Starch biosynthesis by AGPase, but not starch degradation by BAM1/3 and SEX1, is rate-limiting for CO2-regulated stomatal movements under short-day conditions

Tamar Azoulay-Shemer, Nikki Schwankl, Ido Rog, Menachem Moshelion, Julian I. Schroeder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Starch in guard cells functions in osmoregulation during stomatal movements. Starch metabolism is controlled by the circadian clock. We investigated the role of starch metabolism in stomatal responses to CO2 under different photoperiodic conditions. Guard cell starch levels correlate with low/high [CO2] exposure. Starch biosynthesis-deficient AGPase (ADG1) mutants but, unexpectedly, not the starch degradation-deficient BAM1, BAM3, and SEX1 mutants alone, are rate-limiting for stomatal conductance responses to [CO2]-shifts. Interestingly, AGPase is rate-limiting solely under short- but not long-day conditions. These findings suggest a model of enhanced AGPase activity in guard cells under short days such that starch biosynthesis becomes rate-limiting for CO2-induced stomatal closing.

Original languageAmerican English
Pages (from-to)2739-2759
Number of pages21
JournalFEBS Letters
Volume592
Issue number16
DOIs
StatePublished - Aug 2018

Bibliographical note

Publisher Copyright:
© 2018 Federation of European Biochemical Societies

Keywords

  • Arabidopsis
  • gas exchange
  • guard cell
  • photoperiod
  • starch degradation
  • starch synthesis

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