Phytosphingosine-phosphate is a signal for AtMPK6 activation and Arabidopsis response to chilling

Authors

  • Christelle Dutilleul,

    1. 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
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  • Ghouziel Benhassaine-Kesri,

    1. 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
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  • Chantal Demandre,

    1. 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
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  • Nathalie Rézé,

    1. 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
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  • Alban Launay,

    1. 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
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  • Sandra Pelletier,

    1. UMR INRA 1165-CNRS 8114-UEVE, Unité de Recherche en Génomique Végétale (URGV), 2, rue Gaston Crémieux, CP5708, F-91057 Evry Cedex, France
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  • Jean-Pierre Renou,

    1. UMR INRA 1165-CNRS 8114-UEVE, Unité de Recherche en Génomique Végétale (URGV), 2, rue Gaston Crémieux, CP5708, F-91057 Evry Cedex, France
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  • Alain Zachowski,

    1. 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
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  • Emmanuel Baudouin,

    1. 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
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  • Isabelle Guillas

    1. 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
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Author for correspondence:
Isabelle Guillas
Tel: +33(0) 1 44 27 59 18
Email: isabelle.guillas_baudouin@upmc.fr

Summary

  • 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.

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