Hydrogen sulfide alleviates osmotic stress‐induced root growth inhibition by promoting auxin homeostasis

Abstract

Hydrogen sulfide (H 2 S) promotes plant tolerance against various environmental cues, and D-cysteine desulfhydrase (DCD) is an enzymatic source of H 2 S to enhance abiotic stress resistance. However, the role of DCDmediated H 2 S production in root growth under abiotic stress remains to be further elucidated. Here, we report that DCD-mediated H 2 S production alleviates osmotic stress-mediated root growth inhibition by promoting auxin homeostasis. Osmotic stress up-regulated DCD gene transcript and DCD protein levels and thus H 2 S production in roots. When subjected to osmotic stress, a dcd mutant showed more severe root growth inhibition, whereas the transgenic lines DCDox overexpressing DCD exhibited less sensitivity to osmotic stress in terms of longer root compared to the wild-type. Moreover, osmotic stress inhibited root growth through repressing auxin signaling, whereas H 2 S treatment significantly alleviated osmotic stressmediated inhibition of auxin. Under osmotic stress, auxin accumulation was increased in DCDox but decreased in dcd mutant. H 2 S promoted auxin biosynthesis gene expression and auxin efflux carrier PIN-FORMED 1 (PIN1) protein level under osmotic stress. Taken together, our results reveal that mannitolinduced DCD and H 2 S in roots promote auxin homeostasis, contributing to alleviating the inhibition of root growth under osmotic stress.

Metabolomics and transcriptomics combined with physiology reveal key metabolic pathway responses in tobacco roots exposed to NaHS

“…We determined endogenous H 2 S levels as previously described [ 13 ]. However, the protocol has been slightly modified.…”

“…While high concentrations of H 2 S can be malodorous and detrimental to plant growth, optimal levels serve as signaling molecules that regulate plant development and response to environmental stress [ 7 ]. In agricultural settings, the careful application of optimal H 2 S concentrations is involved in modulating several physiological processes essential for plant growth and development, including seed germination [ 8 , 9 ], organogenesis [ 10 , 11 ], adventitious and lateral root formation [ 12 , 13 ], maturation, flower senescence [ 14 ], and enhanced tolerance to environmental stress [ 7 , 15 ]. The role of H 2 S as a signaling molecule in orchestrating physiological processes in plants has garnered significant attention recently.…”

Phytomelatonin: A key regulator of redox and phytohormones signaling against biotic/abiotic stresses

“…H 2 S interacts with phytohormones (Auxin, MT, ETH, ABA) in a significant manner to modulate stress, growth, and development [ [77] , [78] , [79] ]. MT contributes a vital role in maintaining H 2 S homeostasis in plants; a recent study on Solanum lycopersicum L. var.…”