Arabidopsis WAT1 is a vacuolar auxin transport facilitator required for auxin homoeostasis

• Published in: Nature communications Vol. 4; no. 1; p. 2625
• Main Authors: Ranocha, Philippe, Dima, Oana, Nagy, Réka, Felten, Judith, Corratgé-Faillie, Claire, Novák, Ondřej, Morreel, Kris, Lacombe, Benoît, Martinez, Yves, Pfrunder, Stephanie, Jin, Xu, Renou, Jean-Pierre, Thibaud, Jean-Baptiste, Ljung, Karin, Fischer, Urs, Martinoia, Enrico, Boerjan, Wout, Goffner, Deborah
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 2013; Nature Pub. Group
• Subjects: Animals; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - ultrastructure; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis Proteins - pharmacology; Biological Transport; Cell Wall - drug effects; Cell Wall - genetics; Cell Wall - metabolism; Cell Wall - ultrastructure; Developmental Biology; Gene Expression Regulation, Plant; Gene Regulatory Networks; Homeostasis; Indoleacetic Acids - metabolism; Life Sciences; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Membrane Transport Proteins - pharmacology; Mutation; Plant Growth Regulators - metabolism; Saccharomyces cerevisiae - metabolism; Utvecklingsbiologi; Vacuoles - metabolism; Vegetal Biology; Xenopus laevis - metabolism; plant development; endoplasmic reticulum membrane; hormone auxin; auxin transport; plasma membrane; WALLS ARE THIN1
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms3625

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.