Mitochondrial H2S donor AP39 induces stomatal closure by modulating guard cell mitochondrial activity

PANTALENO, ROSARIO; SCUFFI, DENISE; COSTA, ALEX; WELCHEN, ELINA; TORREGROSSA, ROBERTA; WHITEMAN, MATTHEW; GARCÍA-MATA, CARLOS

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Año: 2022

0032-0889

Hydrogen sulfide (H₂S) is a gaseous signaling molecule involved in numerousphysiological processes in plants, including gas exchange with the environmentthrough the regulation of stomatal pore width. The guard cells, pairs of specializedepidermal cells that delimit stomatal pores, have a higher mitochondrial density andmetabolic activity than their neighboring cells, however, there is no clear evidenceon the role of mitochondrial activity in stomatal closure induction.In this work we show that the mitochondrial-targeted H2S donor AP39induced stomatal closure in a dose-dependent manner. Experiments using inhibitorsof the mitochondrial electron transport chain (mETC) or insertional mutants incytochrome c (CYTc) indicated that the activity of mitochondrial complex IV and/orCYTc are required for AP39-dependent stomatal closure. By using fluorescent probesand genetically-encoded biosensors we report that AP39 increased mitochondrialinner potential (Δψm), cytosolic ATP, cytosolic H 2 O 2 levels, and modulated theglutathione redox potential (E GSH ) in guard cells. These findings show that themitochondrial-targeted H2S donors induced stomatal closure, a response thatinvolves guard cell’s mitochondrial ETC activity and has an impact over cytosolicenergetic and oxidative status, pointing to an interplay between mitochondrial H2S,mitochondrial activity and stomatal closure.