Involvement of two-component signalling systems in the regulation of stomatal aperture by light in Arabidopsis thaliana

New Phytol. 2014 Jul;203(2):462-8. doi: 10.1111/nph.12813. Epub 2014 Apr 24.


Two-component signalling (TCS) systems play important roles in cytokinin and ethylene signalling in Arabidopsis thaliana. Although the involvement of histidine kinases (AHKs) in drought stress responses has been described, their role and that of histidine phosphotransferases (AHPs) in guard cell signalling remain to be fully elucidated. Here, we investigated the roles of TCS genes, the histidine phosphotransferase AHP2 and the histidine kinases AHK2 and AHK3, previously reported to play roles in cytokinin and abscisic acid (ABA) signalling. We show that AHP2 is present in the nucleus and the cytoplasm, and is involved in light-induced opening. We also present evidence that there is some redistribution of AHP2 from the nucleus to the cytoplasm on addition of ABA. In addition, we provide data to support a role for the cytokinin receptors AHK2 and AHK3 in light-induced stomatal opening and, by inference, in controlling the stomatal sensitivity to ABA. Our results provide new insights into the operation of TCS in plants, cross-talk in stomatal signalling and, in particular, the process of light-induced stomatal opening.

Keywords: Arabidopsis; guard cells; light; signal integration; stomatal aperture; two-component signalling (TCS) systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Cell Nucleus / metabolism
  • Cytoplasm / metabolism
  • Gene Expression Regulation, Plant
  • Histidine Kinase
  • Light
  • Phosphotransferases / genetics
  • Phosphotransferases / metabolism
  • Plant Cells / metabolism
  • Plant Leaves / physiology
  • Plant Stomata / physiology*
  • Plants, Genetically Modified
  • Protein Kinases / genetics
  • Protein Kinases / metabolism
  • Signal Transduction


  • AHP2 protein, Arabidopsis
  • Arabidopsis Proteins
  • Abscisic Acid
  • Phosphotransferases
  • Protein Kinases
  • Histidine Kinase
  • AHK2 protein, Arabidopsis
  • AHK3 protein, Arabidopsis