Regulation of CncC in insecticide-induced expression of cytochrome P450 CYP9A14 and CYP6AE11 in Helicoverpa armigera

Abstract

The expression of many detoxification genes can be regulated by CncC pathway and contributes to insecticide tolerance in insects. Our previous study has demonstrated that the transcripts of CncC and cytochrome P450s (CYP9A14, CYP6AE11) were significantly up-regulated after different insecticides treatment in Helicoverpa armigera. Further study indicated that H2O2, GSH, and MDA contents and antioxidant enzyme activities of H. armigera were enhanced after chlorantraniliprole, cyantraniliprole, indoxacarb, and spinosad exposure. Silencing CncC by RNA interference significantly down-regulated the expression levels of CYP9A14 and CYP6AE11, and increased the susceptibility of dsRNA-injected larvae to λ-cyhalothrin, chlorantraniliprole, and cyantraniliprole. On the contrary, applying CncC agonist curcumin on H. armigera induced the expression of CYP9A14 and CYP6AE11, and enhanced the tolerance of H. armigera to insecticides. Treatment of ROS scavenger N-acetylcysteine on H. armigera reduced the H2O2 content and antioxidant enzyme activities, suppressed the transcripts of CncC, CYP9A14, and CYP6AE11, and decreased the larval tolerance to insecticides. These results demonstrated that the induced-expression of CYP9A14 and CYP6AE11 related with insecticides tolerance in H. armigera was regulated by CncC, which may be activated by ROS generated by insecticides. This study will help to better understand the underlying regulation mechanisms of CncC pathway in H. armigera tolerance to insecticides.