Functional analysis of CYP6ER1, a P450 gene associated with imidacloprid resistance in Nilaparvata lugens.

Rui Pang,Wenqing Zhang,Zhikun Liang,Meng Chen,Xiangzhao Yue,Hu Ge

doi:10.1038/srep34992

Abstract

The cytochrome P450 CYP6ER1 has been reported to play an important role in imidacloprid resistance of the brown planthopper (BPH), Nilaparvata lugens, and is overexpressed in most resistant populations. In the present study, we confirmed that CYP6ER1 expression can be induced by certain levels of imidacloprid. Developmental expression analysis revealed that CYP6ER1 was expressed highly in the adult stage, and tissue distribution analysis showed that CYP6ER1 was expressed mainly in the fat body and midgut. RNA interference (RNAi) of CYP6ER1 and transgenic expression of CYP6ER1 in Drosophila melanogaster both suggested that the expression of CYP6ER1 is sufficient to confer imidacloprid resistance. Furthermore, we analyzed the interaction of imidacloprid and CYP6ER1 monooxygenase by using dynamic simulations and molecular docking. We found that Nitrogen atoms in the heterocycle of the imidacloprid molecule may bind to iron atoms in the center of the homology model of CYP6ER1 via 4,5-dihedro-1H-imidazole. This finding contributes to a better understanding of how CYP6ER1 takes part in the insecticide metabolism.

Highlights

The cytochrome P450 CYP6ER1 has been reported to play an important role in imidacloprid resistance of the brown planthopper (BPH), Nilaparvata lugens, and is overexpressed in most resistant populations
We found that the mRNA level of CYP6ER1 in the fieldcaught strain was 2.1-fold higher than that observed for the susceptible strain, and the mRNA expression level in the samples treated with 30 ppm and 60 ppm imidachloprid was significantly higher than that observed for the untreated field-caught strain
It is generally believed that detoxifying enzymes, referred to as esterase, glutathione S-transferase and P450s, contribute to defending against and catabolizing toxins and insecticides in insects, and that many involve point mutations of target genes for insecticide which increase the copy number of the gene, mRNA level and the diversification of the coding sequence[27]

Summary

Introduction

The cytochrome P450 CYP6ER1 has been reported to play an important role in imidacloprid resistance of the brown planthopper (BPH), Nilaparvata lugens, and is overexpressed in most resistant populations. We found that Nitrogen atoms in the heterocycle of the imidacloprid molecule may bind to iron atoms in the center of the homology model of CYP6ER1 via 4,5-dihedro-1H-imidazole. This finding contributes to a better understanding of how CYP6ER1 takes part in the insecticide metabolism. The over-expression or up-regulation of P450, can increase pests’ ability to resist to insecticide An example of this is, CYP6G1 overexpression in Drosophila and the associated resistance to DDT14.

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Conclusion