AVALIAÇÃO DE RIZÓBIOS NO INCREMENTO DA PRODUÇÃO DE FEIJÃO (Phaseolus vulgaris L.) E NO BIOCONTROLE DO FUNGO Macrophomina phaseolina
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Data
2020-02
Autores
Orientador
Sperotto, Raul Antonio
Banca
Freitas, Elisete Maria de
Castro, Luís César de
Cagliari, Alexandro
Título do periódico
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Título do Volume
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Resumo
O cultivo de feijão comum (Phaseolus vulgaris L.) é de importância econômica, nutricional e cultural em diversos países. Esta espécie leguminosa pode estabelecer relações simbióticas com bactérias nodulíferas, popularmente conhecidas como rizóbios, resultando na Fixação Biológica do Nitrogênio (FBN). Além de desempenhar um papel fundamental na FBN, este grupo de microrganismos pode reduzir a incidência de doenças causadas por fitopatógenos em várias culturas. Nesse sentido, este trabalho objetivou avaliar, a campo, a resposta do feijoeiro comum à inoculação de rizóbios nativos, estudando seus efeitos sobre indicadores de crescimento e nutrição dessa planta, e também estudar a capacidade dessas bactérias no biocontrole das principais doenças da podridão das raízes do feijão comum. A resposta de Rhizobium sp. no
desenvolvimento de M. phaseolina MP 53 foi inicialmente avaliada in vitro. Para a avaliação a campo, duas espécies de rizóbios (SEMIA4107 e SEMIA4108), previamente selecionadas em função da sua resposta em experimentos em casa de vegetação, foram avaliadas frente à estirpe recomendada comercialmente para o feijoeiro comum (SEMIA 4088 - Rhizobium tropici). O delineamento experimental empregado foi em blocos ao acaso, totalizando quatro repetições, sendo avaliados cinco tratamentos: ausência de fertilizante nitrogenado (-N); adição de N- mineral (+N); inoculante líquido contendo a estirpe recomendada (SEMIA 4088); tratamentos contendo os inoculantes com os isolados SEMIA4108 e SEMIA4107. As avaliações agronômicas deram-se a partir de 45 e 90 dias após a emergência das plantas (DAE). As plantas inoculadas com os rizóbios SEMIA 4107 apresentaram uma produtividade de grãos ligeiramente maior do que o controle nitrogenado (+N). O desenvolvimento de plantas inoculadas foi diferente do padrão observado para o controle nitrogenado (+N), porém, nenhuma perda de produtividade foi detectada. Para a avaliação do antagonismo in vitro contra o M. phaseolina MP53, isolados de rizóbios foram obtidos através do método de planta-isca,
utilizando-se plantas de feijão comum. Após a avaliação do antagonismo, amostras do meio líquido foram filtradas e submetidas a rota-evaporação para posterior identificação dos metabólitos pela técnica de cromatografia gasosa associada à espectrometria de massas (GC-MS). Entre as 40 estirpes de rizóbios isoladas, somente os isolados R26, L5 e VC28 tiveram efeito inibitório in vitro contra o fitopatógeno, com redução de aproximadamente 50% na massa micelial. Os metabólitos identificados por GC-MS já foram caracterizados na literatura como antimicrobianos e podem estar relacionados à atividade de antagonismo observada. Dessa forma, esse trabalho demonstrou dois resultados impactantes na busca por uma agricultura mais sustentável. Primeiro, a utilização de rizóbios pode ser uma alternativa à produção do feijão comum, tanto pela sua utilização como inoculante na FBN em substituição ao uso tradicional de adubos nitrogenados, quanto pela diversificação na busca por novas estirpes adaptadas a essa cultura. Além disso, essas bactérias possuem potencial para o biocontrole das principais doenças da podridão das raízes do feijão comum.
Common bean (Phaseolus vulgaris L.) cultivation is of economic, nutritional and cultural importance in several countries. This legume species can establish symbiotic relationships with noduliferous bacteria, popularly known as rhizobia, resulting in Biological Nitrogen Fixation (BNF). In addition to playing a key role in BNF, this group of microorganisms can reduce the incidence of diseases caused by phytopathogens in various crops. Thus, this work aimed to evaluate the response of common bean to the inoculation of native rhizobia, studying its effects on growth and nutrition indicators of this plant and also to study the capacity of these bacteria in the biocontrol of the main rot diseases in common bean plants. The response of Rhizobium sp. on development of M. phaseolina MP 53 was evaluated in vitro. For field tests, two rhizobia species, SEMIA4107 and SEMIA4108, previously selected for their response in greenhouse experiments, were evaluated against the commercially recommended strain for common bean, SEMIA 4088 - Rhizobium tropici). The experimental design was randomized blocks, totaling four replications, and five treatments were evaluated: absence of nitrogen fertilizer (-N); addition of N-mineral (+ N); liquid inoculant containing the recommended strain (SEMIA 4088); treatments containing inoculants with SEMIA4108 and SEMIA4107 isolates. Agronomic evaluations took place 45 and 90 days after plant emergence (DAE). Plants inoculated with SEMIA 4107 rhizobia showed slightly higher grain yield than the nitrogen control (+ N). The development of inoculated plants was different from the standard observed for nitrogen control (+ N), but no yield losses were detected. For the evaluation of in vitro antagonism against M. phaseolina MP53, rhizobia isolates were obtained by the bait plant method using common bean plants. After the evaluation of the antagonism, samples of the liquid medium were filtered and subjected to rotary evaporation, for subsequent identification of the metabolites by gas chromatography mass spectrometry-associated (GC-MS) technique. Among the 40 isolated rhizobia strains, only the isolates R26, L5 and VC28 presented an in vitro inhibitory effect against phytopathogen, with a reduction of approximately 50% in mycelial mass. The metabolites identified by GC-MS have already been characterized as antimicrobials, and may be related to the antagonism activity observed. Thus, this work showed two important results in the search for a more sustainable agriculture. First, the use of rhizobia may be an alternative to common bean production, both for its use as an inoculant in BNF as a substitute for the traditional use of nitrogenous fertilizers, as well as for the diversification in the search for new strains adapted to this crop. In addition, these bacteria have the potential for biocontrol of major common bean root rot diseases.
Common bean (Phaseolus vulgaris L.) cultivation is of economic, nutritional and cultural importance in several countries. This legume species can establish symbiotic relationships with noduliferous bacteria, popularly known as rhizobia, resulting in Biological Nitrogen Fixation (BNF). In addition to playing a key role in BNF, this group of microorganisms can reduce the incidence of diseases caused by phytopathogens in various crops. Thus, this work aimed to evaluate the response of common bean to the inoculation of native rhizobia, studying its effects on growth and nutrition indicators of this plant and also to study the capacity of these bacteria in the biocontrol of the main rot diseases in common bean plants. The response of Rhizobium sp. on development of M. phaseolina MP 53 was evaluated in vitro. For field tests, two rhizobia species, SEMIA4107 and SEMIA4108, previously selected for their response in greenhouse experiments, were evaluated against the commercially recommended strain for common bean, SEMIA 4088 - Rhizobium tropici). The experimental design was randomized blocks, totaling four replications, and five treatments were evaluated: absence of nitrogen fertilizer (-N); addition of N-mineral (+ N); liquid inoculant containing the recommended strain (SEMIA 4088); treatments containing inoculants with SEMIA4108 and SEMIA4107 isolates. Agronomic evaluations took place 45 and 90 days after plant emergence (DAE). Plants inoculated with SEMIA 4107 rhizobia showed slightly higher grain yield than the nitrogen control (+ N). The development of inoculated plants was different from the standard observed for nitrogen control (+ N), but no yield losses were detected. For the evaluation of in vitro antagonism against M. phaseolina MP53, rhizobia isolates were obtained by the bait plant method using common bean plants. After the evaluation of the antagonism, samples of the liquid medium were filtered and subjected to rotary evaporation, for subsequent identification of the metabolites by gas chromatography mass spectrometry-associated (GC-MS) technique. Among the 40 isolated rhizobia strains, only the isolates R26, L5 and VC28 presented an in vitro inhibitory effect against phytopathogen, with a reduction of approximately 50% in mycelial mass. The metabolites identified by GC-MS have already been characterized as antimicrobials, and may be related to the antagonism activity observed. Thus, this work showed two important results in the search for a more sustainable agriculture. First, the use of rhizobia may be an alternative to common bean production, both for its use as an inoculant in BNF as a substitute for the traditional use of nitrogenous fertilizers, as well as for the diversification in the search for new strains adapted to this crop. In addition, these bacteria have the potential for biocontrol of major common bean root rot diseases.
Descrição
Palavras-chave
Fixação biológica de nitrogênio; Contaminação ambiental; Rizóbios nativos; Biocontrole; Macrophomina phaseolina; Metabólitos antimicrobianos; Biological nitrogen fixation; Environmental contamination; Indigenous Rhizobium; Biocontrol; Macrophomina phaseolina; Antimicrobial metabolites
Citação
SCHMIDT, Thomas Müller. AVALIAÇÃO DE RIZÓBIOS NO INCREMENTO DA PRODUÇÃO DE FEIJÃO (Phaseolus vulgaris L.) E NO BIOCONTROLE DO FUNGO Macrophomina phaseolina. 2020. Tese (Doutorado) – Curso de Biotecnologia, Universidade do Vale do Taquari - Univates, Lajeado, 15 fev. 2020. Disponível em: http://hdl.handle.net/10737/2813.