Inactivation of AtRac1 by abscisic acid is essential for stomatal closure Journal Article


Authors: Lemichez, E.; Wu, Y.; Sanchez, J. P.; Mettouchi, A.; Mathur, J.; Chua, N. H.
Article Title: Inactivation of AtRac1 by abscisic acid is essential for stomatal closure
Abstract: Plant water homeostasis is maintained by the phytohormone abscisic acid (ABA), which triggers stomatal pore closure in response to drought stress. We identified the Arabidopsis small guanosine triphosphatase (GTPase) protein AtRac1 as a central component in the ABA-mediated stomatal closure process. ABA treatment induced inactivation of AtRac GTPases and disruption of the guard cell actin cytoskeleton. In contrast, in the ABA-insensitive mutant abi1-1, which is impaired in stomatal closure, neither AtRac inactivation nor actin cytoskeleton disruption was observed on ABA treatment. These observations indicate that AtRac1 inactivation is a limiting step in the ABA-signaling cascade leading to stomatal closure. Consistent with these findings, expression of a dominant-positive mutant of AtRac1 blocked the ABA-mediated effects on actin cytoskeleton and stomatal closure in wild-type plants, whereas expression of a dominant-negative AtRac1 mutant recapitulated the ABA effects in the absence of the hormone. Moreover, the dominant-negative form of AtRac1 could also restore stomatal closure in abi1-1. These results define AtRac1 as a central element for plant adaptation to drought.
Keywords: unclassified drug; mutation; nonhuman; actin; computational biology; carboxy terminal sequence; molecular cloning; amino acid sequence; sequence homology, amino acid; enzyme inactivation; stress; protein family; cytoskeleton; dissociation; arabidopsis; guanosine triphosphatase; vegetable protein; actin filament; rac; rac1 gtp-binding protein; plant leaves; plant growth; abscisic acid; plant proteins; phytohormone; plants, genetically modified; priority journal; article; turgor pressure; guard cell; pp2c; protein atrac1
Journal Title: Genes and Development
Volume: 15
Issue: 14
ISSN: 0890-9369
Publisher: Cold Spring Harbor Laboratory Press  
Date Published: 2001-07-15
Start Page: 1808
End Page: 1816
Language: English
DOI: 10.1101/gad.900401
PUBMED: 11459830
PROVIDER: scopus
PMCID: PMC312738
DOI/URL:
Notes: Export Date: 21 May 2015 -- Source: Scopus
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