Cloning and expression analysis of a novel Glutathione S-transferase gene, MsGST, from alfalfa (Medicago sativa)

Glutathione S-transferases are important enzymes in protecting cells by scavenging reactive oxygen species induced by various stresses. In this study, a novel GST gene, MsGST (KM044312), was cloned and characterized from alfalfa. The open reading frame of MsGST contains 660bp nucleotides, encoding 219 amino acid residues. Amino acid sequence alignment indicated that the deduced MsGSTprotein was highly homologous to other plant tau class GST sequences. According to amino acid phylogenetic analysis, the MsGST gene was clustered into the same branch with other legume plants. Real-time quantitative, PCR (qRT-PCR) revealed that the expression levels of MsGSTwere up-regulated in both shoots and roots under ABA treatment and various stresses, including salt, drought, cold and heat stress. The effect of nodules on MsGSTgene expression indicated that the induction of MsGST expression by abiotic stress is independent of rhizobium symbiosis. In conclusion, the MsGSTgene may be involved in response to different abiotic stresses in alfalfa.