Caracterização molecular de isolados bacterianos de nódulos e rizosfera de soja em diferentes manejos de cultivo
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Data
2011-08-02
Autores
Costa, Maira Rejane [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O crescimento da produção e o aumento da capacidade competitiva da soja brasileira estão associados aos avanços científicos e à disponibilização de tecnologias ao setor produtivo. A fim de maximizar os benefícios da FBN, o estudo da diversidade genética de Bradyrhizobium japonicum e Bradyrhizobium elkanii relacionada com diferentes sistemas de manejo da cultura da soja é imprescindível para entender as interações entre a população de rizóbios presentes no solo com as estirpes de inoculantes em ambientes diferentes. O objetivo deste trabalho foi avaliar a variabilidade genética de rizóbios em solos cultivados com soja sob diferentes sistemas de manejo caracterizados com rotação e sucessão de culturas recomendadas para o estado de Mato Grosso do Sul. A partir de amostras de DNA extraídos destas bactérias foi utilizado o marcador molecular fAFLP para estimar a diversidade genética dos 119 isolados de nódulos de soja, e em seguida realizado o sequenciamento parcial do gene 16S rDNA para definir a posição das bactérias em nível de gênero e, em alguns casos, em nível de espécie. Os resultados obtidos, com base no fAFLP, permitiu a divisão dos isolados em dois grupos. No primeiro grupo posicionaram se a maioria dos isolados do sistema plantio direto e dois representantes do sistema convencional que pertencem à safra 2006-2007. Em relação ao segundo grupo, foi observada uma heterogeneidade elevada entre os isolados de diferentes safras e sistemas de manejo (convencional, plantio direto e sistema integrado lavoura pecuária. Com a análise de diversidade genética com base no sequenciamento do gene 16S rDNA, as sequências das 42 estirpes (incluindo as estirpes padrões recomendadas para a fabricação de inoculantes para soja) foi constatado a formação de 2 filos: Proteobactérias...
The growth of crop production and increased competitiveness of Brazilian soybean are associated with scientific advances and the availability of technology to the productive sector. In order to maximize the benefits of BNF, the study of genetic diversity of Bradyrhizobium japonicum and Bradyrhizobium elkanii related to different management systems of the soybean crop is essential to understand the interactions between the population of rhizobia in the soil with the inoculant strains in different environments. The objective of this study was to assess the genetic diversity of rhizobia in soils cultivated with soybean under different management systems characterized by crop rotation and succession recommended for the state of Mato Grosso do Sul. Fluorescent AFLP molecular marker was used to estimate the genetic diversity of 119 isolates from soybean nodules. Samples of DNA extracted from these bacteria were used and partial sequencing of the 16S rDNA was performed to define the position of bacteria at genus level and, in some cases, species level. The results, based on fAFLP, allowed the division of the isolates into two groups. Most isolates of the no-tillage system and two isolates from the conventional system that belong to the 2006-2007 season represented the first group. The second group was represented by a high heterogeneity among the isolates from different crops and management systems (conventional, no-tillage and integrated crop-livestock). The analysis of genetic diversity based on the sequencing of the 16S rDNA of forty-two strains (including standard strains recommended for the production of inoculants for soybeans) allowed the formation of two phyla: Proteobacteria (with the alpha, beta and gamma classes) and Firmicutes. Also a sister group of Firmicutes was... (Complete abstract click electronic access below)
The growth of crop production and increased competitiveness of Brazilian soybean are associated with scientific advances and the availability of technology to the productive sector. In order to maximize the benefits of BNF, the study of genetic diversity of Bradyrhizobium japonicum and Bradyrhizobium elkanii related to different management systems of the soybean crop is essential to understand the interactions between the population of rhizobia in the soil with the inoculant strains in different environments. The objective of this study was to assess the genetic diversity of rhizobia in soils cultivated with soybean under different management systems characterized by crop rotation and succession recommended for the state of Mato Grosso do Sul. Fluorescent AFLP molecular marker was used to estimate the genetic diversity of 119 isolates from soybean nodules. Samples of DNA extracted from these bacteria were used and partial sequencing of the 16S rDNA was performed to define the position of bacteria at genus level and, in some cases, species level. The results, based on fAFLP, allowed the division of the isolates into two groups. Most isolates of the no-tillage system and two isolates from the conventional system that belong to the 2006-2007 season represented the first group. The second group was represented by a high heterogeneity among the isolates from different crops and management systems (conventional, no-tillage and integrated crop-livestock). The analysis of genetic diversity based on the sequencing of the 16S rDNA of forty-two strains (including standard strains recommended for the production of inoculants for soybeans) allowed the formation of two phyla: Proteobacteria (with the alpha, beta and gamma classes) and Firmicutes. Also a sister group of Firmicutes was... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Genetic diversity, Soil management practices, Soja - Manejos de cultivo, Manejo do solo, Isolados bacterianos - Caracterização molecular, Plantas - Resistência aos insetos
Como citar
COSTA, Maira Rejane. Caracterização molecular de isolados bacterianos de nódulos e rizosfera de soja em diferentes manejos de cultivo. 2011. xii, 72 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2011.