Hydrogen sulfide attenuates intracellular oxidative stress via repressing glycolate oxidase activities in Arabidopsis thaliana.

BACKGROUND

Hydrogen sulfide (HS) has been proposed to exert anti-oxidative effect under many environmental stresses; however, how it influences oxidative stress remains largely unclear.

RESULTS

Here, we assessed the effects of HS on oxidative stress responses such as salicylic acid (SA)-dependent cell death, which triggered by increased HO availability in Arabidopsis thaliana catalase-deficient mutants cat2 displaying around 20% wild-type catalase activity. HS generation and its producing enzyme -cysteine desulfhydrase (LCD/DES) were found to transient increase in response to intracellular oxidative stress. Although introducing the mutation of des1, an important LCD, into the cat2 background produced little effect, HS fumigation not only rescued the cell death phenotype of cat2 plant, but also attenuated SA accumulation and oxidation of the glutathione pool. Unexpectedly, the activities of major components of ascorbate-glutathione pathway were less affected by the presence of HS treatment, but decreased glycolate oxidase (GOX) in combination with accumulation of glycolate implied HS treatment impacts the cellular redox homeostasis by repressing the GOX-catalyzed reaction likely via altering the major GOX transcript levels.

CONCLUSIONS

Our findings reveal a link between HS and peroxisomal HO production that has implications for the understanding of the multifaceted roles of HS in the regulation of oxidative stress responses.