Silencing NADPH-cytochrome P450 reductase results in reduced acaricide resistance in Tetranychus cinnabarinus (Boisduval).

Li Shi,Zhifeng Xu,Peng Wei,Lin He,Guangmao Shen,Qiang Xu,Jiao Zhang,Yichao Zhang

doi:10.1038/srep15581

Abstract

Cytochrome P450 monooxygenases (P450s) are involved in metabolic resistance to insecticides and require NADPH cytochrome P450 reductase (CPR) to transfer electrons when they catalyze oxidation reactions. The carmine spider mite, Tetranychus cinnabarinus is an important pest mite of crop and vegetable plants worldwide, and its resistance to acaricides has quickly developed. However, the role of CPR on the formation of acaricide-resistance in T. cinnabarinus is still unclear. In this study, a full-length cDNA encoding CPR was cloned and characterized from T. cinnabarinus (designated TcCPR). TcCPR expression was detectable in all developmental stages of T. cinnabarinus, but it’s much lower in eggs. TcCPR was up-regulated and more inducible with fenpropathrin treatment in the fenpropathrin-resistant (FeR) strain compared with the susceptible SS strain. Feeding of double-strand RNA was effective in silencing the transcription of TcCPR in T. cinnabarinus, which resulted in decreasing the activity of P450s and increasing the susceptibility to fenpropathrin in the FeR strain but not in the susceptible strain. The current results provide first evidence that the down-regulation of TcCPR contributed to an increase of the susceptibility to fenpropathrin in resistant mites. TcCPR could be considered as a novel target for the development of new pesticides.

Highlights

The carmine spider mite, Tetranychus cinnabarinus, is one of the major pest species of agriculture crops in China[1]
All functional domains involved in the binding of cofactors, such as Flavin Mononucleotide (FMN) and Flavin Adenine Dinucleotide (FAD), and involved in the receiving electrons from Nicotinamide Adenine Dinucleotide Phosphate (NADPH) were identified in the predicted TcCPR protein primary and tertiary structures
The P450 monooxygenases (P450s) specific activity decreased significantly 48 h after feeding of dsRNA-TcCPR compared with DEPC-water or dsRNA-Green Fluorescent Protein (GFP) feeding. These results suggested that TcCPR played a central role in P450 activities in T. cinnabarinus and that TcCPR was a key factor of P450s in conferring metabolic resistance against acaricide in mites

Summary

Introduction

The carmine spider mite, Tetranychus cinnabarinus, is one of the major pest species of agriculture crops in China[1]. Cytochrome P450 monooxygenases (P450s) belong to a superfamily of hemecontaining enzymes that catalyze the monooxygenation of xenobiotics and endogenous compounds They play important roles in metabolic resistance of agricultural insects and mites[7]. Recent studies have demonstrated that silencing CPR by RNAi in Cimex lectularius[20] and Anopheles gambiae[21] increases susceptibility to pyrethroid insecticides, revealing an essential role for CPR in P450s-mediated biochemical processes in insects, and it would be of great interest to develop synthetic inhibitors targeting this gene for the use in insect pest management. This study indicates that the suppression of TcCPR transcription contributes to an increase of acaricide susceptibility in resistant mites and helps to reveal the role of P450-mediated metabolic detoxification in the fenpropathrin-resistance in T. cinnabarinus (Fig. 1B)

Methods

Results

Conclusion