS Supremo and RAZ 49. Tests were performed in laboratory under controlled humidity, temperature and photophase conditions. In free choice test, 10 g of bean genotypes seeds were distributed in circular openings placed equidistant from each other in aluminum trays, where 70 couples were released. The attractiveness was evaluated 24 hours and seven days after the experiment started, and then the number of eggs was evaluated. In non choice test, 10 g of seeds were used where seven couples of Z. subfasciatus, 24 hours-old, were released, remaining seven days, and after the adults retreat, the total number eggs, viable and unviable eggs, the number and percentage of emerged adults, weight, longevity and period from egg to adult of males and females, sex ratio, dry mass and dry mass consumed by insect were evaluated. In the genotype IAC Harmonia was observed the lower oviposition; RAZ 49 was the most non preference-type resistant for feeding and/or antibiosis-type resistant; BRS Supremo, IAC Carioca-Eté and IAPAR 81 are no preference for feeding and/or antibiosis-type moderate resistant; IAC Galante is susceptible and the other genotypes are highly susceptible to Z. subfasciatus

  5. Identification of distinct quantitative trait loci associated with defence against the closely related aphids Acyrthosiphon pisum and A. kondoi in Medicago truncatula

    KAUST Repository

    Guo, Su-Min

    2012-03-21

    Aphids are a major family of plant insect pests. Medicago truncatula and Acyrthosiphon pisum (pea aphid, PA) are model species with a suite of resources available to help dissect the mechanism underlying plant-aphid interactions. A previous study focused on monogenic and relatively strong resistance in M. truncatula to PA and other aphid species. In this study a moderate resistance to PA was characterized in detail in the M. truncatula line A17 and compared with the highly susceptible line A20 and the more resistant line Jester. The results show that PA resistance in A17 involves both antibiosis and tolerance, and that resistance is phloem based. Quantitative trait locus (QTL) analysis using a recombinant inbred line (RIL) population (n=114) from a cross between A17 and A20 revealed that one locus, which co-segregated with AIN (Acyrthosiphon-induced necrosis) on chromosome 3, is responsible for the reduction of aphid biomass (indicator of antibiosis) for both PA and bluegreen aphid (BGA, A. kondoi), albeit to a lesser degree for PA than BGA. Interestingly, two independent loci on chromosomes 5 and 3 were identified for the plant biomass reduction (indicator of plant tolerance) by PA and BGA, respectively, demonstrating that the plant\\'s tolerance response to these two closely related aphid species is distinct. Together with previously identified major resistant (R) genes, the QTLs identified in this study are powerful tools to understand fully the spectrum of plant defence against sap-sucking insects and provide opportunities for breeders to generate effective and sustainable strategies for aphid control. 2012 The Author.

  6. A numerical study of combined use of two biocontrol agents with different biocontrol mechanisms in controlling foliar pathogens.

    Science.gov (United States)

    Xu, X-M; Jeffries, P; Pautasso, M; Jeger, M J

    2011-09-01

    Effective use of biocontrol agents is an important component of sustainable agriculture. A previous numerical study of a generic model showed that biocontrol efficacy was greatest for a single biocontrol agent (BCA) combining competition with mycoparasitism or antibiosis. This study uses the same mathematical model to investigate whether the biocontrol efficacy of combined use of two BCAs with different biocontrol mechanisms is greater than that of a single BCA with either or both of the two mechanisms, assuming that two BCAs occupy the same host tissue as the pathogen. Within the parameter values considered, a BCA with two biocontrol mechanisms always outperformed the combined use of two BCAs with a single but different biocontrol mechanism. Similarly, combined use of two BCAs with a single but different biocontrol mechanism is shown to be far less effective than that of a single BCA with both mechanisms. Disease suppression from combined use of two BCAs was very similar to that achieved by the more efficacious one. As expected, a higher BCA introduction rate led to increased disease suppression. Incorporation of interactions between two BCAs did not greatly affect the disease dynamics except when a mycoparasitic and, to a lesser extent, an antibiotic-producing BCA was involved. Increasing the competitiveness of a mycoparasitic BCA over a BCA whose biocontrol mechanism is either competition or antibiosis may lead to improved biocontrol initially and reduced fluctuations in disease dynamics. The present study suggests that, under the model assumptions, combined use of two BCAs with different biocontrol mechanisms in most cases only results in control efficacies similar to using the more efficacious one alone. These predictions are consistent with published experimental results, suggesting that combined use of BCAs should not be recommended without clear understanding of their main biocontrol mechanisms and relative competitiveness, and experimental evaluation.

  7. SOIL FUNGISTASIS AGAINST FUSARIUM GRAMINEARUM UNDER DIFFERENT CROP MANAGEMENT SYSTEMS

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    Bruno Brito Lisboa

    2015-02-01

    Full Text Available Soil management, in terms of tillage and cropping systems, strongly influences the biological properties of soil involved in the suppression of plant diseases. Fungistasis mediated by soil microbiota is an important component of disease-suppressive soils. We evaluated the influence of different management systems on fungistasis against Fusarium graminearum, the relationship of fungistasis to the bacterial profile of the soil, and the possible mechanisms involved in this process. Samples were taken from a long-term experiment set up in a Paleudult soil under conventional tillage or no-tillage management and three cropping systems: black oat (Avena strigose L. + vetch (Vicia sativa L./maize (Zea mays L. + cowpea (Vigna sinensis L., black oat/maize, and vetch/maize. Soil fungistasis was evaluated in terms of reduction of radial growth of F. graminearum, and bacterial diversity was assessed using ribosomal intergenic spacer analysis (RISA. A total of 120 bacterial isolates were obtained and evaluated for antibiosis, and production of volatile compounds and siderophores. No-tillage soil samples showed the highest level of F. graminearum fungistasis by sharply reducing the development of this pathogen. Of the cropping systems tested, the vetch + black oat/maize + cowpea system showed the highest fungistasis and the oat/maize system showed the lowest. The management system also affected the genetic profile of the bacteria isolated, with the systems from fungistatic soils showing greater similarity. Although there was no clear relationship between soil management and the characteristics of the bacterial isolates, we may conclude that antibiosis and the production of siderophores were the main mechanisms accounting for fungistasis.

  8. Distinct roles of T-cell lymphopenia and the microbial flora for gastrointestinal and CNS autoimmunity.

    Science.gov (United States)

    Fischer, Henrike J; Witte, Ann-Kathrin; Walter, Lutz; Gröne, Hermann-Josef; van den Brandt, Jens; Reichardt, Holger M

    2016-05-01

    T-cell lymphopenia is a major risk factor for autoimmunity. Here we describe congenic Lewis (LEW) rats with a loss-of-function mutation in the Gimap5 gene, leading to a 92% reduction in peripheral T-cell numbers. Gimap5-deficient LEW rats developed eosinophilic autoimmune gastroenteritis accompanied by a 40-fold increase in IgE serum levels. This phenotype was ameliorated by antibiotic treatment, indicating a critical role of the microbial flora in the development of inflammatory bowel disease. Interestingly, Gimap5-deficient LEW rats showed strongly aggravated experimental autoimmune encephalomyelitis (EAE) after immunization with guinea pig myelin basic protein. This phenotype, however, persisted after antibiosis, confirming that the enhanced CNS autoimmune response in T-cell lymphopenic Gimap5-deficient LEW rats was unrelated to the composition of the microbial flora. Rather, it seems that it was caused by the 7-fold increase in the percentage of activated T cells producing IL-17 and IFN-γ, and the skewed T-cell receptor (TCR) repertoire, both of which were the result of T-cell lymphopenia and not affected by antibiosis. This notion was supported by the observation that adoptive T-cell transfer corrected the TCR repertoire and improved EAE. Collectively, our findings confirm a critical albeit differential role of T-cell lymphopenia in the susceptibility to organ-specific autoimmune responses.-Fischer, H. J., Witte, A.-K., Walter, L., Gröne, H.-J., van den Brandt, J., Reichardt, H. M. Distinct roles of T-cell lymphopenia and the microbial flora for gastrointestinal and CNS autoimmunity. © FASEB.

  9. Trichoderma species from the cacao agroecosystem with biocontrol potential of Moniliophthora roreri

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    Omar Reyes-Figueroa

    2016-01-01

    Full Text Available La moniliasis del cacao ( Moniliophthora roreri es la principal limitante parasítica de la producción de cacao ( Theobroma cacao en México. Una alternativa sostenible para el control de la enfermedad es el uso del hongo Trichoderma . El objetivo del presente estudio fue seleccionar aislamientos nativos de Trichoderma con las mejores características antagónicas y fisiológicas in vitro, para el control de M. roreri . Para ello, se caracterizaron 50 aislamientos de Trichoderma , obtenidos del agroecosistema cacao. El crecimiento micelial y la producción de conidios a 25, 30 y 35 °C se consideraron variables fisiológicas. El micoparasitismo, antibiosis y antagonismo potencial fueron las variables antagónicas. Se encontraron diferencias significativas ( P = 0.0001 en todas las variables evaluadas . El intervalo de temperatura óptima para el crecimiento micelial y producción de conidios fue de 25 a 30 °C. El micoparasitismo varió de 0 a 100 % y solo los aislamientos de seis especies mostraron esta característica. La antibiosis osciló entre 6.8 y 55.5 %, y el antagonismo potencial varió de 3.4 a 69 %. Trichoderma virens (TTC017 y T. harzianum (TTC090, TTC039, TTC073 mostraron el mejor biocontrol potencial in vitro , por lo que son cepas prometedoras para futuras investigaciones sobre control biológico de la moniliasis del cacao.

  10. Aislamiento de microorganismos para control biológico de Moniliophthora roreri

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    Liliana Yanet Suárez Contreras

    2013-12-01

    Full Text Available Moniliophthora roreri es un hongo que causa la moniliasis, una enfermedad de la mazorca en el cultivo de cacao (Theobroma cacao, con pérdidas hasta del 60% de la cosecha. El control biológico utilizando microorganismos endófitos surge como una alternativa para el manejo de esta enfermedad. En la presente investigación se evaluaron microorganismos con potencial para control biológico de M. roreri en Norte de Santander, Colombia. Para el efecto, se aisló e identificó este fitopatógeno y se utilizaron protocolos de desinfección de los posibles microorganismos antagonistas con siembras por diluciones seriadas, selección de los géneros microbianos con mayor potencial antagónico y evaluación de las cepas por la prueba de plato dual para evaluar el efecto biocontrolador de los hongos y la antibiosis para bacterias. Se tomaron muestras en los municipios de Cúcuta, Sardinata, El Tarra, Tibú y El Zulia, de las cuales se aislaron 17 cepas del fitopatógeno y 20 entre hongos y bacterias. De éstas se seleccionaron cuatro cepas de hongos y tres de bacterias por su capacidad antagónica contra M. roreri. Los mejores porcentajes de inhibición de crecimiento radial (PICR se alcanzaron con Paecilomyces sp. (HC002 vs M. roreri, con una media de 80.72%, seguido del tratamiento con Paecilomyces sp. (HZ002 vs M. roreri con 79.45%. Se demostró que el hongo Paecilomyces sp. también tiene un alto potencial antagónico in vitro frente a M. roreri. Al evaluar la antibiosis de las bacterias aisladas, se encontró que Bacillus brevis (BZ005 fue la más efectiva en todos los sitios del estudio, con porcentajes superiores a 89%.

  11. Seleção de genótipos de capim-elefante quanto à resistência à cigarrinha-das-pastagens Selection of elephant grass genotypes for resistance to spittlebug

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    Alexander Machado Auad

    2007-08-01

    Full Text Available O objetivo deste trabalho foi avaliar genótipos de capim-elefante (Pennisetum purpureum Schum. quanto à resistência à cigarrinha-das-pastagens (Mahanarva spectabilis. Para avaliação da antibiose, aos trinta dias após o plantio, cada planta foi infestada com seis ovos próximos à eclosão, em delineamento inteiramente casualizado, com 30 genótipos e dez repetições. Quarenta e cinco dias após a eclosão das ninfas, avaliou-se a porcentagem de sobrevivência do inseto-praga nos diferentes genótipos. Para avaliação da não-preferência, foram quantificados, quinzenalmente, o número e tamanho de ninfas por vaso, em plantas mantidas em casa de vegetação, onde adultos de M. spectabilis eram periodicamente liberados, em delineamento inteiramente casualizado, com três repetições por genótipo, em dois períodos de amostragem. Os genótipos Cameroon de Piracicaba, Pioneiro, Cuba 169, Santa Rita, Mineiro Ipeaco, Mercker Comum de Pinda e CNPGL 96-27-3 foram selecionados quanto à resistência, pelo mecanismo de antibiose. O número e o tamanho médio das ninfas variaram significativamente em razão do genótipo de capim-elefante, no estudo da não-preferência. Os genótipos Roxo de Botucatu e Pioneiro são candidatos à testemunha suscetível e resistente, respectivamente, pelo mecanismo de antibiose, e os genótipos Cameroon e Cameroon Piracicaba são promissores pelo mecanismo de não-preferência.The objective of this work was to evaluate genotypes of elephant grass (Pennisetum purpureum Schum. regarding resistance to the spittlebug Mahanarva spectabilis. For antibiosis evaluation, each plant was infested with six eggs near hatching, thirty days after planting, in a completely randomized design with 30 genotypes and ten repetitions. Forty-five days after the nymphs hatched, the insect survival rate was evaluated on the different genotypes. For nonpreference mechanism evaluation, the size and number of the nymphs per pot were

  12. ASPECTOS BIOLÓGICOS DE Anticarsia gemmatalis HÜEBNER (LEPIDOPTERA: NOCTUIDAE EM CULTIVARES DE SOJA (Glycine max MERRIL BIOLOGICAL ASPECTS OF Anticarsia gemmatalis HÜEBNER (LEPIDOPTERA: NOCTUIDAE ON SOYBEAN CULTIVARS

    Directory of Open Access Journals (Sweden)

    José Baldin Pinheiro

    2007-09-01

    Full Text Available

    O trabalho foi desenvolvido no Laboratório de Entomologia da Escola de Agronomia da Universidade Federal de Goiás, em condições controladas de temperatura (25+2ºC, umidade relativa (40+10% e fotofase de 13h, com o objetivo de estudar o efeito das cultivares Emgopa 316, FT-Estrela, IAC 100 e IAC 17, no desenvolvimento de Anticarsia gemmatalis. Foram observadas a duração do período larval, o tamanho e o peso de lagartas e peso de pupas. Na cultivar Emgopa 316, as larvas apresentaram uma diminuição no período larval e um aumento nos pesos larval e pupal, enquanto IAC 100 mostrou alguma evidência de antibiose, aumentando o período larval e diminuindo o peso de lagartas e de pupas.

    PALAVRAS-CHAVE: Resistência; antibiose; insecta.

    A laboratory work was conducted at Universidade Federal de Goiás, under controlled conditions of temperature (25+2º, relative humidity (40+10% and photophase (13h. The objective was to evaluate the effect of the soybean cultivars Emgopa 316, FT-Estrela, IAC 100 and IAC 17 on the development of Anticarsia gemmatalis Hüebner, 1818. Duration of the development phases, length of larvae and weight of pupae were observed. Emgopa 316 showed a decreasing duration of larval stage and an increase in larvae and pupae weight; IAC 100 showed some evidence of antibiosis, increasing the larval stage and decreasing larvae and pupae weight.

    KEY-WORDS: Insecta; resistance; antibiosis.

  13. Parâmetros biológicos de Bemisia Tabaci (genn. biótipo B (hemiptera: aleyrodidae em genótipos de algodoeiro Biological parameters of Bemisia Tabaci B biotype on cotton genotypes

    Directory of Open Access Journals (Sweden)

    Zeneide Ribeiro Campos

    2009-01-01

    Full Text Available A mosca-branca Bemisia tabaci biótipo B é uma praga de grande importância econômica para muitas culturas em todo o mundo. No Brasil, especialmente no Estado da Bahia, essa praga causou perdas que variam entre 30% e 70% em cultura de algodão. Essa pesquisa foi desenvolvida com o objetivo de avaliar parâmetros biológicos de B. tabaci biótipo B em genótipos de algodoeiro para verificar a possível ocorrência de antibiose como mecanismo de resistência sob condições de casa de vegetação. Os genótipos estudados foram IAC-23, Coodetec 406, BRS Aroeira, Fabrika, Coodetec 407, IAC-24, Makina, IAC 20-233, Coodetec 401 e CNPA Acala I. Foram avaliados os períodos de incubação e ninfal, o desenvolvimento total e a longevidade. Dos genótipos avaliados observou-se em Coodetec 406 maior período ninfal (14,7 dias e IAC-23 a menor viabilidade de ninfas (30,7%, indicando a ocorrência de resistência do tipo antibiose contra essa mosca-branca.The silverleaf whitefly Bemisia tabaci B biotype is an important pest of many crops throughout the world. In Brazil, specifically in the Bahia State, this insect caused losses estimated to 30-70% on cotton crops. The purpose of this research was to investigate biological parameters of the silverleaf whitefly biotype B in genotype of cotton bush to verify a possible occurrence of antibiosis as resistance mechanism cotton, under greenhouse conditions. The duration of the egg and nymphal stages, and the adult longevity of B. tabaci biotype B were evaluated in the genotypes IAC-23, Coodetec 406, BRS Aroeira, Fabrika, Coodetec 407, IAC-24, Makina, IAC 20-233, Coodetec 401 and CNPA Acala I. Among those evaluated genotypes, Coodetec 406 increased the nymph stage (14.7 days and IAC-23 reduced the nymphal viability (30.7%, suggesting the occurrence of antibiosis against this whitefly.

  14. Antagonism of Bacillus spp. against Xanthomonas campestris pv. campestris

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    Leila Monteiro

    2005-01-01

    Full Text Available The antagonism of eight Bacillus isolates was investigated against nine strains of Xanthomonas campestris pv. campestris (causal agent of crucifers black rot to assess the role of lipopeptides in this process. Antimicrobial and hemolytic (surfactant activity tests were performed in vitro using agar diffusion methods. Antibiosis and hemolysis were positive for four Bacillus isolates against all X. campestris pv. campestris strains. The correlation observed between antimicrobial and hemolytic activities indicated that lipopeptides were involved in the antibiosis mechanism of the studied antagonists. Fermentation studies were carried out with the isolates that showed highest antimicrobial and hemolytic activities, to follow up growth and production of bioactive and surfactant compounds. Production of bioactive and surfactant compounds was observed during the late growth phase of the Bacillus isolates.Investigação sobre o antagonismo de oito isolados de Bacillus: B. subtilis R14, B. megaterium pv. cerealis RAB7, B. megaterium pv. cerealis C211, B. megaterium C116, Bacillus sp. RAB9, B. cereus C240, Bacillus sp. C11 e B. cereus C210, contra nove linhagens de X. campestris pv. campestris (bactéria responsável pela podridão negra das crucíferas foi realizada para se verificar a participação de lipopeptídeos neste mecanismo. Testes de atividades antimicrobiana e hemolítica (surfactante foram realizados, utilizando-se o método de difusão em ágar. Antibiose e hemólise foram positivas para quatro isolados de Bacillus: R14, RAB7, C116 e C210. A correlação observada entre as atividades antimicrobiana e a hemolítica indica que lipopeptídeos estão envolvidos no mecanismo de antibiose dos isolados investigados. As fermentações foram realizadas com os isolados que demonstraram melhores resultados nos testes de atividades antimicrobiana e hemolítica: R14, RAB7 e C116, para acompanhar o crescimento e a produção de compostos bioativos e

  15. Molecular evolution and phylogenetic analysis of biocontrol genes acquired from SCoT polymorphism of mycoparasitic Trichoderma koningii inhibiting phytopathogen Rhizoctonia solani Kuhn.

    Science.gov (United States)

    Gajera, H P; Hirpara, Darshna G; Katakpara, Zinkal A; Patel, S V; Golakiya, B A

    2016-11-01

    The biocontrol agent Trichoderma (T. harzianum, T. viride, T. virens, T. hamantum, T. koningii, T. pseudokoningii and Trichoderma species) inhibited variably (15.32 - 88.12%) the in vitro growth of Rhizoctonia solani causing root rot in cotton. The T. koningii MTCC 796 evidenced highest (88.12%) growth inhibition of test pathogen followed by T. viride NBAII Tv23 (85.34%). Scanning electron microscopic study confirmed mycoparasitism for MTCC 796 and Tv23 which were capable of completely overgrowing on R. solani by degrading mycelia, coiling around the hyphae with hook-like structures. The antagonists T. harzianum NBAII Th1 and, T. virens NBAII Tvs12 exhibited strong antibiosis and formed 2-4 mm zone of inhibition for 70.28% and 46.62%, respectively growth inhibition of test pathogen. Mycoparasitism is a strong mode of action for biocontrol activity compared with antibiosis. The antagonists Trichoderma strains were performed for start codon targeted (SCoT) polymorphism to acquire biocontrol genes from potent antagonist. The six unique SCoT fragments amplified by genomic DNA of best mycoparasitic antagonist MTCC 796 strain are subjected to DNA sequencing resulted to confirm two functional sequences for activity related to biocontrol genes. The phylogenetic and molecular evolution of functional 824 bp of SCoT-3 (920) and 776 bp of SCoT-6 (806) fragments signify sequence homology with biocontrol genes endochitinase (partial cds of 203 amino acids) and novel hmgR genes (partial cds of 239 amino acids), respectively and the same were annotated and deposited in NCBI GenBank database. The hmgR gene is liable to be express hmg - CoA reductase which is a key enzyme for regulation of terpene biosynthesis and mycoparasitic strains produced triterpenes during antagonism to inhibit growth of fungal pathogen as evidenced with GC-MS profile. The biocontrol genes are found in best antagonist T. koningii MTCC 796 for mycoparasitic activity to restrain the growth of test pathogen R

  16. [Biological control in the preservation of pome fruits].

    Science.gov (United States)

    Viñas, I

    1995-03-01

    Fresh fruits are susceptible of be attacked by several pathogenic fungi after harvest due to both their high water and nutrients content and their loss of most of the intrinsic resistance that protected them over their development while attached to the plant. Most rot pathogens can be controlled by various methods such as refrigeration, controlled atmospheres and fungicides. Biological control strategies are emerging as promising alternatives to the use of synthetic fungicides. Several factors must be considered for the selection of biocontrol agents to be used against postharvest fruits diseases. Survivability of the antagonist is a major factor to determine its usefulness. Antagonists must survive and be effective after their exposure to both postharvest treatments and storage conditions. Several antagonistic microorganisms have been found that can effectively inhibit postharvest diseases. Just as there is a diversity among microorganisms, there is also a diversity of mechanisms by which they operate. Although in most cases these mechanisms have not been satisfactorily elucidated, they are likely to involve antibiosis, nutrient competition, stimulation of host defense, predation and parasitism. In many cases, probably more than one mechanism operate. The marketing of some of these antagonists may be feasible and they could be an alternative to synthetic pesticides.

  17. Selection of endophytic fungi from comfrey (Symphytum officinale L.) for in vitro biological control of the phytopathogen Sclerotinia sclerotiorum (Lib.)

    Science.gov (United States)

    Rocha, Rafaeli; da Luz, Daniela Eleutério; Engels, Cibelle; Pileggi, Sônia Alvim Veiga; de Souza Jaccoud Filho, David; Matiello, Rodrigo Rodrigues; Pileggi, Marcos

    2009-01-01

    Biological control consists of using one organism to attack another that may cause economic damage to crops. Integrated Pest Management (IPM) is a very common strategy. The white mold produced by Sclerotinia sclerotiorum (Lib.) causes considerable damage to bean crops. This fungus is a soil inhabitant, the symptoms of which are characterized by water-soaked lesions covered by a white cottony fungal growth on the soil surface and/or the host plant. Possible biological control agents taken from plants are being investigated as phytopathogen inhibitors. These are endophytic microorganisms that inhabit the intercellular spaces of vegetal tissues and are often responsible for antimicrobial production. The objective of the present study was to select endophytic fungi isolated from comfrey (Symphytum officinale L.) leaves with in vitro antagonist potential against the phytopathogenic fungus S. sclerotiorum. Twelve isolates of endophytic fungi and a pathogenic strain of S. sclerotiorum were used in the challenge method. With the aid of this method, four endophytes with the best antagonistic activity against S. sclerotiorum were selected. Pathogen growth inhibition zones were considered indicative of antibiosis. The percentages of pathogenic mycelia growth were measured both with and without the antagonist, resulting in growth reductions of 46.7% to 50.0% for S. sclerotiorum. These analyses were performed by evaluating the endophytic/pathogenic mycelia growth in mm/day over an eight-day period of antagonistic tests. PMID:24031320

  18. Selección de rizobacterias por su antagonismo frente a microorganismos patógenos de cucurbitáceas /Screening of rhizobacteria for their antagonism against microbial pathogens of cucurbits.

    Directory of Open Access Journals (Sweden)

    Gilda Jiménez Montejo

    2014-04-01

    Full Text Available Resumen:El desarrollo de inoculantes microbianos a partir de aislamientos de rizobacterias con potencial para el control biológico de enfermedades de los cultivos agrícolas requiere de una rigurosa selección. Se obtuvieron aislamientos bacterianos de la rizosfera de papa (Solanum tuberosum L. y de maíz (Zea mays L. y de semillas de frijol (Phaseolus vulgaris L.. Las colonias que mostraron in vitro halos de inhibición de los patógenos de cucurbitáceas: Xanthomonas cucurbitae, Acidovorax avenae subsp. citrull y Fusarium oxysporum, se seleccionaron como antagonistas. A partir de las características morfológicas, fisiológicas y bioquímicas las cepas antagonistas F16/95 y Xph se identificaron con la especie Bacillus subtilis y la cepa 14A como Pseudomonas putida. Las pruebas presuntivas de producción de antibiocinas in vitro sugirieron modos de acción de las rizobacterias relacionados con antibiosis y competencia por el hierro mediante la producción de sideróforos. Los resultados indicaron el potencial de las cepas de rizobacterias antagonistas Bacillus subtilis (F16/95, Xph y Pesudomonas putida 14A para el control biológico de enfermedades de las cucurbitáceas./Abstract:

  19. Antagonistic activity Trichoderma harzianum Rifai on the causal agent of rice blast (Pyricularia grisea Sacc.

    Directory of Open Access Journals (Sweden)

    Ernesto Juniors Pérez Torres

    2017-10-01

    Full Text Available With the objective to evaluate the antagonistic activity of T. harzianum (strain A-34 on the causal agent of rice blast (P. grisea, were developed several in vitro experiments. It was evaluated the biocontrol mechanisms such as competition through mounted the percent inhibition of radial growth of hyphae of P. grisea from 24 to 240 hours and the antagonistic capacity. In addition, was evaluated micoparasitism to inclination the observation of events Microscopy winding, penetration, vacuolization, lysis, and antibiosis by observing 24 hours a confrontation between the hyphae of the phytopathogenic fungus and biological control agent. It was obtained at 120 hours 100 % inhibition of micelial growth of causal agent, what corresponded with the degree 1 of antagonistic capacity (scale and is recorded as a hyperparasitic action on P. grisea. It was evidenced an antibiotic effect of metabolites produced by T. harzianum (strain A-34 to 24 hours of confrontation, where there was time interaction between the hyphae of microorganisms with 14,3 % inhibition, also was evidence the micoparasitism events by penetration, vacuolization and lysis in the cells of phytopathogenic fungus. These results demonstrated the ability of T. harzianum (strain A-34 on causal agent of rice blast (P. grisea.

  20. Histopathology Caused by the Entomopathogenic Fungi, Beauveria bassiana and Metarhizium anisopliae, in the Adult Planthopper, Peregrinus maidis, a Maize Virus Vector

    Science.gov (United States)

    Toledo, A.V.; de Remes Lenicov, A.M.M.; López Lastra, C.C.

    2010-01-01

    The planthopper Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae) is an important vector of maize viruses in tropical and subtropical areas. Planthoppers are biologically controlled with several species of entomopathogenic fungi that have been isolated from these insect pests of rice in Asia. Beauveria bassiana (Balsamo-Crivelli) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) appear to be the most useful against planthoppers because of their ease of mass production, storage, virulence, and application. In the present study, adults of P. maidis infected with B. bassiana and M. anisopliae were observed under light and scanning electron microscopy to characterize morphologically the process of infection and the development of these fungi, prior to and after the death of the host. The hydrophobic conidia of both fungal species were able to attach to all body regions, with a preference for surfaces containing hairs. Few germinated conidia were observed on the insect's body surface at 24, 48, and 72 hr post-inoculation. On the cuticular surface of P. maidis treated with B. bassiana and M. anisopliae, bacillus-like bacteria were observed. These microorganisms could be interacting with fungal conidia, playing a role of antibiosis that will not allow the fungal pathogens to germinate and penetrate. In the colonization events observed in this study, the formation and multiplication of hyphal bodies by both fungal species inside the host's body was noted. The host's whole body was invaded by hyphae between five and six days post-inoculation, and body fat was the most affected tissue. PMID:20578956

  1. Eksplorasi Cendawan Endofit Asal Padi Sawah sebagai Agens Pengendali Penyakit Blas pada Padi Sawah

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    Irwanto Sucipto

    2016-02-01

    Full Text Available Blast disease (Pyricularia oryzae in Indonesia is initially known to cause problem on upland rice, but since 2000’s blast disease was also reported occurred on lowland rice. Application of endophytic fungi is very potential to be used as disease control method. This study was conducted to isolates endophytic fungi from lowland rice, and determine its capability to reduce  blast disease severity. Isolation of endophytic fungi was done from root, tiller, and the leaves of lowland rice.  Kencana Bali variety was used for in vivo inhibition test due to its most susceptible response against P. oryzae. Forty seven endophytic fungi isolates were obtained from Bogor, Sukabumi and Blitar. Based on colony morphology, endophytic fungi can be differentiated into 9 morphotype. Four out of fourteen endophytic fungi showed antibiosis activity in in vitro inhibition test against P. oryzae. Inhibition test conducted on Kencana Bali variety in the green house showed that four isolates was able to suppress blast disease development by 30-70%.

  2. Active wound dressing with artificial capillaries for temporary wound irrigation and skin cell supply.

    Science.gov (United States)

    Plettig, Jörn; Johnen, Christa M; Bräutigam, Kirsten; Zeilinger, Katrin; Borneman, Reinhard; Gerlach, Jörg C

    2012-04-01

    Medical treatment of burns and chronic wounds remains a challenge. We discussed a therapy concept that combines skin cell spray transplantation with a novel wound dressing based on artificial hollow fiber membrane capillaries. In skin cell-based therapy development, autologous skin progenitor cells are isolated from a healthy skin area and sprayed onto the wound. A medical device was introduced that uses perfused capillaries, known from clinical plasma separation, as a temporarily applied extracorporeal wound capillary bed. The functions of the dressing are comparable with those of dialysis; the capillaries, however, are applied externally onto the wound. Perfusion with a clinical peripheral nutrition and buffer solution can provide wound irrigation, wound debris removal, cell nutrition, pH regulation, and electrolyte balance while potentially serving to address delivery of regenerative factors and antibiosis. An innovative active skin wound dressing that provides cell support and stimulates regeneration by wound irrigation is discussed. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  3. Biological aspects of Bemisia tabaci (Genn.) B biotype (Hemiptera: Aleyrodidae) on six bean genotypes; Aspectos biologicos de Bemisia tabaci (Genn.) biotipo B (Hemiptera: Aleyrodidae) em seis genotipos de feijoeiro

    Energy Technology Data Exchange (ETDEWEB)

    Oriani, Maria A. de G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Ecologia e Biologia Evolutiva; Vendramin, Jose D. [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Dept. de Entomologia, Fitopatologia e Zoologia Agricola; Brunherotto, Rogerio [Fundacao Municipal de Ensino Superior de Braganca Paulista, SP (Brazil)

    2008-03-15

    The silverleaf whitefly is one of the most harmful pests that attack bean crops, mainly for extracting large quantities of phloem sap and transmitting the bean golden mosaic virus. Resistant germplasm plants can be an important method for controlling this pest. The biological aspects of Bemisia tabaci B biotype on bean (Phaseolus vulgaris) genotypes were evaluated. The tests were conducted under laboratory conditions, with the following genotypes: Arc 1, Arc 3s, Arc 5s, G13028, G11056 and Porrillo 70. The bean plants in a stage IV-1 were infested during one day with silverleaf white flies. Afterwards the eggs and nymphs were observed until adult emergence. Longevity and fecundity of emerged insects were also evaluated. The longest development time occurred for nymphs fed on Arc 3s genotype (26.5 days), following by G11056 (25.9 days) and G13028 (25.3 days). The development period was 5.5 days longer in Arc 3s when compared with Porrillo 70. Also, the wild genotypes Arc 3s and G11056 showed higher mortality rates (94.7% and 83.1%, respectively), which may suggest antibiosis and/or feeding non preference resistance type. For this reason, although longevity and fecundity were not influenced when the whitefly fed on resistant genotypes (Arc 3s, G11056, G13028 and Arc 5s), those genotypes can be used for bean breeding program towards B. tabaci B biotype. (author)

  4. QTL mapping of antixenosis resistance to common cutworm (Spodoptera litura Fabricius) in wild soybean (Glycine soja).

    Science.gov (United States)

    Oki, Nobuhiko; Kaga, Akito; Shimizu, Takehiko; Takahashi, Masakazu; Kono, Yuhi; Takahashi, Motoki

    2017-01-01

    The common cutworm (CCW; Spodoptera litura Fabricius) is a serious herbivorous insect pest of soybean (Glycine max) in Asia and Oceania. Previously, we identified quantitative trait loci (QTLs) for CCW-antibiosis-resistance, CCW-1 and CCW-2, and antixenosis-resistance, qRslx1 and qRslx2, in the cultivar 'Himeshirazu'. The effects of these QTLs are useful in the breeding of CCW-resistant cultivars. In this study, we conducted an antixenosis bioassay on CCW using recombinant inbred lines derived from a cross between a wild soybean (Glycine soja) and the leading cultivar 'Fukuyutaka' to identify CCW-resistance genes in G. soja. The QTL analysis revealed six and four novel antixenosis-resistance QTLs in 2012 and 2013, respectively. Among them, the QTLs on chromosomes 2 and 7, designated qRslx4 and qRslx3, respectively, were stably detected in both years. qRslx3 exhibited the largest effect in both years, suggesting that qRslx3 can be exploited in the breeding of CCW-resistant soybean. Furthermore, qRslx3 and qRslx4 can be used, along with previously reported QTLs from 'Himeshirazu', to enhance the CCW-resistance of soybean cultivars because their chromosomal positions are unique. These new CCW-resistance QTLs from G. soja should play important roles in the breeding of CCW-resistant soybean cultivars.

  5. The progress of silver nanoparticles in the antibacterial mechanism, clinical application and cytotoxicity.

    Science.gov (United States)

    You, Chuangang; Han, Chunmao; Wang, Xingang; Zheng, Yurong; Li, Qiyin; Hu, Xinlei; Sun, Huafeng

    2012-09-01

    Nanotechnology is a highly promising field, with nanoparticles produced and utilized in a wide range of commercial products. Silver nanoparticles (AgNPs) has been widely used in clothing, electronics, bio-sensing, the food industry, paints, sunscreens, cosmetics and medical devices, all of which increase human exposure and thus the potential risk related to their short- and long-term toxicity. Many studies indicate that AgNPs are toxic to human health. Interestingly, the majority of these studies focus on the interaction of the nano-silver particle with single cells, indicating that AgNPs have the potential to induce the genes associated with cell cycle progression, DNA damage and mitochondrial associated apoptosis. AgNPs administered through any method were subsequently detected in blood and were found to cause deposition in several organs. There are very few studies in rats and mice involving the in vivo bio-distribution and toxicity, organ accumulation and degradation, and the possible adverse effects and toxicity in vivo are only slowly being recognized. In the present review, we summarize the current data associated with the increased medical usage of nano-silver and its related nano-materials, compare the mechanism of antibiosis and discuss the proper application of nano-silver particles.

  6. Evaluation of forage grass resistance to Mahanarva fimbriolata (Stål

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    Eliane Grisoto

    2017-12-01

    Full Text Available ABSTRACT The aim of this study was to select forage grasses with potential resistance to Mahanarva fimbriolata by assessing effects on insect. No-choice assays were conducted with 12 genotypes and laboratory-reared insects. The following parameters were assessed: mortality and duration of the nymphal stage; adult weight and longevity; pre-oviposition period; number of eggs/female; viability and duration of the embryonic period. As main result it was verified that the mortality of nymphs reared on Panicum maximum cv. Paredão is almost complete and that this forage grass may be characterized as resistant to this insect by antibiosis. Further, the grasses can be divided into three groups following a cluster analysis: P. maximum cv. Aries, Setaria sphacelata cv. Kazungula, Brachiaria humidicola, A. gayanus and P. maximum cv. Aruana, which are insect-resistant grasses; Brachiaria decumbens cv. Basilisk, B. dictyoneura, B. brizantha cv. MG-4 and B. ruziziensis, which are moderately resistant grasses; and B. brizantha MG-5 and B. brizantha ecotype BB185, which are susceptible grasses.

  7. Susceptibility, Oviposition Preference, and Biology of Grapholita molesta (Lepidoptera: Tortricidae) in Prunus Spp. Rootstock Genotypes.

    Science.gov (United States)

    Bernardi, D; Lazzari, J C; Andreazza, F; Mayer, N A; Botton, M; Nava, D E

    2017-08-01

    Studying the susceptibility of peach trees to Grapholita molesta (Busck) is one of the major steps in the development of pest-resistant peach varieties. This work evaluated the susceptibility of 55 genotypes of the "Prunus Rootstock Collection" ("Coleção Porta-enxerto de Prunus") of Embrapa Temperate Climate (Pelotas, Rio Grande do Sul, Brazil) to the natural infestation of G. molesta, assessed the oviposition preference of G. molesta in choice and no-choice bioassays, and estimated the biological parameters and the fertility life table on different Prunus spp. genotypes in the laboratory. Genotypes Prunus kansuensis (Rehder), I-67-52-9, and I-67-52-4 were the most susceptible to G. molesta infestation in the field (>60% of branches infested), while 'Sharpe' (Prunus angustifolia x Prunus spp.) and Prunus sellowii (Koehne) were the least infested (0% of branches infested). In choice and no-choice bioassays, G. molesta preferred to oviposit on P. kansuensis when compared with Sharpe. The Sharpe genotype also showed an antibiosis effect, resulting in negative effects on the fertility life table parameters when compared with the genotypes P. kansuensis and 'Capdeboscq.' The results found in the present study can provide information to initiate a long-term breeding program moving desired G. molesta resistance traits from the rootstock into the Prunus spp. cultivars. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Investigation of fungal root colonizers of the invasive plant Vincetoxicum rossicum and co-occurring local native plants in a field and woodland area in Southern Ontario

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    Cindy Bongard

    2013-06-01

    Full Text Available Fungal communities forming associations with plant roots have generally been described as ranging from symbiotic to parasitic. Disruptions to these associations consequently can have significant impacts on native plant communities. We examined how invasion by Vincetoxicum rossicum, a plant native to Europe, can alter both the arbuscular mycorrhizal fungi, as well as the general fungal communities associating with native plant roots in both field and woodland sites in Southern Ontario. In two different sites in the Greater Toronto Area, we took advantage of invasion by V. rossicum and neighbouring uninvaded sites to investigate the fungal communities associating with local plant roots, including goldenrod (Solidago spp., wild red raspberry (Rubus idaeus, Canada anemone (Anemone canadensis, meadow rue (Thalictrum dioicum, and wild ginger (Asarum canadense. Fungi colonizing roots were characterized with terminal restriction fragment length polymorphism (T-RFLP analysis of amplified total fungal (TF and arbuscular mycorrhizal fungal (AMF ribosomal fragments. We saw a significant effect of the presence of this invader on the diversity of TF phylotypes colonizing native plant roots, and a composition shift of both the TF and AMF community in native roots in both sites. In native communities invaded by V. rossicum, a significant increase in richness and colonization density of TF suggests that invaders such as V. rossicum may be able to influence the composition of soil fungi available to natives, possibly via mechanisms such as increased carbon provision or antibiosis attributable to unique root exudates.

  9. Poplar and its bacterial endophytes: coexistence and harmony

    Energy Technology Data Exchange (ETDEWEB)

    van der Lelie, D.; Taghavi, S.; Monchy, S.; Schwender, J.; Miller, L.; Ferrieri, R.; Rogers, A.; Zhu, W.; Weyens, N.; Vangronsveld, J.; Newman, L.

    2009-09-01

    Associations between plants and microorganisms are very complex and are the subject of an increasing number of studies. Here, we specifically address the relationship between poplar and its endophytic bacteria. The role and importance of endophytic bacteria in growth and development of their host plants is still underestimated. However, since many endophytes have a beneficial effect on their host, an improved understanding of the interaction between poplar and its endophytic bacteria has the potential to provide major breakthroughs that will improve the productivity of poplar. Endophytic bacteria can improve plant growth and development in a direct or indirect way. Direct plant growth promoting mechanisms may involve nitrogen fixation, production of plant growth regulators such as auxins, cytokinins and gibberellins, and suppression of stress ethylene synthesis by 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Endophytic bacteria can indirectly benefit the plant by preventing the growth or activity of plant pathogens through competition for space and nutrients, antibiosis, production of hydrolytic enzymes, inhibition of pathogen-produced enzymes or toxins, and through systemic induction of plant defense mechanisms. Examples of applications for custom endophyte-host partnerships include improved productivity and establishment of poplar trees on marginal soils and the phytoremediation of contaminated soils and groundwater. A systems biology approach to understand the synergistic interactions between poplar and its beneficial endophytic bacteria represents an important field of research, which is facilitated by the recent sequencing of the genomes of poplar and several of its endophytic bacteria.

  10. Role of the 4-phosphopantetheinyl transferase of Trichoderma virens in secondary metabolism and induction of plant defense responses.

    Science.gov (United States)

    Velazquez-Robledo, R; Contreras-Cornejo, H A; Macias-Rodriguez, L; Hernandez-Morales, A; Aguirre, J; Casas-Flores, S; Lopez-Bucio, J; Herrera-Estrella, A

    2011-12-01

    Trichoderma virens is a ubiquitous soil fungus successfully used in biological control due to its efficient colonization of plant roots. In fungi, 4-phosphopantetheinyl transferases (PPTases) activate enzymes involved in primary and secondary metabolism. Therefore, we cloned the PPTase gene ppt1 from T. virens and generated PPTase-deficient (?ppt1) and overexpressing strains to investigate the role of this enzyme in biocontrol and induction of plant defense responses. The ?ppt1 mutants were auxotrophic for lysine, produced nonpigmented conidia, and were unable to synthesize nonribosomal peptides. Although spore germination was severely compromised under both low and high iron availability, mycelial growth occurred faster than the wild type, and the mutants were able to efficiently colonize plant roots. The ?ppt1 mutants were unable of inhibiting growth of phytopathogenic fungi in vitro. Arabidopsis thaliana seedlings co-cultivated with wild-type T. virens showed increased expression of pPr1a:uidA and pLox2:uidA markers, which correlated with enhanced accumulation of salicylic acid (SA), jasmonic acid, camalexin, and resistance to Botrytis cinerea. Co-cultivation of A. thaliana seedlings with ?ppt1 mutants compromised the SA and camalexin responses, resulting in decreased protection against the pathogen. Our data reveal an important role of T. virens PPT1 in antibiosis and induction of SA and camalexin-dependent plant defense responses.

  11. Fabrication of Magnetic-Antimicrobial-Fluorescent Multifunctional Hybrid Microspheres and Their Properties

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    Ling-Han Xiao

    2013-04-01

    Full Text Available Novel magnetic-antimicrobial-fluorescent multifunctional hybrid microspheres with well-defined nanostructure were synthesized by the aid of a poly(glycidyl methacrylate (PGMA template. The hybrid microspheres were fully characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD and digital fluorescence microscope. The as-synthesized microspheres PGMA, amino-modified PGMA (NH2-PGMA and magnetic PGMA (M-PGMA have a spherical shape with a smooth surface and fine monodispersity. M-PGMA microspheres are super-paramagnetic, and their saturated magnetic field is 4.608 emu·g−1, which made M-PGMA efficiently separable from aqueous solution by an external magnetic field. After poly(haxemethylene guanidine hydrochloride (PHGH functionalization, the resultant microspheres exhibit excellent antibacterial performance against both Gram-positive and Gram-negative bacteria. The fluorescence feature originating from the quantum dot CdTe endowed the hybrid microspheres with biological functions, such as targeted localization and biological monitoring functions. Combination of magnetism, antibiosis and fluorescence into one single hybrid microsphere opens up the possibility of the extensive study of multifunctional materials and widens the potential applications.

  12. Functional role of an endophytic Bacillus amyloliquefaciens in enhancing growth and disease protection of invasive English ivy (Hedera helix L.)

    Science.gov (United States)

    Soares, Marcos Antonio; Li, Jai-Yan; Bergen, Marshall; da Silva, Joaquim Manoel; Kowalski, Kurt P.; White, James Francis

    2015-01-01

    BackgroundWe hypothesize that invasive English ivy (Hedera helix) harbors endophytic microbes that promote plant growth and survival. To evaluate this hypothesis, we examined endophytic bacteria in English ivy and evaluated effects on the host plant.MethodsEndophytic bacteria were isolated from multiple populations of English ivy in New Brunswick, NJ. Bacteria were identified as a single species Bacillus amyloliquefaciens. One strain of B. amyloliquefaciens, strain C6c, was characterized for indoleacetic acid (IAA) production, secretion of hydrolytic enzymes, phosphate solubilization, and antibiosis against pathogens. PCR was used to amplify lipopeptide genes and their secretion into culture media was detected by MALDI-TOF mass spectrometry. Capability to promote growth of English ivy was evaluated in greenhouse experiments. The capacity of C6c to protect plants from disease was evaluated by exposing B+ (bacterium inoculated) and B− (non-inoculated) plants to the necrotrophic pathogen Alternaria tenuissima.ResultsB. amyloliquefaciens C6c systemically colonized leaves, petioles, and seeds of English ivy. C6c synthesized IAA and inhibited plant pathogens. MALDI-TOF mass spectrometry analysis revealed secretion of antifungal lipopeptides surfactin, iturin, bacillomycin, and fengycin. C6c promoted the growth of English ivy in low and high soil nitrogen conditions. This endophytic bacterium efficiently controlled disease caused by Alternaria tenuissima.ConclusionsThis study suggests that B. amyloliquefaciens plays an important role in enhancing growth and disease protection of English ivy.

  13. Evaluación de Hongos Antagonistas De Botrytis cinerea Pers., en Plantaciones de Mora, Costa Rica

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    María Angélica Marín-Chacón

    2017-01-01

    Full Text Available Se realizó el aislamiento, identificación y evaluación in vitro y en campo de hongos antagonistas de Botrytis cinerea Pers., en plantaciones de mora. La obtención de organismos antagonistas se hizo en Cartago en las localidades de La Luchita, Bajo Canet, Jardín y División durante el 2012. De los frutos se obtuvo un grupo de 43 aislamientos pertenecientes a 10 géneros distintos de los hongos: Aspergillus sp., Bispora sp., Cladosporium spp., Colletotrichum sp., Curvularia sp., Macrophoma sp., Paecilomyces spp., Pestalotia spp., Rhizoctonia sp., y Trichoderma spp. A todos los aislamientos se les realizaron pruebas de capacidad antagónica, mediante la técnica de cultivos duales, competencia por sustrato y antibiosis. Se seleccionaron solamente los aislamientos que superaron un 70% del PIC, y estos fueron 4 aislamientos (BC1, J14, J2.2 y J2.1 del género Trichoderma spp. Para las pruebas de campo se utilizaron 3 aislamientos (BC1, J2.2 y J2.1 del presente trabajo y 3 (BV1, SM13B y SM18 del mismo género previamente aislados. Las pruebas de campo se realizaron en el 2013. Los aislamientos de Trichoderma spp., que tuvieron estadísticamente (p≤0,0001 mayor efecto sobre B. cinerea fueron BV1 y BC1, los cuales dieron menos frutos enfermos.

  14. RESISTÊNCIA DE GENÓTIPOS DE FEIJÃO-VAGEM AO ATAQUE DE BRUQUÍ-NEOS, EM CONDIÇÕES DE LABORATÓRIO

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    DALINE BENITES BOTTEGA

    2012-01-01

    Full Text Available The aim of this paper was to determine resistance types of snap beans genotypes under infestation of bruchins Zabrotes subfasciatus (Bohemann, 1833 of Acanthoscelides obtectus (Say, 1831 in a no choice and free choice tests. The treatments were arranged in a completely randomized design with four and five replications, respectively. In no choice test, it was evaluated the total number of viable and unviable eggs, dry weight of the consumed food, percentage of emerged insects, weight of insects, longevity of adults and biological cycle of egg to adult. In a free choice test, the number of attracted insects for each genotype and total number of eggs were evaluated. The genotype ARFVI047 presents oviposition non-preference resistance type to Z. subfasciatus. The genotype ARFVI008 presents resistance type of the antibiosis to Z. subfasciatus. The genotypes ARFVI006, ARFVI008 and ARFVI029 present resistance of non-preference for oviposition type to Z. subfasciatus and the genotype HAV 56 black seed presents resistance of non-preference type for feeding of A. obtectus.

  15. A Three-Way Transcriptomic Interaction Study of a Biocontrol Agent (Clonostachys rosea), a Fungal Pathogen (Helminthosporium solani), and a Potato Host (Solanum tuberosum).

    Science.gov (United States)

    Lysøe, Erik; Dees, Merete W; Brurberg, May Bente

    2017-08-01

    Helminthosporium solani causes silver scurf, which affects the quality of potato. The biocontrol agent Clonostachys rosea greatly limited the severity of silver scurf symptoms and amount of H. solani genomic DNA in laboratory experiments. Transcriptomic analysis during interaction showed that H. solani gene expression was highly reduced when coinoculated with the biocontrol agent C. rosea, whereas gene expression of C. rosea was clearly boosted as a response to the pathogen. The most notable upregulated C. rosea genes were those encoding proteins involved in cellular response to oxidative stress, proteases, G-protein signaling, and the methyltransferase LaeA. The most notable potato response to both fungi was downregulation of defense-related genes and mitogen-activated protein kinase kinase kinases. At a later stage, this shifted, and most potato defense genes were turned on, especially those involved in terpenoid biosynthesis when H. solani was present. Some biocontrol-activated defense-related genes in potato were upregulated during early interaction with C. rosea alone that were not triggered by H. solani alone. Our results indicate that the reductions of silver scurf using C. rosea are probably due to a combination of mechanisms, including mycoparasitism, biocontrol-activated stimulation of plant defense mechanisms, microbial competition for nutrients, space, and antibiosis.

  16. Compatibility study of Trichoderma harzianum Rifai and rice fungicides, and effects on three fungal plant pathogens

    Directory of Open Access Journals (Sweden)

    Manuel Francisco Rodríguez Saldaña

    2017-04-01

    Full Text Available This research took place at the Provincial Plant Sanitation Laboratory, in Camaguey, Cuba, between September 2013 and September 2015. The in vitro compatibility and antagonistic capacity of Trichoderma harzianum Rifai (strain A-34 on rice pathogens (Bipolaris oryzae Breda de Haan, Sarocladium oryzae (Sawada w., Gams and D. Hawksworth and Magnaporthe grisea (Hebert Barr, was determined against pesticides used on rice. Assessment using traditional methods of microbiological isolation of mycelial growth, sporulation and conidial germination of the antagonist, to determine if the action mechanisms (antibiosis, competence, parasitism against fungal pathogens, was made between 24 and 216 hours of application. A bifactorial design in dual culture was used for statistical analysis, along with scales for determination of microbial antagonistic capacity. Active ingredients tebuconazol + procloraz, trifloxistrobin+ ciproconazole, and epoxiconazole + kresoxim-methyl, affected mycelial growth of the antagonist. Moreover, the antagonist against active ingredients carbendazim, copper oxychloride, azoxystrobin and tebuconazo + triadimenol showed mycelial growth, sporulation and pathogen interaction, affecting their growth by means of coiling, penetration, granulation, and cell lysis, between 96 and 216 hours.

  17. Potential of bulb-associated bacteria for biocontrol of hyacinth soft rot caused by Dickeya zeae.

    Science.gov (United States)

    Jafra, S; Przysowa, J; Gwizdek-Wiśniewska, A; van der Wolf, J M

    2009-01-01

    Dickeya zeae is a pectinolytic bacterium responsible for soft rot disease in flower bulb crops. In this study, the possibility of controlling soft rot disease in hyacinth by using antagonistic bacteria isolated from hyacinth bulbs was explored. Bacterial isolates with potential for biocontrol were selected on the basis of antibiosis against D. zeae, siderophore production, and the N-acyl homoserine lactones (AHLs)-inactivation. In in vitro assays, 35 out of 565 hyacinth-associated bacterial isolates produced antimicrobial substances against D. zeae, whereas 20 degraded AHLs, and 35 produced siderophores. Isolates of interest were identified by 16S rDNA sequence analysis and reaction in BIOLOG tests. Twenty-six isolates that differed in characteristics were selected for pathogenicity testing on hyacinth cultivars, Pink Pearl and Carnegie. Two strains identified as Rahnella aquatilis and one as Erwinia persicinus significantly reduced tissue maceration caused by D. zeae 2019 on hyacinth bulbs, but not on leaves. Hyacinth bulbs harbour bacteria belonging to different taxonomic groups that are antagonistic to D. zeae, and some can attenuate decay of bulb tissue. Selected hyacinth-associated bacterial isolates have potential for control of soft rot disease caused by D. zeae in hyacinth bulb production.

  18. Potential of Epicoccum purpurascens Strain 5615 AUMC as a Biocontrol Agent of Pythium irregulare Root Rot in Three Leguminous Plants.

    Science.gov (United States)

    Koutb, Mostafa; Ali, Esam H

    2010-12-01

    Epicoccum purpurascens stain 5615 AUMC was investigated for its biocontrol activity against root rot disease caused by Pythium irregulare. E. purpurascens greenhouse pathogenicity tests using three leguminous plants indicated that the fungus was nonpathogenic under the test conditions. The germination rate of the three species of legume seeds treated with a E. purpurascens homogenate increased significantly compared with the seeds infested with P. irregulare. No root rot symptoms were observed on seeds treated with E. purpurascens, and seedlings appeared more vigorous when compared with the non-treated control. A significant increase in seedling growth parameters (seedling length and fresh and dry weights) was observed in seedlings treated with E. purpurascens compared to pathogen-treated seedlings. Pre-treating the seeds with the bioagent fungus was more efficient for protecting seeds against the root rot disease caused by P. irregulare than waiting for disease dispersal before intervention. To determine whether E. purpurascens produced known anti-fungal compounds, an acetone extract of the fungus was analyzed by gas chromatography mass spectrometry. The extract revealed a high percentage of the cinnamic acid derivative (trimethylsiloxy) cinnamic acid methyl ester. The E. purpurascens isolate grew more rapidly than the P. irregulare pathogen in a dual culture on potato dextrose agar nutrient medium, although the two fungi grew similarly when cultured separately. This result may indicate antagonism via antibiosis or competition.

  19. Evaluation of Clonostachys rosea for Control of Plant-Parasitic Nematodes in Soil and in Roots of Carrot and Wheat.

    Science.gov (United States)

    Iqbal, Mudassir; Dubey, Mukesh; McEwan, Kerstin; Menzel, Uwe; Franko, Mikael Andersson; Viketoft, Maria; Jensen, Dan Funck; Karlsson, Magnus

    2018-01-01

    Biological control is a promising approach to reduce plant diseases caused by nematodes. We tested the effect of the fungus Clonostachys rosea strain IK726 inoculation on nematode community composition in a naturally nematode infested soil in a pot experiment, and the effect of C. rosea on plant health. The numbers of plant-parasitic nematode genera extracted from soil and plant roots decreased by 40 to 73% when C. rosea was applied, while genera of nonparasitic nematodes were not affected. Soil inoculation of C. rosea increased fresh shoot weight and shoot length of wheat plants by 20 and 24%, respectively, while only shoot dry weight increased by 48% in carrots. Light microscopy of in vitro C. rosea-nematode interactions did not reveal evidence of direct parasitism. However, culture filtrates of C. rosea growing in potato dextrose broth, malt extract broth and synthetic nutrient broth exhibited toxicity toward nematodes and immobilized 57, 62, and 100% of the nematodes, respectively, within 48 h. This study demonstrates that C. rosea can control plant-parasitic nematodes and thereby improve plant growth. The most likely mechanism responsible for the antagonism is antibiosis through production of nematicidal compounds, rather than direct parasitism.

  20. Immobilization of silver nanoparticles in Zr-based MOFs: induction of apoptosis in cancer cells

    Science.gov (United States)

    Han, Congcong; Yang, Jian; Gu, Jinlou

    2018-03-01

    Silver nanoparticles (AgNPs) are a potential class of nanomaterial for antibiosis and chemotherapeutic effects against human carcinoma cells. However, the DNA-damaging ability of free AgNPs pose the critical issues in their biomedical applications. Herein, we demonstrated a facile method to capture Ag+ ions and reduce them into active AgNPs within Zr-based metal-organic frameworks (MOFs) of UiO-66 with a mild reductant of DMF (AgNPs@UiO-66(DMF)). The average diameters of UiO-66 carriers and AgNPs were facilely controlled to be 140 and 10 nm, respectively. The obtained UiO-66 nanocarriers exhibited excellent biocompatibility and could be effectively endocytosed by cancer cells. Additionally, the AgNPs@UiO-66(DMF) could rapidly release Ag+ ions and efficiently inhibit the growth of cancer cells. The half maximal inhibitory concentration (IC50) values of the encapsulated AgNPs were calculated to be 2.7 and 2.45 μg mL-1 for SMMC-7721 and HeLa cells, respectively, which were much lower than those of free AgNPs in the reported works. Therefore, the developed AgNPs@UiO-66(DMF) not only maintained the therapeutic effect against cancer cells but also reduced the dosage of free AgNPs in chemotherapy treatment. [Figure not available: see fulltext.

  1. Tolerance: the forgotten child of plant resistance

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    Robert K.D. Peterson

    2017-10-01

    Full Text Available Plant resistance against insect herbivory has greatly focused on antibiosis, whereby the plant has a deleterious effect on the herbivore, and antixenosis, whereby the plant is able to direct the herbivore away from it. Although these two types of resistance may reduce injury and yield loss, they can produce selection pressures on insect herbivores that lead to pest resistance. Tolerance, on the other hand, is a more sustainable pest management strategy because it involves only a plant response and therefore does not cause evolution of resistance in target pest populations. Despite its attractive attributes, tolerance has been poorly studied and understood. In this critical, interpretive review, we discuss tolerance to insect herbivory and the biological and socioeconomic factors that have limited its use in plant resistance and integrated pest management. First, tolerance is difficult to identify, and the mechanisms conferring it are poorly understood. Second, the genetics of tolerance are mostly unknown. Third, several obstacles hinder the establishment of high-throughput phenotyping methods for large-scale screening of tolerance. Fourth, tolerance has received little attention from entomologists because, for most, their primary interest, research training, and funding opportunities are in mechanisms which affect pest biology, not plant biology. Fifth, the efforts of plant resistance are directed at controlling pest populations rather than managing plant stress. We conclude this paper by discussing future research and development activities.

  2. Genetic variation and constraints on the evolution of defense against spittlebug (Philaenus spumarius) herbivory in Mimulus guttatus.

    Science.gov (United States)

    Ivey, C T; Carr, D E; Eubanks, M D

    2009-03-01

    Plants mediate carbon into most ecosystems and are thus under persistent attack by diverse enemies. The evolution of defense against such assaults will depend on the availability of genetic variation, as well as the costs and constraints on defense. We estimated the magnitude of genetic variation for defense against spittlebug (Philaenus spumarius) herbivory in Mimulus guttatus using a diallel cross-grown in a greenhouse. Except for flowering time, additive genetic variation for the plant traits we measured was negligible, regardless of herbivory environment. In contrast, nonadditive genetic variation contributed significantly to all plant traits measured. We found significant additive genetic variation among plants for biomass of adult spittlebugs, suggesting heritability for resistance to herbivory. The other putative resistance trait measured, spittlebug maturation time, was not significantly heritable. We found no evidence for significant genetic variation for tolerance to herbivory except for a small non-nuclear paternal contribution to tolerance for flower number. Additive genetic correlations indicated that more resistant plant genotypes (in terms of adult spittlebug biomass) were also smaller in the absence of spittlebugs, suggesting a potential cost of resistance to herbivory. We found no other significant genetic correlations indicating a cost of defense, nor did we find evidence for a tradeoff between resistance and tolerance to herbivory. Overall, these results suggest the future adaptive evolution of tolerance to spittlebugs in this population will be limited primarily by available genetic variation, whereas the future evolution of antibiosis resistance may be constrained by allocation costs of resistance.

  3. [Secondary metabolites, lethality and antimicrobial activity of extracts from three corals and three marine mollusks from Sucre, Venezuela].

    Science.gov (United States)

    Ordaz, Gabriel; D'Armas, Haydelba; Yáñez, Dayanis; Hernández, Juan; Camacho, Angel

    2010-06-01

    The study of biochemical activity of extracts obtained from marine organisms is gaining interest as some have proved to have efficient health or industrial applications. To evaluate lethality and antimicrobial activities, some chemical tests were performed on crude extracts of the octocorals Eunicea sp., Muricea sp. and Pseudopterogorgia acerosa and the mollusks Pteria colymbus, Phyllonotus pomum and Chicoreus brevifrons, collected in Venezuelan waters. The presence of secondary metabolites like alkaloids, unsaturated sterols and pentacyclic triterpenes in all invertebrates, was evidenced. Additionally, sesquiterpenlactones, saponins, tannins, cyanogenic and cardiotonic glycosides were also detected in some octocoral extracts, suggesting that biosynthesis of these metabolites is typical in this group. From the lethality bioassays, all extracts resulted lethal to Artemia salina (LC50<1000 microg/ml) with an increased of lethal activity with exposition time. P. pomum extract showed the highest lethality rate (LC50=46.8 microg/ml). Compared to the octocorals, mollusks extracts displayed more activity and a greater action spectrum against different bacterial strains, whereas octocorals also inhibited some fungi strains growth. Staphylococcus aureus was the most susceptible to the antimicrobial power of the extracts (66.7%), whereas Pseudomonas aeruginosa, Candida albicans and Aspergillus niger were not affected. The antibiosis shown by marine organisms extracts indicates that some of their biosynthesized metabolites are physiologically active, and may have possible cytotoxic potential or as a source of antibiotic components.

  4. Isolation and analysis of mannose/trehalose/maltose specific lectin from jack bean with antibruchid activity.

    Science.gov (United States)

    Shanmugavel, Sakthivelkumar; Velayutham, Veeramani; Kamalanathan, Tamilarasan; Periasamy, Mullainadhan; Munusamy, Arumugam; Sundaram, Janarthanan

    2016-10-01

    A lectin with insecticidal property against the stored product pest, Callosobruchus maculatus was successfully isolated from the seeds of Canavalia virosa using standard affinity chromatography. The isolated molecule typically behaved like a lectin in its characteristics. It agglutinated indicator red blood cells (RBC) in its native as well as enzyme treated conditions. The enzyme treated RBC types exhibited a very high hemagglutination (HA) titre values and this property of isolated molecule behaved like arcelin, the lectin-like molecules reported from several species of Phaseolus. As a characteristic feature of a lectin, the isolated molecule effectively inhibited the agglutination of indicator RBC types with simple and complex carbohydrates including glycoproteins. This nature of the isolated molecule also relate with characteristic feature of arcelin isoforms in inhibiting HA activity with complex glycoproteins as reported in many studies. Most interestingly, the present study disclosed trehalose as a potent inhibitor of C. virosa lectin. Therefore, feeding insect pests on the lectin like arcelin could serve as antibiosis factor/anti-insect activity. The molecular characteristics of this isolated molecule and its mass studies too revealed its homology with arcelin, arcelin-1, 2 and 6 isoforms of P. vulgaris and lectin from Canavalia cathartica, C. lineata and C. brasiliensis. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Pantoea agglomerans Strain EH318 Produces Two Antibiotics That Inhibit Erwinia amylovora In Vitro

    Science.gov (United States)

    Wright, Sandra A. I.; Zumoff, Cathy H.; Schneider, Lois; Beer, Steven V.

    2001-01-01

    Pantoea agglomerans (synonym: Erwinia herbicola) strain Eh318 produces through antibiosis a complex zone of inhibited growth in an overlay seeded with Erwinia amylovora, the causal agent of fire blight. This zone is caused by two antibiotics, named pantocin A and B. Using a genomic library of Eh318, two cosmids, pCPP702 and pCPP704, were identified that conferred on Escherichia coli the ability to inhibit growth of E. amylovora. The two cosmids conferred different antibiotic activities on E. coli DH5α and had distinct restriction enzyme profiles. A smaller, antibiotic-conferring DNA segment from each cosmid was cloned. Each subclone was characterized and mutagenized with transposons to generate clones that were deficient in conferring pantocin A and B production, respectively. Mutated subclones were introduced into Eh318 to create three antibiotic-defective marker exchange mutants: strain Eh421 (pantocin A deficient); strain Eh439 (pantocin B deficient), and Eh440 (deficient in both pantocins). Cross-hybridization results, restriction maps, and spectrum-of-activity data using the subclones and marker exchange mutants, supported the presence of two distinct antibiotics, pantocin A and pantocin B, whose biosynthetic genes were present in pCPP702 and pCPP704, respectively. The structure of pantocin A is unknown, whereas that of pantocin B has been determined as (R)-N-[((S)-2-amino-propanoylamino)-methyl]-2-methanesulfonyl-succinamic acid. The two pantocins mainly affect other enteric bacteria, based on limited testing. PMID:11133457

  6. Rhizobacterially induced protection of watermelon against Didymella bryoniae.

    Science.gov (United States)

    Nga, N T T; Giau, N T; Long, N T; Lübeck, M; Shetty, N P; de Neergaard, E; Thuy, T T T; Kim, P V; Jørgensen, H J L

    2010-08-01

    To identify rhizobacteria from the Mekong Delta of Vietnam, which can systemically protect watermelon against Didymella bryoniae and elucidate the mechanisms involved in the protection conferred by isolate Pseudomonas aeruginosa 23(1-1). Bacteria were isolated from watermelon roots and their antagonistic ability tested in vitro. Of 190 strains, 68 were able to inhibit D. bryoniae by production of antibiotics. Four strains were able to reduce foliar infection by D. bryoniae when applied to watermelon seeds before sowing. Strain Ps. aeruginosa 23(1-1) was chosen for investigations of the mechanisms involved in protection and ability to control disease under field conditions. In the field, the bacterium was able to significantly reduce disease in two consecutive seasons and increase yield. Furthermore, it colonized watermelon plants endophytically, with higher numbers in plants infected by D. bryoniae than in noninoculated plants. To elucidate the mechanisms involved in protection, the infection biology of the pathogen was studied in bacterially treated and control plants. Pseudomonas aeruginosa 23(1-1) treatment inhibited pathogen penetration and this was associated with hydrogen peroxide accumulation, increased peroxidase activity and occurrence of new peroxidase isoforms, thus indicating that resistance was induced. The endophytic bacterium Ps. aeruginosa 23(1-1) can control D. bryoniae in watermelon by antibiosis and induced resistance under greenhouse and field conditions. These findings suggest that rhizobacteria from native soils in Vietnam can be used to control gummy stem blight of watermelon through various mechanisms including induction of resistance.

  7. Assessment of the Role of Local Strawberry Rhizosphere—Associated Streptomycetes on the Bacterially—Induced Growth and Botrytis cinerea Infection Resistance of the Fruit

    Directory of Open Access Journals (Sweden)

    D. İpek Kurtböke

    2010-12-01

    Full Text Available The future need for sustainable agriculture will be met in part by wider use of biological control of plant pathogens over conventional fungicides hazardous to the environment and to public health. Control strategies involving both (i direct use of microorganisms antagonistic to the phytopathogen, and (ii use of bioactive compounds (secondary metabolites/antibiotic compounds from microorganisms on the phytopathogen were both adapted in order to investigate the ability of streptomycetes isolated from the rhizosphere of strawberry plants to promote the growth of the fruit and suppress Botrytis cinerea causing strawberry rot on the Sunshine Coast, Queensland, Australia. In vitro studies showed that 25/39 streptomycetes isolated from strawberry field soils inhibited B. cinerea growth by antifungal activity, ranging from antibiosis to volatile compound production. However, when non-volatile antifungal compounds were extracted and applied aerially to the actively growing strawberry fruits infected with B. cinerea, a significant disease reduction was not recorded. On the other hand, plant and fruit growth was promoted by the presence of actively growing streptomycetes in container media. Findings might indicate that live streptomycete inoculum can be used as growth promoting agent in container media for this economically important crop.

  8. miRNA-mediated auxin signalling repression during Vat-mediated aphid resistance in Cucumis melo.

    Science.gov (United States)

    Sattar, Sampurna; Addo-Quaye, Charles; Thompson, Gary A

    2016-06-01

    Resistance to Aphis gossypii in melon is attributed to the presence of the single dominant R gene virus aphid transmission (Vat), which is biologically expressed as antibiosis, antixenosis and tolerance. However, the mechanism of resistance is poorly understood at the molecular level. Aphid-induced transcriptional changes, including differentially expressed miRNA profiles that correspond to resistance interaction have been reported in melon. The potential regulatory roles of miRNAs in Vat-mediated aphid resistance were further revealed by identifying the specific miRNA degradation targets. A total of 70 miRNA:target pairs, including 28 novel miRNA:target pairs, for the differentially expressed miRNAs were identified: 11 were associated with phytohormone regulation, including six miRNAs that potentially regulate auxin interactions. A model for a redundant regulatory system of miRNA-mediated auxin insensitivity is proposed that incorporates auxin perception, auxin modification and auxin-regulated transcription. Chemically inhibiting the transport inhibitor response-1 (TIR-1) auxin receptor in susceptible melon tissues provides in vivo support for the model of auxin-mediated impacts on A. gossypii resistance. © 2016 John Wiley & Sons Ltd.

  9. Coevolution of antibiotic production and counter-resistance in soil bacteria.

    Science.gov (United States)

    Laskaris, Paris; Tolba, Sahar; Calvo-Bado, Leo; Wellington, Elizabeth M; Wellington, Liz

    2010-03-01

    We present evidence for the coexistence and coevolution of antibiotic resistance and biosynthesis genes in soil bacteria. The distribution of the streptomycin (strA) and viomycin (vph) resistance genes was examined in Streptomyces isolates. strA and vph were found either within a biosynthetic gene cluster or independently. Streptomyces griseus strains possessing the streptomycin cluster formed part of a clonal complex. All S. griseus strains possessing solely strA belonged to two clades; both were closely related to the streptomycin producers. Other more distantly related S. griseus strains did not contain strA. S. griseus strains with only vph also formed two clades, but they were more distantly related to the producers and to one another. The expression of the strA gene was constitutive in a resistance-only strain whereas streptomycin producers showed peak strA expression in late log phase that correlates with the switch on of streptomycin biosynthesis. While there is evidence that antibiotics have diverse roles in nature, our data clearly support the coevolution of resistance in the presence of antibiotic biosynthetic capability within closely related soil dwelling bacteria. This reinforces the view that, for some antibiotics at least, the primary role is one of antibiosis during competition in soil for resources.

  10. Sinorhizobium meliloti can protect Medicago truncatula against Phoma medicaginis attack

    Directory of Open Access Journals (Sweden)

    Moncef MRABET

    2011-09-01

    Full Text Available The Sinorhizobium meliloti microsymbiont of Medicago spp. was used in an antibiosis test against Phoma medicaginis and in bioprotection assays of Medicago truncatula JA17 from the pathogen. Among 17 S. meliloti strains isolated from root nodules of M. truncatula and Medicago laciniata grown in Tunisian soils, six showed up to 60% growth inhibition of five P. medicaginis strains isolated from infected field-grown M. truncatula. Two S. meliloti strains with differing in vitro effects on P. medicaginis, 10.16/R6 antagonist and 5M6 non antagonist, were used in a bioprotection assay of M. truncatula JA17 from the pathogen. The inoculation of P. medicaginis caused complete root and stem rotting, and the mortality of all treated plantlets. Inoculation of the antagonist S. meliloti strain 10.16/R6 to M. truncatula JA17 infected with P. medicaginis was associated with a significant 65% decrease of vegetative rotting length, an 80% decrease of plant mortality, an increase of root length, and enhancement of root and shoot biomass comparatively to control plantlets treated with P. medicaginis. The inoculation of the non antagonistic S. meliloti strain 5M6 slightly decreased disease and slightly increased plant growth parameters.

  11. Antagonismo direto e biocontrole da podridão-mole-do-tomateiro pelo uso de procariotas Direct antagonism and biocontrol of tomato soft rot using prokaryotes

    Directory of Open Access Journals (Sweden)

    Victor Rafael Barra

    2009-03-01

    Full Text Available O objetivo deste trabalho foi avaliar procariotas quanto ao potencial de antagonismo direto para o biocontrole da podridão-mole-do-tomateiro (Pectobacterium carotovorum subsp. carotovorum. Avaliaram-se 45 isolados bacterianos pelo teste de antibiose contra o patógeno. Foram feitos dois ensaios em que sementes de tomate (Lycopersicon esculentum Mill. cv. Santa Clara foram infectadas com isolados antagônicos. As mudas foram transplantadas para solos infestados com suspensões de propágulos P. carotovorum com OD540 de 0,45 e 0,65. Os antagonistas UFV-0005, UFV-043, UFV-BF112 e UFV-0006 foram eficientes em proteger plantas de tomateiro contra a podridão-mole.This work aimed to evaluate prokaryotes to provide direct antagonism and biocontrol of tomato soft rot (Pectobacterium carotovorum subsp. carotovorum. Forty-five bacterial isolates previously selected for biological control of several tomato (Lycopersicon esculentum Mill. diseases were evaluated using an antibiosis test. 'Santa Clara' tomato seeds were inoculated with potential antagonist isolates and transplanted to a soil infested with the pathogen, in two asseys, at a propagule concentration of OD540 0.45 and 0.65. Antagonists UFV-0005, UFV-043, UFV-BF112, and UFV-0006 protected tomato plants against soft rot disease.

  12. Marine Isolates of Trichoderma spp. as Potential Halotolerant Agents of Biological Control for Arid-Zone Agriculture ▿ †

    Science.gov (United States)

    Gal-Hemed, Inbal; Atanasova, Lea; Komon-Zelazowska, Monika; Druzhinina, Irina S.; Viterbo, Ada; Yarden, Oded

    2011-01-01

    The scarcity of fresh water in the Mediterranean region necessitates the search for halotolerant agents of biological control of plant diseases that can be applied in arid-zone agriculture irrigated with saline water. Among 29 Trichoderma strains previously isolated from Mediterranean Psammocinia sp. sponges, the greatest number of isolates belong to the Trichoderma longibrachiatum-Hypocrea orientalis species pair (9), H. atroviridis/T. atroviride (9), and T. harzianum species complex (7), all of which are known for high mycoparasitic potential. In addition, one isolate of T. asperelloides and two putative new species, Trichoderma sp. O.Y. 14707 and O.Y. 2407, from Longibrachiatum and Strictipilosa clades, respectively, have been identified. In vitro salinity assays showed that the ability to tolerate increasing osmotic pressure (halotolerance) is a strain- or clade-specific property rather than a feature of a species. Only a few isolates were found to be sensitive to increased salinity, while others either were halotolerant or even demonstrated improved growth in increasingly saline conditions. In vitro antibiosis assays revealed strong antagonistic activity toward phytopathogens due to the production of both soluble and volatile metabolites. Two marine-derived Trichoderma isolates, identified as T. atroviride and T. asperelloides, respectively, effectively reduced Rhizoctonia solani damping-off disease on beans and also induced defense responses in cucumber seedlings against Pseudomonas syringae pv. lachrimans. This is the first inclusive evaluation of marine fungi as potential biocontrol agents. PMID:21666030

  13. Khamir Antagonis untuk Pengendalian Penyakit Antraknosa pada Buah Avokad Selama Penyimpanan

    Directory of Open Access Journals (Sweden)

    Yuli Fitriati

    2014-08-01

    Full Text Available Anthracnose caused by Colletotrichum gloeosporioides is an important disease in avocado fruit during storage. An effective, cheap, and safe control method is necessary as an alternative to subtitute the use of fungicides in postharvest disease control. This research aimed to identify yeast antagonist from avocados that are effective in controlling anthracnose disease on avocado fruit. Research was started with isolation of C. gloeosporioides and yeast from avocado fruit, followed by in vivo bioassay, antibiosis assay, and chitinolitic activity assay. In vivo bioassay was done by dipping avocado fruit on yeast cell suspension. As many as 23 yeasts isolates was obtained from avocado fruits. Eight yeast isolates (A28, A32, A33, A34, A35, A36, A37, A38 showed very effective for inhibiting anthracnose disease in avocado fruit at concentration of 106 mL-1 and 107 mL-1. However, only four isolates were chosen for further characterization based on morphological and molecular identification. Two species of yeast was identified as Pichia anomala, i.e. isolates A33 and A37 and Candida intermedia, i.e. isolates A35 and A36.

  14. Performance of Bemisia tabaci Biotype B on Soybean Genotypes.

    Science.gov (United States)

    Cruz, P L; Baldin, E L L

    2017-04-01

    Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) has been recognized as an important pest of many agricultural systems including soybean [Glycine max (L.) Merrill] crops. As an alternative to chemical control, the use of resistant genotypes represents an important tool for integrated pest management (IPM). This study aimed to evaluate the biological development of Bemisia tabaci biotype B confined on 13 soybean genotypes under greenhouse conditions. Initially, the nymphal period, complete development period (egg-adult), and the viability of the silverleaf whitefly nymphs were evaluated in all genotypes. Then, four genotypes promising for resistance ('Jackson,' UX-2569-159, 'P98Y11,' and 'TMG132 RR') and a susceptible genotype (PI-227687) were selected for further assays, where two insect populations were compared: a first population from the initial rearing (cabbage plants) and another corresponding to insects previously reared out on the selected genotypes. In addition to the parameters evaluated in preliminary tests, we also determined the viability and incubation period of eggs. Moderate levels of resistance (antibiosis/antixenosis) to B. tabaci biotype B were found in three genotypes. 'P98Y11' and 'TMG132 RR' were less suitable for insect development, extending the development cycle, and UX-2569-159 caused high nymphal mortality. We did not observe a significant increase in the level of plant resistance by the use of previously stressed insects. This suggests that the evaluation of a single whitefly generation may be sufficient to make correct decisions on promising soybean genotypes.

  15. Morphological, Physiological, and Taxonomic Characterization of Actinobacterial Isolates Living as Endophytes of Cacao Pods and Cacao Seeds.

    Science.gov (United States)

    Tchinda, Romaric Armel Mouafo; Boudjeko, Thaddée; Simao-Beaunoir, Anne-Marie; Lerat, Sylvain; Tsala, Éric; Monga, Ernest; Beaulieu, Carole

    2016-01-01

    Vascular plants are commonly colonized by endophytic actinobacteria. However, very little is known about the relationship between these microorganisms and cacao fruits. In order to determine the physiological and taxonomic relationships between the members of this community, actinobacteria were isolated from cacao fruits and seeds. Among the 49 isolates recovered, 11 morphologically distinct isolates were selected for further characterization. Sequencing of the 16S rRNA gene allowed the partition of the selected isolates into three phylogenetic clades. Most of the selected endophytic isolates belonged to the Streptomyces violaceusniger clade. Physiological characterization was carried out and a similarity index was used to cluster the isolates. However, clustering based on physiological properties did not match phylogenetic lineages. Isolates were also characterized for traits commonly associated with plant growth-promoting bacteria, including antibiosis and auxin biosynthesis. All isolates exhibited resistance to geldanamycin, whereas only two isolates were shown to produce this antibiotic. Endophytes were inoculated on radish seedlings and most isolates were found to possess plant growth-promoting abilities. These endophytic actinobacteria inhibited the growth of various plant pathogenic fungi and/or bacteria. The present study showed that S. violaceusniger clade members represent a significant part of the actinobacterial community living as endophytes in cacao fruits and seeds. While several members of this clade are known to be geldanamycin producers and efficient biocontrol agents of plant diseases, we herein established the endophytic lifestyle of some of these microorganisms, demonstrating their potential as plant health agents.

  16. Bacterial selection for biological control of plant disease: criterion determination and validation

    Directory of Open Access Journals (Sweden)

    Monalize Salete Mota

    Full Text Available Abstract This study aimed to evaluate the biocontrol potential of bacteria isolated from different plant species and soils. The production of compounds related to phytopathogen biocontrol and/or promotion of plant growth in bacterial isolates was evaluated by measuring the production of antimicrobial compounds (ammonia and antibiosis and hydrolytic enzymes (amylases, lipases, proteases, and chitinases and phosphate solubilization. Of the 1219 bacterial isolates, 92% produced one or more of the eight compounds evaluated, but only 1% of the isolates produced all the compounds. Proteolytic activity was most frequently observed among the bacterial isolates. Among the compounds which often determine the success of biocontrol, 43% produced compounds which inhibit mycelial growth of Monilinia fructicola, but only 11% hydrolyzed chitin. Bacteria from different plant species (rhizosphere or phylloplane exhibited differences in the ability to produce the compounds evaluated. Most bacterial isolates with biocontrol potential were isolated from rhizospheric soil. The most efficient bacteria (producing at least five compounds related to phytopathogen biocontrol and/or plant growth, 86 in total, were evaluated for their biocontrol potential by observing their ability to kill juvenile Mesocriconema xenoplax. Thus, we clearly observed that bacteria that produced more compounds related to phytopathogen biocontrol and/or plant growth had a higher efficacy for nematode biocontrol, which validated the selection strategy used.

  17. Cepas nativas del bacterioneuston marino y su actividad inhibitoria de bacterias ictiopatógenas

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    Jorge León

    2014-06-01

    Full Text Available En la literatura científica, las bacterias marinas han sido consideradas con frecuencia como productores de sustancias antibacterianas. En este estudio, se investigó el potencial de actividad antibiótica in vitro de cepas nativas de bacterioneuston marino aisladas de las pozas intermareales de Montemar, Bahía de Valparaiso, Chile. Se aislaron 71 cepas neustónicas antagonistas a Staphylococcus aureus ATCC 11632. Veinticinco de ellas, productoras de sustancias fuertemente inhibitorias, fueron evaluadas por su antagonismo frente a una colección de 15 bacterias ictiopatógenas. Aplicando métodos clásicos para bacterias marinas, se caracterizaron fenotípicamente orientados a la identificación. Los resultados de antibiosis indican que la totalidad cle las ictiopatógenas en prueba son susceptibles a la actividad inhibitoria de las cepas neustónicas, siendo V anguillarum NCMB 2133, V ordalii 84/2559 y V tubiashii EX1 las más sensibles. Entre las cepas aisladas del neuston se identificaron miembros de los géneros Vibrio spp. (28%, Flavobacterium spp. (12%, Alteromonas-Marinomonas (12%, Pseudomonas spp (8% y Micrococcus spp, (4%. Nueve cepas (36% no fueron identificadas. Los resultados de actividades inhibitorias frente a ictiopatógenos sugieren que dichas cepas o sus productos pudieran ser útiles en actividades de cultivos intensivos de maricultura de peces, moluscos y crustáceos.

  18. Selection of endophytic fungi from comfrey (Symphytum officinale L.) for in vitro biological control of the phytopathogen Sclerotinia sclerotiorum (Lib.).

    Science.gov (United States)

    Rocha, Rafaeli; da Luz, Daniela Eleutério; Engels, Cibelle; Pileggi, Sônia Alvim Veiga; de Souza Jaccoud Filho, David; Matiello, Rodrigo Rodrigues; Pileggi, Marcos

    2009-01-01

    Biological control consists of using one organism to attack another that may cause economic damage to crops. Integrated Pest Management (IPM) is a very common strategy. The white mold produced by Sclerotinia sclerotiorum (Lib.) causes considerable damage to bean crops. This fungus is a soil inhabitant, the symptoms of which are characterized by water-soaked lesions covered by a white cottony fungal growth on the soil surface and/or the host plant. Possible biological control agents taken from plants are being investigated as phytopathogen inhibitors. These are endophytic microorganisms that inhabit the intercellular spaces of vegetal tissues and are often responsible for antimicrobial production. The objective of the present study was to select endophytic fungi isolated from comfrey (Symphytum officinale L.) leaves with in vitro antagonist potential against the phytopathogenic fungus S. sclerotiorum. Twelve isolates of endophytic fungi and a pathogenic strain of S. sclerotiorum were used in the challenge method. With the aid of this method, four endophytes with the best antagonistic activity against S. sclerotiorum were selected. Pathogen growth inhibition zones were considered indicative of antibiosis. The percentages of pathogenic mycelia growth were measured both with and without the antagonist, resulting in growth reductions of 46.7% to 50.0% for S. sclerotiorum. These analyses were performed by evaluating the endophytic/pathogenic mycelia growth in mm/day over an eight-day period of antagonistic tests.

  19. Compatibilidad de Trichoderma harzianum Rifai con fungicidas del arroz y su efecto sobre tres fitopatógenos fúngicos

    Directory of Open Access Journals (Sweden)

    Manuel Francisco Rodríguez Saldaña

    2016-04-01

    Full Text Available Resumen La investigación se realizó en el Laboratorio Provincial de Sanidad Vegetal en Camagüey, en la etapa comprendida de septiembre de 2013 a septiembre de 2015, en condiciones in vitro donde se determinó la compatibilidad y capacidad antagónica frente a pesticidas usados en el arroz, de Trichoderma harzianum Rifai cepa A-34 sobre los patógenos del arroz (Bipolaris oryzae Breda de Haan, Saracladium oryzae (Sawada w. Gams & D.Hawksworth y Magnaporthe grisea (Hebert Barr. Las evaluaciones mediante métodos tradicionales de aislamiento microbiológico del crecimiento micelial, la esporulación y la germinación conidial del antagonista para determinar si ejerce los mecanismos de acción de antibiosis, competencia, y parasitismo ante los patógenos fúngicos se efectuaron a partir desde las 24 hasta las 216 horas empleando. Para el análisis estadístico se empleó un diseño bifactorial en el cultivo dual, además de las escalas para la determinación de la capacidad antagónica de los microorganismos. Los ingredientes activos tebuconazol + procloraz, trifloxistrobin+ ciproconazol, y epoxiconazol + kresoxim- metil, afectaron el crecimiento micelial del antagonista, por otra parte el antagonista frente a los ingredientes activos carbendazim, oxicloruro de cobre, azoxistrobina y tebuconazol + triadimenol tuvo crecimiento micelial, esporulación e interacción con los patógenos afectándose el crecimiento de los mismos a través de los mecanismos de acción de enrollamiento, penetración, granulación , y lisis celular desde las 96 hasta las 216 horas. Trichoderma harzianum Rifai compatibility with fungicides and its effect on three fungal plant rice pathogens. ABSTRACT The research was conducted at the Provincial Laboratory of Plant Protection in Camagüey, in the fall period September 2013 to September 2015, under in vitro conditions where compatibility and antagonistic capacity was determined against used in rice pesticides, Trichoderma

  20. Evaluation of onion cultivars for resistance to onion thrips (Thysanoptera: Thripidae) and Iris yellow spot virus.

    Science.gov (United States)

    Diaz-Montano, John; Fuchs, Marc; Nault, Brian A; Shelton, Anthony M

    2010-06-01

    Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), a worldwide pest of onion, Allium cepa L., can reduce onion yield by > 50% and be even more problematic when it transmits Iris yellow spot virus (family Bunyaviridae, genus Tospovirus, IYSV). Because T. tabaci is difficult to control with insecticides and other strategies, field studies on onion, Allium cepa L., resistance to T. tabaci and IYSV were conducted in 2007 and 2008 in two locations in New York state. Forty-nine cultivars were evaluated for resistance by counting the number of larvae weekly and recording leaf damage. In another experiment, the impact of T. tabaci and IYSV on plant growth and yield was examined by spraying half of the plants with an insecticide. Eleven of the 49 cultivars had very little leaf damage and were considered resistant to T. tabaci. Visual assessment indicated that all resistant cultivars had yellow-green- colored foliage, whereas the other 38 had blue-green- colored foliage. The visual assessment of color agreed with data on color taken with a HunterLab Ultra Scan XE colorimeter. The onions 'Colorado 6' and 'NMSU 03-52-1' had the lowest numbers of T. tabaci, suggesting strong antibiosis and/or antixenosis. The other nine cultivars had variable numbers of T. tabaci, indicating a possible combination of categories of resistance. In the nonprotected treatments there were significant reductions in plant height and plant weight in most of the resistant cultivars, but there were reductions in bulb weight only in a few of them. The average of plants infected with IYSV was 10% in 2007 and 60% in 2008. Our findings indicate potential for developing onion resistance to T. tabaci as part of an overall integrated pest management strategy but suggest difficulties in identifying resistance to IYSV.

  1. The microbe-free plant: fact or artefact?

    Directory of Open Access Journals (Sweden)

    Laila P. Pamela Partida-Martinez

    2011-12-01

    Full Text Available Plant-microbe interactions are ubiquitous. Plants are often colonized by pathogens but even more commonly engaged in neutral or mutualistic interactions with microbes: below-ground microbial plant associates are mycorrhizal fungi, Rhizobia and rhizosphere bacteria, above-ground plant parts are colonized by bacterial and fungal endophytes and by microbes in the phyllosphere. We emphasize here that a completely microbe-free plant is an exotic exception rather than the biologically relevant rule. The complex interplay of such microbial communities with the host plant affects plant nutrition, growth rate, resistance to biotic and abiotic stress, and plant survival and distribution. The mechanisms involved reach from nutrient acquisition, the production of plant hormones or direct antibiosis to effects on host resistance genes or interactions at higher trophic levels. Plant-associated microbes are heterotrophic and cause costs to their host plant, whereas the benefits depend on the environment. Thus, the outcome of the interaction is highly context-dependent. Considering the microbe-free plant as the ‘normal’ or control stage significantly impairs research into important phenomena such as (1 phenotypic and epigenetic plasticity, (2 the ‘normal’ ecological outcome of a given interaction and (3 the evolution of plants. For the future, we suggest cultivation-independent screening methods using direct PCR from plant tissue of more than one fungal and bacterial gene to collect data on the true microbial diversity in wild plants. The patterns found could be correlated to host species and environmental conditions, in order to formulate testable hypotheses on the biological roles of plant endophytes in nature. Experimental approaches should compare different host-endophyte combinations under various environmental conditions and study at the genetic, transcriptional and physiological level the parameters that shift the interaction along the mutualism

  2. Endophytic fungal communities of Polygonum acuminatum and Aeschynomene fluminensis are influenced by soil mercury contamination

    Science.gov (United States)

    Mello, Ivani Souza; Vendruscullo, Suzana Junges; da Silva, Gilvan Ferreira; da Cunha, Cátia Nunes; White, James Francis

    2017-01-01

    The endophytic fungal communities of Polygonum acuminatum and Aeschynomene fluminensis were examined with respect to soil mercury (Hg) contamination. Plants were collected in places with and without Hg+2 for isolation and identification of their endophytic root fungi. We evaluated frequency of colonization, number of isolates and richness, indices of diversity and similarity, functional traits (hydrolytic enzymes, siderophores, indoleacetic acid, antibiosis and metal tolerance) and growth promotion of Aeschynomene fluminensis inoculated with endophytic fungi on soil with mercury. The frequency of colonization, structure and community function, as well as the abundant distribution of taxa of endophytic fungi were influenced by mercury contamination, with higher endophytic fungi in hosts in soil with mercury. The presence or absence of mercury in the soil changes the profile of the functional characteristics of the endophytic fungal community. On the other hand, tolerance of lineages to multiple metals is not associated with contamination. A. fluminensis depends on its endophytic fungi, since plants free of endophytic fungi grew less than expected due to mercury toxicity. In contrast plants containing certain endophytic fungi showed good growth in soil containing mercury, even exceeding growth of plants cultivated in soil without mercury. The data obtained confirm the hypothesis that soil contamination by mercury alters community structure of root endophytic fungi in terms of composition, abundance and species richness. The inoculation of A. fluminensis with certain strains of stress tolerant endophytic fungi contribute to colonization and establishment of the host and may be used in processes that aim to improve phytoremediation of soils with toxic concentrations of mercury. PMID:28742846

  3. Thiamine treatments alleviate aphid infestations in barley and pea.

    Science.gov (United States)

    Hamada, Afaf M; Jonsson, Lisbeth M V

    2013-10-01

    Treatment of plants with thiamine (Vitamin B1) has before been shown to activate plant defence against microorganisms. Here, we have studied the effects of thiamine treatments of plants on aphid reproduction and behaviour. The work was mainly carried out with bird cherry-oat aphid (Rhopalosiphum padi L.) on barley (Hordeum vulgare L.). Aphid population growth and aphid acceptance on plants grown from seeds soaked in a 150μM thiamine solution were reduced to ca. 60% of that on control plants. R. padi life span and the total number of offspring were reduced on barley plants treated with thiamine. Healthy aphids and aphids infected with the R. padi virus were similarly affected. Spraying or addition of thiamine at 150μM to nutrient solutions likewise resulted in reduced aphid population growth to ca. 60%, as did plant exposure to thiamine odour at 4mM. Thiamine treatments resulted in reduced aphid population growth also when tested with grain aphid (Sitobion avenae F.) on barley and pea aphid (Acyrthosiphon pisum H.) on pea (Pisum sativum L.). There was no direct effect of thiamine on aphid reproduction or thiamine odour on aphid behaviour, as evaluated using artificial diets and by olfactometer tests, respectively. Two gene sequences regulated by salicylic acid showed higher transcript abundance and one gene sequence regulated by methyl jasmonate showed lower transcript abundance in thiamine-treated plants but not in control plants after aphid infestation. These results suggest that the aphid antibiosis and antixenosis effects may be related to priming of defence, but more studies are needed to explain the effects against aphids. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Functional role of bacteria from invasive Phragmites australis in promotion of host growth

    Science.gov (United States)

    Soares, M. A.; Li, H-Y; Kowalski, Kurt P.; Bergen, M.; Torres, M. S.; White, J. F.

    2016-01-01

    We hypothesize that bacterial endophytes may enhance the competitiveness and invasiveness of Phragmites australis. To evaluate this hypothesis, endophytic bacteria were isolated from P. australis. The majority of the shoot meristem isolates represent species from phyla Firmicutes, Proteobacteria, and Actinobacteria. We chose one species from each phylum to characterize further and to conduct growth promotion experiments in Phragmites. Bacteria tested include Bacillus amyloliquefaciens A9a, Achromobacter spanius B1, and Microbacterium oxydans B2. Isolates were characterized for known growth promotional traits, including indole acetic acid (IAA) production, secretion of hydrolytic enzymes, phosphate solubilization, and antibiosis activity. Potentially defensive antimicrobial lipopeptides were assayed for through application of co-culturing experiments and mass spectrometer analysis. B. amyloliquefaciens A9a and M. oxydans B2 produced IAA. B. amyloliquefaciens A9a secreted antifungal lipopeptides. Capability to promote growth of P. australis under low nitrogen conditions was evaluated in greenhouse experiments. All three isolates were found to increase the growth of P. australis under low soil nitrogen conditions and showed increased absorption of isotopic nitrogen into plants. This suggests that the Phragmites microbes we evaluated most likely promote growth of Phragmites by enhanced scavenging of nitrogenous compounds from the rhizosphere and transfer to host roots. Collectively, our results support the hypothesis that endophytic bacteria play a role in enhancing growth of P. australis in natural populations. Gaining a better understanding of the precise contributions and mechanisms of endophytes in enabling P. australis to develop high densities rapidly could lead to new symbiosis-based strategies for management and control of the host.

  5. A retrospective study of 113 consecutive cases of surgically treated spondylodiscitis patients. A single-center experience.

    Science.gov (United States)

    Shiban, Ehab; Janssen, Insa; Wostrack, Maria; Krieg, Sandro M; Ringel, Florian; Meyer, Bernhard; Stoffel, Michael

    2014-06-01

    Recommendations for the operative treatment of spondylodiscitis are still a controversial issue. A retrospective review identified 113 consecutive patients who underwent surgical debridement and instrumentation for spondylodiscitis between 2006 and 2010 at our department. The mean age at presentation was 65 years; 78 patients were male (69 %). Distribution of the inflammation was lumbar in 68 (60 %), thoracic in 19 (17 %) and cervical in 20 (18 %) cases. Six patients (5 %) had two concomitant non-contiguous spondylodiscitis foci in different segments of the spine. Epidural abscess was found in 33 patients (29 %). One hundred four patients (92 %) had pain. Neurological deficit was found in 40 patients (35 %). In the thoracic and lumbar cases, dorsal instrumentation alone was considered sufficient in 26 cases; additional interbody fusion from the posterior was performed in 44 cases. A 360° instrumentation was performed in 22 cases. In the cervical cases, only ventral spondylodesis and plating were performed in eight cases, only dorsal instrumentation in five and 360° instrumentation in seven. Postoperative intravenous antibiotics were administered for 14.4 ± 9.3 (mean ± SD) days followed by 3.2 ± 0.8 (mean ± SD) months of oral antibiosis. Complete healing of the inflammation was achieved in 111 (98 %) cases. Two patients died because of septic shock, both with fulminant endocarditis. Pain resolved in all cases. Neurological deficits were completely resolved in 20 patients, and 14 patients had a partial recovery. The results of our retrospective study show that surgical treatment of spondylodiscitis with a staged surgical approach (if needed) and a short 1-2-week period of intravenous antibiotics followed by 3 months of oral antibiotics is appropriate for most patients in whom conservative treatment has failed or is not advisable. Furthermore, surgical treatment of newly diagnosed spondylodiscitis might be recommended as an initial treatment option in

  6. Effect of plant development (age and size) on the Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci.

    Science.gov (United States)

    Rodríguez-Álvarez, C I; Muñiz, M; Nombela, G

    2017-12-01

    Whitefly, Bemisia tabaci, is one of the most important pests of tomato, Solanum lycopersicum L. The Mi-1 gene mediates tomato resistance to the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) species of B. tabaci, three species of root-knot nematodes, Meloidogyne spp., and the potato aphid, Macrosiphum euphorbiae. Tomato seedlings bearing the Mi-1 gene are resistant to nematodes soon after germination but resistance to aphids is developmentally regulated; a reliable conclusion about Mi-1 resistance to B. tabaci was not available to date. In the present work, 3-, 5- and 8-week-old plants of the tomato cultivars Motelle and Moneymaker (bearing and lacking the Mi-1 gene, respectively) were simultaneously tested under free-choice (antixenosis) and no-choice (antibiosis) conditions, to assess the real influence of plant age on the Mi-1-mediated resistance to the MED species of B. tabaci. Subsequently, plants of the same age but with different level of development were compared to check whether the plant size can also affect this tomato resistance. Obtained results demonstrated that Mi-1-mediated resistance to B. tabaci is developmentally regulated, as variations in the age of bearing-Mi-1 plants affects most infestation parameters tested. Differences between cultivars with and without the Mi-1 gene were significant for 8- but not for 3-week-old plants. For 5-week-old plants, differences between cultivars were less pronounced than in older plants, expressing an intermediate level of resistance in Motelle. Plant size also influenced whitefly infestation and reproductive activity on the resistant cultivar. However, plant age has more impact than plant size on the Mi-1-mediated resistance of tomato to B. tabaci.

  7. Comparison of the neurotoxicities between volatile organic compounds and fragrant organic compounds on human neuroblastoma SK-N-SH cells and primary cultured rat neurons

    Directory of Open Access Journals (Sweden)

    Yasue Yamada

    2015-01-01

    Full Text Available These are many volatile organic compounds (VOCs that are synthesized, produced from petroleum or derived from natural compounds, mostly plants. Fragrant and volatile organic compounds from plants have been used as food additives, medicines and aromatherapy. Several clinical and pathological studies have shown that chronic abuse of VOCs, mainly toluene, causes several neuropsychiatric disorders. Little is known about the mechanisms of neurotoxicity of the solvents. n-Octanal, nonanal, and 2-ethyl-1-hexanol, which are used catalyzers or intermediates of chemical reactions, are released into the environment. Essential oils have the functions of self-defense, sterilization, and antibiosis in plants. When volatile organic compounds enter the body, there is the possibility that they will pass through the blood–brain barrier (BBB and affect the central nervous system (CNS. However, the direct effects of volatile organic compounds on neural function and their toxicities are still unclear. We compared the toxicities of n-octanal, nonanal and 2-ethyl-1-hexanol with those of five naturally derived fragrant organic compounds (FOCs, linalool, cis-3-hexen-1-ol, isoamyl alcohol, n-propyl alcohol and n-phenethyl alcohol. MTT assay of human neuroblastoma SK-N-SH cells showed that the IC50 values of linalool, cis-3-hexen-1-ol, isoamyl alcohol, n-propyl alcohol and phenethyl alcohol were 1.33, 2.3, >5, >5, and 2.39 mM, respectively, and the IC50 values of toluene, n-octanal, nonanal and 2-ethyl-1-hexanol were 850, 37.2, 8.31 and 15.1 μM, respectively. FOCs showed lower toxicities than those of VOCs. These results indicate that FOCs are safer than other compounds.

  8. Modelling response patterns of physico-chemical indicators during high-rate composting of green waste for suppression of Pythium ultimum.

    Science.gov (United States)

    St Martin, Chaney C G; Bekele, Isaac; Eudoxie, Gaius D; Bristol, Dexter; Brathwaite, Richard A I; Campo, Kenia-Rosa

    2014-01-01

    High-rate composting studies on green waste, i.e. banana leaves (BL) and lawn clippings (LC), were conducted in 0.25-m3 rotary barrel composters to evaluate and model changes in key physico-chemical parameters during composting. Time to compost maturity and antagonistic effects and relationships of composts against Pythium ultimum were also investigated. Higher temperatures were achieved in LC compost (LCC), which did not translate to higher total organic carbon (TOC) loss but resulted in lower carbon to nitrogen ratio (C:N) and a more mature compost. With the exception of electrical conductivity (EC), net decreases were observed in pH, TOC and C:N across compost types. Total Kjeldahl nitrogen (TKN) showed a net increase in LCC and a net decrease in BLC. With the exception of TOC and pH, the results showed that compost type and time had a significant effect on the respective TKN, EC and C:N models. Compost temperature and TOC were best described by the critical exponential and rectangular hyperbola functions, respectively. Whereas TKN, C:N and pH were described using double Fourier functions and EC using Fourier functions. Composts achieved maturity within 19 days and significantly inhibited the growth of P. ultimum. Bacterial population was positively related to growth inhibition (GI) across compost types, whereas total microbial population had a positive relationship with GI in LCC. Evidence suggests that multiple groups of microorganisms contributed to GI through antibiosis and competition for resources. Composts were determined to be suitable for use as components of plant growth substrates based on compost maturity indices.

  9. Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid1[OPEN

    Science.gov (United States)

    Louis, Joe; Basu, Saumik; Varsani, Suresh; Castano-Duque, Lina; Jiang, Victoria; Williams, W. Paul; Felton, Gary W.; Luthe, Dawn S.

    2015-01-01

    Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. Previously, it was reported that the synergistic combination of ethylene (ET) and jasmonic acid (JA) was required for accumulation of the maize insect resistance1 (mir1) gene product, a cysteine (Cys) proteinase that is a key defensive protein against chewing insect pests in maize (Zea mays). However, this study suggests that mir1-mediated resistance to corn leaf aphid (CLA; Rhopalosiphum maidis), a phloem sap-sucking insect pest, is independent of JA but regulated by the ET-signaling pathway. Feeding by CLA triggers the rapid accumulation of mir1 transcripts in the resistant maize genotype, Mp708. Furthermore, Mp708 provided elevated levels of antibiosis (limits aphid population)- and antixenosis (deters aphid settling)-mediated resistance to CLA compared with B73 and Tx601 maize susceptible inbred lines. Synthetic diet aphid feeding trial bioassays with recombinant Mir1-Cys Protease demonstrates that Mir1-Cys Protease provides direct toxicity to CLA. Furthermore, foliar feeding by CLA rapidly sends defensive signal(s) to the roots that trigger belowground accumulation of the mir1, signifying a potential role of long-distance signaling in maize defense against the phloem-feeding insects. Collectively, our data indicate that ET-regulated mir1 transcript accumulation, uncoupled from JA, contributed to heightened resistance to CLA in maize. In addition, our results underscore the significance of ET acting as a central node in regulating mir1 expression to different feeding guilds of insect herbivores. PMID:26253737

  10. EKSPLORASI DAN UJI SENYAWA BIOAKTIF BAKTERI AGENSIA HAYATI UNTUK PENGENDALIAN PENYAKIT KRESEK PADA PADI

    Directory of Open Access Journals (Sweden)

    Sri Kurniawati

    2016-03-01

    Full Text Available Exploration of bacterial biocontrol agent and its potential bioactive compound to control rice bacterial leaf blight. The research aims were to obtain bacterial isolates which were potential as biological control agent of X. oryzae pv. oryzae, the causal agent of rice bacterial blight and to assess the effectiveness of their bioactive compounds, and to identify of the potential isolates. The research steps included bacterial isolation, screening based on antibiosis activity and pathogenicity test, characterization based on chitinolytic enzyme production, siderophores, and phosphate dissolution test, effectiveness test of bioactive compounds and molecular identification of potential isolates. Out of 156 bacterial isolates from rice crop tested, 11 isolates showed to be non plant pathogenic and to have activity as biological agents against X. oryzae pv. oryzae pathotype III, IV and VIII. Further characterization of 11 isolates resulted in 2 isolates that showrd ability to produce chitinase (isolates T5-1118 and R7-1018, phosphatase (isolates T5-1105 and T6-1109, and siderophores (isolates T5-1118 and T6- 1109. The test of bioactive compound effectiveness of 4 isolates to the growth of X. oryzae pv. oryzae showed thatT5-1118, T5-1105, T6-1109 and R7-1018 have ability to inhibit X. oryzae pv. oryzae at 48 hours after inoculation of 66,61%, 62,4%, 23,97% and 12,40%, respectively. Identification of 4 bacterial biocontrol isolates with partial sequencing of 16S rRNA gene showed that those bacteria are close to Bacillus nealsonii strain F22 (R7-1018, Chromobacterium sp. MWU328 (T5-1118, Streptomyces sp. Antag 1 (T5-1105 and Kitasatospora nipponensis strains H2-4 (T6-1109.

  11. The Microbe-Free Plant: Fact or Artifact?

    Science.gov (United States)

    Partida-Martínez, Laila P.; Heil, Martin

    2011-01-01

    Plant–microbe interactions are ubiquitous. Plants are threatened by pathogens, but they are even more commonly engaged in neutral or mutualistic interactions with microbes: belowground microbial plant associates are mycorrhizal fungi, Rhizobia, and plant-growth promoting rhizosphere bacteria, aboveground plant parts are colonized by internally living bacteria and fungi (endophytes) and by microbes in the phyllosphere (epiphytes). We emphasize here that a completely microbe-free plant is an exotic exception rather than the biologically relevant rule. The complex interplay of such microbial communities with the host–plant affects multiple vital parameters such as plant nutrition, growth rate, resistance to biotic and abiotic stressors, and plant survival and distribution. The mechanisms involved reach from direct ones such as nutrient acquisition, the production of plant hormones, or direct antibiosis, to indirect ones that are mediated by effects on host resistance genes or via interactions at higher trophic levels. Plant-associated microbes are heterotrophic and cause costs to their host plant, whereas the benefits depend on the current environment. Thus, the outcome of the interaction for the plant host is highly context dependent. We argue that considering the microbe-free plant as the “normal” or control stage significantly impairs research into important phenomena such as (1) phenotypic and epigenetic plasticity, (2) the “normal” ecological outcome of a given interaction, and (3) the evolution of plants. For the future, we suggest cultivation-independent screening methods using direct PCR from plant tissue of more than one fungal and bacterial gene to collect data on the true microbial diversity in wild plants. The patterns found could be correlated to host species and environmental conditions, in order to formulate testable hypotheses on the biological roles of plant endophytes in nature. Experimental approaches should compare different host

  12. Cementless two-staged total hip arthroplasty with a short term interval period for chronic deep periprosthetic infection. Technique and long-term results.

    Science.gov (United States)

    Erhart, Jochen; Jaklitsch, Karl; Schurz, Mark; Vécsei, Vilmos; Ehall, Reinhard

    2010-05-01

    The two-staged exchange with delayed reimplantation is the most reliable method to treat a deep periprosthetic infection after a total hip arthroplasty (THR). Nether uniform recommendations for the technique of cementless reimplantation, nor long term clinical and radiological results are reported. Our protocol is performed under short term antibiosis with cementless primary porous hip implants to treat chronic deep periprosthetic infections following THR. A retrospective study was performed to evaluate the clinical and radiological long term outcome and the rate of persistent infection of 14 patients. In a five year minimum follow up persistent infection was observed twice in a two-staged revision THR. A dislocation of the hip components was observed in three cases, and could be surgically treated in twice and by wearing a hip-brace in one case. We could not find a loosening of THR components. Three patients had a good or excellent, 11 patients a fair or bad functional outcome. There was a significant correlation between functional outcome and length of interval of prosthesis exand reimplantation. Patients have an increased comfort resulting from a short, CRP depending time interval between ex- and reimplantation. Functional outcome is the better the shorter the interval is. The reinfection rate is comparable to those of cemented revision THR's with a long term interval. We could observe advantages in a reduced amount of bone loss and better osseous integration of the uncemented implants, compared to cemented implants reviewing literature. Alterations of acetabular bone stock and soft tissue are responsible for a high rate of instability of the THR. An inaccurate gait pattern is caused by gluteal weakness in the majority of patients. Repeated surgical intervention and duration of immobilization have to be minimalized.

  13. Resistance of irradiated and non-irradiated corn grain genotypes against the weevil Sitophilus zeamais Mots., 1855 (Coleoptera: Curculionidae)

    International Nuclear Information System (INIS)

    Oliveira, Carolina Natali de

    2005-01-01

    The resistance of 13 /////com grain genotypes was evaluated against the attack of Sitophilus zeamais (Mots.) by means of a no-choice test; 6 of them were selected (AGN 2012, AGN 30AOO, AGN 31A31, AGN 25A23, AGN 32A43, and AGN 35A42) and then submitted to a free-choice test where attractiveness and non preference for oviposition were assessed. The grain from the selected genotypes were later treated with Cobalt-60 gamma radiation at the doses of 0.0; 0.5; 1.0; and 1.5 kGy and submitted to the same tests. Based on the results, it was verified that genotypes AGN 2012 (30.6 eggs), AGN 31A31 (33.6 eggs), and AGN 30AOO (34.8 eggs) showed a non-preference for oviposition type of resistance, while non-preference for feeding and/or antibiosis were observed in the first two genotypes only. Genotypes AGN 25A23, AGN 32A43, and AGN 35A42 were the most susceptible to com weevil. The increasing gamma radiation ( 60 Co) doses reduced the mean mass of adults in genotype AGN 2012; however, the same parameter increased in genotype AGN 35A42; when treated at the dose of 1.5 kGy, genotypes AGN 2012 and AGN 31A31 showed a reduction in their mean masses of adults, while genotypes AGN 30AOO and AGN 35A42 showed higher mean mass of adults values. The increasing gamma radiation doses ( 60 Co) provided a reduction in mean grain dry mass consumed by the weevil; however, it was concluded that irradiation did not break com grain resistance and can be used for S. zeamais disinfestation prior to storage. (author)

  14. In vitro interaction studies between Glomus intraradices and Armillaria mellea in vines

    Energy Technology Data Exchange (ETDEWEB)

    Nogales, A.; Camprubi, A.; Estaun, V.; Marfa, V.; Calvet, C.

    2010-07-01

    An interaction study was performed with mycorrhizal plants of the grapevine rootstock Richter 110 (Vitis berlandieri Planch x Vitis rupestris Scheele) and the root pathogenic fungus Armillaria mellea (Vahl:Fr.) P. Kumm using an autotrophic in vitro culture system. Micro propagated plant lets were transferred to Petri plates with MSR medium lacking sugar and vitamins. Inocula of Glomus intraradices (BEG 72) and of Armillaria mellea obtained from a root organ culture and from a mycelium colony grown in malt agar respectively, were added to the plates according to each treatment: non-inoculated, inoculated with G. intra radices, inoculated with A. mellea, and dual-inoculated plants. There were ten replicates per treatment. Fourteen weeks later, the pathogen's mycelium occupied most of the surface/volume of the plate and had produced rhizomorphs. In dual inoculated plates, A. mellea's growth was not affected by the presence of G. intraradices, but the latter produced a lower number of spores and its extra radical phase showed granulation, vacuolation and tip swelling. The pathogen induced necrosis and growth decrease in the root. Glomus intra radices alleviated these symptoms and there were no differences in root biomass between non-inoculated plants and plants inoculated with both fungi. There were no symptoms of the disease in shoots and G. intra radices stimulated shoot growth both, although mycorrhizal colonization was lower when A. mellea was present. No direct antagonism or antibiosis against the pathogen was observed, thus the protective effect exerted by the symbiotic fungus in grapevines must be indirect, mediated through the host plant physiology. (Author) 38 refs.

  15. From pattern to process: species and functional diversity in fungal endophytes of Abies beshanzuensis.

    Science.gov (United States)

    Yuan, Zhi-Lin; Rao, Long-Bing; Chen, Yi-Cun; Zhang, Chu-Long; Wu, You-Gui

    2011-03-01

    The biodiversity-functional relationship in fungal ecology was recently developed and debated, but has rarely been addressed in endophytes. In this study, an integrative culture system was designed to capture a rich fungal consortium from the conifer Abies beshanzuensis. Results indicate an impressive diversity of fungal lineages (a total of 84 taxa classified in Dikarya) and a relatively high proportion of hitherto unknown species (27.4%). The laccase gene was used as a functional marker due to its involvement in lignocellulose degradation. Remarkable diversity of laccase genes was found across a wide range of taxa, with at least 35 and 19 distinct sequences in ascomycetes and basidiomycetes respectively, were revealed. Many groups displayed variable ability to decompose needles. Furthermore, many ascomycetes, including three volatile-producing Muscodor species (Xylariaceae), showed the ability to inhibit pathogens. Notably, most laccase-producing species showed little or no antibiosis and vice versa. Clavicipitalean and ustilaginomycetous fungi, specifically toxic to insects, were inferred from taxonomic information. Intra-specific physiological variation in Pezicula sporulosa, a second dominant species, was clearly high. We conclude that a suite of defensive characteristics in endophytes contributes to improving host fitness under various stresses and that a diversity of laccase genes confers an ecological advantage in competition for nutrients. Intra-specific diversity may be of great ecological significance for ecotypic adaptation. These findings suggest a fair degree of functional complementarity rather than redundancy among endemic symbionts of natural plant populations. Copyright © 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  16. Economic Injury Levels for Aphis glycines Matsumura (Hemiptera: Aphididae) on the Soybean Aphid Tolerant KS4202 Soybean.

    Science.gov (United States)

    Marchi-Werle, Lia; Baldin, Edson L L; Fischer, Hillary D; Heng-Moss, Tiffany M; Hunt, Thomas E

    2017-10-01

    The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an invasive species from Asia that has been the major economic insect pest of soybeans, Glycine max (L.) Merrill, since 2000. While use of soybeans expressing antibiosis and antixenosis is a well-studied strategy to manage this pest, aphid-tolerant soybeans remain underexplored. This study examined the relationship between cumulative aphid-days (CAD) and yield loss in the tolerant soybean KS4202 during two growing seasons to determine the economic injury levels (EILs) for soybean aphids on KS4202. Soybean aphid infestations were initiated during the soybean reproductive stages. A range of CAD treatments (3,000-45,000 CADs) were applied during the growing seasons. Aphid populations reached 45,000 CAD in 2011 and 38,000 CAD in 2013 in plots that were not treated with insecticides. It was estimated that the population doubling time was 9.4 d. In infested plots, soybean yield was reduced by 1.4-13.3%, equivalent to a 3.1% yield loss for every 10,000 CAD. Overall, most CAD treatments did not affect yield parameters, although CAD > 39,000 caused a significant reduction in most yield parameters. The EILs calculated for KS4202 ranged from 526 to 2,050 aphids/plant, which were approximately 2.5-fold higher when compared to EILs previously calculated for susceptible soybean. The adoption of soybean aphid tolerant soybean with higher EILs may help mitigate treatment delay problems by lengthening the treatment lead-time and possibly reduce the number of insecticide applications. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Desirable Traits of a Good Biocontrol Agent against Verticillium Wilt.

    Science.gov (United States)

    Deketelaere, Silke; Tyvaert, Lien; França, Soraya C; Höfte, Monica

    2017-01-01

    The soil-borne fungus Verticillium causes serious vascular disease in a wide variety of annual crops and woody perennials. Verticillium wilt is notoriously difficult to control by conventional methods, so there is great potential for biocontrol to manage this disease. In this study we aimed to review the research about Verticillium biocontrol to get a better understanding of characteristics that are desirable in a biocontrol agent (BCA) against Verticillium wilt. We only considered studies in which the BCAs were tested on plants. Most biocontrol studies were focused on plants of the Solanaceae, Malvaceae , and Brassicaceae and within these families eggplant, cotton, and oilseed rape were the most studied crops. The list of bacterial BCAs with potential against Verticillium was dominated by endophytic Bacillus and Pseudomonas isolates, while non-pathogenic xylem-colonizing Verticillium and Fusarium isolates topped the fungal list. Predominant modes of action involved in biocontrol were inhibition of primary inoculum germination, plant growth promotion, competition and induced resistance. Many BCAs showed in vitro antibiosis and mycoparasitism but these traits were not correlated with activity in vivo and there is no evidence that they play a role in planta . Good BCAs were obtained from soils suppressive to Verticillium wilt, disease suppressive composts, and healthy plants in infested fields. Desirable characteristics in a BCA against Verticillium are the ability to (1) affect the survival or germination of microsclerotia, (2) colonize the xylem and/or cortex and compete with the pathogen for nutrients and/or space, (3) induce resistance responses in the plant and/or (4) promote plant growth. Potential BCAs should be screened in conditions that resemble the field situation to increase the chance of successful use in practice. Furthermore, issues such as large scale production, formulation, preservation conditions, shelf life, and application methods should be

  18. Biocontrol Potential ofStreptomyces hydrogenansStrain DH16 towardAlternaria brassicicolato Control Damping Off and Black Leaf Spot ofRaphanus sativus.

    Science.gov (United States)

    Manhas, Rajesh K; Kaur, Talwinder

    2016-01-01

    Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola , causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v) of S. hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10%) and streptomycete cells significantly improved seed germination (75-80%) and vigor index (1167-1538). Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers.

  19. Biocontrol Potential of Streptomyces hydrogenans strain DH16 Towards Alternaria brassicicola to Control Damping Off and Black Leaf Spot of Raphanus sativus

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    Rajesh Kumari Manhas

    2016-12-01

    Full Text Available Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola, causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v of Streptomyces hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10% and streptomycete cells significantly improved seed germination (75-80% and vigour index (1167-1538. Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers.

  20. The large universal Pantoea plasmid LPP-1 plays a major role in biological and ecological diversification

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    De Maayer Pieter

    2012-11-01

    Full Text Available Abstract Background Pantoea spp. are frequently isolated from a wide range of ecological niches and have various biological roles, as plant epi- or endophytes, biocontrol agents, plant-growth promoters or as pathogens of both plant and animal hosts. This suggests that members of this genus have undergone extensive genotypic diversification. One means by which this occurs among bacteria is through the acquisition and maintenance of plasmids. Here, we have analyzed and compared the sequences of a large plasmid common to all sequenced Pantoea spp. Results and discussion The Large PantoeaPlasmids (LPP-1 of twenty strains encompassing seven different Pantoea species, including pathogens and endo-/epiphytes of a wide range of plant hosts as well as insect-associated strains, were compared. The LPP-1 plasmid sequences range in size from ~281 to 794 kb and carry between 238 and 750 protein coding sequences (CDS. A core set of 46 proteins, encompassing 2.2% of the total pan-plasmid (2,095 CDS, conserved among all LPP-1 plasmid sequences, includes those required for thiamine and pigment biosynthesis. Phylogenetic analysis reveals that these plasmids have arisen from an ancestral plasmid, which has undergone extensive diversification. Analysis of the proteins encoded on LPP-1 also showed that these plasmids contribute to a wide range of Pantoea phenotypes, including the transport and catabolism of various substrates, inorganic ion assimilation, resistance to antibiotics and heavy metals, colonization and persistence in the host and environment, pathogenesis and antibiosis. Conclusions LPP-1 is universal to all Pantoea spp. whose genomes have been sequenced to date and is derived from an ancestral plasmid. LPP-1 encodes a large array of proteins that have played a major role in the adaptation of the different Pantoea spp. to their various ecological niches and their specialization as pathogens, biocontrol agents or benign saprophytes found in many diverse

  1. Microflora en semillas de frijol

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    Jos\\u00E9 B. Membre\\u00F1o

    2001-01-01

    Full Text Available Microflora en semillas de frijol (Phaseolus vulgaris L.. Se estudió la microflora bacteriana presente en semillas de frijol y su relación con Xanthomonas campestris pv. phaseoli (Xcp, en 118 genotipos procedentes de VIDAC-98, INTA- Nicaragua, TARS-USDA e Isabela-P.R. Se utilizaron cinco métodos de aislamiento: semilla desinfectada con hipoclorito de sodio, semilla en caldo nutritivo refrigerada por una hora, dispersión de 0,1 ml de suspensión de semillas en medio sólido, siembra líquida de 1 ml de suspensión y semilla en caldo nutritivo, agitado y refrigerado por 24 horas. Se aislaron 104 colonias amarillas de 41 genotipos. Treinta y seis colonias fueron KOH positivo (Gram negativo, 68 negativo (Gram positivo y 34 hidrolizaron almidón. Las colonias de pigmentación amarilla resultaron no patogénicas bajo condiciones de invernadero. Estas se identificaron con el sistema BIOLOG como: Pantoea agglomerans (25, Xanthomonas campestris (2, Enterobacter agglomerans (2, Sphingomonas paucimobilis (2, Pseudomonas fluorescens y Flavimonas oryzihabitans. En adición, los genotipos portaron colonias con pigmentación distinta a la amarilla. En las pruebas de antagonismo se identificaron colonias con actividad de deoxyribonucleasa y de antibiosis a Xcp. De éstas, 15 colonias inhibieron a Xcp significativamente. Se identificaron los hongos Rhizoctonia solani, Penicillium spp., Fusarium spp., Aspergillus flavus, Rhizopus nigricans y Macrophomina phaseolina en un 52,9 % del total de genotipos evaluados

  2. Potensi Cendawan Endofit sebagai Pengendali Hayati Penyakit Busuk Pangkal Batang (Phytophthora capsici pada Bibit Cabai

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    Evan Purnama Ramdan

    2018-01-01

    Full Text Available Stem rot disease caused by Phytophthora capsici is an important disease on chilli. Eight endophytic fungi that had been isolated and screened based on pathogenecity test were further tested for their potential as the biological control agent of the stem rot disease of chilli. The endophytic fungi suspension was applied twice during the trial. The first application was on 100 seed lot, by soaking them in 100 mL of suspension. The second application was on the 3 weeks-old chili seedlings by drenching them with 10 mL suspension per plant. The concentration of endophytic fungi  in the suspension was 2.8 × 106 cfu mL-1. The disease intensity and AUDPC value were measured for 4 weeks after the pathogen inoculation. The growth inhibition test of P. capsici  was performed in vitro and the colonization abilities of endophytic fungi were observed at 4 weeks-old chilli seedlings. Eight endophytic fungi  inhibited the growth of the P. capsici, and two of those isolates namely Penicillium strain MAG1 and Penicillium strain PAB2 showed antibiosis mechanism. Endophytic fungi has the ability more to colonize at the root (26–60% than in the stem (20–40%. Fusarium strain MAGR1 has the highest level of endophytic colonization i.e. 60% compared to others.  Based on in vivo assay, six endophytic fungi isolates, i.e. Fusarium strain MAGR1, Penicillium strain MAG1, Penicillium strain PAB2, sterile hyphae HAJ1, sterile hyphae HAJ2, and  sterile hyphae PBG7, showed the potency to control stem rot disease with inhibition level of 25.5–35.5%

  3. Desirable Traits of a Good Biocontrol Agent against Verticillium Wilt

    Directory of Open Access Journals (Sweden)

    Silke Deketelaere

    2017-07-01

    Full Text Available The soil-borne fungus Verticillium causes serious vascular disease in a wide variety of annual crops and woody perennials. Verticillium wilt is notoriously difficult to control by conventional methods, so there is great potential for biocontrol to manage this disease. In this study we aimed to review the research about Verticillium biocontrol to get a better understanding of characteristics that are desirable in a biocontrol agent (BCA against Verticillium wilt. We only considered studies in which the BCAs were tested on plants. Most biocontrol studies were focused on plants of the Solanaceae, Malvaceae, and Brassicaceae and within these families eggplant, cotton, and oilseed rape were the most studied crops. The list of bacterial BCAs with potential against Verticillium was dominated by endophytic Bacillus and Pseudomonas isolates, while non-pathogenic xylem-colonizing Verticillium and Fusarium isolates topped the fungal list. Predominant modes of action involved in biocontrol were inhibition of primary inoculum germination, plant growth promotion, competition and induced resistance. Many BCAs showed in vitro antibiosis and mycoparasitism but these traits were not correlated with activity in vivo and there is no evidence that they play a role in planta. Good BCAs were obtained from soils suppressive to Verticillium wilt, disease suppressive composts, and healthy plants in infested fields. Desirable characteristics in a BCA against Verticillium are the ability to (1 affect the survival or germination of microsclerotia, (2 colonize the xylem and/or cortex and compete with the pathogen for nutrients and/or space, (3 induce resistance responses in the plant and/or (4 promote plant growth. Potential BCAs should be screened in conditions that resemble the field situation to increase the chance of successful use in practice. Furthermore, issues such as large scale production, formulation, preservation conditions, shelf life, and application methods

  4. Biological Control of Rhizoctonia solani AG1-1A, the Causal Agent of Rice Sheath Blight with Trichoderma Strains

    Directory of Open Access Journals (Sweden)

    Shahram NAEIMI

    2011-01-01

    Full Text Available Sheath blight caused by Rhizoctonia solani is one of the most serious rice diseases worldwide. The disease is currently managed only by the excessive application of chemical fungicides which are toxic and not environmentally friendly. Therefore, greater emphasis should be given to biological control as being both safe and effective. Trichoderma species are ubiquitous fungi in the soil and have an antagonistic activity against several soil-borne plant pathogens including R. solani. The present study was undertaken to evaluate the potential of indigenous Trichoderma strains from Mazandaran province, Northern Iran (a Mediterranean region on the southern coast of the Caspian Sea against R. solani AG1-IA  in vitro, and against sheath blight disease in the glasshouse, in order to find biocontrol isolates for application in the field. More than 200 Trichoderma strains were isolated from the soil, plant debris and the phyllosphere in rice felds. Strains were first screened for their antagonism to R. solani by in vitro antagonism tests including dual culture, antibiosis, the effect of Trichoderma strains on the production and viability of R. solani sclerotia, and hyperparasitism on microscopic slides. According to the in vitro experiments, several strains belonging to T. harzianum, T. virens and T. atroviride showed excellent biocontrol. These potential antagonist strains were further evaluated for their effectiveness in controlling sheath blight under glasshouse conditions. Among the 55 selected strains, seven significantly controlled the disease. T. harzianum AS12-2 was the most effective strain in controlling rice sheath blight, better even than propiconazole, the most commonly used fungicide in Iran.

  5. Trichoderma ROLE IN AGROFORESTRY-CACAOTAL SYSTEMS AS AN ANTAGONAL AGENT

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    Úrsula del Carmen López-Ferrer

    2017-05-01

    Full Text Available Agricultural and cocoa agroforestry systems are important for food production and biodiversity conservation. Among this diversity there is a group of fungi of the genus Trichoderma that present antagonistic effects against phytopathogens and this action can be used as a form of biological control of plant pathogens. In the agroforestry-cacao system the diseases with the highest frequency and with the greatest impact on cocoa production (Theobroma cacao are black rot (Phytophthora spp., Broom broom (Moniliophthora perniciosa and moniliasis (Moniliophthora roreri. The objective of this work was to perform an analysis of the main theoretical and practical aspects about the genus Trichoderma and its role in agriculture as an antagonistic agent. One of the microscopic features in the delimitation of the genus, especially by the presence of structures called phalid. The antagonistic mechanisms used by Trichoderma spp. Are described as competition, antibiosis and mycoparasitism. Mycoparasitism is having a relevance on the implications of extracellular enzymes such as chitinases, cellulases, β-1-3-glucanases and proteases that lyse or digest the walls of fungi, Moniliophthora roreri disease. This fungus can inhibit the growth of other fungi and bacteria by producing several volatile and non-volatile secondary metabolites. On the other hand, it participates in the production of regulators of growth and stimulation of the division, differentiation and cellular growth in the plant by the elicitor agent. Trichoderma species that are commercialized for biological control, growth promoter and biofertilizer are T. viride, T. polysporum and T. harzianum. The T. virens and T. harzianum species are most used for the antagonistic control of M. roreri, Phytophthora spp., and M. perniciosa in agroforestry-cacao systems (Theobroma cacao L. with optimal results to the inhibitory effect for these diseases.

  6. Metabolitos secundarios, letalidad y actividad antimicrobiana de los extractos de tres corales y tres moluscos marinos de Sucre, Venezuela

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    Gabriel Ordaz

    2010-06-01

    Full Text Available A los extractos crudos de los octocorales Eunicea sp., Muricea sp. y Pseudopterogorgia acerosa y de los moluscos Pteria colymbus, Phylonotus pomum y Chicoreus brevifrons, se les realizaron pruebas químicas, las cuales evidenciaron en todos ellos, la presencia de metabolitos secundarios como alcaloides, esteroles insaturados y triterpenos pentacíclicos. Sólo se detectaron sesquiterpenlactonas, saponinas, taninos, glicósidos cianogénicos y glicósidos cardiotónicos en algunos de los extractos de los octocorales, lo cual sugiere que la biosíntesis de estos metabolitos es propia de este grupo de organismos. Asimismo, se evaluó la actividad letal y antimicrobiana de los extractos de los octocorales y moluscos. En el bioensayo de letalidad, todos los extractos resultaron letales frente al crustáceo Artemia salina (CL50<1.000μg/ml. La actividad letal incrementσ con el tiempo de exposiciσn. El extracto de P. pomum presentó la mayor actividad letal (CL50=46.8μg/ml. En los ensayos de actividad antimicrobiana, los extractos orgαnicos de los moluscos presentaron una mayor actividad y un espectro de acción mayor contra diferentes cepas de bacterias, respecto a los octocorales; aunque estos últimos también inhibieron el crecimiento de algunas cepas de hongos. Staphylococcus aureus, fue la bacteria más susceptible al poder antimicrobiano de los extractos (66.7%, mientras que la bacteria Pseudomonas aeruginosa y los hongos Candida albicans y Aspergillus niger, no fueron afectados. La antibiosis mostrada por los extractos de los diferentes invertebrados marinos estudiados, indica que algunos de los metabolitos biosintetizados por éstos son fisiológicamente activos con posible potencial citotóxico y/o antibiótico.

  7. Resistance of irradiated and non-irradiated corn grain genotypes against the weevil Sitophilus zeamais Mots., 1855 (Coleoptera: Curculionidae).; Resistencia de graos de genotipos de milho irradiados e nao irradiados ao gorgulho Sitophilus zeamais Mots., 1855 (Coleoptera: Curculionidae)

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Carolina Natali de

    2005-07-01

    The resistance of 13 /////com grain genotypes was evaluated against the attack of Sitophilus zeamais (Mots.) by means of a no-choice test; 6 of them were selected (AGN 2012, AGN 30AOO, AGN 31A31, AGN 25A23, AGN 32A43, and AGN 35A42) and then submitted to a free-choice test where attractiveness and non preference for oviposition were assessed. The grain from the selected genotypes were later treated with Cobalt-60 gamma radiation at the doses of 0.0; 0.5; 1.0; and 1.5 kGy and submitted to the same tests. Based on the results, it was verified that genotypes AGN 2012 (30.6 eggs), AGN 31A31 (33.6 eggs), and AGN 30AOO (34.8 eggs) showed a non-preference for oviposition type of resistance, while non-preference for feeding and/or antibiosis were observed in the first two genotypes only. Genotypes AGN 25A23, AGN 32A43, and AGN 35A42 were the most susceptible to com weevil. The increasing gamma radiation ({sup 60}Co) doses reduced the mean mass of adults in genotype AGN 2012; however, the same parameter increased in genotype AGN 35A42; when treated at the dose of 1.5 kGy, genotypes AGN 2012 and AGN 31A31 showed a reduction in their mean masses of adults, while genotypes AGN 30AOO and AGN 35A42 showed higher mean mass of adults values. The increasing gamma radiation doses ({sup 60}Co) provided a reduction in mean grain dry mass consumed by the weevil; however, it was concluded that irradiation did not break com grain resistance and can be used for S. zeamais disinfestation prior to storage. (author)

  8. Inhibition of Salmonella enterica by plant-associated pseudomonads in vitro and on sprouting alfalfa seed.

    Science.gov (United States)

    Fett, William F

    2006-04-01

    Foodborne illness due to the consumption of contaminated raw or lightly cooked sprouts is a continuing food safety concern. In this study, we tested several plant-associated pseudomonads for their ability to inhibit the growth of Salmonella enterica both in vitro and in situ. An agar spot bioassay method was used with three different media. Only Pseudomonas fluorescens 2-79 produced clear zones of inhibition when tested against five serovars of S. enterica, and activity was dependent on media type and serovar. The antibiosis by derivative strains of P. fluorescens 2-79 defective in the production of phenazine-1-carboxylic acid and fluorescent siderophore was not reduced, indicating that these known antimicrobial metabolites were not responsible for the inhibition observed in our studies. However, mutants defective in the regulatory gene gacS (global antibiotic and cyanide control) were severely reduced in inhibitory activity. In tryptic soy broth, the control cultures of a cocktail of S. enterica strains reached approximately 10 log CFU/ml by 24 h but, when coinoculated with P. fluorescens 2-79, reached only approximately 5 log CFU/ml. The addition of P. fluorescens 2-79 to the seed soak water prior to the germination of alfalfa seed previously inoculated with a cocktail of S. enterica strains led to an average reduction of 5 log CFU/g at 6 days of sprouting without an adverse effect on sprout yield or appearance. Time course studies indicated that S. enterica outgrowth was controlled on days 1 through 6 of sprouting. Competitive exclusion as a potential food safety intervention for seed sprouts merits further study.

  9. A trio of viral proteins tunes aphid-plant interactions in Arabidopsis thaliana.

    Science.gov (United States)

    Westwood, Jack H; Groen, Simon C; Du, Zhiyou; Murphy, Alex M; Anggoro, Damar Tri; Tungadi, Trisna; Luang-In, Vijitra; Lewsey, Mathew G; Rossiter, John T; Powell, Glen; Smith, Alison G; Carr, John P

    2013-01-01

    Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: 'peach-potato aphid', 'green peach aphid'). Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between the effects of Fny-CMV on this plant and those seen previously in tobacco

  10. Mapping novel aphid resistance QTL from wild soybean, Glycine soja 85-32.

    Science.gov (United States)

    Zhang, Shichen; Zhang, Zhongnan; Bales, Carmille; Gu, Cuihua; DiFonzo, Chris; Li, Ming; Song, Qijian; Cregan, Perry; Yang, Zhenyu; Wang, Dechun

    2017-09-01

    Two novel QTLs conferring aphid resistance were mapped and validated on soybean chromosomes 8 and 16, respectively. Closely linked markers were developed to assist breeding for aphid resistance. Soybean aphid, Aphis glycines Matsumura, is a highly destructive pest for soybean production. E08934, a soybean advanced breeding line derived from the wild soybean Glycine soja 85-32, has shown strong resistance to aphids. To dissect the genetic basis of aphid resistance in E08934, a mapping population (070020) consisting of 140 F 3 -derived lines was developed by crossing E08934 with an aphid-susceptible line E00003. This mapping population was evaluated for aphid resistance in a greenhouse trial in 2010 and three field trials in 2009, 2010, and 2011, respectively. The broad-sense heritability across the field trials was 0.84. In the mapping population 070020, two major quantitative trait loci (QTL) were detected as significantly associated with aphid resistance, and designated as Rag6 and Rag3c, respectively. Rag6 was mapped to a 10.5 centiMorgan (cM) interval between markers MSUSNP08-2 and Satt209 on chromosome 8, explaining 19.5-46.4% of the phenotypic variance in different trials. Rag3c was located at a 7.5 cM interval between markers MSUSNP16-10 and Sat_370 on chromosome 16, explaining 12.5-22.9% of the phenotypic variance in different trials. Rag3c had less resistance effect than Rag6 across all the trials. Furthermore, Rag6 and Rag3c were confirmed in two validation populations with different genetic backgrounds. No significant interaction was detected between Rag6 and Rag3c in either the mapping population or the validation populations. Both Rag6 and Rag3c were indicated as conferring antibiosis resistance to aphids by a no-choice test. The new aphid-resistance gene(s) derived from the wild germplasm G. soja 85-32 are valuable in improving soybeans for aphid resistance.

  11. Spondylodiscitis severity code: scoring system for the classification and treatment of non-specific spondylodiscitis.

    Science.gov (United States)

    Homagk, L; Homagk, N; Klauss, J R; Roehl, K; Hofmann, G O; Marmelstein, D

    2016-04-01

    Established treatment options of spondylodiscitis, a rare but serious infection of the spine, are immobilization and systemic antibiosis. However, the available data for specific treatment recommendations are very heterogeneous. Our intention was to develop a classification of the severity of spondylodiscitis with appropriate treatment recommendations. From 10/1/1998 until 12/31/2004, 37 cases of spondylodiscitis were examined regarding medical history, gender status, location and extent of spondylodiscitis, type and number of operations. Subsequently, a classification of six grades according to severity has been developed with specific treatment recommendations. The further evaluation of our classification and corresponding treatment modalities from 1/1/2005 to 12/31/2009 including further 132 cases, resulted in a classification of only three grades of severity (the SSC--spondylodiscitis severity code), with a follow-up until 12/31/2011. Between 01/01/2012 and 12/31/2013, a prospective study of 42 cases was carried out. Overall, 296 cases were included in the study. 26 conservatively treated cases were excluded. The main localization of spondylodiscitis was the lumbar spine (55%) followed by the thoracic spine (34%). The classification of patients into 3 grades of severity depends on clinical and laboratory parameters, the morphological vertebral destruction seen in radiological examinations and the current neurological status. Therapies are adapted according to severity and they include a specific surgical management, systemic antibiotic therapy according to culture and sensitivity tests, physiotherapy and initiation of post-hospital follow-up. 40.6% of patients are associated with neurological deficits, classified as severity grade 3 and treated surgically with spinal stabilization and decompression. 46.9% of patients corresponded to severity grade 2, with concomitant vertebral destruction were dorsoventrally stabilized. The 31 patients of severity Grade 1 were

  12. Resistência de genótipos de feijoeiro a Bemisia tabaci biótipo B Resistance of bean genotypes to Bemisia tabaci biotype B

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    Lucas Castro Torres

    2012-01-01

    Full Text Available O estudo de genótipos de feijoeiro resistentes à mosca-branca Bemisia tabaci (Genn. biótipo B (Hemiptera: Aleyrodidae é de grande importância devido aos danos ocasionados por essa praga à cultura. Neste trabalho, foram estudados a atratividade para adultos, a preferência para oviposição em testes com e sem chance de escolha, o ciclo ovo-adulto e o tipo e número de tricomas presentes nos folíolos. Os experimentos foram realizados em casa de vegetação avaliando-se, inicialmente, cem genótipos de feijoeiro. A resistência do tipo não-preferência para alimentação e/ou antibiose foi observada nos genótipos ARC-3, IAC-Alvorada e Canário 101, sendo a emergência de adultos fortemente influenciada pelos genótipos. Também se observou correlação negativa moderada entre o número de ovos e o número de tricomas glandulares, e correlação positiva muito forte entre o número de ovos e o número de tricomas tectores unciformes.The study of bean genotypes resistant to the whitefly Bemisia tabaci (Genn. B biotype (Hemiptera: Aleyrodidae has been of great importance due to the damage caused by this pest. In this research, bean genotypes were evaluated regarding attractiveness to whitefly adults, the preference for oviposition in free-choice and non choice tests, egg-to-adult development time and characterized for the presence, type and number of trichomes. The experiments were carried out under greenhouse conditions initially evaluating 100 bean genotypes. The non-preference type of resistance for feeding and/or antibiosis was observed in the genotypes ARC-3, IAC-Alvorada and Canário 101, and the emergence of adults was strongly influenced by the genotypes. It was also observed a moderate negative correlation between the number of eggs and the number of glandular trichomes, as well as a very strong positive correlation between the number of eggs and the number of unciform non-glandular trichomes.

  13. The formation of microorganism communities in the soil under the effect of chitosan and runner bean (Phaseolus coccineus L. cultivation

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    Danuta Pięta

    2013-12-01

    Full Text Available The subject of the studies was the soil with introduced solutions containing 0,1% chitosan. These materials were obtained from the Institute of Chemical Fibres in L6d2 (in the form of a microcrystalline gel and also from the Department of Food Biochemistry and Chemistry of the University of Agriculture in Lublin (in a liquid form,i.e.dissolved in acetic acid. In order to set an experiment in a growth chamber, grey brown podzolic soil formed from loesses and taken from a mechanically treated belt of black fallow was used. The soil (1000 g was watered every 8 days with 100 ml of examined chitosan solutions per pot. Control soil was watered with sterile distilled water. Seven days after each watering, soil samples were taken for microbiological analysis. Then 25 runner bean seeds were sown into each pot. After six weeks of plants' growth the experiment was finished and the number of plants was counted, their healthiness determined and soil microbiological analysis was performed. Regardless of chitosan form introduced to the soil it stimulated the growth of bacteria and fungi, since in these experimental combinations was found a significantly higher number of microorganisms as compared with the control. A particular high increase in the number of microorganism colonies was observed with simultaneous growth of plants and the application of chitosan. A considerable increase of fungi colonies from the Trichoderma genus was found in the soil treated with chitosan in the form ofboth a microcrystalline gel and a liquid. The species of this genus are considered to be antagonists; it affects pathogenic fungi through competition, antibiosis and over-parasitism. An increase in colonies of saprophytic microorganisms, including antagonistic ones of Bacillus spp. and Pseudomonas spp. was observed in the soil treated with chitosan . On the other hand, in the soil after the growth of bean and treated watered with chitosan only few colonies of Fusarium oxysporum f

  14. A Trio of Viral Proteins Tunes Aphid-Plant Interactions in Arabidopsis thaliana

    Science.gov (United States)

    Du, Zhiyou; Murphy, Alex M.; Anggoro, Damar Tri; Tungadi, Trisna; Luang-In, Vijitra; Lewsey, Mathew G.; Rossiter, John T.; Powell, Glen; Smith, Alison G.; Carr, John P.

    2013-01-01

    Background Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: ‘peach-potato aphid’, ‘green peach aphid’). Methodology/Principal Findings Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Conclusions/Significance Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between

  15. Inhibition coefficient and molecular diversity of multi stress tolerant Trichoderma as potential biocontrol agent against Sclerotium rolfsii Sacc.

    Science.gov (United States)

    Hirpara, Darshna G; Gajera, H P; Hirapara, Jaydeep G; Golakiya, B A

    2017-11-01

    Trichoderma is one of the most exploited biocontrol agent for the management of plant diseases. Twenty strains of Trichoderma (six of T. harzianum, four of T. viride, three of T. virens, three of T. koningii, each one of T. hamatum, T. reesei, T. parceramosum and Trichoderma spp.) subjected to in vitro antagonism up to 12days after inoculation against Sclerotium rolfsii Sacc. causing stem rot in groundnut. A new concept was developed to determine inhibition coefficient representing pathogen biology and biocontrol related biophysical variables. Results explained differential inhibition coefficient of test pathogen by Trichoderma antagonists. The inhibition coefficient of test pathogen was examined highest (91.13%) by T. virens NBAII Tvs12 followed by T. virens MTCC 794 (89.33%) and T. koningii MTCC 796 (62.39%). Microscopic study confirmed biocontrol mechanism as mycoparasitism for Tvs12 and antibiosis for T. koningii MTCC 796. The sclerotial biogenesis of test pathogen was elevated during weak antagonism and diminished in interactions with strong antagonists. The inhibition coefficient of S. rolfsii was significantly negatively correlated with sclerotia formation and lipid peroxidation during the antagonism. Trichoderma strains were screened for fungicides (carbendazim and tebuconazole, thiram and mancozeb) and abiotic stress (drought and salt) tolerance. Results indicated that T. koningii MTCC 796 efficiently grew better than the other strains with maximum radial growth under adverse conditions. The genetic variability among the Trichoderma was determined using 34 gene specific markers which amplified 146 alleles. The SSR similarities explained substantial diversity (15 to 87%) across Trichoderma strains and pathogen S. rolfsii. Principal coordinates analysis (PCA) were comparable to the cluster analysis and first three most informative PC components explained 64.45% of the total variation. In PCA, potent antagonists appear to be distinct from other strains. Five

  16. Penicillium expansum versus antagonist yeasts and patulin degradation in vitro

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    Alexandre Rodrigo Coelho

    2007-07-01

    Full Text Available Taking into account the preliminary antagonistic/biodegradation property showed by Pichia membranifaciens and Sporobolomyces roseus, which decreased the initial patulin concentration of 588.4 to 290.0 µg/mL, ability of P. ohmeri 158 in biocontrol against Penicillium expansum and patulin decrease in vitro was performed. The culture supernatant of P. ohmeri 158 was effective against 66.17% micelial growth, indicating antibiosis related with the killer phenomenon. The initial patulin concentration of 223 µg in the presence of P. ohmeri 158 cells was decreased over 83% of the original concentration, when incubated at 25ºC/2 days and > 99% after 5 days incubation time, with undetectable patulin level after 15 days. The initial pH 4.0 decreased to pH 3.3 along 15 days experiment, suggesting that patulin decrease was an active process and a consequence of yeast metabolism. The results suggested that P. ohmeri 158 could be a promising alternative for the inhibition of P. expansum growth and patulin degradation.Considerando o antagonismo e degradação de patulina detectados em Pichia membranifaciens e Sporobolomyces roseus no estudo preliminar, este trabalho avaliou o efeito antagônico de Pichia ohmeri 158 no desenvolvimento de Penicillium expansum e a degradação de patulina "in vitro". O sobrenadante do cultivo de P. ohmeri 158 inibiu 66,17% do desenvolvimento micelial, indicando antibiose relacionada ao fator killer. A concentração inicial de patulina (223 µg na presença de células íntegras de P. ohmeri foi reduzida em mais de 83% após dois dias de incubação a 25ºC e superior a 99% após 5 dias, com níveis indetectáveis no 15º dia. O decréscimo do pH 4,0 inicial para pH 3,3 sugeriu que a eliminação de patulina é um processo ativo e uma conseqüência do metabolismo da levedura. Os resultados obtidos concluem que P. ohmeri 158 é uma alternativa promissora na inibição do desenvolvimento de P. expansum e na degradação de

  17. Effect of salt stressed wheat varieties on life history of tribolium castaneum (hebrst) (tenebrionidae: coleoptera)

    International Nuclear Information System (INIS)

    Fatima, R.; Ambreen, S.; Khan, R.R.; Ahmed, S.

    2010-01-01

    In the present investigation an attempt was made to determine the antibiosis of three salt stressed wheat varieties (Shafaq, Inqlab-91 and Sehar-2006) at three salinity levels (8, 12 and 16 dS m/sup -1/) to red flour beetle, Tribolium castaneum (Herbst). The grains of three varieties were ground and sieved through 80 mesh. Life history parameters, i.e., larval and pupal durations and survivals, adult emergence, fecundity and egg hatching was observed by introducing 10 pairs of pupae, from previously reared beetles, on three varieties at their respective salt levels. One control was included with grains of the plants, which were irrigated with distilled water only. Results have shown that varieties had significant difference among the treatments for larval duration, which was significantly extended in different varieties at various salt levels. Mean longest larval duration (31.67 days) was recorded in Shafaq as respectively 8 (33.00 days), 12 (33.33 days) and 16 (30.33 days) dS m/sup -1/ salt level as compared to its control (31.00 days). Fecundity and egg hatching of T. castaneum differed among the wheat varieties irrespective of salt levels. In another experiment, response of SARC-1, SARC-2, SARC-3, SARC-4, SARC-5, SARC-6, SARC-7, SARC-8, LU-26S, to life history parameters of T. castaneum showed that significant difference in the number of eggs, hatching percentage, larval and pupal survival was found. The number of eggs was significantly lower in variety SARC 1 (126.00) followed by SARC 2 (128.75), SARC 3 (132.25) while was significantly higher in SARC 5 (151.75). Egg hatching percentage was lower in SARC 6 (39.38%) and significantly higher in SARC 5 (58.42%). Larval survival was significantly less in SARC 7 (36.99%) and more in SAR (52.25%). Pupal survival was significantly lower in SARC 1 (20.54%) while higher in SARC 8 (42.11%). Based on results it may be stated that salt stressed wheat varieties have significant impact of the biology of T. castaneum. (author)

  18. Bacteriocins: molecules of fundamental impact on the microbial ecology and potential food biopreservatives

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    Evandro Leite de Souza

    2005-07-01

    Full Text Available Bacteriocins are proteic molecules synthesized for various lineages of Gram-positive and Gram-negative bacteria when exposed to stressful conditions. Bacteriocins have been characterized as molecules of high antimicrobial property even at low concentrations, provoking the microbial survival inhibition by antibiosis. These substances have their synthesis mediated for genetic mechanisms and develop their lethal action on the microbial cell by multiples mechanisms that can act of isolated or concomitant way culminating with microbial cell killing. This molecules class presents characteristic of stability to heat, low pH, refrigeration and freezing, and resistance to weak organics solvents, salts and enzymes. On the other hand, they are very sensitive to proteolytic enzymes action. Bacteriocins could appear as potential agents to be applied in food conservation systems in order to provide microbiologically stable foods.Bacteriocinas são moléculas protéicas sintetizadas por várias linhagens de bactérias Gram-positivas e Gram-negativas quando submetidas a condições de stress. São ainda caracterizadas como moléculas de alto poder antimicrobiano mesmo em baixas concentrações, provocando a inibição da sobrevivência microbiana através de uma ação de antibiose. As bacteriocinas têm seu processo de síntese mediado por mecanismos genéticos, e desenvolvem sua ação letal sobre a célula microbiana por intermédio de múltiplos mecanismos que podem agir de forma isolada ou concomitante culminando com a morte da célula microbiana. Estas moléculas apresentam características de estabilidade ao calor, baixo pH, refrigeração, congelamento, resistência a ácidos orgânicos fracos, sais e enzimas, porém são muito sensíveis à enzimas proteolíticas. Assim, as bacteriocinas podem aparecer como potenciais agentes para serem aplicados em sistemas de conservação de alimentos com objetivo de prover alimentos microbiologicamente estáveis.

  19. Resistência de genótipos de batata ao pulgão Potato genotypes resistance to the green peach aphid Myzus persicae

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    Fernando M. Lara

    2004-12-01

    for resistance (and antibiosis to the green peach aphid Myzus persicae, in experiments carried out with potted plants using vases (no choice tests, in Jaboticabal, São Paulo State, Brazil. Sixteen genotypes were used in six experiments: 'Achat', 'Apuã', 'Aracy', 'Aracy Ruiva', 'Bintje', 'Ibitu Açu', 'Itararé', 'N 140-201', 'NYL 235-4', '288.719-13', '288.764-26', '288.776-3', '288.776-6', '288.794-19', '288.801-6' and '288.814-7'. In each experiment different combinations of these genotypes were used. In the first two experiments the plants were infested with 30 adults distributed in three leaves; after infestation three evaluations were done during the subsequent weeks. The third experiment was carried out arresting two adult females inside small cages fastened in the lower surface of the leaflets; the reproduction of the aphid was evaluated after seven days using two plantings. In the fourth experiment, 15 aphids were placed on each plant to evaluate the growth of the population, by counting the number of aphids/plant in three subsequent weeks. In the fifth experiment the number of nymphs/female was evaluated, while in the sixth experiment the nymphs weight was evaluated at the seventh day of life. The density of glandular trichomes was measured on lower laminar surface and on the main vein of mature leaves. The functionality of the glandular trichomes was also evaluated. The commercial genotype Ibitu Açu presented a high degree of antibiosis to M. persicae; the genotypes 288.776-3 and 288.794-19 also presented this mechanism of resistance, in moderate degree; '288.719-13' and '288.764-26' were also resistant to the green peach aphid, probably due to the presence of functional glandular trichomes, types A and B, in their leaflets (antixenosis. The commercial genotype Bintje and the clone 288.801-6 were the most susceptible.

  20. Controle biológico da mancha-aquosa do melão por compostos bioativos produzidos por Bacillus spp. Biocontrol of bacterial fruit blotch of melon by bioactive compounds produced by Bacillus spp.

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    Elizama Roza Santos

    2006-09-01

    presence of bioactive compounds produced during fermentations. All treatments were different from the control (P = 0.05% but they did not differ among them. The B. megaterium pv. cerealis RAB7 reduced disease incidence (89.1%, disease index (92.7%, increased the incubation period from 9.8 to 11.9 days and reduced the area under disease progress curve from 3.36 to 0.17. In the in vitro tests, all strains showed antibiosis against Aac and the bioactive compounds were partially characterized as lipopeptides.

  1. Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft.

    Science.gov (United States)

    Winkler, Heinz

    2009-09-04

    biomechanical properties. Efficient cementing techniques will result in tight bonding with the underlying bone, making eventual removal time consuming and possibly associated with further damage to the osseous structures. All these issues are likely to make uncemented revisions more desirable. Allograft bone may be impregnated with high loads of antibiotics using special incubation techniques. The storage capacities and pharmacological kinetics of the resulting antibiotic bone compound (ABC) are more advantageous than the ones of antibiotic loaded cement. ABC provides local concentrations exceeding those of cement by more than a 100fold and efficient release is prolonged for several weeks. The same time they are likely to restore bone stock, which usually is compromised after removal of an infected endoprosthesis. ABC may be combined with uncemented implants for improved long term results and easy removal in case of a failure. Specifications of appropriate designs are outlined. Based on these considerations new protocols for one stage exchange of infected TJR have been established. Bone voids surrounding the implants may be filled with antibiotic impregnated bone graft; uncemented implants may be fixed in original bone. Recent studies indicate an overall success rate of more than 90% without any adverse side effects. Incorporation of allografts appears as after grafting with unimpregnated bone grafts. Antibiotic loaded bone graft seems to provide sufficient local antibiosis for protection against colonisation of uncemented implants, the eluted amounts of antibiotics are likely to eliminate biofilm remnants, dead space management is more complete and defects may be reconstructed efficiently. Uncemented implants provide improved long term results in case of success and facilitated re-revision in case of failure. One stage revision using ABC together with uncemented implants such should be at least comparably save as multiple stage procedures, taking advantage of the obvious

  2. Effect of arcelin protein on the biology of Zabrotes subfasciatus (Boheman 1833, in dry beans Efeito da proteína arcelina na biologia de Zabrotes subfasciatus (Boheman 1833, em feijoeiro

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    Flávia Rabelo Barbosa

    1999-10-01

    Full Text Available Arcelin is a seed protein found in wild beans (Phaseolus vulgaris which gives resistance to Mexican bean weevil, Zabrotes subfasciatus (Boheman 1833 (Coleoptera: Bruchidae. Studies were carried out with the objective of estimating the effect of four alleles of protein arcelin (Arc1, Arc2, Arc3 and Arc4 on the biology of Z. subfasciatus. The experiment was carried out in laboratory at Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão, in Santo Antônio de Goiás, GO, Brazil, under non controlled conditions. The highest levels of antibiosis to Z. subfasciatus were observed in Arc1, with reduction in the number of eggs, number of emerged adults, adults longevity. In the line Arc2 only reduction in the number of emerged adults was observed. The lines Arc3 and Arc4 showed low efficiency on the reduction of progeny of Z. subfasciatus and effects in the longevity and egg-adult cycle were not detected. Insect sexual ratio was not altered by the presence of Arc1, Arc2, Arc3 and Arc4 in the seeds.A arcelina é uma proteína encontrada em feijões silvestres (Phaseolus vulgaris e que confere resistência ao caruncho-do-feijão, Zabrotes subfasciatus (Boheman 1833 (Coleoptera: Bruchidae. Estudos foram conduzidos com o objetivo de conhecer o efeito de quatro alelos da proteína arcelina (Arc1, Arc2, Arc3 e Arc4, na biologia de Z. subfasciatus. O experimento foi conduzido no laboratório da Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão, no município de Santo Antônio de Goiás, GO, em condições não controladas. O mais alto nível de antibiose a Z. subfasciatus foi constatado na linhagem portadora do alelo Arc1, observando-se redução do número de ovos produzidos, redução do número de adultos emergidos, redução da longevidade de adultos. Na linhagem Arc2 constatou-se redução apenas no número de adultos emergidos. As linhagens Arc3 e Arc4 apresentaram baixa eficiência na redução da progênie de Z. subfasciatus, não observando

  3. Métodos de analise dos danos da lagarta da espiga¹, em médias de gerações envolvendo IAC Maya e Zapalote Chico Method for analysis of damage of the corn earworm heliothis zea in generation means from IAC Maya and Zapalote Chico

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    Jorge Alberto Marques Rezende

    1982-01-01

    utilizing the revised scale described by WIDSTROM (27. The data obtained was analised by two different ways. The grades were distributed at first in two different classes: grades 0 and 1 and grades > 2. The grades were afterwards distributed in the following two classes: grades 0 and grades > 1. The chi-square test was applied to verify which of the two types of classes adjusts better with their respective expected ratios. The results showed that when the grades were divided in the classes 0+1 and > 2 the data were more uniform within each treatment. The analysis of variance for each damage class separately, presented F values highly significant for the classes zero and zero plus one, whereas for the classes > 1 and > 2 the damage averages were very similar and the F values were not significant. The class zero plus one had F value higher and the coefficient of variation smaller than the class zero. The ZC 2451 corn compared to the variety IAC Maya XII, exibited good resistance to the corn earworm, under the field conditions of Campinas, State of São Paulo, Brazil. This resistance is of the type non preference and or antibiosis, because there was a higher percentage of ears of ZC 2451 free of earworm damage.

  4. Resistance of squash cultivars to Aphis gossypii Resistência de cultivares de abobrinha italiana a Aphis gossypii

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    Edson LL Baldin

    2009-09-01

    Full Text Available The Cucurbitaceae plants are damaged by attack of a wide spectrum of insects and microorganisms. Among the sucker insects causing damages on squash Cucurbita pepo (L., the aphid Aphis gossypii (Glover (Hemiptera: Aphididae is pointed as one of the most important, once their nymphs and adults suck the sap of the leaves continuously, besides being potential vector of virus. The present research evaluated different cultivars, aiming to identify the resistance against this aphid. The cultivars Novita, Sandy, Caserta Cac Melhorada, Novita Plus, Samira, AF-2858 and Caserta TS were used in laboratory assays (T= 25±2ºC; RH= 70±10% and fotophase= 12 h. In the immature phase the duration of nymphal instars was evaluated, the total duration and their viability, confining individuals on leaf disks from cultivars. In the adult phase the duration of reproductive period, the fecundity and the biological cycle were observed. The cultivar 'Sandy' expressed high level of antibiosis and feeding non-preference against A. gossypii, increasing the nymphal stage and causing mortality near to 70%. Besides, this cultivar reduced the production of nymphs and the longevity of the insects. The 'Novita Plus' cultivar also induced significant nymphal mortality, however in lower levels than those verified in 'Sandy', indicating a moderate resistance.As plantas da família Cucurbitaceae são prejudicadas pelo ataque de um amplo espectro de insetos e microrganismos. Dentre os insetos sugadores que atacam a abobrinha Cucurbita pepo (L., o pulgão Aphis gossypii (Glover (Hemiptera: Aphididae merece destaque, uma vez que suas ninfas e adultos sugam a seiva das folhas constantemente, além de ser potencial vetor de vírus. A presente pesquisa foi realizada com o objetivo de avaliar diferetes cultivares de abobrinha italiana quanto à resistência a esse pulgão. Utilizaram-se as cultivares Novita, Sandy, Caserta Cac Melhorada, Novita Plus, Samira, AF-2858 e Caserta TS em ensaios

  5. Aspectos biológicos de Dione juno juno (Cramer (Lepidoptera: Nymphalidae em genótipos de maracujazeiro Biological aspects of Dione juno juno (Cramer (Lepidoptera: Nymphalidae on passion fruit genotypes

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    Arlindo Leal Boiça Júnior

    2008-03-01

    . edulis f. flavicarpa Deg. ('Sul Brasil', P. edulis f. flavicarpa, P. edulis f. flavicarpa ('Maguary FB-100' and P. foetida L. Fifty larvae from eggs collected in the field were used per genotype. Larvae were kept on passion fruits branches inside PVC tubes until pupation. Daily observations were performed and branches were replaced whenever necessary. The following parameters were evaluated: duration and viability of larval and pupal phases, larval and pupal weight and adult longevity. The experiment was arranged in randomized blocks design with seven treatments and ten replications. Data were subjected to an ANOVA and means were compared by Tukey test at 5% of probability. The least adequate genotypes for D. juno juno development were P. alata , P. serrato-digitata and P. foetida, showing a high level of antibiosis, while P. edulis, P. edulis f. flavicarpa, 'Maguary FB-100' and 'Sul Brasil' were the most suitable.

  6. Selection of endophytic fungi from comfrey (Symphytum officinale L. for in vitro biological control of the phytopathogen Sclerotinia sclerotiorum (Lib. Seleção de fungos endofíticos de confrei (Symphytum officinale L., buscando controle biológico in vitro do fitopatógeno Sclerotinia sclerotiorum (Lib.

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    Rafaeli Rocha

    2009-03-01

    Full Text Available Biological control consists of using one organism to attack another that may cause economic damage to crops. Integrated Pest Management (IPM is a very common strategy. The white mold produced by Sclerotiniasclerotiorum (Lib. causes considerable damage to bean crops. This fungus is a soil inhabitant, the symptoms of which are characterized by water-soaked lesions covered by a white cottony fungal growth on the soil surface and/or the host plant. Possible biological control agents taken from plants are being investigated as phytopathogen inhibitors. These are endophytic microorganisms that inhabit the intercellular spaces of vegetal tissues and are often responsible for antimicrobial production. The objective of the present study was to select endophytic fungi isolated from comfrey (Symphytumofficinale L. leaves with in vitro antagonist potential against the phytopathogenic fungus S. sclerotiorum. Twelve isolates of endophytic fungi and a pathogenic strain of S. sclerotiorum were used in the challenge method. With the aid of this method, four endophytes with the best antagonistic activity against S. sclerotiorum were selected. Pathogen growth inhibition zones were considered indicative of antibiosis. The percentages of pathogenic mycelia growth were measured both with and without the antagonist, resulting in growth reductions of 46.7% to 50.0% for S. sclerotiorum. These analyses were performed by evaluating the endophytic/pathogenic mycelia growth in mm/day over an eight-day period of antagonistic tests.O controle biológico consiste no uso de organismos que atacam outros que causam danos a culturas de plantas. Esta é uma estratégia muito utilizada no Controle Integrado de Pragas (CIP. O mofo branco, causado por Sclerotiniasclerotiorum (Lib., causa danos em culturas de feijão. Este fungo é encontrado no solo e seus sintomas são caracterizados por lesões úmidas cobertas por micélios algodonosos, crescidos a partir do solo e/ou da planta

  7. Biology of Bemisia tabaci (Genn. B biotype (Hemiptera, Aleyrodidae on tomato genotypes Biologia de Bemisia tabaci (Genn. Biótipo B (Hemiptera, Aleyrodidae em genótipos de tomateiro

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    Maria Auxiliadora de Godoy Oriani

    2011-02-01

    Full Text Available Brazil is one of the main tomato (Solanum lycopersicum producers worldwide. Nevertheless, considerable part of the production is lost due to Bemisia tabaci (Genn. B biotype attacks. Resistant plants can be an important method for controlling this pest in an integrated pest management. Tests for evaluating some biological aspects of B. tabaci were carried out on 18 tomato genotypes, in controlled laboratory greenhouse conditions. Thirty-day-old plants placed in plastic cages were infested with 20 whitefly pairs each, for 24 h. The development of at least 30 eggs in three leaflets per plant (repetition was observed until adult emergence. The development period of insects grown in LA1335, PI365928 and LA722 genotypes took three days longer when compared to the ones grown in PI134418 (20.3 days. The highest mortality rate of whitefly nymphs occurred in PI365928, LA1335 and LA722 genotypes (63.8, 54.5 and 53.3%, respectively, and the smallest ones in IAC294 and IAC68F-22-2 genotypes (4.9 e 6.2%, respectively. LA1335, PI365928 and LA722 genotypes presented moderate feeding nonpreference and/or antibiosis-based resistance to B. tabaci B biotype.O Brasil é um dos maiores produtores mundiais de tomate (Solanum lycopersicum, porém grande parte da produção é perdida devido ao ataque de Bemisia tabaci (Genn. biótipo B. Entre as táticas de controle dessa praga num manejo integrado de pragas, pode-se relacionar a resistência de plantas. Ensaios para avaliar alguns aspectos biológicos de B. tabaci foram realizados com 18 genótipos de tomateiro, em condições controladas de laboratório (casa de vegetação. Plantas com 30 dias de idade foram colocadas em gaiolas plásticas e infestadas com 20 casais de moscas-brancas cada, durante 24h. Acompanhou-se então o desenvolvimento de pelo menos 30 ovos em três folíolos por planta (repetição até a emergência dos insetos. Os insetos criados nos genótipos LA1335, PI365928 e LA722 apresentaram