Identification of putative cytochrome P450 monooxygenase genes from the small white butterfly, Pieris rapae (Lepidoptera: Pieridae), and their response to insecticides

The small white butterfly, Pieris rapae (Lepidoptera: Pieridae), is an important pest on Brassicaceae plants, causing heavy crop loss each year. Cytochrome P450 monooxygenase (CYP) is a superfamily of enzymes involved in the detoxification of various xenobiotic compounds, including insecticides. However, little is known about the role of CYP genes in P. rapae. In this study, we identified 63 CYP genes in P. rapae, and analyzed their phylogenetic relationships, exon–intron structures and genomic locations. Moreover, our insecticide‐response transcription profiling showed that LD₅ doses of lambda‐cyhalothrin, chlorantraniliprole, and abamectin significantly increased expression of five (CYP4M59, CYP6AE119, CYP6AE120, CYP6AE121, and CYP6BD18), three (CYP4AU1, CYP6AE120, and CYP6AW1), and five (CYP4L40, CYP4AU1, CYP6AE119, CYP6AW1, and CYP6BD19) CYP genes, respectively; and LD₂₀ doses of the three pesticides significantly upregulated six (CYP4M59, CYP6AE119, CYP6AE120, CYP6AE121, CYP4AU1, and CYP6BD18), six (CYP4G168, CYP4L40, CYP4AU1, CYP6AE120, CYP6AW1, and CYP6BD19), and five (CYP4L40, CYP4AU1, CYP6AB108, CYP6AE119, and CYP6BD19) genes, respectively. When we used LD₅₀ doses of the three insecticides, we reported significantly elevated expression levels of five (CYP4M59, CYP6AE119, CYP6AE120, CYP6BD17, and CYP6BD18), eight (CYP4G168, CYP4L40, CYP4AU1, CYP6AE120, CYP6AE121, CYP6AW1, CYP6BD18, and CYP6BD19), and six (CYP4L40, CYP4S34, CYP6AB108, CYP6AE119, CYP6AE120, and CYP6BD19) genes, respectively. Our expression analysis also revealed that five (CYP4G168, CYP4G169, CYP4S34, CYP6AW1, and CYP6CT3) and three (CYP4L40, CYP6AN33, and CYP6BD17) CYP genes were mainly expressed in the midgut and fat body, respectively, and one CYP gene (CYP6AE119) in the Malpighian tubules. This is the first large‐scale report into the characterization of CYP genes in P. rapae.