Suscetibilidade de Spodoptera frugiperda (Lepidoptera: Noctuidae) a proteína inseticida mutante de Cry1Ab
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Data
2021-12-07
Autores
Rocha, Beatriz Batista
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Universidade Estadual Paulista (Unesp)
Resumo
A Spodoptera frugiperda é uma praga polífaga, com grande variabilidade genética, além disso, possui alta capacidade reprodutiva e migratória, que a permitiu recentemente invadir o continente asiático. As principais formas de controle, produtos químicos e plantas Bt tem apresentado problemas devido a rápida evolução da resistência, devido à exposição de pragas a baixa dose e mutações em genes que codificam receptores. Uma alternativa é a utilização de toxinas mutantes de Bacillus thuringiensis (Bt) para quebrar da resistência. Nesse estudo foi avaliada o potencial de toxidade das proteínas inseticidas mutantes de Cry1Ab G439D e N514A em duas populações de S. frugiperda, uma população suscetível e outra resistente a Cry1F, Cry1A.105 e Cry2Ab2. Para tanto, realizou-se a extração, quantificação das proteínas e testes de suscetibilidade de S. frugiperda, utilizando-se 100 lagartas de primeiro instar por tratamento e sete concentrações das proteínas inseticidas. Somente na população suscetível as concentrações letais CL50 e CL90 foram estimadas, pois a população resistente apresentou baixa suscetibilidade e a proteínas inseticida mutante Cry1AbN514A foi a mais virulenta com CL50 estimada oito vezes maior do que a toxina selvagem.
Spodoptera frugiperda is a polyphagous pest, with great genetic variability, in addition, it has a high reproductive and migratory capacity, which has recently started to invade the Asian continent. As the main forms of control, chemicals and Bt plants have presented problems due to the rapid evolution of resistance, due to exposure to low-dose pests and mutations in genes that encode receptors. An alternative is to use mutant toxins from Bacillus thuringiensis (Bt) to break down resistance. In this study, the potential for toxicity of mutant insecticidal proteins of Cry1Ab G439D and N514A in two populations of S. frugiperda, a susceptible population and a resistant population to Cry1F, Cry1A.105 and Cry2Ab2. For that, the extraction, quantification of proteins and susceptibility tests of S. frugiperda were carried out, using 100 first-instar caterpillars per treatment and seven concentrations of insecticidal proteins. Only in the susceptible population the lethal concentrations LC50 and LC90 were estimated, as the resistant population showed low susceptibility and the mutant insecticide protein Cry1AbN514A was the most virulent with LC50 estimated eight times higher than the wild toxin.
Spodoptera frugiperda is a polyphagous pest, with great genetic variability, in addition, it has a high reproductive and migratory capacity, which has recently started to invade the Asian continent. As the main forms of control, chemicals and Bt plants have presented problems due to the rapid evolution of resistance, due to exposure to low-dose pests and mutations in genes that encode receptors. An alternative is to use mutant toxins from Bacillus thuringiensis (Bt) to break down resistance. In this study, the potential for toxicity of mutant insecticidal proteins of Cry1Ab G439D and N514A in two populations of S. frugiperda, a susceptible population and a resistant population to Cry1F, Cry1A.105 and Cry2Ab2. For that, the extraction, quantification of proteins and susceptibility tests of S. frugiperda were carried out, using 100 first-instar caterpillars per treatment and seven concentrations of insecticidal proteins. Only in the susceptible population the lethal concentrations LC50 and LC90 were estimated, as the resistant population showed low susceptibility and the mutant insecticide protein Cry1AbN514A was the most virulent with LC50 estimated eight times higher than the wild toxin.
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Mutagênese, Biologia molecular, Resistência aos inseticidas