title: Arabidopsis WAT1 is a vacuolar auxin transport facilitator required for auxin homoeostasis.
abstract: The plant hormone auxin (indole-3-acetic acid, IAA) has a crucial role in plant development. Its spatiotemporal distribution is controlled by a combination of biosynthetic, metabolic and transport mechanisms. Four families of auxin transporters have been identified that mediate transport across the plasma or endoplasmic reticulum membrane. Here we report the discovery and the functional characterization of the first vacuolar auxin transporter. We demonstrate that WALLS ARE THIN1 (WAT1), a plant-specific protein that dictates secondary cell wall thickness of wood fibres, facilitates auxin export from isolated Arabidopsis vacuoles in yeast and in Xenopus oocytes. We unambiguously identify IAA and related metabolites in isolated Arabidopsis vacuoles, suggesting a key role for the vacuole in intracellular auxin homoeostasis. Moreover, local auxin application onto wat1 mutant stems restores fibre cell wall thickness. Our study provides new insight into the complexity of auxin transport in plants and a means to dissect auxin function during fibre differentiation.
authors.affiliation: 1] Université de Toulouse; UPS; UMR 5546, Laboratoire de Recherche en Sciences Végétales; BP 42617, F-31326, Castanet-Tolosan, France [2] Centre National de la Recherche Scientifique; CNRS; UMR5546; Laboratoire de Recherche en Sciences Végétales; BP 42617, F-31326, Castanet-Tolosan, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ranocha
authors.forename: Oana
authors.initials: O
authors.lastname: Dima
authors.forename: Réka
authors.initials: R
authors.lastname: Nagy
authors.forename: Judith
authors.initials: J
authors.lastname: Felten
authors.forename: Claire
authors.initials: C
authors.lastname: Corratgé-Faillie
authors.forename: Ondřej
authors.initials: O
authors.lastname: Novák
authors.forename: Kris
authors.initials: K
authors.lastname: Morreel
authors.forename: Benoît
authors.initials: B
authors.lastname: Lacombe
authors.forename: Yves
authors.initials: Y
authors.lastname: Martinez
authors.forename: Stephanie
authors.initials: S
authors.lastname: Pfrunder
authors.forename: Xu
authors.initials: X
authors.lastname: Jin
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Renou
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Thibaud
authors.forename: Karin
authors.initials: K
authors.lastname: Ljung
authors.forename: Urs
authors.initials: U
authors.lastname: Fischer
authors.forename: Enrico
authors.initials: E
authors.lastname: Martinoia
authors.forename: Wout
authors.initials: W
authors.lastname: Boerjan
authors.forename: Deborah
authors.initials: D
authors.lastname: Goffner
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D001692:Biological Transport; D002473:Cell Wall / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D006706:Homeostasis; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D009154:Mutation; D010937:Plant Growth Regulators / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism*; D014982:Xenopus laevis / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D010937:Plant Growth Regulators; C560559:Wat1 protein, Arabidopsis; C030737:indoleacetic acid