[Stress-responsive expression analysis of glutathione-S-transferase gene of Ipomoea batatas (L.) Lam].

A prokaryotic expression plasmid pET-IbGST, which contains the full encoding region of a glutathione-S- transferase (GST) gene of sweet potato, was constructed. The recombinant IBGSTU1 protein was expressed in Escherichia coli and found in the soluble fraction, as well as in insoluble inclusion bodies of lysed cells. Its enzymatic activity was detected using UV spectrophotometer. The protein was purified and used to prepare antibody. Semi-quantitative RT-PCR and Western blotting analyses demonstrated that IBGSTU1 gene was not expressed under normal conditions. When subjected to some environ-mental stresses such as cold-stress or heavy-medal stress, the organism switches on the expression of IBGSTU1 at both mRNA and protein levels, and its expression has tissue specificity.