Elucidating the intricacies of the H2S signaling pathway in gasotransmitters: Highlighting the regulation of plant thiocyanate detoxification pathways

Abstract

In recent decades, there has been increasing interest in elucidating the role of sulfur-containing compounds in plant metabolism, particularly emphasizing their function as signaling molecules. Among these, thiocyanate (SCN^-), a compound imbued with sulfur and nitrogen, has emerged as a significant environmental contaminant frequently detected in irrigation water. This compound is known for its potential to adversely impact plant growth and agricultural yield. Although adopting exogenous SCN^- as a nitrogen source in plant cells has been the subject of thorough investigation, the fate of sulfur resulting from the assimilation of exogenous SCN^- has not been fully explored. There is burgeoning curiosity in probing the fate of SCN^- within plant systems, especially considering the possible generation of the gaseous signaling molecule, hydrogen sulfide (H₂S) during the metabolism of SCN^-. Notably, the endogenous synthesis of H₂S occurs predominantly within chloroplasts, the cytosol, and mitochondria. In contrast, the production of H₂S following the assimilation of exogenous SCN^- is explicitly confined to chloroplasts and mitochondria. This phenomenon indicates complex interplay and communication among various subcellular organelles, influencing signal transduction and other vital physiological processes. This review, augmented by a small-scale experimental study, endeavors to provide insights into the functional characteristics of H₂S signaling in plants subjected to SCN^--stress. Furthermore, a comparative analysis of the occurrence and trajectory of endogenous H₂S and H₂S derived from SCN^--assimilation within plant organisms was performed, providing a focused lens for a comprehensive examination of the multifaceted roles of H₂S in rice plants. By delving into these dimensions, our objective is to enhance the understanding of the regulatory mechanisms employed by the gasotransmitter H₂S in plant adaptations and responses to SCN^--stress, yielding invaluable insights into strategies for plant resilience and adaptive capabilities.

Keywords: Assimilation; Hydrogen sulfide; Signaling molecule; Thiocyanate; Uptake and toxicity.