Acessando o microbioma da rizosfera de cana-de-açúcar em cultivo orgânico comparado ao convencional
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Data
2019-08-26
Autores
Campanari, Maria Fernanda Zaneli [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O cultivo intensivo agrícola, apesar de altamente produtivo, possui diversos pontos questionáveis, como suplementação acentuada de insumos sintéticos, além da aplicação de defensivos para o controle de pragas que muitas vezes são danosos ao meio ambiente. Como alternativa, a agricultura orgânica propõe uma forma de manejo menos agressiva, que promove o uso sustentável dos recursos naturais renováveis, como o aproveitamento de resíduos orgânicos, além de possuir um maior valor agregado no produto final. No presente estudo, investigamos por meio de uma abordagem metagenômica os efeitos do manejo (orgânico ou convencional) na microbiota da rizosfera de cana-de-açúcar, região da planta que notoriamente causa um grande impacto no seu desenvolvimento e produtividade. Identificamos a abundância maior na rizosfera com manejo orgânico de porções genômicas que codificam enzimas associadas ao metabolismo do nitrogênio e enxofre, sendo que estes são nutrientes fundamentais para o sucesso da planta e assim, seu desenvolvimento e produtividade em campo. Contraditoriamente, encontramos também que os genomas da microbiota orgânica possuem conteúdo ligado a um potencial mais acentuado para a degradação de compostos xenobióticos, que são ativamente aplicados no manejo convencional. De acordo com nossa predição, os microrganismos dessa microbiota poderiam realizar sua completa mineralização, o que é muito favorável na remoção desses resíduos no ambiente. Esses achados indicam que há um potencial único para exploração do cultivo orgânico, além da capacidade de fornecer alimentos livres de agroquímicos por meio de um manejo que propende causar um menor impacto ao ambiente agroecológico. Consideramos, com base nos resultados, que esse ambiente pode ser uma fonte de bioprospecção de microrganismos associados aos ciclos de nutrientes, como N e S, além de potenciais degradadores de xenobióticos para biorremediação.
Modern industrialized agriculture although highly productive, has several sustainability problems such as the for intense supplementation of synthetic inputs, beyond the application of pesticides for pest control. Which are often harmful to environment. As an alternative to this system, organic agriculture is considered more environmentally progressive, having several characteristics favorable to the crop producer, promotes sustainable use of renewable natural resources, such as the use of organic waste, besides that a higher aggregated value in the final product. This study investigates the changes that an organic system brings when compared to conventional management for the sugarcane rhizosphere microbiome, a plant region known to be determinant of plant development and associated with net productivity, using a metagenomic approach. We identified a higher abundance of genomic portions which encode enzymes associated with nitrogen and sulphur metabolism, which are fundamental nutrients for plant success and subsequently, crop productivity. Conversely, we also found that genomes of the organic microbiome contain higher portions linked to xenobiotic degradation, compounds that are actively applied in conventional management. Microorganisms from this sequenced microbiome could perform complete mineralization of these damaging compounds, which is desirable in their removal from the environment. These findings indicate that there is a unique potential for exploitation of organic farming, in addition to the ability to provide agrochemical-free through management that tends to have a lower impact on the agroecological environment. Based on the results, the organic system environment may be a source of microorganisms associated with nutrient cycles - nitrogen and sulphur, as well as microbes associated with bioremediation through xenobiotics degradation.
Modern industrialized agriculture although highly productive, has several sustainability problems such as the for intense supplementation of synthetic inputs, beyond the application of pesticides for pest control. Which are often harmful to environment. As an alternative to this system, organic agriculture is considered more environmentally progressive, having several characteristics favorable to the crop producer, promotes sustainable use of renewable natural resources, such as the use of organic waste, besides that a higher aggregated value in the final product. This study investigates the changes that an organic system brings when compared to conventional management for the sugarcane rhizosphere microbiome, a plant region known to be determinant of plant development and associated with net productivity, using a metagenomic approach. We identified a higher abundance of genomic portions which encode enzymes associated with nitrogen and sulphur metabolism, which are fundamental nutrients for plant success and subsequently, crop productivity. Conversely, we also found that genomes of the organic microbiome contain higher portions linked to xenobiotic degradation, compounds that are actively applied in conventional management. Microorganisms from this sequenced microbiome could perform complete mineralization of these damaging compounds, which is desirable in their removal from the environment. These findings indicate that there is a unique potential for exploitation of organic farming, in addition to the ability to provide agrochemical-free through management that tends to have a lower impact on the agroecological environment. Based on the results, the organic system environment may be a source of microorganisms associated with nutrient cycles - nitrogen and sulphur, as well as microbes associated with bioremediation through xenobiotics degradation.
Descrição
Palavras-chave
Metagenômica, Rizosfera, Cana-de-açúcar, Ecologia microbiana, Sequenciamento de nucleotídeos em larga escala, Whole-metagenome shotgun, plant-associated microbiome, plant growth promoting rhizobacteria