Iris lactea var. chinensis (Fisch.) cysteine-rich gene llCDT1 enhances cadmium tolerance in yeast cells and Arabidopsis thaliana

摘要

IlCDT1, a cysteine-rich protein, was isolated from Iris lactea var. chinensis (Fisch.) (I. lactea var. chinensis). Its transcription was up-regulated by the exogenous application of Cd. The truncated IlCDT1 (25- 54) containing 14 Cys residues confers Cd tolerance to yeast as the intact IlCDT1, indicating that Cys residues are required for Cd tolerance presumably by chelating Cd. When the gene was constitutively expressed in A. thaliana, root length of transgenic lines was longer than that of wild-type under 100 mu M or 200 mu M Cd stress. However, Cd absorption in wild-type was more than in two trangenic lines under 100 RIVI Cd exposure. IlCDT1 may directly bind Cd, through chelating Cd and avoiding the Cd uptake into the cells. Together, IlCDTI may be a promising gene for the Cd tolerance improvement.