Curtobacterium flaccumfaciens PV. flaccumfaciens: sobrevivência, gama de hospedeiras e efeito do pré-plantio de aveia e trigo na ocorrência da doença
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Data
2011-05-13
Autores
Silva Júnior, Tadeu Antônio Fernandes da [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A murcha-de-curtobacterium, causada por Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), é uma das principais doenças bacterianas da cultura do feijoeiro, acarretando grandes perdas na produção dessa cultura. Até o momento existem poucas informações sobre os diferentes nichos de sobrevivência desta bactéria e de sua gama de hospedeiras. Em vista disso, este trabalho teve por objetivos principais verificar a capacidade de sobrevivência saprofítica de Cff em restos de cultura de feijoeiro mantidos na superfície do solo e enterrados à 20 cm de profundidade; a influência da temperatura, umidade e do tipo de solo no período de sobrevivência da bactéria em solo; determinar a gama de hospedeiras de Cff inoculadas artificialmente, tanto por ferimento no caule, como por aspersão de suspensão bacteriana na parte aérea das plantas; a capacidade de colonização de Cff do rizoplano de plantas de aveia e trigo; e o efeito do pré-plantio de aveia e trigo na ocorrência da murcha-de-curtobacterium. Quanto à capacidade de sobrevivência de Cff em restos de cultura de feijoeiro, foi demonstrado que a bactéria possui menor capacidade de sobrevivência quando os restos vegetais são incorporados ao solo e também em épocas com maiores índices de precipitação e temperaturas mais altas. O período de sobrevivência do patógeno nos restos culturais de feijoeiro mantidos na superfície do solo variou entre 165 e 240 dias e nos restos vegetais enterrados a 20 cm de profundidade, o período de sobrevivência foi inferior a 30 dias. Quanto à sobrevivência de Cff na forma de células livres no solo, foi verificado que a temperatura, a umidade e o tipo do solo têm influencia na capacidade de sobrevivência da bactéria. O tempo de sobrevivência de Cff variou entre dois e quinze dias. Das 30 espécies botânicas inoculadas artificialmente com Cff, a bactéria causou lesões na parte...
Bacterial wilt caused by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) is one of the main bacterial diseases affecting bean culture, leading to great losses in its production. So far there is scarce information about the different survival niches and host range of this bacterium. Thus, the present study had as major aims to verify Cff capability of saprophytically surviving in bean debris kept on the soil surface and buried at 20 cm depth; to assess the influence of temperature, humidity and soil type on the survival period of this bacterium in soil; to determine the host range for artificially inoculated Cff, either through stem injury or through bacterial sprinkling onto the shoot of plants; to verify Cff capability of colonizing the rhizoplane of oat and wheat plants; and to assess the effect of oat and wheat pre-planting on the occurrence of bean bacterial wilt. Cff had decreased capability of surviving in bean debris when the latter were incorporated into the soil and during periods of higher rainfall rates and temperatures. The pathogen survival period in bean culture remnants kept on the soil surface ranged from 165 and 240 days, while in plant debris buried at 20 cm depth the survival period was inferior to 45 days. The survival capability of Cff as free cells in soil was influenced by temperature, humidity and soil type. Cff survival time varied between two and fifteen days. Of 30 plant species artificially inoculated with Cff, bean and soy shoot had lesions caused by the bacterium which endophytically colonized wheat leaves and soy and wheat stem and leaves. Cff was also shown to have no capability of colonizing oat and wheat rhizoplane while the pre-planting of these grass plants, before bean culture establishment, had no effect on the occurrence of bean bacterial wilt
Bacterial wilt caused by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) is one of the main bacterial diseases affecting bean culture, leading to great losses in its production. So far there is scarce information about the different survival niches and host range of this bacterium. Thus, the present study had as major aims to verify Cff capability of saprophytically surviving in bean debris kept on the soil surface and buried at 20 cm depth; to assess the influence of temperature, humidity and soil type on the survival period of this bacterium in soil; to determine the host range for artificially inoculated Cff, either through stem injury or through bacterial sprinkling onto the shoot of plants; to verify Cff capability of colonizing the rhizoplane of oat and wheat plants; and to assess the effect of oat and wheat pre-planting on the occurrence of bean bacterial wilt. Cff had decreased capability of surviving in bean debris when the latter were incorporated into the soil and during periods of higher rainfall rates and temperatures. The pathogen survival period in bean culture remnants kept on the soil surface ranged from 165 and 240 days, while in plant debris buried at 20 cm depth the survival period was inferior to 45 days. The survival capability of Cff as free cells in soil was influenced by temperature, humidity and soil type. Cff survival time varied between two and fifteen days. Of 30 plant species artificially inoculated with Cff, bean and soy shoot had lesions caused by the bacterium which endophytically colonized wheat leaves and soy and wheat stem and leaves. Cff was also shown to have no capability of colonizing oat and wheat rhizoplane while the pre-planting of these grass plants, before bean culture establishment, had no effect on the occurrence of bean bacterial wilt
Descrição
Palavras-chave
Feijão, Bacterias patogenicas, Bean, Bean bacterial wilt, Curtobacterium flaccumfaciens pv. flaccumfaciens, Host range, Phaseolus vulgaris, Survival
Como citar
SILVA JÚNIOR, Tadeu Antônio Fernandes da. Curtobacterium flaccumfaciens PV. flaccumfaciens: sobrevivência, gama de hospedeiras e efeito do pré-plantio de aveia e trigo na ocorrência da doença. 2011. x, 98 f. Tese (doutorado) - Universidade EStadual Paulista, Faculdade de Ciências Agronômicas, 2011.