Functional verification of a landmark gene EVM713 involved in spermatogenesis in the marine bivalve Chlamys nobilis.

The formation of broodstock gametes is closely linked to the yield and quality in aquaculture production, yet molecular mechanisms underlying this process remain insufficiently understood. The noble scallop Chlamys nobilis, an economically significant dioecious bivalve species, serves as an excellent model for studying gametogenesis. In this study, the adult scallops with testis at different developmental stage were chosen for histological examination and transcriptome analysis to dig genes related gonad development. Totally, 2663 DEGs and their set modules significantly related to spermatogenesis were obtained using WGCNA, including 40 candidate genes represented by EVM713. The gene was specifically expressed in the testis. RNA interference (RNAi) of EVM713 led to impaired testis development, marked by sparse sperm cell arrangement, spermatocytes detaching from the follicle wall, and reduced spermatocyte numbers. Meanwhile, 24 h after RNAi, the expression levels of Bax, and Caspase3 significantly increased (P < 0.05), while those of Bcl2, Dmrt2 and Tssk4 were significantly decreased (P < 0.05). These results indicate that EVM713 is essential for spermatogenesis in bivalves, regulating testis development through the modulation of Dmrt2 and Tssk4 expression. This study provides the first evidence of EVM713 function in mollusks, which is conducive to better understanding molecular mechanisms underlying gametogenesis in marine invertebrates.