Molecular mechanism of stomatal opening induced by red light

August 26, 2025

Sucrose accumulation promotes phosphorylation of plasma membrane H⁺-ATPase

An international research group comprising scientists from Nagoya University, the RIKEN CSRS, the University of Mississippi, and Pennsylvania State University has elucidated the molecular mechanism by which red light induces stomatal opening. The research group discovered that sucrose, synthesized via photosynthesis in mesophyll cells, is a “mesophyll messenger” that promotes stomatal opening.

While it is known that plants respond to blue and red light in sunlight by opening their stomata to facilitate gas exchange, the molecular mechanism underlying red light-induced stomatal opening has remained unclear. In this study, the researchers conducted comprehensive metabolomic analysis of the apoplast—an extracellular space comprising cell walls, xylem vessels, and intercellular air spaces—and found that sucrose, a photosynthetic product, accumulates in the apoplast of leaves exposed to red light. Subsequent experiments revealed that treating the epidermis with sucrose induces stomatal opening. This process involves phosphorylation of a threonine residue at the C-terminus of the plasma membrane H⁺-ATPase in guard cells, which activates the proton pump. Additionally, sucrose suppresses the activity of anion channels that promote stomatal closure. Stomata play a crucial role in plant growth, yield, and drought response. The molecular insights gained from this study provide a foundation for future strategies to control stomatal aperture, potentially leading to the development of crops with optimized gas exchange and water use efficiency.

 

Original article

Nature Plants　doi: 10.1038/s41477-025-02078-7

Y. Zait, M. Zhu, E. Ando, Y. Zhou, A. Yaaran, S. Yon, M. Okamoto, Y. Hayashi, M. Y. Hirai, T. Jegla, T. Kinoshita, S. Chen, S. M. Assmann,

"Apoplastic metabolomics reveals sugars as mesophyll messengers regulating guard cell ion transport under red light".

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Masami Hirai
Division Director
Technology Platform Division