Gaseous signaling molecule H 2 S as a multitasking signal molecule in ROS metabolism of Oryza sativa under thiocyanate (SCN - ) pollution.

The induction of disruption in the electronic transport chain by thiocyanate (SCN ^- ) leads to an excessive generation of reactive oxygen species (ROS) within rice (Oryza sativa). Hydrogen sulfide (H ₂ S) assumes a crucial role as a gaseous signaling molecule, holding significant potential in alleviating SCN ^- -related stress. Nevertheless, there remains a dearth of understanding regarding the intricate interplay between H ₂ S and ROS in Oryza sativa amidst SCN ^- pollution. In this investigation, a hydroponics-based experiment was meticulously devised to explore how H ₂ S-mediated modifications influence the genetic feedback network governing ROS metabolism within the subcellular organelles of Oryza sativa when exposed to varying effective concentrations (EC ₂₀ : 24 mg SCN/L; EC ₅₀ : 96 mg SCN/L; EC ₇₅ : 300 mg SCN/L) of SCN ^- . The findings unveiled the enhanced capacity of Oryza sativa to uptake SCN ^- under H ₂ S + SCN ^- treatments in comparison to SCN ^- treatments alone. Notably, the relative growth rate (RGR) of seedlings subjected to H ₂ S + SCN ^- exhibited a superior performance when contrasted with seedlings exposed solely to SCN ^- . Furthermore, the application of exogenous H ₂ S yielded a significant reduction in ROS levels within Oryza sativa tissues during SCN ^- exposure. To elucidate the intricacies of gene regulation governing ROS metabolism at the mRNA level, the 52 targeted genes were categorized into four distinct types, namely: initial regulatory ROS generation genes (ROS-I), direct ROS scavenging genes (ROS-II), indirect ROS scavenging genes (ROS-III), and lipid oxidation genes (ROS-IV). On the whole, exogenous H ₂ S exhibited the capacity to activate the majority of ROS-I ∼ ROS-IV genes within both Oryza sativa tissues at the EC ₂₀ concentration of SCN ^- . However, genetic positive/negative feedback networks emphasized the pivotal role of ROS-II genes in governing ROS metabolism within Oryza sativa. Notably, these genes were predominantly activated within the cytoplasm, chloroplasts, mitochondria, peroxisomes, and the cell wall.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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