Heat shock proteins consist of several families of highly conserved proteins that play an essential role in a number of cellular processes. Among the 70 kD family of heat shock proteins, heat shock cognate protein 70 kD (Hsc70) and inducible heat shock protein 70 kD (Hsp70) have been extensively studied in vertebrates and invertebrates. Several cDNAs encoding HSP70 have been described in molluscs, including the oyster (), Zhikong scallop (). Recent studies examining HSP70 expression in different species of mollusc have recognized the physiological and ecological importance of heat-shock gene expression in response to changing environments. We isolated an EST sequencewith high homology with heat shock protein 70 gene from the cDNA library of. Then, the complete express sequence of this gene was obtained using PCR and 5′RACE. The cDNA of this gene was 2 335 bp, and consisted of a 76 bp 5′ untranslated region (UTR), a 1 950 bp open reading frame (ORF) and a 309 bp 3′ UTR. The translated protein consisted of 649 amino acids (70.89 kD)and its calculated isoelectric point was 5.28. Sequence analysis of the protein revealed that this gene contained three signature sequences of the heat shock protein 70 family (HSP70 family), two glycosylation sites and one ATP-GTP binding site. Four terapeptides of GGXP and a cytoplasm characteristic motif of EEVD were detected in the carboxyl terminal region of the deduced amino acid sequence. This HSP70 is a member of the HSC70 (constitutive genes) subfamily in the HSP70 family, and is designated as . Phylogenetic analysis suggested that the protein was most similar to those of Quantitative reverse transcriptase (qRT-PCR) analyses revealed that mRNA was expressed constitutively in all the tissues tested. Expression was lowest in the mantle and highest in the water pipe and liver. Following challenge with mRNA expression first increased in the liver of then decreased. Expression peaked after 20 and 30 h post-challenge with , respectively. There was a significant increase in parahaemolyticus compared to the control group at 4, 12, and 30 h post-challenge. Similarly, there was a significant increase in anguillarum 4, 8, 12, 20, 30, and 48 h post-challenge. S. constricta