CYP4G subfamily genes mediate larval integument development in Spodoptera frugiperda

Cytochrome P450 (CYP) 4G subfamily is closely related to the synthesis of cuticular hydrocarbons, leading to the enhanced desiccation and insecticide resistance of pests. However, functions of CYP4Gs in larval integument development remain unknown in Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which is a major transboundary migratory pest and become a common pest in China. On the basis of the genome and transcriptome datasets of S. frugiperda, CYP4G74, CYP4G75, CYP4G108, and CYP4G109 were identified, which contained the conserved domains of P450s and CYP4Gs. The spatial and temporal expression analysis showed that CYP4G74 and CYP4G75 were significantly highly expressed in adults and larval integuments, while CYP4G108 and CYP4G109 had low expressions in larval integuments. After silencing CYP4G74 and CYP4G75 by RNA interference, abnormal integument development occurred in larvae, some of which became smaller and dead, indicating important roles of CYP4G74 and CYP4G75 in the synthesis and development of integuments. The results clarify the functions of CYP4Gs in S. frugiperda and provide potential targets for the control of this pest.