Hydrogen Sulfide Mediated Stress Responses in Plants

Hydrogen sulfide (H₂S) has emerged as a vital gaseous signal in plant biology, orchestrating adaptive responses to a spectrum of abiotic stresses including heavy metals, salinity, drought and temperature extremes. Endogenously produced by enzymes such as L-cysteine desulfhydrases and D-cysteine desulfhydrases, H₂S modulates reactive oxygen species (ROS) homeostasis, adjusts ion transport and influences hormone pathways. Central to its function is protein persulfidation, a post-translational modification in which a thiol group (–SH) is converted into a persulfide (–SSH), thereby altering activity, stability or localisation of target proteins. Through regulation of antioxidant enzymes, ion-translocating ATPases, ion channels and aquaporins, H₂S maintains cellular redox balance and ionic equilibrium under stress. Exogenous application of H₂S donors has demonstrated practical benefits for crop resilience, while genetic manipulation of H₂S biosynthetic pathways offers new avenues for stress tolerance breeding. Collectively, H₂S signalling integrates metabolic, transcriptional and physiological networks to safeguard plant growth and productivity in challenging environments.

Research from Nature Portfolio

Recent studies have elucidated the protective role of H₂S in cadmium-stressed rice, where exogenous H₂S donors enhanced growth, photosynthetic pigment retention and antioxidant capacity. This alleviation of cadmium toxicity was accompanied by improved redox status, increased activities of ROS- and methylglyoxal-detoxifying enzymes and maintenance of mineral homeostasis in roots and shoots. The necessity of H₂S was confirmed by scavenger treatments that abolished its beneficial effects.

Investigations in barley seedling roots under salt stress revealed that low concentrations of an H₂S donor restored growth by modulating the Na⁺/K⁺ balance. H₂S promoted expression and activity of plasma-membrane H⁺-ATPases, Na⁺/H⁺ antiporters and K⁺-uptake transporters, while coordinating nitric oxide signalling to fine-tune ion compartmentation and preserve cellular ion homeostasis.

In Arabidopsis roots exposed to cadmium, a coordinated H₂S–cysteine cycle was activated, driving rapid H₂S release and cysteine accumulation. This cycle induced alternative respiration and antioxidant enzymes, stimulated metallothionein and phytochelatin gene expression and suppressed ROS bursts, collectively enhancing cadmium tolerance at the root level.

Hydrogen Sulfide Mediated Stress Responses in Plants publication trend

The graph below shows the total number of articles in hydrogen sulfide mediated stress responses in plants across all publications each year (not limited to Nature Index journals).

Technical terms

Gasotransmitter: Small gaseous signalling molecule, exemplified by H₂S, that diffuses freely across membranes to regulate cellular functions.

Persulfidation: Post-translational modification converting a protein cysteine thiol (–SH) into a persulfide (–SSH), thereby modulating protein activity or localisation.

Reactive oxygen species (ROS): Highly reactive molecules derived from oxygen (e.g. superoxide, hydrogen peroxide) that accumulate under stress and require detoxification.

Ion homeostasis: Regulation of intracellular and tissue ion concentrations and gradients, crucial for cellular osmotic balance and metabolic function.

Antioxidant enzymes: Enzymatic defences such as superoxide dismutase, catalase and peroxidases that neutralise ROS and protect cellular components from oxidative damage.

References

1. A D-cysteine desulfhydrase, SlDCD2, participates in tomato fruit ripening by modulating ROS homoeostasis and ethylene biosynthesis. Horticulture Research (2023).
2. Persulfidation proteome reveals the regulation of protein function by hydrogen sulfide in diverse biological processes in Arabidopsis. Journal of Experimental Botany (2017).
3. Hydrogen sulfide modulates cadmium-induced physiological and biochemical responses to alleviate cadmium toxicity in rice. Scientific Reports (2015).
4. Hydrogen sulfide enhances salt tolerance through nitric oxide-mediated maintenance of ion homeostasis in barley seedling roots. Scientific Reports (2015).
5. Hydrogen sulfide - cysteine cycle system enhances cadmium tolerance through alleviating cadmium-induced oxidative stress and ion toxicity in Arabidopsis roots. Scientific Reports (2016).
6. H2S Alleviates Salinity Stress in Cucumber by Maintaining the Na+/K+ Balance and Regulating H2S Metabolism and Oxidative Stress Response. Frontiers in Plant Science (2019).