Sulfur in the Alleviation of Cadmium-Induced Oxidative Stress in Plants

The toxicity of cadmium (Cd) is an emerging environmental problem that has attracted the attention of plant scientists all over the world. It deteriorates soil, plant and human health. Researchers have focused their attention in evolving strategies to reduce its toxicity at cellular, molecular and/or whole plant level. Sulfur is an important plant nutrient that takes part in plant metabolism and provides vigor to plants under stressful environments. This nutrient element could be used in agricultural system for reducing Cd toxicity and increasing sustainability. Sulfur uptake results in the formation of the first stable product cysteine through a cascade of enzymatic reactions. The formation of cysteine leads to the synthesis of glutathione, a nonenzymatic antioxidant known to be involved in Cd detoxification either through quenching reactive oxygen species or formation of phytochelatin that binds Cd and sequester it into vacuole. Manipulation of sulfur-assimilating enzymes, cysteine, glutathione and/or phytochelatin content could possibly lead to Cd detoxification. The present work gives insight into the role of sulfur in the alleviation of Cd stress.