title: Cooperative function of PLDδ and PLDα1 in abscisic acid-induced stomatal closure in Arabidopsis.
abstract: Phospholipase D (PLD) is involved in responses to abiotic stress and abscisic acid (ABA) signaling. To investigate the roles of two Arabidopsis (Arabidopsis thaliana) PLDs, PLDα1 and PLDδ, 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 pldδ 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 cytosolic 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.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Misugi
authors.initials: M
authors.lastname: Uraji
authors.forename: Takeshi
authors.initials: T
authors.lastname: Katagiri
authors.forename: Eiji
authors.initials: E
authors.lastname: Okuma
authors.forename: Wenxiu
authors.initials: W
authors.lastname: Ye
authors.forename: Mohammad Anowar
authors.initials: MA
authors.lastname: Hossain
authors.forename: Choji
authors.initials: C
authors.lastname: Masuda
authors.forename: Aya
authors.initials: A
authors.lastname: Miura
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Izumi C
authors.initials: IC
authors.lastname: Mori
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005816:Genetic Complementation Test; D018525:Germination / Q000187:drug effects; D009154:Mutation; D009569:Nitric Oxide / Q000378:metabolism; D010641:Phenotype; D010739:Phospholipase D / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D054046:Plant Stomata / Q000187:drug effects / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D015221:Potassium Channels; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D000040:Abscisic Acid; C446530:phospholipase D delta; D010739:Phospholipase D