H₂S activates succinate dehydrogenase through persulfidation to induce stomatal closure in Arabidopsis

Recent studies have demonstrated that hydrogen sulfide (H₂S), an important gasotransmitter, participates in stomatal closure and is associated with the regulation of cellular bioenergetics. However, the coupling mechanism between H₂S signal transduction and ATP production during guard cell movement in plants remains unclear. We explored the role of succinate dehydrogenase (SDH, EC 1.3.5.1), an important member of the electron transport chain, in H₂S-induced stomatal closure.

Pharmacological experiments and non-invasive micro-test techniques were used to study the stomatal movement under treatment with the SDH inhibitor 2-thenoyltrifluoroacetone (TTFA) and H₂S. Biotin-switch assay analysis detected the persulfidation level (H₂S covalently modifies the active Cys residue of the target protein, converting the C-SH groups to C-SSH groups) of SDH1-1 in vivo and in vitro. Furthermore, the study encompassed the analysis of biochemical variables such as ATP content and SDH enzyme activity.

The results confirmed that K⁺, Ca²⁺, and Cl⁻ channels were all involved in stomatal closure induced by H₂S, with Cl⁻ channels being the most responsive. Physiological concentration of H₂S enhanced the expression of SDH1-1 at both the transcriptional and protein translation levels. On the other hand, ATP production was promoted by H₂S, but the enhancement in sdh1-1 was considerably weaker compared with that of WT. Meanwhile, H₂S triggered the persulfidation of SDH1-1, which coincided with an increase in its enzyme activity.

SDH was involved in H₂S-induced stomatal closure, possibly acting as a pivotal hub for H₂S-involved energy production in plants.