Characterization of the transcriptional cellular response in midgut tissue of temephos- resistant Aedes aegypti larvae

Abstract

Background Resistance to organophosphate compounds is a serious concern in dealing with the control of mosquito vectors. Understanding the genetic and molecular basis of resistance is important not only to create strategies aimed at detecting and monitoring resistance in the field, but also to implement efficient control measures and support the development of new insecticides. Despite the extensive literature on insecticide resistance, the molecular basis of metabolic resistance is still poorly understood. Methods In order to better understand the mechanisms of Aedes aegypti resistance to temephos, we performed NGS sequencing of RNA from the midgut tissue of Aedes aegypti larvae from temephos resistant (RecR) and susceptible (RecL) colonies. Bioinformatics analyses were then performed to assess the biological functions of differentially expressed genes, and the sequencing data were validated by quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Results The transcriptome analysis mapped 6.084 genes, of which 202 were considered upregulated in RecR, with genes representing many detoxification enzyme families, including cytochrome-P450 oxidative enzymes, glutathione-S-transferases and glucosyl transferases. Other upregulated genes were mainly involved in the cuticle, carbohydrates, and lipid biosynthesis. For the downregulated profiles, we found 106 downregulated genes in the RecR colony, with molecules involved in protein synthesis, immunity and apoptosis process. Furthermore, we observed an enrichment of KEGG metabolic pathways related to resistance mechanisms. The results found in RT-qPCR confirm the findings of the transcriptome data. Conclusions In this study, we investigated the changes in the transcriptome levels in an Ae. aegypti colony resistant to temephos. Our dataset showed that metabolic resistance mediated by multiple families of detoxifying enzymes is strongly associated with temephos metabolism, but other mechanisms may also contribute to temephos resistance in Ae. aegypti RecR colony.