Hydrogen Sulfide in Plant Abiotic Stress Tolerance

Hydrogen sulfide (H2S) is an emerging, multitasking cell signaling molecule in plants often considered as third gasotransmitter after nitric oxide and carbon monoxide. Accumulating evidence has imparted many biological functions to H2S including seed germination, plant growth, and physiology as well as the moderation of defense responses. While its production in plants during sulfur assimilation has been known for quite a while, our knowledge of the complete synthesis and signaling role of H2S only started emerging recently. Several recent reports have pointed the controlled release of H2S in plant cells as a crucial signal for the survival under abiotic stress conditions. Besides, H2S priming also induce systemic resistance against a range of abiotic stress conditions majorly by reestablishment of redox homeostasis, maintaining ion balance, enhancing osmolyte accumulation, regulating gene expression. Additionally, mounting evidence indicates that H2S signaling interacts with plant hormones, hydrogen peroxide, nitric oxide, and other signaling molecules. However, current research on the role of H2S mediated post translational modification, S‐sulfhydration, and its direct effects on the activity of proteins is still in its infancy in plants. The growing importance of H2S and our insufficient knowledge on its functions and targets in plants calls for further detailed analyses at the physiological, biochemical and molecular levels before fully accepting its signaling roles in plant stress tolerance.