title: The Arabidopsis root stele transporter NPF2.3 contributes to nitrate translocation to shoots under salt stress.
abstract: In most plants, NO(3)(-) constitutes the major source of nitrogen, and its assimilation into amino acids is mainly achieved in shoots. Furthermore, recent reports have revealed that reduction of NO(3)(-) translocation from roots to shoots is involved in plant acclimation to abiotic stress. NPF2.3, a member of the NAXT (nitrate excretion transporter) sub-group of the NRT1/PTR family (NPF) from Arabidopsis, is expressed in root pericycle cells, where it is targeted to the plasma membrane. Transport assays using NPF2.3-enriched Lactococcus lactis membranes showed that this protein is endowed with NO(3)(-) transport activity, displaying a strong selectivity for NO(3)(-) against Cl(-). In response to salt stress, NO(3)(-) translocation to shoots is reduced, at least partly because expression of the root stele NO(3)(-) transporter gene NPF7.3 is decreased. In contrast, NPF2.3 expression was maintained under these conditions. A loss-of-function mutation in NPF2.3 resulted in decreased root-to-shoot NO(3)(-) translocation and reduced shoot NO(3)(-) content in plants grown under salt stress. Also, the mutant displayed impaired shoot biomass production when plants were grown under mild salt stress. These mutant phenotypes were dependent on the presence of Na(+) in the external medium. Our data indicate that NPF2.3 is a constitutively expressed transporter whose contribution to NO(3)(-) translocation to the shoots is quantitatively and physiologically significant under salinity.
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Taochy
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gaillard
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Ipotesi
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Ronald
authors.initials: R
authors.lastname: Oomen
authors.affiliation: Laboratoire de Biologie du Développement des Plantes, Institut de Biologie Environnementale et Biotechnologie, Laboratoire des Echanges Membranaires et Signalisation, UMR 7265 CNRS/CEA/Université Aix-Marseille II, F-13108, St Paul lez Durance, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leonhardt
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Zimmermann
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Jean-Benoît
authors.initials: JB
authors.lastname: Peltier
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Szponarski
authors.affiliation: Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Institut de Biologie Intégrative des Plantes, UMR 0759 INRA/Montpellier SupAgro, F-34060, Montpellier, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Simonneau
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Sentenac
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Rémy
authors.initials: R
authors.lastname: Gibrat
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS, UMR 0386 INRA/Montpellier SupAgro/Université de Montpellier, F-34060, Montpellier, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Boyer
mesh_terms: D027321:Anion Transport Proteins / Q000378:metabolism* / Q000502:physiology*; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000502:physiology*; D013294:Lactococcus lactis; D026901:Membrane Transport Proteins / Q000502:physiology*; D000091285:Nitrate Transporters; D010940:Plant Proteins / Q000502:physiology*; D055049:Salt Tolerance / Q000502:physiology*
chemical_list: D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C101492:NRT1.1 protein, Arabidopsis; D000091285:Nitrate Transporters; C098241:PTR2 protein, Arabidopsis; D010940:Plant Proteins
keywords: Arabidopsis thaliana; Lactococcus lactis; NAXT; NPF family; ion transporter; nitrate; root-to-shoot translocation; salt stress