Function Analysis of P450 and GST Genes to Imidacloprid in Aphis craccivora (Koch).

Yuan-Xue Yang,Rong-Hua Lin,Chao Xue,Ming Zhao,Ai-Yu Wang,Jian-Hua Zhang,Zhuo Li,Ai-Ling Duan

doi:10.3389/fphys.2020.624287

Abstract

Aphis craccivora (Koch) is an economically important pest that affects legumes in worldwide. Chemical control is still the primary efficient method for A. craccivora management. However, the mechanism underlying insecticide resistance in A. craccivora has not been elucidated. A previous study observed that piperonyl butoxide (PBO) and diethyl maleate (DEM) significantly synergized imidacloprid in A. craccivora field populations, indicating that cytochrome P450 (P450) and glutathione S-transferase (GST) genes may play pivotal roles in imidacloprid resistance. In this study, 38 P450 genes and 10 GST genes were identified in A. craccivora through transcriptomic analysis. The expression levels of these P450 and GST genes were measured in susceptible (SUS) strains of A. craccivora under imidacloprid treatment with LC15, LC50, and LC85 doses. The expression levels of CYP18A1, CYP6CY21, CYP6DA1, CYP6DA2, CYP4CJ1, CYP4CJ2, and CYP380C6 were up-regulated in the three treatments. Most of these genes belong to CYP3 and CYP4 Clans. In addition, the expression levels of all P450 and GST genes in A. craccivora were also measured in the Juye (JY) and Linqing (LQ) field populations. The expression levels of CYP6DA2, CYP4CJ1, and CYP380C6 were up-regulated in the SUS strain after imidacloprid treatment at three doses, and these genes were overexpressed in the JY population. Furthermore, the sensitivity of A. craccivora to imidacloprid was significantly increased after knockdown of CYP380C6 and CYP6DA2 through RNA interference. These results may help to elucidate the mechanisms underlying of imidacloprid resistance in A. craccivora.

Highlights

The Aphis craccivora (Koch), is one of the most important worldwide, affecting multiple legumes, such as pea, cowpea, and peanut
Different levels of imidacloprid resistance have been developed in various aphids, such as A. gossypii, M. persicae, and Aphis glycines
In the A. craccivora transcriptome, 38 P450 monooxygenases (P450s) genes were identified, and most of the genes belonged to the CYP3 and CYP4 Clans, which is in keeping line with results the finding observed in other insect species (Zhang et al, 2010, 2016b; Yang and Liu, 2011)

Summary

Introduction

The Aphis craccivora (Koch), is one of the most important worldwide, affecting multiple legumes, such as pea, cowpea, and peanut. The molecular mechanism underlying insecticide resistance primarily includes the reduction of target insensitivity and the enhancement of metabolic detoxification. Metabolic resistance to insecticides primarily due to the overexpression of three enzymes, including cytochrome P450 monooxygenases (P450s), glutathione S-transferases (GSTs), and carboxylesterase (CarEs; Li et al, 2007). The GST genes can be divided into seven classes, including Delta, Epsilon, Omega, Sigma, Theta, Zeta, and Microsomal (Enayati et al, 2005). The Delta and Epsilon classes are insect-specific, playing important roles in xenobiotic detoxification (Che-Mendoza et al, 2009). In Aphis gossypii, the increased expression of CarEs was related to resistance to omethoate (Gong et al, 2014)

Methods

Results

Conclusion