Lateral oviduct-secreted proteins in the brown planthopper

Oviducts are the "traffic hubs" of the female reproductive system, serving as the crucial conduits for egg transportation. By performing LC-MS/MS proteomic detection together with transcriptomic analysis, 80 lateral oviduct-secreted proteins were identified, and 5 genes (NlOdsp, NlOdsp1, NlOdsp2, NlOdsp3 and NlOdsp4) specifically expressed in the oviducts of the brown planthopper Nilaparvata lugens, the most destructive rice pest, were authenticated. qRT-PCR analysis revealed that these genes and proteins were mainly/specifically expressed in the female reproductive system in adulthood. RNA interference (RNAi) against the 5 NlOdsp genes significantly affected the survival rates (3.4% - 68.7% of the control) and fecundities of female adults (3.9% - 57.6% of the control) at 8 d post injection (p.i.). In addition, the lack of NlOdsp1 caused decreases in the gel-like brown secretions inside the lateral oviducts, while increased secretions were found in the dsNlOdsp2-treated groups. In addition, NlOdsp3 is a pleiotropic gene involved in both oocyte development and egg movement through the lateral oviducts, similar to the role of NlOdsp in egg transportation. The results deepen our understanding of oviduct-secreted proteins in female insects and provide novel target genes for RNAi-based insect pest control. SIGNIFICANCE: Oviduct plays a vital role in animal reproductive processes and it serves as the crucial conduit for egg transportation. Though oviduct secretes have been well documented in high animals, the proteomic information of insect oviduct secretes remains poorly understood. The present study revealed 80 oviduct secreted proteins, including 19 unknown proteins, from the rice planthopper, the most destructive rice pest which lay eggs in plant tissues. Five of the 19 proteins were further functionally characterized. The results not only deepen our understanding of the oviduct secreted proteins in insect reproductive biology, but also provide basis for interaction between insects and host plants, and provide novel target genes for RNAi-based insect pest control.