A subsidiary cell-localized glucose transporter promotes stomatal conductance and photosynthesis

Hai Wang, Shijuan Yan, Hongjia Xin, Wenjie Huang, Hao Zhang, Shouzhen Teng, Ya Chi Yu, Alisdair R. Fernie, Xiaoduo Lu, Pengcheng Li, Shengyan Li, Chunyi Zhang, Yong Ling Ruan, Li Qing Chen, Zhihong Langa

Research output: Contribution to journalArticlepeer-review


It has long been recognized that stomatal movement modulates CO2 availability and as a consequence the photosynthetic rate of plants, and that this process is feedback-regulated by photoassimilates. However, the genetic components and mechanisms underlying this regulatory loop remain poorly understood, especially in monocot crop species. Here, we report the cloning and functional characterization of a maize (Zea mays) mutant named closed stomata1 (cst1). Map-based cloning of cst1 followed by confirmation with the clustered regularly interspaced short palindromic repeats (CRISPR)/ CRISPR associated protein 9 system identified the causal mutation in a Clade I Sugars Will Eventually be Exported Transporters (SWEET) family gene, which leads to the E81K mutation in the CST1 protein. CST1 encodes a functional glucose transporter expressed in subsidiary cells, and the E81K mutation strongly impairs the oligomerization and glucose transporter activity of CST1. Mutation of CST1 results in reduced stomatal opening, carbon starvation, and early senescence in leaves, suggesting that CST1 functions as a positive regulator of stomatal opening. Moreover, CST1 expression is induced by carbon starvation and suppressed by photoassimilate accumulation. Our study thus defines CST1 as a missing link in the feedback-regulation of stomatal movement and photosynthesis by photoassimilates in maize.

Original languageEnglish (US)
Pages (from-to)1328-1343
Number of pages16
JournalPlant Cell
Issue number6
StatePublished - Jun 2019

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology


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