The transcription factor CncC/Maf modulates imidacloprid susceptibility by regulating UGT392C1 in Locusta migratoria

As key members of xenobiotic transcription factors (XFTs), CncC and Maf mediate insecticide sensitivity by regulating detoxification enzyme genes. In this study, with Locusta migratoria as a model, investigations revealed that LmCncC showed particularly high expression in the foregut, midgut, hindgut, and fat bodies. In contrast, LmMaf expression was predominantly localized to the midgut and fat bodies. Functional analysis demonstrated that RNAi-mediated knockdown of LmCncC / LmMaf significantly increased sensitivity to deltamethrin and imidacloprid. To identify the LmCncC - and LmMaf -regulated genes, a comparative transcriptomics analysis was constructed and further identified three key uridine diphosphate-glucuronosyltransferase (UGT) genes downstream of the CncC/Maf pathway. To investigate the role of UGTs in insecticide detoxification, treatment of L. migratoria with sulfinpyrazone, a UGT inhibitor, reduced UGT activity by 42.2% and enhanced sensitivity to imidacloprid and deltamethrin. Among these UGT genes, RNAi-mediated knockdown of LmUGT392C1 significantly enhanced susceptibility to imidacloprid in insecticide bioassays. CRISPR-Cas9-generated LmCncC and LmUGT392C1 mutants validated the essential role of this pathway in imidacloprid detoxification. To clarify the regulatory mechanism of the CncC/Maf signaling pathway on LmUGT392C1, a 2623 bp promoter sequence of LmUGT392C1 was obtained. Dual-luciferase reporter gene assays confirmed that co-overexpression of LmCncC and LmMaf directly activates the promoter of LmUGT392C1 . Our study elucidates the CncC/Maf- LmUGT392C1 regulatory axis in insecticide sensitivity, which is applicable to designing new formulations to overcome detoxification or identify potential new resistance mechanisms.