The mRNA expression profiles demonstrating versatile roles of glutathione S-transferase genes in the mollusk Chlamys farreri

Glutathione S-transferase (GST) is a superfamily of multifunction enzymes with varying catalytic roles in cellular detoxification to protect hosts against oxidative damage. In the present study, six GST genes were identified from Chlamys farreri, including CfGST omega, CfGST sigma-1, CfGST sigma-2, CfGST rho, CfGST zeta and CfmGST. CfGSTs shared high similarities with their counterparts from other species, and were clustered with their homologues into the corresponding clades in the phylogenetic tree, respectively. We investigated the distribution of their mRNA transcripts in different tissues and their temporal expression profiles in hemocytes after microbe stimulations by quantitative real-time PCR. The six CfGST genes were detectable in all the tested tissues, including hemocytes, muscle, mantle, gill, hepatopancreas, and gonad. Stimulations with various microbes drastically induced the mRNA transcripts of all the CfGSTs with different expression profiles. For examples, CfGST omega could be induced by three kinds of microbes, including Vibrio anguillarum, Micrococcus luteus and Pichia pastoris, whereas CfmGST could be only induced by V. anguillarum. These results indicated a powerful detoxification system of GSTs in scallop. Moreover, the distinct mRNA expression profiles of CfGSTs indicated their versatile and immune-challenge specific roles in the mollusk C. farreri.