Stomatal responses to VPD utilize guard cell intracellular signaling components

Yotam Zait*, Ariel Joseph, Sarah M. Assmann*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Stomatal pores, vital for CO2 uptake and water loss regulation in plants, are formed by two specialized guard cells. Despite their importance, there is limited understanding of how guard cells sense and respond to changes in vapor pressure difference (VPD). This study leverages a selection of CO2 hyposensitive and abscisic acid (ABA) signaling mutants in Arabidopsis, including heterotrimeric G protein mutants and RLK (receptor-like kinase) mutants, along with a variety of canola cultivars to delve into the intracellular signaling mechanisms prompting stomatal closure in response to high VPD. Stomatal conductance response to step changes in VPD was measured using the LI-6800F gas exchange system. Our findings highlight that stomatal responses to VPD utilize intracellular signaling components. VPD hyposensitivity was particularly evident in mutants of the ht1 (HIGH LEAF TEMPERATURE1) gene, which encodes a protein kinase expressed mainly in guard cells, and in gpa1-3, a null mutant of the sole canonical heterotrimeric Gα subunit, previously implicated in stomatal signaling. Consequently, this research identifies a nexus in the intricate relationships between guard cell signal perception, stomatal conductance, environmental humidity, and CO2 levels.

Original languageAmerican English
Article number1351612
JournalFrontiers in Plant Science
StatePublished - 2024

Bibliographical note

Publisher Copyright:
Copyright © 2024 Zait, Joseph and Assmann.


  • Arabidopsis thaliana
  • Brassica napus
  • Oryza sativa
  • guard cell
  • heterotrimeric G proteins
  • stomatal conductance
  • vapor pressure difference (VPD)


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