Atividade inseticida de metabólitos produzidos por Streptomyces sp. ENT-21 sobre lagartas de Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae)
Carregando...
Arquivos
Data
2019-07-25
Autores
Santos, Ana Letícia Zéro dos
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A possibilidade da evolução da resistência dos insetos à maioria dos inseticidas disponíveis e a necessidade por moléculas específicas para o manejo de organismos alvos e não tóxicas ao meio ambiente guiam a contínua busca por novos compostos com atividade inseticida. No presente trabalho, investigamos o potencial da actinobactéria Streptomyces sp. ENT-21 como fonte de moléculas inseticidas sobre lagartas de Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), uma importante praga da cana-de-açúcar. Um extrato quitinolítico foi produzido a partir do cultivo de Streptomyces sp. ENT-21 em meio contendo quitina. Este extrato foi fracionado por filtração molecular (Sephadex G25) e separado em amostras proteicas e não proteicas. Os efeitos do extrato quitinolítico bruto e fracionado sobre a taxa de mortalidade e peso das lagartas de D. saccharalis foram avaliados. A adição do extrato quitinolítico bruto de Streptomyces sp. ENT-21 à dieta artificial resultou em 100% de mortalidade das lagartas de D. saccharalis. Após fracionamento a amostra não proteica resultou em maior mortalidade e redução do peso das lagartas em relação à fração proteica. Esses dados sugerem que a atividade quitinolítica não seja o principal modo de ação responsável pela atividade inseticida do extrato quitinolítico. Os dados também sugerem um possível efeito sinérgico entre os composto proteicos e não proteicos presentes no extrato bruto de Streptomyces sp. ENT-21.
Insect resistance to most of the available insecticides and the requirement for specific molecules for pest management and safe to the environment guide a continuous search of new insecticidal compounds. In this work, we investigated the potential of the actinobacterium Streptomyces sp. ENT-21 as a source of insecticidal molecules against larval Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), an important sugarcane pest. The chitinolytic extract was prepared by cultivating Streptomyces sp. ENT-21 in a chitin containing medium. This extract was fractionated using molecular filtration (Sephadex G25) forming protein and non-protein fractions. The effects of the crude chitinolytic extract as well of the fractions were evaluated over the development of D. saccharalis larvae in bioassays conducted using artificial diet. The addition of the crude chitinolytic extract to the artificial diet used for rearing larval D. saccharalis resulted in 100% of larval mortality. A non-protein fraction resulted in a higher mortality rate and weight reduction over surviving larvae than the protein fraction, suggesting that the chitinolytic activity present in the protein fraction is not the main mode of action involved in the insecticidal activity of the chitinolytic produced extract. Results also suggest a possible synergic effect among protein and non protein compounds in the crude chitinolytic extract from Streptomyces sp. ENT-21.
Insect resistance to most of the available insecticides and the requirement for specific molecules for pest management and safe to the environment guide a continuous search of new insecticidal compounds. In this work, we investigated the potential of the actinobacterium Streptomyces sp. ENT-21 as a source of insecticidal molecules against larval Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), an important sugarcane pest. The chitinolytic extract was prepared by cultivating Streptomyces sp. ENT-21 in a chitin containing medium. This extract was fractionated using molecular filtration (Sephadex G25) forming protein and non-protein fractions. The effects of the crude chitinolytic extract as well of the fractions were evaluated over the development of D. saccharalis larvae in bioassays conducted using artificial diet. The addition of the crude chitinolytic extract to the artificial diet used for rearing larval D. saccharalis resulted in 100% of larval mortality. A non-protein fraction resulted in a higher mortality rate and weight reduction over surviving larvae than the protein fraction, suggesting that the chitinolytic activity present in the protein fraction is not the main mode of action involved in the insecticidal activity of the chitinolytic produced extract. Results also suggest a possible synergic effect among protein and non protein compounds in the crude chitinolytic extract from Streptomyces sp. ENT-21.
Descrição
Palavras-chave
Quitinase, Metabólitos secundários, Simbiose, Biotecnologia, Manejo de insetos