Biochemical role of gasotransmitters on plant growth, development, biomass, and tolerance under As stress

The gasotransmitters nitric oxide (NO) and hydrogen sulfide (H2S) have emerged as vital signaling biomolecules in controlling several plant physiological processes. Additionally, both gasotransmitters are potent defense key molecules to alleviate abiotic stress in plants, including metal/metalloid toxicity, such as arsenic (As) toxicity. As is a harmful toxic element that severely restricts plant growth and development. Indeed, As-induced toxicity decreases the activities of antioxidant enzymes and biomolecules, enhances the generation of reactive oxygen species (ROS), and causes lipid peroxidation and cell death. Plants have developed defense mechanisms that include increasing the endogenous production of NO and H2S. These molecules impair As uptake and translocation by plant tissues/cells. The administration of exogenous NO or H2S donors is a recent approach that has been successfully used in plants under As toxicity. NO/H2S donors can scavenger ROS generation by improving plant defense mechanisms. These include enhancing the antioxidant activity and cross talk between these two plant defense gasotransmitters. NO and H2S can work together to boost plant defense in mechanisms involving protein modifications by posttranslational protein modifications. This chapter discusses current progress in using NO and H2S donors to alleviate As toxicity in plants. These donors can find important agricultural applications to increase crop productivity.