Potencial de Bacillus spp. no controle de estresses biótico e abiótico e na promoção de crescimento de tomateiro
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Data
2018-01-12
Autores
Albuquerque, Carlos Alberto Cavalcante de
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Universidade Estadual Paulista (Unesp)
Resumo
O gênero Bacillus tem demonstrado em diversos estudos eficiência no controle de estresses bióticos e abióticos, tornando-se uma alternativa viável para o manejo desses problemas. O objetivo desse estudo foi avaliar o potencial de isolados de Bacillus spp. em induzir resistência em plantas de tomateiro a estresses bióticos (Fusarium oxysporum f. sp. lycopersici raça 3 e Oidium), abiótico (estresse salino) e em promover crescimento. Inicialmente, foi realizada uma seleção in vitro utilizando testes bioquímicos (produção de ácido indol acético e sideróforos, solubilização de fosfato, fixação assimbiótica de nitrogênio e produção de celulase e de catalase) com 154 isolados. Posteriormente, com quatro isolados selecionados nessa primeira fase, mais um produto comercial à base de Bacillus subtilis QST-713, foram avaliados o potencial desses isolados na promoção de crescimento das plantas, na indução de resistência ao estresse salino e no controle de F. oxysporum f. sp. lycopersici e Oidium em plantas de tomate. Os isolados de Bacillus estimularam o crescimento das plantas no ensaio de promoção de crescimento sem estresse salino. No segundo estudo avaliou-se a indução de resistência ao estresse salino mediada por Bacillus e foram observados efeitos dos isolados de Bacillus na altura das plantas aos 41 e 48 dias após a semeadura e para a massa do sistema radicular, também os isolados de Bacillus estimularam a produção das enzimas peroxidase, fenilalanina amônia-liase, polifenoloxidase e de L-prolina indicando que os isolados de Bacillus ativaram ao menos dois mecanismos de defesa contra o estresse com sal. O isolado AP3 foi o mais eficiente no controle de Fusarium oxysporum f. sp. lycopersici raça 3 e de Oidium do tomateiro. Diante dos resultados conclui-se que o gênero Bacillus possuí versatilidade em promover controle biológico e o desenvolvimento das plantas em situação de estresse.
The Bacillus genus has demonstrated in several studies efficiency in the control of biotic and abiotic stresses, making it a viable alternative for the management of these problems. The objective of this study was to evaluate the potential of Bacillus spp. in inducing resistance in tomato plants to biotic stresses (Fusarium oxysporum f. sp. lycopersici race 3 and Oidium), abiotic (saline stress) and in growth promoting. Initially, an in vitro selection was performed using biochemical tests (indolacetic acid and siderophore production, phosphate solubilization, nitrogen assimilation and cellulase and catalase production) with 154 isolates. Then, with four isolates selected in this first phase, plus a commercial product based on Bacillus subtilis QST713, the potential of these isolates in the promotion of plant growth, induction of resistance to saline stress and in the control of Fusarium and Oidium in tomato plants were evaluated. Bacillus isolates stimulated plant growth in the growth promotion trial without saline stress. The second study evaluated the induction of resistance to saline stress mediated by Bacillus and observed effects of Bacillus isolates at plant height at 41 and 48 days after sowing and for root system mass. Bacillus isolates also stimulated production of the enzymes peroxidase, phenylalanine ammonia-lyase, polyphenoloxidase and L-proline, indicating that Bacillus isolates activated at least two defense mechanisms against salt stress. The AP3 isolate was the most efficient in the control of Fusarium oxysporum f. sp. lycopersici race 3 and Oidium in tomato. We concluded that Bacillus has the versatility to promote biological control and the development of plants under stress.
The Bacillus genus has demonstrated in several studies efficiency in the control of biotic and abiotic stresses, making it a viable alternative for the management of these problems. The objective of this study was to evaluate the potential of Bacillus spp. in inducing resistance in tomato plants to biotic stresses (Fusarium oxysporum f. sp. lycopersici race 3 and Oidium), abiotic (saline stress) and in growth promoting. Initially, an in vitro selection was performed using biochemical tests (indolacetic acid and siderophore production, phosphate solubilization, nitrogen assimilation and cellulase and catalase production) with 154 isolates. Then, with four isolates selected in this first phase, plus a commercial product based on Bacillus subtilis QST713, the potential of these isolates in the promotion of plant growth, induction of resistance to saline stress and in the control of Fusarium and Oidium in tomato plants were evaluated. Bacillus isolates stimulated plant growth in the growth promotion trial without saline stress. The second study evaluated the induction of resistance to saline stress mediated by Bacillus and observed effects of Bacillus isolates at plant height at 41 and 48 days after sowing and for root system mass. Bacillus isolates also stimulated production of the enzymes peroxidase, phenylalanine ammonia-lyase, polyphenoloxidase and L-proline, indicating that Bacillus isolates activated at least two defense mechanisms against salt stress. The AP3 isolate was the most efficient in the control of Fusarium oxysporum f. sp. lycopersici race 3 and Oidium in tomato. We concluded that Bacillus has the versatility to promote biological control and the development of plants under stress.
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Bacillus. estresse salino. promoção de crescimento. Solanum lycopersicom.