Genome-wide transcriptomic analysis reveals autophagy and HSP70-mediated mechanisms underlying thermal stress adaptation in Mytilus coruscus.

Rising ocean temperatures driven by global warming pose a major threat to marine organisms. In this study, we examined physiological and molecular changes in the muscle, gill, foot, and mantle tissues of Mytilus coruscus under thermal stress, demonstrating that elevated temperatures significantly induce molecular heat shock responses and oxidative stress. Transcriptomic analysis further revealed conserved and divergent transcriptional responses across these tissues at the genome-wide level, implicating stress-related processes such as autophagy, heat response, and ROS regulation. Eight autophagy-related genes (ATGs) and five heat shock protein 70 genes (HSP70) were identified as significantly upregulated during thermal stress, with their heat resistance confirmed by functional analysis in Saccharomyces cerevisiae. Protein interaction analysis showed that ATG8c interacts with four HSP70 proteins, suggesting a cooperative role of autophagy and the heat shock response in regulating thermal stress. Collectively, these findings reveal organ-specific thermal stress responses in M. coruscus and highlight autophagy and HSP70 pathways as potential molecular targets for studying thermal adaptation in sessile marine species.