Genome-wide identification and low-salinity stress analysis of the Hsp70 gene family in swimming crab (Portunus trituberculatus)

No genome-wide identification and expression analysis have been performed on the heat shock protein 70 (Hsp70) gene family, which is essential to key cellular processes and responses to environmental change, in decapods. In the present study, we identified nine members of the Hsp70 gene family within the genome of swimming crab (Portunus trituberculatus) and provided insights into their response to long-term low-salinity stress. Results demonstrated that gene structure and motifs are conserved among members of this gene family in P. trituberculatus. Under low-salinity stress, the expression of this gene family in the gill of P. trituberculatus showed that hsc70l.2 was significantly upregulated, hyou1 was significantly downregulated. The hsc70l.4 was not expressed. Furthermore, selection test on duplicated genes showed a negative selection on hsc70l.1, hsc70l.2, hsc70l.3, and hsc70l.4, suggesting functional redundancy. This may be the first study that systematically identified and analyzed the Hsp70 gene family in decapods. These results can provide fundamental data for the biological research of P. trituberculatus and enhance understanding of the biological function of Hsp70 in crustaceans adapting to salinity changes.