AUTHOR=Toh Shigeo , Takata Naoki , Ando Eigo , Toda Yosuke , Wang Yin , Hayashi Yuki , Mitsuda Nobutaka , Nagano Soichiro , Taniguchi Toru , Kinoshita Toshinori 

TITLE=Overexpression of Plasma Membrane H+-ATPase in Guard Cells Enhances Light-Induced Stomatal Opening, Photosynthesis, and Plant Growth in Hybrid Aspen

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.766037

DOI=10.3389/fpls.2021.766037

ISSN=1664-462X

ABSTRACT=<p>Stomata in the plant epidermis open in response to light and regulate CO<sub>2</sub> 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<sup>+</sup>-ATPase in guard cells. Overexpression of PM H<sup>+</sup>-ATPase in guard cells promotes light-induced stomatal opening, enhancing photosynthesis and growth in <italic>Arabidopsis thaliana</italic>. In this study, transgenic hybrid aspens overexpressing Arabidopsis PM <italic>H<sup>+</sup>-ATPase</italic> (<italic>AHA2</italic>) in guard cells under the strong guard cell promoter Arabidopsis <italic>GC1</italic> (<italic>AtGC1</italic>) showed enhanced light-induced stomatal opening, photosynthesis, and growth. First, we confirmed that <italic>AtGC1</italic> induces GUS expression specifically in guard cells in hybrid aspens. Thus, we produced <italic>AtGC1::AHA2</italic> transgenic hybrid aspens and confirmed expression of <italic>AHA2</italic> in <italic>AtGC1::AHA2</italic> transgenic plants. In addition, <italic>AtGC1::AHA2</italic> transgenic plants showed a higher PM H<sup>+</sup>-ATPase protein level in guard cells. Analysis using a gas exchange system revealed that transpiration and the photosynthetic rate were significantly increased in <italic>AtGC1::AHA2</italic> transgenic aspen plants. <italic>AtGC1::AHA2</italic> transgenic plants showed a&gt;20% higher stem elongation rate than the wild type (WT). Therefore, overexpression of PM H<sup>+</sup>-ATPase in guard cells promotes the growth of perennial woody plants.</p>