The gasotransmitter Hydrogen sulfide (H2S) acts upstream of H2O2 and phospholipase D (PLD)-derived phosphatidic acid (PA) during stomatal closure.

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

Congreso; International Plant Molecular Biology (IPMB); 2015

Stomatal pore regulation is a key process for carbon and water homeostasis of terrestrial plants. The pore size is modulated through changes in the guard cell volume, driven by variations in the osmotic potential of the guard cells. This process is closely regulated by a complex signaling network that involves the participation of several second messengers including hydrogen sulfide (H2S), H2O2 and phospholipase D (PLD)-derived phosphatidic acid (PA). H2S is a small gas considered as the third endogenous gasotransmitter. In Arabidopsis thaliana is enzymatically produced in the cytosol by the L-cysteine desulfhydrase 1 (DES1). In our lab we have shown that both H2S and PLDδ isoform are required for ABA-induced stomatal closure in different plant species.. In this work we demonstrate the existence of an interaction between H2S, PLD-derived PA and H2O2 in the signaling events leading to stomatal closure. Results show that Arabidopsis DES1 mutants close the stomata normally in response to H2O2. However, exogenous addition of 100 µM a H2S donor does not induce stomatal closure when epidermal peels from wild type plants are treated with DPI. H2S-induced stomatal closure is also impaired in epidermal peels of pldδ mutants. Furthermore, exogenous H2S induces an increase of 40% of PA in epidermal peels and leaf disc of Arabidopsis wild type but not in pldδ mutant plants. All together, these data strongly support that H2S is acting upstream of H2O2 and PA during stomatal closure in Arabidopsis