title: Phytosphingosine-phosphate is a signal for AtMPK6 activation and Arabidopsis response to chilling.
abstract: • Long-chain bases (LCBs) are pleiotropic sphingolipidic signals in eukaryotes. We investigated the source and function of phytosphingosine-1-phosphate (PHS-P), a phospho-LCB rapidly and transiently formed in Arabidopsis thaliana on chilling. • PHS-P was analysed by thin-layer chromatography following in vivo metabolic radiolabelling. Pharmacological and genetic approaches were used to identify the sphingosine kinase isoforms involved in cold-responsive PHS-P synthesis. Gene expression, mitogen-activated protein kinase activation and growth phenotypes of three LCB kinase mutants (lcbk1, sphk1 and lcbk2) were studied following cold exposure. • Chilling provoked the rapid and transient formation of PHS-P in Arabidopsis cultured cells and plantlets. Cold-evoked PHS-P synthesis was reduced by LCB kinase inhibitors and abolished in the LCB kinase lcbk2 mutant, but not in lcbk1 and sphk1 mutants. lcbk2 presented a constitutive AtMPK6 activation at 22°C. AtMPK6 activation was also triggered by PHS-P treatment independently of PHS/PHS-P balance. lcbk2 mutants grew comparably with wild-type plants at 22 and 4°C, but exhibited a higher root growth at 12°C, correlated with an altered expression of the cold-responsive DELLA gene RGL3. • Together, our data indicate a function for LCBK2 in planta. Furthermore, they connect PHS-P formation with plant response to cold, expanding the field of LCB signalling in plants.
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Dutilleul
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Ghouziel
authors.initials: G
authors.lastname: Benhassaine-Kesri
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Demandre
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Rézé
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Alban
authors.initials: A
authors.lastname: Launay
authors.affiliation: UMR INRA 1165-CNRS 8114-UEVE, Unité de Recherche en Génomique Végétale (URGV), 2, rue Gaston Crémieux, CP5708, F-91057 Evry Cedex, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Pelletier
authors.affiliation: UMR INRA 1165-CNRS 8114-UEVE, Unité de Recherche en Génomique Végétale (URGV), 2, rue Gaston Crémieux, CP5708, F-91057 Evry Cedex, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Renou
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Zachowski
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Baudouin
authors.affiliation: UPMC Univ Paris 06, UR 5, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France and CNRS, EAC 7180, Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, F-75252, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Guillas
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004269:DNA, Bacterial / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D005615:Freezing; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D016254:Mutagenesis, Insertional / Q000187:drug effects / Q000235:genetics; D009154:Mutation / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D018085:Regulon / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D047428:Protein Kinase Inhibitors; C036483:T-DNA; C117422:phytosphingosine-1-phosphate; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D013110:Sphingosine