Identification of a novel cytochrome P450 CYP3356A1 linked with insecticide detoxification in Bradysia odoriphaga

Cytochrome P450 monooxygenases play an important role in the metabolic detoxification of insecticides in insect pests. However, little is known about the role of a specific P450 gene and its responses to insecticide exposure in Bradysia odoriphaga, a major pest in Chinese chive production.In this study, a novel P450 gene, CYP3356A1, was cloned from Bradysia odoriphaga. The full-length cDNA sequence of CYP3356A1 is 2153 bp and its open reading frame (ORF) encodes 508 amino acids. Quantitative real time PCR(qRT-PCR) analyses in different tissues showed that CYP3356A1 expression was the highest in the Malpighian tubule. Moreover, among the different developmental stages of the insect, the highest expression of CYP3356A1 was found in fourth-instar larvae. Expression of CYP3356A1 was upregulated by treatment with imidacloprid, thiamethoxam, and β-cypermethrin at median lethal concentrations (LC50 ). RNA interference (RNAi)-mediated silencing of CYP3356A1 significantly increased mortality by 36.90%, 25.17%, and 36.73 when fourth-instar B. odoriphaga larvae were exposed to imidacloprid, thiamethoxam, and β-cypermethrin, respectively, at the LC50 dose.These results demonstrate that CYP3356A1 is related to the detoxification of imidacloprid, thiamethoxam, and β-cypermethrin in B. odoriphaga. Moreover, the study also increased our understanding of the molecular mechanisms of insecticide detoxification in this pest insect. © 2018 Society of Chemical Industry.