Implications of the fate of hydrogen sulfide derived from assimilation of thiocyanate in rice plants

Abstract

Thiocyanate (SCN^-) is a sulfur-containing pollutant, which is frequently detected in irrigation water and has negative effects on plant growth and crop yields. Uptake and assimilation of exogenous SCN^- in rice plants was evident, in which two metabolic pathways, carbonyl sulfide (COS) and cyanate (CNO), are activated. Hydrogen sulfide (H₂S) is an important concomitant derived from detoxification of exogenous SCN^- in rice plants, which may cause coupling action on the endogenous source of H₂S from sulfur metabolism. Since H₂S has dual regulatory effects, the fate of H₂S derived from assimilation of SCN^- in plants is critical for clarifying the inclusiveness of H₂S in various physiological activities. In fact, application of exogenous H₂S not only positively changed the root phenotype traits of SCN^--treated seedlings, but also effectively mitigated the toxic effects of SCN^- in rice seedlings by stimulating the process of the PSII repair cycle. In this study, it is tempting to analyze and clarify the flux of the concomitant production of H₂S from assimilation of exogenous SCN^- into the innate pool, which may function in signaling regulation and other physiological processes in rice plants. This study would update our understanding of the fate of H₂S derived from assimilation of SCN^- in plants and provide new insights into the affirmative actions of H₂S in direct proximity to SCN^- exposure.

Keywords: Assimilation; Cysteine; Hydrogen sulfide; Rice; Thiocyanate.