Role of hydrogen sulfide (H2S) and participation of calcium (Ca2+) in stomatal immunity of Arabidopsis thaliana.

SCHIEL, PAULA; PANTALENO, ROSARIO; SCUFFI, DENISE; GARCÍA-MATA, CARLOS; LAXALT, ANA M.

Rosario, Santa Fe

Conferencia; Reunión Argentina de Fisiología Vegetal (RAFV); 2024

Sociedad Argentina de Fisiología Vegetal

Stomata are pores in the epidermis of most land plants surrounded by pairs of specialized cells called guard cells (GCs). Changes in GCs turgor pressure modulate the stomatal aperture, which controls gas exchange with the environment. Some pathogens can enter through the stomatal pores to infect the plants, so the induction of stomatal closure implies a first barrier of plant defense, mechanism known as stomatal immunity.The recognition of Pathogen Associated Molecular Patterns, as the bacterial elicitor flg22, triggers a signaling cascade that involves an increase of cytosolic calcium (Ca2+cyt) and reactive oxygen species (ROS), leading to stomatal closure.Hydrogen sulfide (H2S) is a gasotransmitter that has been described to induce stomatal closure. Its main mechanism of action is persulfidation of proteins, a posttranslational modification (PTM) in cysteine residues that regulates the activity or localization of the target protein. Preliminary results obtained in our lab show several persulfidation targets associated with the immune response, specifically in GCs. Among them, PHOSPHOLIPASE C2 (PLC2), which is involved in stomatal closure induced by flg22 and H2S; and some Ca2+-dependent protein kinases.In our lab, we demonstrated that the main H2S cytosolic source L-CYSTEINE DESULFHYDRASE 1 (DES1), participates in flg22-induced stomatal closure, but there is no information on the interaction with signaling components of this response. The aim of this study is to investigate the role of H2S/DES1 in stomatal immunity In the present work we show that stomatal closure induced by Ca2+ is impaired in des1 mutant plants. However, Ca2+cyt increase in GCs treated with flg22 shows the same dynamic as wild type plants. Moreover, PLC2-silenced plants present reduced production of cytosolic ROS in GCs in response to H2S.