Hydrogen Sulfide Increases Production of NADPH Oxidase-Dependent Hydrogen Peroxide and Phospholipase D-Derived Phosphatidic Acid in Guard Cell Signaling

Scuffi D, Nietzel T, Di Fino LM, Meyer AJ, Lamattina L, Schwarzländer M, Laxalt AM, García-Mata C

Zusammenfassung

Hydrogen sulfide (H2S) is an important gaseous signaling molecule in plants that participates in stress responses anddevelopment. L-Cys desulfhydrase 1, one of the enzymatic sources of H2S in plants, participates in abscisic acid-inducedstomatal closure. We combined pharmacological and genetic approaches to elucidate the involvement of H2S in stomatalclosure and the interplay between H2S and other second messengers of the guard cell signaling network, such as hydrogenperoxide (H2O2) and phospholipase D (PLD)-derived phosphatidic acid in Arabidopsis (Arabidopsis thaliana). Both NADPHoxidase isoforms, respiratory burst oxidase homolog (RBOH)D and RBOHF, were required for H2S-induced stomatal closure.In vivo imaging using the cytosolic ratiometric fluorescent biosensor roGFP2-Orp1 revealed that H2S stimulates H2O2 productionin Arabidopsis guard cells. Additionally, we observed an interplay between H2S and PLD activity in the regulation of reactiveoxygen species production and stomatal movement. The PLDa1 and PLDd isoforms were required for H2S-induced stomatalclosure, and most of the H2S-dependent H2O2 production required the activity of PLDa1. Finally, we showed that H2S inducedincreases in the PLDd-derived phosphatidic acid levels in guard cells. Our results revealed the involvement of H2S in thesignaling network that controls stomatal closure, and suggest that H2S regulates NADPH oxidase and PLD activity in guardcells.