The role of mitocondrial H2S in stomatal immunity response

PANTALENO, ROSARIO; SCUFFI, DENISE; GARCÍA-MATA, CARLOS

Santa Fe

Congreso; RAFV XXXIII; 2021

SAFV

Stomata are microscopic structures in most land plants, responsible for the gas exchange between plant and its environment and water homeostasis through transpiration stream. They are formed by a central pore delimited by pairs of specialized cells, the guard cells (GCs), which sense different stimuli and integrate them into a signalling network that modifies GC volume to control pore size. Pathogens use stomatal pores as a natural entrance, so plants evolved to detect them and induce stomatal closure as a first mechanical barrier in order to prevent infection. The signalling molecule hydrogen sulfide (H2S) is a low-weight molecule, member of the group of the so called gasotransmitters. H2S is endogenously synthesized in plant mitochondria, by the activity of the enzyme CAS-C1, which catalyzes the reaction between cysteine and CN⁻ to form β-cyanoalanine and H2S. However, the function of mitochondrial H2S is mostly unknown. Results obtained in our lab show that mitochondrial-targeted H2S donors induce stomatal closure in a dose-dependent manner, requiring the normal activity of mitochondrial electron transport chain (mETC) to trigger this response. On the other hand, the mutant in the mitochondrial source of H2S, cas-c1, has an impaired stomatal closure and a lower apoplastic ROS production when treated with the bacterial elicitor flagellin (flg22). Our current objective is to further study the role of H2S over mitochondrial activity during stomatal closure induced by pathogens.