A Novel Cuticular Protein-like Cpr21L Is Essential for Nymph Survival and Male Fecundity in the Brown Planthopper.

Cuticular proteins (CPs) are a large family and perform a variety of functions. However, the physiological roles of cuticle protein 21-like () in the brown planthopper (, BPH), one of the most destructive insect pests of rice, are largely unclear. In this study, was revealed to be expressed in both BPH nymphs and adults, and the mRNA expression level was much higher in male adults than female adults. Spatially, the expression of in the testis was higher than in the ovary. The RNA interference (RNAi) of seriously decreased nymph survival, and no individual survived 8 days post-ds injection. The RNAi of in adults also decreased the fertility of males, especially in the ds♂ × ds♀ group. The average number of eggs laid by one female in this group significantly decreased by 50.1%, and the eggs' hatchability decreased from 76.5% to 23.8% compared with the control (ds♂ × ds♀). Furthermore, observations under a stereomicroscope showed that the RNAi of severely impaired the development of the testes. Therefore, is essential for the nymphal survival and male fecundity of BPH, thus providing a possible target for pest control.