title: The high-affinity metal Transporters NRAMP1 and IRT1 Team up to Take up Iron under Sufficient Metal Provision.
abstract: Iron (Fe) and manganese (Mn) are essential metals which, when scarce in the growth medium, are respectively taken up by the root high affinity transporters IRT1 and NRAMP1 in Arabidopsis thaliana. The molecular bases for low affinity transport however remained unknown. Since IRT1 and NRAMP1 have a broad range of substrates among metals, we tested the hypothesis that they might be functionally redundant by generating nramp1 irt1 double mutants. These plants showed extreme Fe-deficiency symptoms despite optimal provision of the metal. Their phenotype, which includes low Fe and Mn contents and a defect of Fe entry into root cells as revealed by Fe staining, is rescued by high Fe supply. Using a promoter swap-based strategy, we showed that root endodermis retains the ability to carry out high affinity Fe transport and furthermore might be important to high-affinity Mn uptake. We concluded that NRAMP1 plays a pivotal role in Fe transport by cooperating with IRT1 to take up Fe in roots under replete conditions, thus providing the first evidence for a low affinity Fe uptake system in plants.
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5004, Institut de Biologie Intégrative des Plantes, Montpellier, France.
authors.forename: Loren
authors.initials: L
authors.lastname: Castaings
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5004, Institut de Biologie Intégrative des Plantes, Montpellier, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Caquot
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5004, Institut de Biologie Intégrative des Plantes, Montpellier, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Loubet
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5004, Institut de Biologie Intégrative des Plantes, Montpellier, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Curie
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007501:Iron / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D008670:Metals / Q000378:metabolism*; D009154:Mutation; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D000099173:Natural Resistance-associated Macrophage Protein 1
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D007501:Iron; D008345:Manganese; D008670:Metals; C099651:IRT1 protein, Arabidopsis; C000627632:NRAMP1 protein, Arabidopsis; D000099173:Natural Resistance-associated Macrophage Protein 1