Hydrogen sulfide enhances salt tolerance through nitric oxide-mediated maintenance of ion homeostasis in barley seedling roots

Abstract

Hydrogen sulfide (H2S) and nitric oxide (NO) are emerging as messenger molecules involved in the modulation of plant physiological processes. Here, we investigated a signalling network involving H2S and NO in salt tolerance pathway of barley. NaHS, a donor of H2S, at a low concentration of either 50 or 100 μM, had significant rescue effects on the 150 mM NaCl-induced inhibition of plant growth and modulated the K+/Na+ balance by decreasing the net K+ efflux and increasing the gene expression of an inward-rectifying potassium channel (HvAKT1) and a high-affinity K+ uptake system (HvHAK4). H2S and NO maintained the lower Na+ content in the cytoplast by increasing the amount of PM H+-ATPase, the transcriptional levels of PM H+-ATPase (HvHA1) and Na+/H+ antiporter (HvSOS1). H2S and NO modulated Na+ compartmentation into the vacuoles with up-regulation of the transcriptional levels of vacuolar Na+/H+ antiporter (HvVNHX2) and H+-ATPase subunit β (HvVHA-β) and increased in the protein expression of vacuolar Na+/H+ antiporter (NHE1). H2S mimicked the effect of sodium nitroprusside (SNP) by increasing NO production, whereas the function was quenched with the addition of NO scavenger. These results indicated that H2S increased salt tolerance by maintaining ion homeostasis, which were mediated by the NO signal.

Hydrogen sulfide: a new endogenous player in an old mechanism of plant tolerance to high salinity

“…The K + /Na + homeostasis in salt-treated alfalfa was shown to be maintained by NaHS through the prevention of K + efflux likely triggered by lower expression of shaker-like K + outward-rectifying channel genes (Lai et al 2014). Similar results were shown in roots of salttreated barley seedlings in the presence of NaHS (Chen et al 2015). Remarkably, H 2 S maintained low Na + levels in cells by increasing the transcription of genes that encode for plasma membrane H + -ATPase, H + -ATPase subunit β and vacuolar Na + /H + antiporter and augmenting Na + compartmentation in vacuoles (Chen et al 2015).…”

“…Similar results were shown in roots of salttreated barley seedlings in the presence of NaHS (Chen et al 2015). Remarkably, H 2 S maintained low Na + levels in cells by increasing the transcription of genes that encode for plasma membrane H + -ATPase, H + -ATPase subunit β and vacuolar Na + /H + antiporter and augmenting Na + compartmentation in vacuoles (Chen et al 2015).…”

“…2; Wang et al 2012;Chen et al 2015). The simultaneous treatment of alfalfa with 100 µM NaHS (H 2 S donor) and 100 mM NaCl increased NO levels in cells by 30 %.…”

“…Fragaria × ananassa (Christou et al 2013) Hordeum vulgare (Chen et al 2015) Medicago sativa (Lai et al 2014) Triticum aestivum (Deng et al 2016) Protection of photosynthetic apparatus Fragaria × ananassa (Christou et al 2013) Oryza sativa (Mostofa et al 2015) Stimulation of seed germination and plant growth Arabidopsis thaliana Cucumis sativus (Sun & Luo 2014) Cynodon dactylon (Shi et al 2013) Medicago sativa (Wang et al 2012) Induction of osmoregulators accumulation…”

Responses of barley Albina and Xantha mutants deficient in magnesium chelatase to soil salinity

“…crease photorespiration and induce accumulation of reactive oxygen species (ROS) (Wu et al 2014, Chen et al 2015. ROS are generated in the process of photosynthesis in chloroplasts, especially under the stress conditions such as salt (Li et al 2015).…”