Molecular Cloning and Expression of CYP9A61: A Chlorpyrifos-Ethyl and Lambda-Cyhalothrin-Inducible Cytochrome P450 cDNA from Cydia pomonella

Cytochrome P450 monooxygenases (CYPs or P450s) play paramount roles in detoxification of insecticides in a number of insect pests. However, little is known about the roles of P450s and their responses to insecticide exposure in the codling mothCydia pomonella(L.), an economically important fruit pest. Here we report the characterization and expression analysis of the first P450 gene, designated asCYP9A61, from this pest. The full-length cDNA sequence ofCYP9A61is 2071 bp long and its open reading frame (ORF) encodes 538 amino acids. Sequence analysis shows that CYP9A61 shares 51%–60% identity with other known CYP9s and contains the highly conserved substrate recognition site SRS1, SRS4 and SRS5. Quantitative real-time PCR showed thatCYP9A61were 67-fold higher in the fifth instar larvae than in the first instar, and more abundant in the silk gland and fat body than other tissues. Exposure of the 3rd instar larvae to 12.5 mg L−1of chlorpyrifos-ethyl for 60 h and 0.19 mg L−1of lambda-cyhalothrin for 36 h resulted in 2.20-and 3.47-fold induction ofCYP9A61, respectively. Exposure of the 3rd instar larvae to these two insecticides also significantly enhanced the total P450 activity. The results suggested thatCYP9A61is an insecticide-detoxifying P450.Keywords:Cydia pomonella;cytochrome P450;induction;response;insecticides