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

SCUFFI, DENISE; LAXALT, ANA MARÍA; LAMATTINA, LORENZO; GARCÍA-MATA, CARLOS

Foz do Iguazu

Congreso; 11th International Congress of Plant Molecular Biology; 2015

IPMB

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).The aim of our study is to find out if there is a link among these molecules during stomatal closure. In Arabidopsis, the gasotransmitters H2S is enzymatically produced by the enzyme L-cysteine desulfhydrase (DES1). In our lab we have shown that DES1 and H2S participate in ABA-induced stomatal closure in different plant species. In the present work we show that Arabidopsis DES1 mutants close the stomata normally in response to H2O2, suggesting that H2O2 is downstream or independent of H2S production. Accordingly exogenous addition of 100 µM a H2S donor does not induce stomatal closure when epidermal peels from wild type plants are treated with the NADPH oxidase inhibitor, DPI. In addition we have previously demonstrated that PLDδ isoform is downstream of H2O2 in ABA-dependent stomatal closure in Arabidopsis. Here, we show that H2S-induced stomatal closure is impaired in epidermal peels of pldδ mutants. Furthermore, exogenous application of 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.