Avaliação de características agronômicas e bioquímicas de cultivares de feijoeiro com diferentes níveis de resistência à murcha-de-curtobacterium
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Data
2018-01-03
Autores
Soman, José Marcelo
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Universidade Estadual Paulista (Unesp)
Resumo
A murcha-de-curtobacterium, incitada por Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), é uma das principais doenças do feijoeiro comum (Phaseolus vulgaris L.) no Brasil e em alguns países do mundo. Até o momento, sua principal forma de manejo é a utilização de cultivares com níveis de resistência. Porém há escassez de informações sobre a dinâmica populacional bacteriana, mecanismos de resistência e produtividade nessas cultivares. Diante disto, os objetivos deste trabalho foram: avaliar a dinâmica populacional de Cff em cultivares resistentes e suscetíveis de feijoeiro; caracterizar as principais alterações fisiológicas em resposta ao processo de infecção das plantas por Cff e; avaliar as características agronômicas das plantas de feijoeiro de cultivares resistentes e suscetíveis em resposta à infecção por Cff. Para tal, os ensaios foram conduzidos em casa-de-vegetação, na Faculdade de Ciências Agronômicas, UNESP, Botucatu-SP. No primeiro ensaio e na sua repetição, foi avaliada a dinâmica populacional bacteriana em cultivares resistentes e suscetíveis de feijoeiro nos quatro primeiros entrenós. No segundo ensaio, foi avaliada a atividade das enzimas superóxido dismutase (SOD), polifenoloxidase (PFO), peroxidase (POX) e a concentração de proteínas e compostos fenólicos totais em nove coletas realizadas às 0, 12, 24, 48, 72, 96, 120, 168 e 336 horas após a inoculação. No terceiro ensaio, em três repetições, foram avaliadas as principais características agronômicas para a cultura do feijoeiro, tais como número de vagens por planta, número de grãos por vagem, massa de 100 grãos, juntamente com a severidade da doença. Foi observado que a colonização em cultivares com níveis de resistência é mais lenta e estas apresentam menor número de bactérias em seus tecidos em relação às cultivares suscetíveis, sendo este resultado influenciado por temperaturas médias mais elevadas. As enzimas avaliadas responderam com maior intensidade ao estresse oxidativo gerado pela presença da bactéria em cultivares resistentes em comparação às suscetíveis, podendo ser utilizadas como marcadores de resistência. Os teores de proteínas e compostos fenólicos também foram aumentados nessas cultivares em resposta à doença. As características agronômicas foram diretamente afetadas pela doença em cultivares suscetíveis, destacando se a cultivar Pérola que teve sua produção extremamente reduzida. A doença também fez com que os níveis de matéria seca fossem diretamente reduzidos nessas cultivares.
The Bacterial wilt, induced by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), is one of the main disease of common bean crops (Phaseolus vulgaris L.) in Brazil and around world. Until now, the basic management form is the cultivars application with levels of resistance, however there is lack of information about bacterial population dynamic, resistance mechanisms and productivity in those cultivars. Based on that, the objectives of this work were: to evaluate the dynamic of Cff population in resistant and susceptible cultivars of common bean; to characterize the main physiological alterations in response to the plant colonization process by Cff and; to measure the agronomic parameters of bean plants from resistant and susceptible cultivars in response to the colonization by Cff. To this end, the assays were performed in greenhouse condition located on Faculdade de Ciências Agronômicas, UNESP, Botucatu-SP. During the first assay and your respective repetition, was evaluated the dynamic bacterial population in resistant and susceptive cultivars of bean in the first four internodes. In the second assay, was evaluate the activity of the enzymes superoxide dismutase (SOD), polyphenoloxidase (PPO), peroxidase (POX) and the concentration of proteins and total phenolic compounds in nine collections accomplished at 0, 12, 24, 48, 72, 96, 120, 168 and 336 hours after the inoculation. About the third assay, with three repetitions, were evaluated the main agronomic parameters for beans crop, such as number of pods per plant, number of grain per pod, mass of one hundred grains, along with the severity of the disease. It was observed that the colonization in cultivars with levels of resistance is slowest and present the smallest number of bacteria in their tissues comparing the susceptive cultivars, as this result influenced by medium temperatures higher. The enzymes evaluated respond with greater intensity to oxidative stress induced by the presence of bacteria in resistant plants comparing to susceptible, which can be used as resistant markers. The levels of proteins and phenolic compounds are also increased in those cultivars as a response to bacterial wilt. The agronomic parameters were directly affected by the disease in susceptive cultivars, highlighting the Pérola cultivar, which it had extremely reduced production. The disease also contributed with the directly decreasing of the levels of dry matter in those cultivars.
The Bacterial wilt, induced by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), is one of the main disease of common bean crops (Phaseolus vulgaris L.) in Brazil and around world. Until now, the basic management form is the cultivars application with levels of resistance, however there is lack of information about bacterial population dynamic, resistance mechanisms and productivity in those cultivars. Based on that, the objectives of this work were: to evaluate the dynamic of Cff population in resistant and susceptible cultivars of common bean; to characterize the main physiological alterations in response to the plant colonization process by Cff and; to measure the agronomic parameters of bean plants from resistant and susceptible cultivars in response to the colonization by Cff. To this end, the assays were performed in greenhouse condition located on Faculdade de Ciências Agronômicas, UNESP, Botucatu-SP. During the first assay and your respective repetition, was evaluated the dynamic bacterial population in resistant and susceptive cultivars of bean in the first four internodes. In the second assay, was evaluate the activity of the enzymes superoxide dismutase (SOD), polyphenoloxidase (PPO), peroxidase (POX) and the concentration of proteins and total phenolic compounds in nine collections accomplished at 0, 12, 24, 48, 72, 96, 120, 168 and 336 hours after the inoculation. About the third assay, with three repetitions, were evaluated the main agronomic parameters for beans crop, such as number of pods per plant, number of grain per pod, mass of one hundred grains, along with the severity of the disease. It was observed that the colonization in cultivars with levels of resistance is slowest and present the smallest number of bacteria in their tissues comparing the susceptive cultivars, as this result influenced by medium temperatures higher. The enzymes evaluated respond with greater intensity to oxidative stress induced by the presence of bacteria in resistant plants comparing to susceptible, which can be used as resistant markers. The levels of proteins and phenolic compounds are also increased in those cultivars as a response to bacterial wilt. The agronomic parameters were directly affected by the disease in susceptive cultivars, highlighting the Pérola cultivar, which it had extremely reduced production. The disease also contributed with the directly decreasing of the levels of dry matter in those cultivars.
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Palavras-chave
Curtobacterium flaccumfaciens pv. flaccumfaciens, Murcha-de-curtobacterium, feijoeiro comum, cultivares resistentes