SnRK1 (SNF1-related kinase 1) has a central role in sugar and ABA signalling in Arabidopsis thaliana

Authors

  • Mathieu Jossier,

    1. Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France
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  • Jean-Pierre Bouly,

    1. Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France
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    • Present address: Laboratoire Physiologie Cellulaire et Moléculaire des Plantes, Université Paris VI, Bâtiment Le Raphaël, 3 rue Galilée, F-94200 Ivry-sur-Seine, France.

  • Patrice Meimoun,

    1. Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France
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  • Alaleh Arjmand,

    1. Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France
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  • Philippe Lessard,

    1. Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France
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    • Present address: Biogemma, ZI du Brézet, 8 rue des Frères Lumière, F-63028 Clermont-Ferrand Cedex 2, France.

  • Simon Hawley,

    1. University of Dundee, Division of Molecular Physiology, College of Life Sciences, Dow Street, Dundee, UK
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  • D. Grahame Hardie,

    1. University of Dundee, Division of Molecular Physiology, College of Life Sciences, Dow Street, Dundee, UK
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  • Martine Thomas

    Corresponding author
    1. Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France
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*(fax +33 1 69 15 34 23; e-mail martine.thomas@u-psud.fr).

Summary

The proteins kinases SNF1/AMPK/SnRK1 are a subfamily of serine/threonine kinases that act as metabolite sensors to constantly adapt metabolism to the supply of, and demand for, energy. In the yeast Saccharomyces cerevisiae, the SNF1 complex is a central component of the regulatory response to glucose starvation. AMP activated protein kinase (AMPK) the mammalian homologue of SNF1, plays a central role in the regulation of energy homeostasis at the cellular as well as the whole-body levels. In Arabidopsis thaliana, SnRK1.1 and SnRK1.2 have recently been described as central integrators of a transcription network for stress and energy signalling. In this study, biochemical analysis established SnRK1.1 as the major SnRK1 isoform both in isolated cells and leaves. In order to elucidate the function of SnRK1.1 in Arabidopsis thaliana, transgenic plants over-expressing SnRK1.1 were produced. Genetic, biochemical, physiological and molecular analyses of these plants revealed that SnRK1.1 is implicated in sugar and ABA signalling pathways. Modifications of the starch and soluble sugar content were observed in the 35S:SnRK1.1 transgenic lines. Our studies also revealed modifications of the activity of essential enzymes such as nitrate reductase or ADP-glucose pyrophosphorylase, and of the expression of several sugar-regulated genes, confirming the central role of the protein kinase SnRK1 in the regulation of metabolism.

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