Identification and Functional Analysis of a Novel Cytochrome P450 Gene CYP9A105 Associated with Pyrethroid Detoxification in Spodoptera exigua Hübner.

In insects, cytochrome P450 monooxygenases (P450s or CYPs) are known to be involved in the detoxification and metabolism of insecticides, leading to increased resistance in insect populations. is a serious polyphagous insect pest worldwide and has developed resistance to various insecticides. In this study, a novel CYP3 clan P450 gene was identified and characterized from . The cDNAs of encoded 530 amino acid proteins, respectively. Quantitative real-time PCR analyses showed that was expressed at all developmental stages, with maximal expression observed in fifth instar stage larvae, and in dissected fifth instar larvae the highest transcript levels were found in midguts and fat bodies. The expression of in midguts was upregulated by treatments with the insecticides -cypermethrin, deltamethrin and fenvalerate at both LC concentrations (0.10, 0.20 and 5.0 mg/L, respectively) and LC concentrations (0.25, 0.40 and 10.00 mg/L, respectively). RNA interference (RNAi) mediated silencing of led to increased mortalities of insecticide-treated 4th instar larvae. Our results suggest that might play an important role in -cypermethrin, deltamethrin and fenvalerate detoxification in .