title: Mobilization of vacuolar iron by AtNRAMP3 and AtNRAMP4 is essential for seed germination on low iron.
abstract: 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.
authors.affiliation: Institut des Sciences du Végétal, CNRS, Gif-sur-Yvette, France.
authors.forename: Viviane
authors.initials: V
authors.lastname: Lanquar
authors.forename: Françoise
authors.initials: F
authors.lastname: Lelièvre
authors.forename: Susanne
authors.initials: S
authors.lastname: Bolte
authors.forename: Cécile
authors.initials: C
authors.lastname: Hamès
authors.forename: Carine
authors.initials: C
authors.lastname: Alcon
authors.forename: Dieter
authors.initials: D
authors.lastname: Neumann
authors.forename: Gérard
authors.initials: G
authors.lastname: Vansuyt
authors.forename: Catherine
authors.initials: C
authors.lastname: Curie
authors.forename: Astrid
authors.initials: A
authors.lastname: Schröder
authors.forename: Ute
authors.initials: U
authors.lastname: Krämer
authors.forename: Hélène
authors.initials: H
authors.lastname: Barbier-Brygoo
authors.forename: Sebastien
authors.initials: S
authors.lastname: Thomine
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D027682:Cation Transport Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018548:Cotyledon / Q000378:metabolism; D018525:Germination / Q000502:physiology*; D007501:Iron / Q000378:metabolism*; D000090463:Iron Deficiencies; D009154:Mutation; D010641:Phenotype; D030821:Plants, Genetically Modified; D012639:Seeds / Q000502:physiology*; D015854:Up-Regulation; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; C099651:IRT1 protein, Arabidopsis; C408073:NRAMP4 protein, Arabidopsis; C408072:Nramp3 protein, Arabidopsis; D007501:Iron