Comparative transcriptome analysis reveals the developmental program in Yesso scallop Patinopecten yessoensis

Yesso scallop Patinopecten yessoensis is an economically and ecologically important cold-water bivalve molluscs. Elucidating the molecular mechanism regulating its early larval development holds great significance in aquaculture. This study performed comparative transcriptomic analysis across nine developmental stages from fertilized eggs to spats. A variety of differentially expressed genes (DEGs) were identified to be potentially involved in larval development, including cell proliferation (cyclins, CDKs, BMPs, TGF-beta), immunity (TLR7, CTLs, cathepsins, SOD, GSTs), larval settlement and metamorphosis (MHC, MELC, paramyosin, D beta H, GABA receptor), shell formation (iMSP5, MSP1, CHS1, CHI3, CAM, CAML5) as well as energy metabolism (glycolysis, TCA cycle and oxidative phosphorylation components). Additionally, weighted gene co-expression network analysis (WGCNA) identified the key indianred4 module, which may play vital roles in body axis formation, neurogenesis and myogenesis in scallop larvae. An integrative framework was established delineating molecular drivers of embryogenesis, larval growth, immune defense, metamorphosis, shell production and bioenergetics throughout larval development in scallops. These findings will help understand the molecular strategies governing larval developmental process, yielding great insights to inform ecological conservation and aquaculture practices.