@article{bc79699716584842b22f5edf8ebfc4a9,
title = "A tonoplast-localized magnesium transporter is crucial for stomatal opening in Arabidopsis under high Mg2+ conditions",
abstract = "Plant stomata play an important role in CO2 uptake for photosynthesis and transpiration, but the mechanisms underlying stomatal opening and closing under changing environmental conditions are still not completely understood. Through large-scale genetic screening, we isolated an Arabidopsis mutant (closed stomata2 (cst2)) that is defective in stomatal opening. We cloned the causal gene (MGR1/CST2) and functionally characterized this gene. The mutant phenotype was caused by a mutation in a gene encoding an unknown protein with similarities to the human magnesium (Mg2+) efflux transporter ACDP/CNNM. MGR1/CST2 was localized to the tonoplast and showed transport activity for Mg2+. This protein was constitutively and highly expressed in guard cells. Knockout of this gene resulted in stomatal closing, decreased photosynthesis and growth retardation, especially under high Mg2+ conditions, while overexpression of this gene increased stomatal opening and tolerance to high Mg2+ concentrations. Furthermore, guard cell-specific expression of MGR1/CST2 in the mutant partially restored its stomatal opening. Our results indicate that MGR1/CST2 expression in the leaf guard cells plays an important role in maintaining cytosolic Mg2+ concentrations through sequestering Mg2+ into vacuoles, which is required for stomatal opening, especially under high Mg2+ conditions.",
author = "Inoue, {Shin ichiro} and Maki Hayashi and Sheng Huang and Kengo Yokosho and Eiji Gotoh and Shuka Ikematsu and Masaki Okumura and Takamasa Suzuki and Takumi Kamura and Toshinori Kinoshita and Ma, {Jian Feng}",
note = "Funding Information: We thank the NASC for providing seed stocks. We also thank T. Horie (Shinshu University), A. Yoshinari (Nagoya University), T. Miyaji, S. Munemasa, and Y. Murata (Okayama University) for discussions, and T. Shinagawa and A. Kawajiri for technical assistance. This work was supported, in part, by the Japan Society for the Promotion of Science (JSPS) (KAKENHI grant nos. 15K07101, 20K06703, and 22H04805 to S‐iI and 16H06296 and 21H05034 to JFM), Grants‐in‐Aid for Scientific Research from MEXT (nos. 20H05687 and 20H05910 to TK), the 30 Botanical Research Grant of the ICHIMURA foundation for New Technology (to S‐iI), the Toyoaki Scholarship Foundation (to S‐iI), and the Joint Usage/Research Center, Institute of Plant Science and Resources, Okayama University (to S‐iI and JFM). th Funding Information: We thank the NASC for providing seed stocks. We also thank T. Horie (Shinshu University), A. Yoshinari (Nagoya University), T. Miyaji, S. Munemasa, and Y. Murata (Okayama University) for discussions, and T. Shinagawa and A. Kawajiri for technical assistance. This work was supported, in part, by the Japan Society for the Promotion of Science (JSPS) (KAKENHI grant nos. 15K07101, 20K06703, and 22H04805 to S-iI and 16H06296 and 21H05034 to JFM), Grants-in-Aid for Scientific Research from MEXT (nos. 20H05687 and 20H05910 to TK), the 30th Botanical Research Grant of the ICHIMURA foundation for New Technology (to S-iI), the Toyoaki Scholarship Foundation (to S-iI), and the Joint Usage/Research Center, Institute of Plant Science and Resources, Okayama University (to S-iI and JFM). Publisher Copyright: {\textcopyright} 2022 The Authors. New Phytologist {\textcopyright} 2022 New Phytologist Foundation.",
year = "2022",
month = nov,
doi = "10.1111/nph.18410",
language = "English",
volume = "236",
pages = "864--877",
journal = "New Phytologist",
issn = "0028-646X",
publisher = "Wiley-Blackwell",
number = "3",
}