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  • The EMBO Journal (2005) 24, 4041 - 4051
  • doi:10.1038/sj.emboj.7600864

Published online: 3 November 2005

Mobilization of vacuolar iron by AtNRAMP3 and AtNRAMP4 is essential for seed germination on low iron

Viviane Lanquar1, Françoise Lelièvre1, Susanne Bolte2, Cécile Hamès1, Carine Alcon1, Dieter Neumann3, Gérard Vansuyt4, Catherine Curie4, Astrid Schröder5, Ute Krämer5, Hélène Barbier-Brygoo1 and Sebastien Thomine1

  1. Institut des Sciences du Végétal, CNRS, Gif-sur-Yvette, France
  2. Plate-forme d'Imagerie et Biologie Cellulaire, IFR 87 'La Plante et son Environnement'/CNRS, Gif-sur-Yvette, France
  3. Leibnitz Institute for Plant Biochemistry, Weinberg, Halle/Saale, Germany
  4. Biochimie et Physiologie Moléculaire des Plantes, CNRS (UMR5004)/INRA/AgroM/Université Montpellier 2, Montpellier, France
  5. Max Planck Institute of Molecular Plant Physiology, Golm, Germany

Correspondence to:

Sebastien Thomine, Institut des Sciences du Végétal, CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France. Tel.: +33 1 69 82 37 93; Fax: +33 1 69 82 37 68; E-mail: thomine@isv.cnrs-gif.fr

Received 3 June 2005; Accepted 11 October 2005

Iron (Fe) is necessary for all living cells, but its bioavailability is often limited. Fe deficiency limits agriculture in many areas and affects over a billion human beings worldwide. In mammals, NRAMP2/DMT1/DCT1 was identified as a major pathway for Fe acquisition and recycling. In plants, AtNRAMP3 and AtNRAMP4 are induced under Fe deficiency. The similitude of AtNRAMP3 and AtNRAMP4 expression patterns and their common targeting to the vacuole, together with the lack of obvious phenotype in nramp3-1 and nramp4-1 single knockout mutants, suggested a functional redundancy. Indeed, the germination of nramp3 nramp4 double mutants is arrested under low Fe nutrition and fully rescued by high Fe supply. Mutant seeds have wild type Fe content, but fail to retrieve Fe from the vacuolar globoids. Our work thus identifies for the first time the vacuole as an essential compartment for Fe storage in seeds. Our data indicate that mobilization of vacuolar Fe stores by AtNRAMP3 and AtNRAMP4 is crucial to support Arabidopsis early development until efficient systems for Fe acquisition from the soil take over.

  • Keywords:

    • Arabidopsis thaliana,
    • germination,
    • iron nutrition,
    • NRAMP transporters,
    • vacuole