Stomatal closure induced by hydrogen-rich water is dependent on GPA1 in Arabidopsis thaliana

Hydrogen (H₂) is a new signaling molecule that regulates stomatal closure via stimulating the generation of reactive oxygen species (ROS) and nitric oxide (NO) in Arabidopsis thaliana. GPA1 is the sole heterotrimeric G protein canonical α subunit found in Arabidopsis genome and functions in stomatal closure. Here, we estimated a possible role of Arabidopsis GPA1 in hydrogen-rich water (HRW)-induced stomatal closure. Our data indicated that HRW induced significant stomatal closure as well as the generation of ROS and NO in the Col-0 guard cells. However, the production of ROS and NO and stomatal closure induced by HRW were absent in the gpa1-4 mutant lacking the expression of AtGPA1. By contrast, overexpression of AtGPA1 in gpa1-4 (AtGPA1-HA/gpa1-4) restored stomatal closure and the generation of NO and ROS in the presence of HRW. Taken together, our results suggest that GPA1 is necessary for HRW-induced stomatal closure in Arabidopsis.