Heat shock proteins confer cellular heat resistance in Yesso scallop hemocytes

Rising seawater temperatures associated with global warming have caused mass mortality of Yesso scallops in aquaculture, resulting in severe economic losses. Although heat-responsive genes and the diversified hsp gene family have been described, direct functional evidence for genes that enhance heat tolerance in scallops has been limited. In this study, we used a gene overexpression system based on primary scallop hemocytes to functionally assess the roles of hsp genes in heat resistance. Transcriptome data screening identified 13 HSP-related genes expressed in scallop hemocytes. Heat-exposure experiments revealed that hsc71 , hsp60 , hsp70-12 A , and hsp70–14 were upregulated in circulating hemocytes under high-temperature condition at 24 °C. Using the hemocyte-based overexpression system, we expressed scallop Hsp-GFP fusion proteins and confirmed their proper expression with distinct subcellular localization. Hemocytes expressing the fusion proteins were then subjected to heat treatment, and cell viability was measured using a luminescence-based assay. The results suggest that scallop hsc71 and hsp60 contribute to improved cell survival at 30 °C. This study demonstrates the feasibility of functional gene validation using hemocytes as an overexpression platform and provides cellular-level evidence that HSP-mediated cytoprotection may contribute to thermal tolerance in scallops, thereby offering a functional framework for evaluating stress resilience in aquaculture species. • Hemocytes constitutively expressed 13 HSP-related genes in the Yesso scallop. • Heat exposure induced the upregulation of 4 HSP-related genes in hemocytes. • Overexpression of hsc71 and hsp60 enhanced cellular heat resistance in hemocytes. • HSP-mediated cytoprotection may contribute to thermal tolerance in the Yesso scallop.