Role of hydrogen sulfide in alleviating oxidative stress in plants through induction of antioxidative defense mechanism, and modulations of physiological and biochemical components

Adverse abiotic stress conditions are considered to be of global environmental concern because they negatively affect the productivity and quality of crop plants. Being a gasotransmitter, hydrogen sulfide can regulate various physiological functions and plant abiotic stress tolerance. Various reports have illustrated that H2S could enhance plants’ ability to adapt to multiple environmental stress conditions by alleviating cellular injuries and toxicity. The role of H2S in specific physiological and metabolic functions such as stomatal movements, seed germination, improved photosynthesis, and maturation of lateral roots have long been reported. The increasing number of studies have shown that H2S can elicit various defense features under abiotic stresses. Moreover, exogenous application of H2S clearly mitigates plant damage from oxidative stress by stimulating various antioxidative components (both enzymatic and nonenzymatic components). H2S treatment improves the activity of antioxidative enzymes such as ascorbate peroxidase, catalase, superoxide dismutase, and glutathione reductase as well as the levels of ascorbate and glutathione to neutralize reactive oxygen species overproduction and protect the cell from oxidative damage. This chapter presents an overview of the biosynthesis and metabolism of H2S and its possible involvement in various signaling pathways in plants. Moreover, in this chapter we have also deliberated upon the role of H2S in the enhancement of antioxidative mechanisms in plants to regulate the oxidative stress under adverse environmental stress conditions.