The involvement of glutathione in cadmium detoxification of Saccharomyces cerevisiae

Divalent cadmium is a toxic environmental pollutant to biological systems. This study confirmed that it causes oxidative stress in yeast cells. The total glutathione levels in yeast cells significantly decreased with increasing cadmium concentrations. The glutathione precursor cysteine induced a concentration-dependent reduction in the superoxide production and malondialdehyde content. The glutathione synthesis deficient strains gsh1 Delta, gsh2 Delta, and cysteine synthesis deficient strain (cys3 Delta) were more sensitive to cadmium than the wild type BY4741, and glutathione could increase the resistance of gsh1 Delta, gsh2 Delta, and cys3 Delta to cadmium, while it could not reverse the sensitivity of ycf1 Delta to cadmium. In addition, the overexpression of ERO1 could enhance the sensitivity of the wild-type and gsh1 Delta cells to cadmium, indicating that the detoxification of cadmium depends on the intracellular glutathione redox levels. However, the prerequisite is that the chelates formed by glutathione and cadmium (GS Cd SG) can be transported to the vacuole by YCF1. Therefore, the reduced glutathione helps to detoxify cadmium in a YCF1-dependent manner in yeast cells. This study contributes to understanding how yeast detoxifies cadmium, which will allow the development of yeast cells for bioremediation of cadmium pollution.