Physiological analysis and transcriptome sequencing revealed that HSPA1 was involved in response to heat stress in thick-shell mussels, Mytilus coruscus.

Mytilus coruscus, being sensitive to temperature variations, has developed a protective mechanism against heat stress through the upregulation of genes encoding heat shock proteins. Past research indicates that exposure to heat stress can activate HSPA1 expression for protection, yet the underlying regulatory mechanisms governing this response are not fully clear. Therefore, the emphasis of this study lies on regulating the expression of HSPA1 in mussels under high temperature stress. This study showed that high temperature could cause tissue damage and induce apoptosis in M. coruscus. Overexpression of HSPA1 at high temperature can mitigate damage. Enzyme activity assays also found that after the overexpression of HSPA1 at high temperature, the enzyme activity of SOD, CAT and GSH-PX increased to cope with the stimulation brought by high temperature, which suggests that the HSPA1 gene plays a critical role in the antioxidant response. Transcriptome analysis showed that under high-temperature stress, key genes including HSPA1S, HSP90, HSPA5, DnaJA1, and JUN showed increased expression in HSPA1-knockdown treatments, with differential gene expression enriched in pathways associated with MAPK signaling, endoplasmic reticulum protein processing, TNF signaling, apoptosis, and cell apoptosis pathways. Based on this, we suggested that M. coruscus may counteract damage induced by high-temperature stress via the above key genes and biology processes, highlighting the crucial role of HSPA1 in mitigating cell damage and apoptosis due to high temperature. Overall, our results revealed HSPA1 regulatory relationship in M. coruscus treated with high temperature, and provided new insights for the conservation and environmental adaptive evolution of bivalve species.