Tissue specific expression analysis of CYP3 clan P450 genes and RNAi in Halyomorpha halys

Insect cytochrome P450 superfamily genes (P450s) play a significant role in detoxifying xenobiotics during nutrient acquisition. These enzymes require NADPH and NAPDH-cytochrome P450 reductase (CPR) for their function. P450 characterization is documented in many insects, revealing their importance in detoxification of plant allelochemicals; however their role is unclear for the polyphagous pest, Halyomorpha halys that is well adapted to a wide range of hosts. CYP 3 clan members (e.g. CYP6), a subclass of P450 superfamily, are known to metabolize xenobiotics including plant secondary compounds. Our objective for the current study is to characterize CYP 3 clan members in tissues of H. halys male and female adults on different hosts (apple, corn and soybean) relative to starved insects (control). Additionally, we have silenced H. halys NADPH-CPR (HhCPR) using RNA interference (RNAi) to observe its effect on the fitness and survival. Results showed elevated expression of 11 out of 13 CYP6 genes studied in female guts that were starved or fed corn compared to other hosts. Whereas 7 CYP6 genes were upregulated in Malpighian tubules of males compared to females across all diets. Preliminarily, RNAi of HhCPR has resulted in reduced expression but caused no significant effect on mortality and fecundity. The results from this study revealed that CYP6 genes have tissue and sex specific expression in H. halys and potentially playing an important role in metabolizing the plant compounds encountered in their diet. Functional analysis of differentially expressed CYP6 genes will identify their role in host adaptation of H. halys.