Nature Communications (Feb 2024)

Light-induced stomatal opening requires phosphorylation of the C-terminal autoinhibitory domain of plasma membrane H+-ATPase

  • Saashia Fuji,
  • Shota Yamauchi,
  • Naoyuki Sugiyama,
  • Takayuki Kohchi,
  • Ryuichi Nishihama,
  • Ken-ichiro Shimazaki,
  • Atsushi Takemiya

DOI
https://doi.org/10.1038/s41467-024-45236-9
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 13

Abstract

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Abstract Plasma membrane H+-ATPase provides the driving force for light-induced stomatal opening. However, the mechanisms underlying the regulation of its activity remain unclear. Here, we show that the phosphorylation of two Thr residues in the C-terminal autoinhibitory domain is crucial for H+-ATPase activation and stomatal opening in Arabidopsis thaliana. Using phosphoproteome analysis, we show that blue light induces the phosphorylation of Thr-881 within the C-terminal region I, in addition to penultimate Thr-948 in AUTOINHIBITED H+-ATPASE 1 (AHA1). Based on site-directed mutagenesis experiments, phosphorylation of both Thr residues is essential for H+ pumping and stomatal opening in response to blue light. Thr-948 phosphorylation is a prerequisite for Thr-881 phosphorylation by blue light. Additionally, red light-driven guard cell photosynthesis induces Thr-881 phosphorylation, possibly contributing to red light-dependent stomatal opening. Our findings provide mechanistic insights into H+-ATPase activation that exploits the ion transport across the plasma membrane and light signalling network in guard cells.