Multiple cytochrome P450 genes: conferring high levels of permethrin resistance in mosquitoes, Culex quinquefasciatus

Ting Yang,Nannan Liu,Ting Li,Xuechun Feng,Ming Li,Shikai Liu

doi:10.1038/s41598-021-88121-x

Abstract

Insecticides, especially pyrethroids, are the most important in the insect pest control and preventing insect vector-borne human diseases. However, insect pests, including mosquitoes, have developed resistance in the insecticides that used against them. Cytochrome P450s are associated with insecticide resistance through overexpression and detoxification mechanisms in insect species. In this study, we utilized a powerful tool, the RNAi technique, to determine the roles of key P450 genes overexpressed in permethrin resistant mosquitoes that confer insecticide resistance to unravel the molecular basis of resistance mechanisms in the mosquito Culex quinquefasciatus. The results showed that knockdown of 8 key P450 genes using RNAi techniques significantly decreased resistance to permethrin in resistant mosquitoes. In silico modeling and docking analysis further revealed the potential metabolic function of overexpressed P450 genes in the development of insecticide resistance in mosquitoes. These findings not only highlighted the functional importance of these P450 genes in insecticide resistance, but also revealed that overexpression of multiple P450 genes was responsible for the high levels of insecticide resistance in a mosquito population of Culex quinquefasciatus.

Highlights

Insecticides, especially pyrethroids, are the most important in the insect pest control and preventing insect vector-borne human diseases
RNA interference (RNAi) on the 8 P450 genes in the larvae of H AmCqG8 mosquitoes showed that the RNAi reduced the mRNA levels of CYP9AL1 to 0.55, CYP9J45 to 0.65, CYP9J35 to 0.70, CYP4C52V1 to 0.55, CYP4D42V1 to 0.35, CYP6BZ2 to 0.30, CYP6P14 to 0.55, CYP325Y6 to 0.60- and CYP6BY3 to 0.70-fold in comparison with the effect of double-stranded RNA (dsRNA) on GFP injection mosquitoes (Fig. 1a), suggesting the expression of these P450 genes has been successfully suppressed by RNAi
Cytochrome P450 genes have been identified as playing a role in pyrethroid resistance in mosquito species through gene overexpression mechanisms, including CYP6Z130 and CYP6P331 in An. gambiae, CYP9J32 in Ae. aegypti[32], CYP4H34, CYP6F1, CYP9M10 and CYP6AA7 in Cx. quinquefasciatus[9,11,33,34,35]

Summary

Introduction

Insecticides, especially pyrethroids, are the most important in the insect pest control and preventing insect vector-borne human diseases. To pinpoint the specific role of P450 genes in resistance, several biological technologies have been employed to investigate the gene functions, such as RNA interference (RNAi), a powerful and robust tool that discovers gene functions by using double-stranded RNA (dsRNA) to disrupt the target m RNA15, transcription activator-like effector nucleases (TALEN)s, and clustered regularly interspaced short palindromic repeats (CRISPR/Cas9)[16] These techniques have made great contribution and applied successfully in many insect species to investigate the specific functions played by individual genes, including development17, metamorphosis[18] and r eproduction[19], as well as to characterize the gene functions in the development of insecticide resistance in insect pests such as the mosquitoes Cx. quinquefasciatus[16,20,21], Anopheles gambiae[22] and Aedes aegypti[23], the cockroach Blattella germanica[24], the common bedbug Cimex lectularius[25], and the aphid Sitobion avenae[26]. Our findings highlighted the functional importance of these P450 genes in insecticide resistance, and revealed that the high levels of insecticide resistance in a single mosquito population were conferred by the increased expressed of multiple P450 genes their detoxification

Methods

Results

Conclusion