Guard-Cell Hexokinase Increases Water-Use Efficiency Under Normal and Drought Conditions

Gilor Kelly, Aiman Egbaria, Belal Khamaisi, Nitsan Lugassi, Ziv Attia, Menachem Moshelion, David Granot*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Water is a limiting resource for many land plants. Most of the water taken up by plants is lost to the atmosphere through the stomata, which are adjustable pores on the leaf surface that allow for gas exchange between the plant and the atmosphere. Modulating stomatal activity might be an effective way to reduce plants’ water consumption and enhance their productivity under normal, as well as water-limiting conditions. Our recent discovery of stomatal regulation by sugars that is mediated by guard-cell hexokinase (HXK), a sugar-sensing enzyme, has raised the possibility that HXK might be used to increase plant water-use efficiency (WUE; i.e., carbon gain per unit of water). We show here that transgenic tomato and Arabidopsis plants with increased expression of HXK in their guard cells (GCHXK plants) exhibit reduced transpiration and higher WUE without any negative effects on growth under normal conditions, as well as drought avoidance and improved photosynthesis and growth under limited-water conditions. Our results demonstrate that exclusive expression of HXK in guard cells is an effective tool for improving WUE, and plant performance under drought.

Original languageAmerican English
Article number1499
JournalFrontiers in Plant Science
StatePublished - 19 Nov 2019

Bibliographical note

Publisher Copyright:
© Copyright © 2019 Kelly, Egbaria, Khamaisi, Lugassi, Attia, Moshelion and Granot.


  • guard cells
  • hexokinase
  • photosynthesis
  • transpiration
  • water-use efficiency


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