Effects of enhancing endogenous and exogenous glutathione in roots on cadmium movement in Arabidopsis thaliana

Abstract

Glutathione (GSH) is a thiol-containing compound involved in many aspects of plant metabolism. In the present study, we investigated how enhancing endogenous and exogenous GSH affects cadmium (Cd) movement and distribution in Arabidopsis plants cultured hydroponically. Transgenic Arabidopsis plants with a strong ability to synthesize GSH in roots were generated by transforming the gene encoding the bifunctional γ-glutamylcysteine synthetase-glutathione synthetase enzyme from Streptococcus thermophiles (StGCS-GS). Enhancing endogenous and exogenous GSH decreased the Cd translocation ratio in different ways. Only exogenous GSH significantly inhibited Cd translocation from roots to shoots in wild-type and transgenic Arabidopsis plants. Our study demonstrated that GSH mainly functions outside root cells to inhibit Cd translocation from roots to shoots.

Keywords: Arabidopsis thaliana; Cadmium (Cd); Glutathione; Glutathione synthetase; Positron-emitting tracer imaging system (PETIS); γ-Glutamylcysteine synthetase.