Foliar application of NaHS alleviates Cd toxicity in soybean plants through regulation of Glutathione metabolism

Abstract

Hydrogen sulfide (H2S) regulates many critical processes of plants and their responses to abiotic stresses such as heavy metals. In the present study, the effect of sodium hydrogen sulfide (NaHS) as an H2S donor (0, and 50 μM) was investigated in soybean plants under Cd stress (0, and 50 μM). These experiments were done according to a factorial design based on a completely randomized design with three replications. Cd exposure reduced growth parameters and relative water content. Cd also caused a reduction in photosynthetic pigment, an increase in ion leakage and oxidative stress as indicated by lipid peroxidation and H2O2 production. These results demonstrated the toxicity of the applied Cd concentrations on soybean plants. However, foliar application of NaHS improved the shoot length and fresh weight on Cd-stressed plants. NaHS also alleviated the toxic effects of Cd on ion leakage, relative water content, and photosynthetic pigments of leaves. The activity of glutathione reductase and the expression of genes to the family of glutathione synthetase including glutathione synthetase, chloroplastic-like (LOC102663288) (GS288), glutathione synthetase, chloroplastic (LOC100778473) (GS473) and homoglutathione synthetase (Gene ID: 547,989) (HGS), were observed to be upregulated under the influence of NaHS treatment. However, the expression of glutathione synthetase, and chloroplastic-like glutathione synthetase (LOC100813419) (GS419)) were reduced by NaHS in Cd-stressed plants. These results confirm the regulatory effect of NaHS application on physiological parameters and glutathione metabolism at molecular levels on soybean plants.