Interplay between hydrogen sulfide (H2S), H2O2 and Phospholipase D (PLD) in Arabidopsis guard cell signaling

DENISE SCUFFI; ANA MARÍA LAXALT; LORENZO LAMATTINA; CARLOS GARCIA-MATA

The 5th PanAmerican Plan Membrane Biology Workshop

Workshop; The 5th PanAmerican Plant Membrane Biology Workshop; 2015

Stomatal pore regulation is a key process for carbon and water homeostasis of terrestrial plants. The stress hormoneAbscicic acid (ABA), induces stomatal closure through volume changes in guard cells. Among the second messengersthat participate in ABA-induced stomatal closure are hydrogen sulfide (H2S), H2O2 and phospholipase D (PLD)-derivedphosphatidic acid (PA). H2S is a small gas considered as the third endogenous gasotransmitter. In Arabidopsis thaliana, H2Sis produced in the cytosol by the L-cysteine desulfhydrase 1 (DES1) and it participates in the ABA-induced stomatalclosure.In our lab we have shown that H2S induces stomatal closure indifferent plant species. In addition we have demonstratedthat both PLDα1 and PLDδ isoforms are required for ABA-induced stomatal closure in Arabidopsis. In this work we reportthe interaction between H2S, H2O2 and PLD-derived PA in signaling process leading to stomatal closure. Results show thatArabidopsis DES1 mutantsdes1-1 and des1-2 close the stomata normally in response to H2O2. However, exogenous additionof 100 μM NaHS, a H2S donor, does not induce stomatal closure wild type epidermal peels treated with DPI, an inhibitor ofNADPH oxidase activity. H2S-induced stomatal closure is also impaired in epidermal peels of pldα1 and pldδ single mutants.Furthermore, exogenous H2S induces an increase of 40% of PA in leaf disc of Arabidopsis wild type but not in pldα1 and pldδsingle mutant plants. All together, these data strongly support that H2S is acting upstream of H2O2 and PA during stomatalclosure in Arabidopsis thaliana.Sponsored by Consejo Nacional De Investigaciones Científicas Y Técnicas (CONICET); Agencia Nacional De PromociónCientífica Y Tecnológica (ANPCyT)