Functional disruption of CYP4CE1 impairs egg development and reproductive capacity in Nilaparvata lugens

Cytochrome P450s participate in various essential physiological processes, including xenobiotic detoxification and the metabolism of endogenous compound. Previously, CYP4CE1 was identified as a key detoxification enzyme contributing to nitenpyram resistance in Nilaparvata lugens. Here, we uncovered its novel function in reproductive regulation of N. lugens. Silencing CYP4CE1 significantly impaired the reproductive capacity of N. lugens, leading to arrested embryonic development, gradual dehydration, shrinkage, and eventual death of eggs. Moreover, a significant reduction of chitin content was observed in the eggs from CYP4CE1-silenced N. lugens. Further investigation revealed that CYP4CE1 might affect chitin synthesis by regulating the expression of chitin synthase (CHS) and UDP-N-acetylglucosamine pyrophosphorylase (UAP). In CYP4CE1-silenced N. lugens, the mRNA expression level of UAP was downregulated in the ovaries, while the expression level of CHS was suppressed predominantly in non-ovarian tissues. Additionally, abnormal expression of cuticular protein genes (Cpr3, Cpr8, Cpr10) suggested that CYP4CE1 might indirectly affect the mechanical strength and permeability of eggshells by modulating the cuticular protein. However, the mechanism through which CYP4CE1 regulates UAP, CHS and Cpr requires further investigation. These findings indicate that suppressing CYP4CE1 provides a novel strategy for integrated pest management by simultaneously disrupting detoxification pathways and reproductive capacity in N. lugens.