Cysteine and glutathione modulate genes involved in cell wall binding, transport, and detoxification of mercury in rice
This study investigated the mechanisms of Hg accumulation and tolerance by exogenous cysteine (Cys) and glutathione (GSH) in rice. Exogenous Cys and GSH significantly enhanced Hg tolerance in rice but exhibited contrasting effects on Hg accumulation. Exogenous Cys significantly increased Hg accumulation in rice roots, primarily in the cell wall, while exogenous GSH decreased root Hg accumulation. Hg and exogenous Cys significantly increased the expression of cell wall biosynthesis genes and several ABC transporters, suggesting enhanced roles in Hg uptake and vacuolar sequestration. In addition, GSH upregulated aquaporin to maintain membrane function and water balance, and Cys primarily induced peroxidase genes to reduce cellular oxidative damage.