Overexpression of cytochrome P450 CYP6BG1 may contribute to chlorantraniliprole resistance in Plutella xylostella (L.)

Abstract

BACKGROUND

The diamondback moth
Plutella xylostella
(L.) is the most widely distributed pest of cruciferous crops and has developed resistance to most commonly used insecticides, including chlorantraniliprole. Resistance to chlorantraniliprole is likely caused by mutations of the target, the ryanodine receptor, and/or mediated by an increase in detoxification enzyme activities. Although target‐site resistance is documented in detail, resistance mediated by increased metabolism has rarely been reported.



RESULTS

The activity of cytochrome P450 was significantly higher in two resistant
P. xylostella
populations than in a susceptible one. Among ten detected cytochrome P450 genes,
CYP6BG1
was significantly overexpressed (over 80‐fold) in a field‐resistant population compared with expression in a susceptible one. Knockdown of
CYP6BG1
by RNA interference dramatically reduced the 7‐ethoxycoumarin‐O‐deethylase (7‐ECOD) activity of P450 by 45.5% and increased the toxicity of chlorantraniliprole toward
P. xylostella
by 26.8% at 48 h postinjection of double‐stranded RNA. By contrast, overexpression of
CYP6BG1
in a transgenic
Drosophila melanogaster
line significantly decreased the toxicity of the insecticide to the transgenic flies.



CONCLUSIONS

Overexpression of
CYP6BG1
may contribute to chlorantraniliprole resistance in
P. xylostella
. Our findings will provide new insights into the mechanisms of resistance to diamide insecticides in other insect pests. © 2017 Society of Chemical Industry