Transcriptomic profile of Lutraria sieboldii larvae: Insights into the molecular mechanisms of attachment and metamorphosis

Abstract

Metamorphosis, the crucial transition from planktonic to sessile life stages, marks a key developmental milestone in marine bivalves, particularly for commercially valuable species like Lutraria sieboldii. We conducted a comprehensive transcriptomic analysis using RNA sequencing (RNA-seq) during the larval settlement stage to elucidate the molecular mechanisms underlying this ecologically and economically significant process. Our study generated 89.64 Gb of high-quality clean data (≥6.20 Gb per sample, Q30 ≥ 92.7 %), ensuring robust and reliable insights into gene expression dynamics. Through weighted gene co-expression network analysis (WGCNA), we identified the turquoise module as a key regulatory network strongly associated with settlement-related traits. This module was significantly enriched in critical biological processes, including mRNA splicing via spliceosome, pathways related to cytoskeletal organization and calcium signaling, and C-type lectin receptor signaling, which are crucial for substrate interaction and tissue remodeling. Notably, hub genes within this module included essential components of the spliceosome (SF3B1, RBM8A), calcium signaling regulators (CALM3), and cytoskeletal modulators (ACTB, MFAP1). Furthermore, transcriptional profiling revealed a significant upregulation of genes involved in inorganic ion transport and metabolism, cytoskeletal dynamics, protein turnover, and energy production. These results offer strong evidence for the coordinated regulation of molecular mechanisms during substrate recognition and tissue restructuring in L. sieboldii metamorphosis. As the first comprehensive transcriptomic resource describing larval settlement in this species, our study advances our understanding of conserved developmental pathways and suggests potential aquaculture strategies, such as optimizing calcium signaling or spliceosome activity to enhance larval settlement efficiency in hatchery settings.