Identification and Functional Characterization of CYP4D2 Putatively Associated with β-Cypermethrin Detoxification in .

, a polyphagous pest, serves as a vector for in China. Currently, there are no effective control strategies for this vector. Agricultural pest control may cause to become a threat due to the development of pesticide resistance. Cytochrome P450s (CYP450) plays a significant role in detoxifying xenobiotics in insects. In this study, we performed RNA sequencing of exposed to β-cypermethrin for 0 and 1 h and then gene cloning of the five up-regulated CYP450 genes. Three CYP450 genes were successfully cloned, and their expression patterns in different developmental stages and in different tissues were analyzed by RT-qPCR. was observed to have the highest expression in the midgut (fold change 2.82 for , 2.62 for , and 1.77 for ). Functional analysis was carried out according to overexpression in S2 cells from the pfastbac1 vector and RNAi with siRNA. The results of the CCK8 assay indicated that the overexpression of the recombinant protein PoCYP4D2 suppressed the decrease in S2 cell viability due to β-cypermethrin. The expression levels of PoCYP4D2 decreased significantly, and the mortality rates increased from 6.25% to 15.0% at 3 h and from 15.0% to 27.5% at 6 h after -siRNA injection. These results suggest that may be an essential key gene in the metabolism of β-cypermethrin in . This study constitutes a foundation to explore further the functions of CYP450 genes in insecticide metabolism.