The SNARE Protein RpUSE1 Is Essential for Female Reproduction and Organelle Homeostasis in Riptortus pedestris

The SNARE protein USE1 plays a critical role in retrograde membrane traffic from the Golgi to the endoplasmic reticulum (ER) in yeast, yet its function in insects remains unclear. This study investigates the role of the RpUSE1 gene in the agricultural pest Riptortus pedestris. Domain analysis confirmed that RpUSE1 is a 248-amino-acid SNARE protein containing a C-terminal transmembrane domain and a SNARE motif featuring a conserved aspartate residue at the central "0" layer. It is ubiquitously expressed in R. pedestris, with the highest transcript levels in the female reproductive system. RNAi-mediated knockdown of RpUSE1 severely impaired nymph survival and development. Moreover, silencing RpUSE1 in adult females completely disrupted egg development and caused structural disorder of the lateral oviducts, including ER disorganization. Notably, there was a significant accumulation of lipid droplets within the lateral oviduct lumen. In contrast, silencing RpUSE1 in male adults did not affect fertility. These findings demonstrate that RpUSE1 is essential for nymphal survival and female reproductive success, highlighting its crucial role in maintaining organelle structure and intracellular transport.