The calcium ion channel protein TRPML is indispensable to the reproduction of Nilaparvata lugens and the transovarial transmission of its yeast-like symbionts.

Transient receptor potential mucolipin (TRPML, also known as mucolipin-3), a critical cation channel protein in mammals, mediates ion transport, and regulates diverse signaling pathways and cellular physiological functions. However, its functional significance in insects remains poorly characterized. In this study, we cloned TRPML of Nilaparvata lugens (NlTRPML), employed bioinformatics tools to predict its structure and function, elucidating its tertiary architecture and potential binding sites for the small-molecule agonist mucolipin synthetic agonist 1(ML-SA1). Quantitative real-time (qRT)-PCR results showed that NlTRPML was ubiquitously expressed across all developmental stages and tissues of N. lugens, and especially highly in the ovaries of pregnant females. Immunofluorescence analysis further revealed that NlTRPML was widely present in the female internal reproductive system. Interestingly, NlTRPML was found highly expressed in epithelial plug of ovarioles when yeast-like symbionts (YLSs) entered it. RNA interference (RNAi) of NlTRPML expression resulted in delayed ovarian development, blocked ovulation, and reduced translocation of YLSs into oocytes. Conversely, ML-SA1 injection markedly increased the number of YLSs in oocytes. These findings demonstrate that NlTRPML is indispensable to the reproduction of N. lugens and the transovarial transmission of YLSs. © 2025 Society of Chemical Industry.