title: An abscisic acid-independent oxylipin pathway controls stomatal closure and immune defense in Arabidopsis.
abstract: Plant stomata function in innate immunity against bacterial invasion and abscisic acid (ABA) has been suggested to regulate this process. Using genetic, biochemical, and pharmacological approaches, we demonstrate that (i) the Arabidopsis thaliana nine-specific-lipoxygenase encoding gene, LOX1, which is expressed in guard cells, is required to trigger stomatal closure in response to both bacteria and the pathogen-associated molecular pattern flagellin peptide flg22; (ii) LOX1 participates in stomatal defense; (iii) polyunsaturated fatty acids, the LOX substrates, trigger stomatal closure; (iv) the LOX products, fatty acid hydroperoxides, or reactive electrophile oxylipins induce stomatal closure; and (v) the flg22-mediated stomatal closure is conveyed by both LOX1 and the mitogen-activated protein kinases MPK3 and MPK6 and involves salicylic acid whereas the ABA-induced process depends on the protein kinases OST1, MPK9, or MPK12. Finally, we show that the oxylipin and the ABA pathways converge at the level of the anion channel SLAC1 to regulate stomatal closure. Collectively, our results demonstrate that early biotic signaling in guard cells is an ABA-independent process revealing a novel function of LOX1-dependent stomatal pathway in plant immunity.
authors.affiliation: CEA Cadarache, Direction des Sciences du Vivant, Institut de Biologie Environnementale et Biotechnologie, Service de Biologie Végétale et de Microbiologie Environnementale, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Unité Mixte de Recherche 7265, Centre National de la Recherche Scientifique/Commissariat à l'Energie Atomique/Aix-Marseille Université, Saint-Paul-lez-Durance, France. jean-luc.montillet@cea.fr
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Montillet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leonhardt
authors.forename: Samuel
authors.initials: S
authors.lastname: Mondy
authors.forename: Sylvain
authors.initials: S
authors.lastname: Tranchimand
authors.forename: Dominique
authors.initials: D
authors.lastname: Rumeau
authors.forename: Marie
authors.initials: M
authors.lastname: Boudsocq
authors.forename: Ana Victoria
authors.initials: AV
authors.lastname: Garcia
authors.forename: Thierry
authors.initials: T
authors.lastname: Douki
authors.forename: Jean
authors.initials: J
authors.lastname: Bigeard
authors.forename: Christiane
authors.initials: C
authors.lastname: Laurière
authors.forename: Anne
authors.initials: A
authors.lastname: Chevalier
authors.forename: Carmen
authors.initials: C
authors.lastname: Castresana
authors.forename: Heribert
authors.initials: H
authors.lastname: Hirt
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D054883:Oxylipins / Q000378:metabolism*; D057865:Plant Immunity / Q000187:drug effects / Q000235:genetics; D054046:Plant Stomata / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D054883:Oxylipins; D000040:Abscisic Acid