Cooperative Function of PLDδ and PLDα1 in Abscisic Acid-Induced Stomatal Closure in Arabidopsis

• Published in: Plant physiology (Bethesda) 2012-05, Vol.159 (1), p.450-460
• Main Authors: Uraji, Misugi, Katagiri, Takeshi, Okuma, Eiji, Ye, Wenxiu, Hossain, Mohammad Anowar, Masuda, Choji, Miura, Aya, Nakamura, Yoshimasa, Mori, Izumi C., Shinozaki, Kazuo, Murata, Yoshiyuki
• Format: Article
• Language: English
• Subjects: Abscisic Acid - pharmacology; Arabidopsis - drug effects; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis Proteins - metabolism; Biological and medical sciences; Calcium; CELL BIOLOGY AND SIGNAL TRANSDUCTION; Cytosol - drug effects; Cytosol - metabolism; Fundamental and applied biological sciences. Psychology; Genes; Genetic Complementation Test; Genetic mutation; Germination - drug effects; Guard cells; Leaves; Mutation; Nitric Oxide - metabolism; Oxides; Phenotype; Phenotypes; Phosphatidic acids; Phospholipase D - metabolism; Plant cells; Plant Leaves - drug effects; Plant Leaves - metabolism; Plant physiology and development; Plant Stomata - drug effects; Plant Stomata - metabolism; Potassium Channels - drug effects; Reactive oxygen species; Reactive Oxygen Species - metabolism; Seeds - drug effects; Seeds - metabolism; Signal Transduction; Transcription, Genetic
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.112.195578

Phospholipase D (PLD) is involved in responses to abiotic stress and abscisic acid (ABA) signaling. To investigate the roles of two Arabidopsis (Arabidopsis thaliam) PLDs, PLDα1 and PLDS, in ABA signaling in guard cells, we analyzed ABA responses in guard cells using Arabidopsis wild type, pldα1 and pldδ single mutants, and a pldα1 pldδ double mutant. ABA-induced stomatal closure was suppressed in the pldα1 pldα double mutant but not in the pld single mutants. The pldα1 and pldδ mutations reduced ABA-induced phosphatidic acid production in epidermal tissues. Expression of either PLDα1 or PLDδ complemented the double mutant stomatal phenotype. ABA-induced stomatal closure in both PLDα1 and PLDδ single mutants was inhibited by a PLD inhibitor (1-butanol), suggesting that both PLDα1 and PLDδ function in ABA-induced stomatal closure. During ABA-induced stomatal closure, wild-type guard cells accumulate reactive oxygen species and nitric oxide and undergo cytosoHc alkalization, but these changes are reduced in guard cells of the PLDα1 PLDδ double mutant. Inward-rectifying K⁺ channel currents of guard cells were inhibited by ABA in the wild type but not in the PLDα1 PLDδ double mutant. ABA inhibited stomatal opening in the wild type and the PLDδ mutant but not in the PLDα1 mutant. In wild-type rosette leaves, ABA significantly increased PLDδ transcript levels but did not change PLDα1 transcript levels. Furthermore, the PLDα1 and PLDδ mutations mitigated ABA inhibition of seed germination. These results suggest that PLDα1 and PLDδ cooperate in ABA signaling in guard cells but that their functions do not completely overlap.