Genome‐wide identification of the <scp>Hsp70</scp> gene family in <scp>Atlantic</scp> cod ( <i>Gadus morhua</i> ) and its response to pathogenic stress

Heat shock protein 70 (Hsp70) is a critical molecular chaperone in most eukaryotes and prokaryotes, significantly contributing to several physiological and biochemical processes and regulating stress response to external stimuli. Gadus morhua is a fish species with exceptionally high nutritional value and significant economic importance, making it highly meaningful to study its response strategies under pathogenic stress. However, systematic analyses of Hsp70 in G. morhua have yet to be performed. In this study, we identified 24 family members of Hsp70 genes from G. morhua and analysed their protein properties, chromosomal distribution, phylogenetic relationships, gene structure and conserved motifs. We observed that some hsp70 members exhibited significantly differential expression under the stress of pathogenic bacteria and worm, suggesting that these genes could be involved in regulating pathogenic immunity. Overall, these findings provide useful information for studying cod Hsp70 gene function and evaluating its role in pathogenic immunity regulation.