Objective Atrina pectinata are important aquatic economic shellfish. Temperature is one of the key environmental factors affecting their growth, development and survival. This study aims to explore the physiological role of heat shock protein 70 (HSP70) in A. pectinata temperature stress response.

Methods The complete domain fragments of HSP70 gene were obtained from the A. pectinata transcriptome library. The cDNA sequence was characterized using bioinformatics analysis software. Tissue distribution and expression levels of the HSP70 gene under different water temperatures at different time points were analyzed using quantitative real-time polymerase chain reaction (qRT-PCR).

Results The results showed that the open reading frame (ORF) of the HSP70 cDNA was 1 968 bp, which encoded 655 amino acids. The theoretical protein molecular weight was 71.51 kD and the theoretical isoelectric point was 5.36. Multiple sequence alignment results showed that HSP70 in Chlamys farreri, Haliotis discus hannai, Mytilus galloprovincialis, Cyclina sinensis, Danio rerio, Mus musculus, and Homo sapiens had more than 85% homology. qRT-PCR results demonstrated ubiquitous expression of HSP70 across all examined tissues (foot, gill, adductor muscle, mantle, hepatopancreas, and gonads), with the foot exhibiting significantly higher relative expression levels compared to other tissues (P<0.05). Under the condition of 30 ℃ (high temperature), the relative expression level of HSP70 gene in gills showed a gradually decreasing trend at different time points. The relative expression level at 6 h was significantly higher than that at other time points (P<0.05), and the lowest was at 5 d. At 6 h, 1 d and 3 d, the relative expression levels of HSP70 gene were significantly higher than those at 20 ℃ (control) (P<0.05), while there was no significant difference in the relative expression level at 5 d compared with 20 ℃ (control) (P>0.05). Under the condition of 10 ℃ (low temperature), the relative expression level of HSP70 gene in gills was the highest at 6 h, significantly higher than that at other time points (P<0.05); at 6 h, the relative expression level of HSP70 gene was significantly higher than that at 20 ℃ (control) (P<0.05).

Conclusion The study analyzed the structural features and expression patterns of A. pectinata and HSP70 gene sequences. It is speculated that A. pectinata exist widely in the body and perform the most basic physiological functions in cells. It may participate in the temperature stress response of A. pectinata, providing a molecular theoretical basis for exploring the role of HSP70 gene in temperature stress.