Transcriptomic Analysis Reveals Dynamics of Gene Expression in Liver Tissue of Spotted Sea Bass Under Acute Thermal Stress

The spotted sea bass (Lateolabrax maculatus), a eurythermal species, exhibits strong adaptability to temperature variations and presents an ideal model for studying heat stress-responsive mechanisms in fish. This study examined the liver transcriptome of spotted sea bass over a 24-h period following exposure to elevated temperatures, rising from 25 to 32 degrees C. The results revealed significant alterations in gene expression in response to this thermal stress. Specifically, we identified 1702, 1199, 3128, and 2636 differentially expressed genes at 3, 6, 12, and 24 h post-stress, respectively. Weighted Gene Co-expression Network Analysis (WGCNA) was used to identify specific gene modules responsive to heat stress, containing hub genes such as aco2, eci2, h6pd, suclg1, fgg, fga, fgb, f2, and apoba, which play central roles in the heat stress response. Enrichment analyses via KEGG and GSEA indicated that upregulated differentially expressed genes (DEGs) are predominantly involved in protein processing in the endoplasmic reticulum, while downregulated genes are primarily associated with the AGE-RAGE signaling pathways. Additionally, 272 genes exhibited differential alternative splicing, primarily through exon skipping, underscoring the complexity of transcriptomic adaptations. These findings provide deeper insights into the molecular responses to thermal stress and are crucial for advancing the breeding of heat-resistant strains of spotted sea bass.