Investigating the Molecular Mechanisms of Organophosphate and Pyrethroid Resistance in the Fall Armyworm Spodoptera frugiperda

Abstract

The fall armyworm Spodoptera frugiperda is an economically important pest of small grain crops that occurs in all maize growing regions of the Americas. The intensive use of chemical pesticides for its control has led to the selection of resistant populations, however, to date, the molecular mechanisms underlying resistance have not been characterised. In this study the mechanisms involved in the resistance of two S. frugiperda strains collected in Brazil to chlorpyrifos (OP strain) or lambda-cyhalothrin (PYR strain) were investigated using molecular and genomic approaches. To examine the possible role of target-site insensitivity the genes encoding the organophosphate (acetylcholinesterase, AChE) and pyrethroid (voltage-gated sodium channel, VGSC) target-site proteins were PCR amplified. Sequencing of the S. frugiperda ace-1 gene identified several nucleotide changes in the OP strain when compared to a susceptible reference strain (SUS). These result in three amino acid substitutions, A201S, G227A and F290V, that have all been shown previously to confer organophosphate resistance in several other insect species. Sequencing of the gene encoding the VGSC in the PYR strain, identified mutations that result in three amino acid substitutions, T929I, L932F and L1014F, all of which have been shown previously to confer knockdown/super knockdown-type resistance in several arthropod species. To investigate the possible role of metabolic detoxification in the resistant phenotype of the OP and PYR stains all EST sequences available for S. frugiperda were used to design a gene-expression microarray. This was then used to compare gene expression in the resistant strains with the susceptible reference strain. Members of several gene families, previously implicated in metabolic resistance in other insects were found to be overexpressed in the resistant strains including glutathione S-transferases, cytochrome P450s and carboxylesterases. Taken together these results provide evidence that both target-site and metabolic mechanisms underlie the resistance of S. frugiperda to pyrethroids and organophosphates.

Organophosphate and pyrethroid resistances in the tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae) from Iran

“…Additionally, Carvalho et al. () showed A201S, G227A and F290V alterations in ace1 in S. frugiperda in response to chlorpyrifos. In this study, we found that the majority of specimens tested had the A201S substitution in the ace1 gene, which was also observed by Haddi et al.…”

“…Increased metabolic detoxification was involved in OP resistance of Spodoptera frugiperda , where Carvalho et al. () showed increased esterase gene expression possibly conferring resistance to organophosphate insecticides. Increased esterase activity associated with organophosphate resistance has been documented in Drosophila melanogaster (Berrada & Fournier, ), Aonidiella aurantii (Levitin & Cohen, ), Schizaphis graminum (Gao & Zhu, ) and Bemisia tabaci (Zhang et al., ).…”

Battle in the New World: Helicoverpa armigera versus Helicoverpa zea (Lepidoptera: Noctuidae)

“…This species presents management challenges because of its biological and behavioral characteristics and rapid adaptation to chemical control (e.g. resistance to organophosphate and pyrethroid insecticides) [15–17]. One alternative to insecticide control has been the use of transgenic hybrids expressing active proteins of the bacterium Bacillus thuringiensis (Bt).…”

RESPOSTAS DA APLICAÇÃO DE SILÍCIO E CÁLCIO EM GENÓTIPOS DE Zea mays L. À INFESTAÇÃO DE Spodoptera frugiperda (LEPIDOPTERA: NOCTUIDAE)

“…As consideráveis perdas econômicas causadas pela Spodoptera frugiperda faz com que os produtores intensifiquem o uso de inseticidas químicos e consequentemente levem ao desenvolvolvimento da resistência a muitos grupos de inseticidas, tornando o seu controle ainda mais difícil (CARVALHO et al, 2013).…”