Sugar and hexokinase suppress expression of PIP aquaporins and reduce leaf hydraulics that preserves leaf water potential

Gilor Kelly, Nir Sade, Adi Doron-Faigenboim, Stephen Lerner, Arava Shatil-Cohen, Yelena Yeselson, Aiman Egbaria, Jayaram Kottapalli, Arthur A. Schaffer, Menachem Moshelion, David Granot*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Sugars affect central aspects of plant physiology, including photosynthesis, stomatal behavior and the loss of water through the stomata. Yet, the potential effects of sugars on plant aquaporins (AQPs) and water conductance have not been examined. We used database and transcriptional analyses, as well as cellular and whole-plant functional techniques to examine the link between sugar-related genes and AQPs. Database analyses revealed a high level of correlation between the expression of AQPs and that of sugar-related genes, including the Arabidopsis hexokinases 1 (AtHXK1). Increased expression of AtHXK1, as well as the addition of its primary substrate, glucose (Glc), repressed the expression of 10 AQPs from the plasma membrane-intrinsic proteins (PIP) subfamily (PIP-AQPs) and induced the expression of two stress-related PIP-AQPs. The osmotic water permeability of mesophyll protoplasts of AtHXK1-expressing plants and the leaf hydraulic conductance of those plants were significantly reduced, in line with the decreased expression of PIP-AQPs. Conversely, hxk1 mutants demonstrated a higher level of hydraulic conductance, with increased water potential in their leaves. In addition, the presence of Glc reduced leaf water potential, as compared with an osmotic control, indicating that Glc reduces the movement of water from the xylem into the mesophyll. The production of sugars entails a significant loss of water and these results suggest that sugars and AtHXK1 affect the expression of AQP genes and reduce leaf water conductance, to coordinate sugar levels with the loss of water through transpiration.

Original languageAmerican English
Pages (from-to)325-339
Number of pages15
JournalPlant Journal
Issue number2
StatePublished - Jul 2017

Bibliographical note

Publisher Copyright:
© 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd


  • Arabidopsis thaliana
  • Hexokinase
  • aquaporins
  • glucose
  • leaf hydraulic conductivity (K)
  • plasma membrane-intrinsic proteins (PIPs)
  • sugar


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