Reação de genótipos de feijoeiro a Curtobacterium flaccumfaciens PV. flaccumfaciens, agressividade e variabilidade molecular de isolados
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Data
2004-11-30
Autores
Souza, Valmir Luiz de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), agente causal da murcha-de-curtobacterium em feijoeiro, é um patógeno de colonização vascular de difícil controle. A doença foi detectada pela primeira vez no Brasil na safra das águas de 1995, no Estado de São Paulo. Além da região Sudeste, atualmente a doença encontra-se distribuída nas regiões Sul e Centro-Oeste. Sintomas típicos da doença incluem a murcha, amarelecimento das folhas e morte de plantas, sintoma variável em resposta aos diferentes níveis de resistência em genótipos de feijoeiro. Por tratar-se de uma doença de difícil controle, o uso de material comercial com resistência genética ao patógeno tem sido a melhor opção. O presente trabalho teve como objetivos avaliar a reação de genótipos de feijoeiro a murcha-de-curtobacterium, frente a 333 acessos pertencentes ao banco de germoplasma de feijoeiro do Instituto Agronômico de Campinas (IAC), comparar por meio da microscopia eletrônica de varredura a colonização de Cff em vasos de xilemas de feijoeiros altamente resistentes e suscetíveis, avaliar através de técnica molecular a especificidade dos iniciadores CffFOR2-CffREV4 e CF4-CF5 em reação de PCR, como ferramenta de identificação de vinte e quatro isolados de Cff de diferentes regiões geográficas e dois isolados de Curtobacterium flaccumfaciens endofíticos de citros, como também a variabilidade genética destes isolados pela técnica de rep-PCR, e por fim a análise da agressividade de Cff, através de inoculação em genótipos de feijoeiro suscetíveis e altamente resistentes. Os resultados mostraram a existência de variabilidade genética nas amostras dos 333 genótipos de feijoeiro avaliados, ao isolado de Cff Feij 2634. Os materiais foram classificados em quatro grupos de resistência:... .
Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), causer agent of the bacterial wilt of common bean. It is a vascular colonization pathogen of difficult control. The disease was first detected in Brazil in the 1995 waters harvest time in São Paulo State. Besides the Southeast region, the disease is currently also distributed in the South and Middle West regions. Typical symptoms of the disease include: wilt yellow leaves and plant death. However, the symptoms are variable according to the different levels of resistance in the plant genotypes. Due to the difficult disease control, genetic resistance has been the better option. The aim of this study was to evaluate the reaction of bean genotypes to the bacterial wilt in common bean in 333 access of the bean plant germoplasm database of the Instituto Agronômico de Campinas (IAC), and to compare the Cff colonization in xylem vessels of highly resistant and susceptible bean plants by scanning electronic microscopy. It also aimed the molecular evaluation of the CffFOR2-CffREV4 and CF4-CF5 primers specificity using PCR reaction in the identification of 24 Cff isolateds from geographically separated regions and 2 citrus endophytic Curtobacterium flaccumfaciens isolated, as well as the genetic variability of these isolates by rep-PCR, and the Cff aggressiveness analysis by the inoculation of susceptible and highly resistant bean plant genotypes. The observed results indicated genetic variability in all 333 genotypes evaluated in relation to the Cff isolate Feij 2634. The materials were classified into four resistance levels: 29 highly resistance genotypes (8.7%), 13 resistant genotypes (3.9%), 18 moderately resistant genotypes (5.0%) and 273 susceptible genotypes (81.0%). Using the scanning electronic microscopy, several bacteria agglutinations involved by filaments and the appearance of tangled structures under the punctuations... (Complete abstract, click electronic address below).
Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), causer agent of the bacterial wilt of common bean. It is a vascular colonization pathogen of difficult control. The disease was first detected in Brazil in the 1995 waters harvest time in São Paulo State. Besides the Southeast region, the disease is currently also distributed in the South and Middle West regions. Typical symptoms of the disease include: wilt yellow leaves and plant death. However, the symptoms are variable according to the different levels of resistance in the plant genotypes. Due to the difficult disease control, genetic resistance has been the better option. The aim of this study was to evaluate the reaction of bean genotypes to the bacterial wilt in common bean in 333 access of the bean plant germoplasm database of the Instituto Agronômico de Campinas (IAC), and to compare the Cff colonization in xylem vessels of highly resistant and susceptible bean plants by scanning electronic microscopy. It also aimed the molecular evaluation of the CffFOR2-CffREV4 and CF4-CF5 primers specificity using PCR reaction in the identification of 24 Cff isolateds from geographically separated regions and 2 citrus endophytic Curtobacterium flaccumfaciens isolated, as well as the genetic variability of these isolates by rep-PCR, and the Cff aggressiveness analysis by the inoculation of susceptible and highly resistant bean plant genotypes. The observed results indicated genetic variability in all 333 genotypes evaluated in relation to the Cff isolate Feij 2634. The materials were classified into four resistance levels: 29 highly resistance genotypes (8.7%), 13 resistant genotypes (3.9%), 18 moderately resistant genotypes (5.0%) and 273 susceptible genotypes (81.0%). Using the scanning electronic microscopy, several bacteria agglutinations involved by filaments and the appearance of tangled structures under the punctuations... (Complete abstract, click electronic address below).
Descrição
Palavras-chave
Feijão, Plantas - Resistencia a doenças e pragas, Phaseolus vulgaris, Variabilidade genética, Agressividade de isolados, Genetic resistance
Como citar
SOUZA, Valmir Luiz de. Reação de genótipos de feijoeiro a Curtobacterium flaccumfaciens PV. flaccumfaciens, agressividade e variabilidade molecular de isolados. 2004. vii, 75 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2004.