Hydrogen sulfide induces Ca2+ signal in guard cells by regulating reactive oxygen species accumulation.

Hydrogen sulfide (H2S) is an important gas signal molecule, but little is known about its signal mechanism. Ca2+ is an important second messenger in plant cells, and its fluctuation in the cytoplasm causes downstream physiological responses. Our previous study found that H2S can induce the accumulation of hydrogen peroxide (H2O2). We also found that reactive oxygen species (ROS) can further induce the Ca2+ influx in guard cells by noninvasive micro-teat technology (NMT). This study confirmed that the accumulation of reactive oxygen species to induce Ca2+ signal in guard cells, resulting in stomatal closure. Thus, revealing a novel mechanism of H2S promoting stomatal closure.