Effects of sublethal concentrations of metaflumizone on detoxifying enzyme activity, and expression of cytochrome P450 genes, in Plutella xylostella (L.)
Author of the article:SHEN Jun1** LU Yan-Hui2 ZHANG Shu-Zhen1 YOU Hong1 LI Jian-Hong1***
Author's Workplace:1. College of Plant Science &Technology, Huazhong Agricultural University, Wuhan 430070, China;2. Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
Key Words:Plutella xylostella, metaflumizone, detoxify enzymes, cytochrome P450 genes
Abstract:
[Objectives] To clarify the effects of sublethal concentrations of metafumizone, a novel sodium channel blocker insecticide, on the activities of detoxifying enzymes (carboxylesterase, glutathione S-transferase and function oxidase), and the expression of cycochrome P450 genes, in Plutella xylostella (L.). [Methods] The activities of the three detoxifying enzymes and the mRNA expression levels of three P450 gene families (PxCYP4, PxCYP6 and PxCYP9) in P. xylostella were measured in 3rd instar larvae treated with sublethal doses of metafumizone (LC10 and LC25) via the leaf-dip bioassay method. [Results] There was no significant difference in carboxylesterase (CarE) activity compared with the control, but glutathione S-transferase activity (GSTs) was distinctly inhibited by sublethal concentrations of metaflumizone (P<0.05). O-demethylation activities of mixed-function oxidases (MFOs) were significantly increased by sublethal concentrations of metaflumizone. When P. xylostella were treated with metaflumizone at LC25 for 72 h, MFOs activity significantly increased (P<0.05) to 1.39-fold that of the control. The relative expression levels of PxCYP4M19, PxCYP6BF1V2, PxCYP6CN1 and PxCYP6CV2 after exposure to metaflumizone (LC25) were, respectively, 2.33-8.5-fold, 1.32-3.48-fold, 1.18-2.53-fold, and 2.02-7.22-fold, those of the control. [Conclusion] The results suggest that metaflumizone up-regulates the expression of four P450 genes and enhances the activity MFOs of in P. xylostella.