A metallothionein-like protein of rice (rgMT) functions in E.coli and its gene expression is induced by abiotic stresses

摘要

A metallothionein-like (rgMT) gene was isolated from a rice (Oryza sativa L.) root cDNA library that was prepared from plants grown under NaHCO_3 stress.The rgMT gene expression was induced in rice leaves and roots under several abiotic stresses from salts (NaCl and NaHCO_3),drought (PEG) and metals (CuCl_2;ZnCl_2,CdCl_2).The results suggested that the rgMT gene was expressed in response to environmental stresses.The rgMT gene was expressed in Escherichia coli,and the final yield of the purified rgMT protein was 4.8 mg g~(-1) dry cells.Tolerance of E.coli expressing GST-rgMT fusion protein to Cu~(2+),Zn~(2+) and Cd~(2+) was enhanced,and cells dry weight increased 0.04 mg,0.17 mg and 0.07 mg in 1 ml culture treated with either CuCl_2,ZnCl_2 or CdCl_2,respectively,compared with control after 6 h culture.