Identificação e caracterização de Xanthomonas euvesicatoria de pimentão no Brasil
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Data
2013-11-20
Autores
Areas, Maysa Souza [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O pimentão é uma hortaliça com grande apreciação no Brasil, tendo elevada importância no mercado de condimentos, temperos e conservas. O Estado de São Paulo é o principal produtor desta hortaliça, com produção aproximada de 85.000 toneladas na safra 2010. Dentre os principais problemas fitossanitários da cultura do pimentão, destaca-se a mancha bacteriana, causada por espécies de Xanthomonas spp. A doença pode ocasionar perdas substanciais na produtividade da cultura, especialmente em períodos de elevadas pluviosidade e temperatura, além da baixa eficácia de controle com produtos químicos, como fungicidas cúpricos. Em vista do exposto, o objetivo do presente trabalho foi caracterizar 59 isolados de Xanthomonas spp. de pimentão obtidos de diferentes regiões produtoras do Brasil, através da utilização de técnicas bioquímicas/fisiológicas, moleculares e verificar a sensibilidade in vitro dos isolados aos sulfatos de cobre e zinco e suas misturas. Para os ensaios bioquímicos/fisiológicos, foram realizados os testes de reação diferencial de Gram, solubilidade em KOH a 3%, hidrólise de amido, atividade pectinolítica e a utilização de 13 fontes de carbono, em microplacas GN2 da Biolog®. A identificação molecular foi realizada através de reações de PCR com os iniciadores específicos para X. euvesicatoria, X.vesicatoria, X. gardneri e X. perforans. A sensibilidade in vitro dos isolados aos sulfatos de cobre e zinco foi avaliada nas concentrações de 50, 100, 200 e 400 μg.mL-1, além da mistura de 50% de cada um dos produtos, nas mesmas concentrações finais no meio de cultura PSA. Com base nos resultados dos testes bioquímicos/fisiológicos e moleculares (PCR) com iniciadores específicos revelaram a prevalência de X. euvesicatoria em pimentão no Brasil. Todos os isolados avaliados foram resistentes ao sulfato de zinco e 85% deles foram resistentes ao...
Pepper is a vegetable with great appreciation in Brazil and high importance for the market of condiments, spices and canned goods. Sao Paulo state is the main producer of pepper in Brazil with almost 85.000 ton in 2010. One of the most important phytosanitary problems for this crop is the bacterial spot, caused by species of Xanthomonas spp. This disease can cause crop productivity losses, especially during periods of high rainfall and temperature, in addition to the low efficacy of chemicals, as copper fungicides. In this study, we characterized 59 strains of Xanthomonas spp. associated with bacterial spot from different producing regions of Brazil, using biochemical/physiological and molecular techniques, and evaluated the in vitro sensitivity of strains to copper and zinc sulfates. For the biochemical/physiological assays, Gram staining, KOH string test, starch hydrolysis, pectinolytic activity and the utilization of 13 carbon sources on Biolog® GN2 microplates were performed. Molecular characterization was performed by PCR with specific initiators for X. euvesicatoria, X.vesicatoria, X. gardneri and X. perforans. In vitro sensitivity of strains to copper and zinc sulfates was evaluated at concentrations 50, 100, 200 and 400 μg.mL-1, together with the mixing of the chemicals, in the same final concentration in culture medium. Based on starch hydrolysis and pectinolytic activity results, strains were divided in two distinct groups: X. vesicatoria with X. perforans (positive pectinolytic and amylolytic activities) and X. euvesicatoria with X. gardneri (negative pectinolytic and amylolytic activities). PCR and carbon sources utilization results revealed the prevalence of X. perforans on pepper in Brazil. All strains were resistant to zinc sulfate and 85% to copper sulfate. The mixing of the chemicals at concentration of 400 μg.ml-1 inhibited the growth of all strains assessed.
Pepper is a vegetable with great appreciation in Brazil and high importance for the market of condiments, spices and canned goods. Sao Paulo state is the main producer of pepper in Brazil with almost 85.000 ton in 2010. One of the most important phytosanitary problems for this crop is the bacterial spot, caused by species of Xanthomonas spp. This disease can cause crop productivity losses, especially during periods of high rainfall and temperature, in addition to the low efficacy of chemicals, as copper fungicides. In this study, we characterized 59 strains of Xanthomonas spp. associated with bacterial spot from different producing regions of Brazil, using biochemical/physiological and molecular techniques, and evaluated the in vitro sensitivity of strains to copper and zinc sulfates. For the biochemical/physiological assays, Gram staining, KOH string test, starch hydrolysis, pectinolytic activity and the utilization of 13 carbon sources on Biolog® GN2 microplates were performed. Molecular characterization was performed by PCR with specific initiators for X. euvesicatoria, X.vesicatoria, X. gardneri and X. perforans. In vitro sensitivity of strains to copper and zinc sulfates was evaluated at concentrations 50, 100, 200 and 400 μg.mL-1, together with the mixing of the chemicals, in the same final concentration in culture medium. Based on starch hydrolysis and pectinolytic activity results, strains were divided in two distinct groups: X. vesicatoria with X. perforans (positive pectinolytic and amylolytic activities) and X. euvesicatoria with X. gardneri (negative pectinolytic and amylolytic activities). PCR and carbon sources utilization results revealed the prevalence of X. perforans on pepper in Brazil. All strains were resistant to zinc sulfate and 85% to copper sulfate. The mixing of the chemicals at concentration of 400 μg.ml-1 inhibited the growth of all strains assessed.
Descrição
Palavras-chave
Pimentão - Resistencia a doenças - Aspectos geneticos, Xanthomonas, Reação em cadeia de polimerase, Disease and pest resistance - Genetic aspects
Como citar
AREAS, Maysa Souza. Identificação e caracterização de Xanthomonas euvesicatoria de pimentão no Brasil. 2013. ix, 56 f. Dissertação (mestrado) - Universidade Estadual Paulista “Julio de Mesquita Filho” , Faculdade de Ciências Agronômicas de Botucatu, 2013.