Comparative transcriptome analysis reveals differences in immune responses to copper ions in Sepia esculenta under high-temperature conditions.

Sepia esculenta is one of the most abundant extant squid populations in Southeast Asia and is of interest due to its rapid reproductive rate and high commercial value. In recent years, with the rapid development of industrialization, issues such as global warming and heavy metal pollution in the oceans have emerged, posing a serious threat to the life activities of marine organisms. In this study, we used transcriptomic techniques to investigate the differences in Cu exposure immune responses in S. esculenta larvae under different temperature conditions. The enrichment of solute carrier family (SLC) genes and genes related to DNA replication and damage was significantly higher in the CuT group than in the Cu group. Functional enrichment analysis revealed that the FcγR-mediated phagocytosis and autophagy pathways were enriched in the CuT group. Based on the analysis of differentially expressed genes (DEGs) and functional enrichment results, we can preliminarily infer that the CuT group caused more severe disruption of intercellular ion transport and DNA replication and repair in larvae compared to the Cu group. This may have further interfered with the normal physiological activities of S. esculenta larvae. Overall, at high temperatures, Cu exposure induces a more intense inflammatory response. The results of this study provide a theoretical foundation for researchers to further understand the effects of environmental factors on the immunity of S. esculenta larvae, as well as preliminary insights into the enhanced toxic effects of metallic copper on aquatic organisms under high-temperature conditions.