Stomata in the plant epidermis open in response to light and regulate CO2 uptake for photosynthesis and transpiration for uptake of water and nutrients from roots. Light-induced stomatal opening is mediated by activation of the plasma membrane (PM) H+-ATPase in guard cells. Overexpression of PM H+-ATPase in guard cells promotes light-induced stomatal opening, enhancing photosynthesis and growth in Arabidopsis thaliana. In this study, transgenic hybrid aspens overexpressing Arabidopsis PM H+-ATPase (AHA2) in guard cells under the strong guard cell promoter Arabidopsis GC1 (AtGC1) showed enhanced light-induced stomatal opening, photosynthesis, and growth. First, we confirmed that AtGC1 induces GUS expression specifically in guard cells in hybrid aspens. Thus, we produced AtGC1::AHA2 transgenic hybrid aspens and confirmed expression of AHA2 in AtGC1::AHA2 transgenic plants. In addition, AtGC1::AHA2 transgenic plants showed a higher PM H+-ATPase protein level in guard cells. Analysis using a gas exchange system revealed that transpiration and the photosynthetic rate were significantly increased in AtGC1::AHA2 transgenic aspen plants. AtGC1::AHA2 transgenic plants showed a>20% higher stem elongation rate than the wild type (WT). Therefore, overexpression of PM H+-ATPase in guard cells promotes the growth of perennial woody plants.
Overexpression of Plasma Membrane H+-ATPase in Guard Cells Enhances Light-Induced Stomatal Opening, Photosynthesis, and Plant Growth in Hybrid Aspen
