Activation of the ROS/CncC Pathway Regulates Cytochrome P450 CYP4CJ2 to Confer Cycloxaprid Tolerance in Aphis gossypii

The inducible P450 gene plays a key role in the response of insects to insecticide stress. However, the transcriptional regulatory mechanism of insecticide-inducible detoxification enzyme genes has not been well clarified. In the present study, a P450 gene, CYP4CJ2, could be induced by cycloxaprid in both susceptible and cycloxaprid-resistant Aphis gossypii strains. RNA interference (RNAi) and transgenic Drosophila results showed that this P450 gene contributes to cycloxaprid tolerance. Moreover, the results of RNAi, dual-luciferase reporter, and yeast one-hybrid assays verified that CYP4CJ2 is regulated by the transcription factor CncC. In addition, although exposure to cycloxaprid resulted in the accumulation of ROS in both susceptible and cycloxaprid-resistant strains, treatment of melon aphids with NAC reduced ROS levels and decreased CncC and CYP4CJ2 expression. These findings suggest that cycloxaprid-induced ROS accumulation activates the CncC pathway, leading to the upregulated expression of CYP4CJ2 and enhancement of cycloxaprid tolerance in melon aphids. These results deepened our understanding of the regulatory mechanism of insecticide-induced detoxification enzyme gene upregulation in insects.