BHLH transcription factors that facilitate k+ uptake during stomatal opening are repressed by abscisic acid through phosphorylation

Yohei Takahashi, Yuta Ebisu, Toshinori Kinoshita, Michio Doi, Eiji Okuma, Yoshiyuki Murata, Ken Ichiro Shimazaki

研究成果: Contribution to journalArticle査読

73 被引用数 (Scopus)

抄録

Stomata open in response to light and close after exposure to abscisic acid (ABA). They regulate gas exchange between plants and the atmosphere, enabling plants to adapt to changing environmental conditions. ABA binding to receptors initiates a signaling cascade that involves protein phosphorylation. We showthat ABA induced the phosphorylation of three basic helix-loop-helix (bHLH) transcription factors, called AKSs (ABA-responsive kinase substrates; AKS1, AKS2, and AKS3), in Arabidopsis guard cells. In their unphosphorylated state, AKSs facilitated stomatal opening through the transcription of genes encoding inwardly rectifying K+ channels. aks1aks2-1 double mutant plants showed decreases in light-induced stomatal opening, K+ accumulation in response to light, activity of inwardly rectifying K+ channels, and transcription of genes encoding major inwardly rectifying K+ channels without affecting ABA-mediated stomatal closure. Overexpression of potassium channel in Arabidopsis thaliana 1 (KAT1), which encodes a major inwardly rectifying K+ channel in guard cells, rescued the phenotype of aks1aks2-1 plants. AKS1 bound directly to the promoter of KAT1, an interaction that was attenuated after ABA-induced phosphorylation. The ABA agonist pyrabactin induced phosphorylation of AKSs. Our results demonstrate that the AKS family of bHLH transcription factors facilitates stomatal opening through the transcription of genes encoding inwardly rectifyingK+ channels and that ABAsuppresses the activity of these channels by triggering the phosphorylation of AKS family transcription factors.

本文言語英語
ページ(範囲)ra48
ジャーナルScience Signaling
6
280
DOI
出版ステータス出版済み - 6 18 2013

All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学

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