title: Arabidopsis thaliana lipid phosphate phosphatase 2 is involved in abscisic acid signalling in leaves.
abstract: Lipid phosphate phosphatases (LPPs, E.C. 3.1.3.4) catalyse the dephosphorylation of diacylglycerol pyrophosphate (DGPP) and phosphatidic acid (PA), which are secondary messengers in abscisic acid (ABA) signalling. In this study, we investigated the effect of ABA on the expression of AtLPP genes as they encode putative ABA-signalling partners. We observed that AtLPP2 expression was down-regulated by ABA and we performed experiments on Atlpp2-2, an AtLPP2 knockout mutant, to determine whether AtLPP2 was involved in ABA signalling. We observed that Atlpp2-2 plantlets contained about twice as much PA as the wild-type Col-0 and exhibited higher PA kinase (PAK) activity than Col-0 plants. In addition, we showed that ABA stimulated diacylglycerol kinase (DGK) activity independently of AtLPP2 activity but that the ABA-stimulation of PAK activity recorded in Col-0 was dependent on AtLPP2. In order to evaluate the involvement of AtLPP2 activity in guard cell function, we measured the ABA sensitivity of Atlpp2-2 stomata. The inhibition of stomatal opening was less sensitive to ABA in Atlpp2-2 than in Col-0. Watered and water-stressed plants of the two genotypes accumulated ABA to the same extent, thus leading us to consider Atlpp2-2 an ABA-signalling mutant. Taken together our observations show that AtLPP2 is a part of ABA signalling and participate to the regulation of stomatal movements.
authors.affiliation: Université Pierre et Marie Curie, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, Unité de Recherche 5-Equipe d'Accueil 7180/CNRS, 4 place Jussieu, Paris Cedex 05, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Paradis
authors.forename: Ana Laura
authors.initials: AL
authors.lastname: Villasuso
authors.forename: Susana Saez
authors.initials: SS
authors.lastname: Aguayo
authors.forename: Régis
authors.initials: R
authors.lastname: Maldiney
authors.forename: Yvette
authors.initials: Y
authors.lastname: Habricot
authors.forename: Christine
authors.initials: C
authors.lastname: Zalejski
authors.forename: Estela
authors.initials: E
authors.lastname: Machado
authors.forename: Bruno
authors.initials: B
authors.lastname: Sotta
authors.forename: Emile
authors.initials: E
authors.lastname: Miginiac
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Jeannette
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D019852:Diacylglycerol Kinase / Q000378:metabolism; D015536:Down-Regulation; D055864:Droughts; D015870:Gene Expression / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D005838:Genotype; D009154:Mutation; D010711:Phosphatidate Phosphatase / Q000235:genetics / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000378:metabolism; D054046:Plant Stomata / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics; D014867:Water / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D010712:Phosphatidic Acids; D014867:Water; D000040:Abscisic Acid; D019852:Diacylglycerol Kinase; D017856:Phosphotransferases (Phosphate Group Acceptor); C099834:phosphatidic acid kinase; C112948:lipid phosphate phosphatase; D010711:Phosphatidate Phosphatase