title: Leaf fructose content is controlled by the vacuolar transporter SWEET17 in Arabidopsis.
abstract: In higher plants, soluble sugars are mainly present as sucrose, glucose, and fructose. Sugar allocation is based on both source-to-sink transport and intracellular transport between the different organelles and depends on actual plant requirements. Under abiotic stress conditions, such as nitrogen limitation, carbohydrates accumulate in plant cells. Despite an increasing number of genetic studies, the genetic architecture determining carbohydrate composition is poorly known. Using a quantitative genetics approach, we determined that the carrier protein SWEET17 is a major factor controlling fructose content in Arabidopsis leaves. We observed that when SWEET17 expression is reduced, either by induced or natural variation, fructose accumulates in leaves, suggesting an enhanced storage capacity. Subcellular localization of SWEET17-GFP to the tonoplast and functional expression in Xenopus oocytes showed that SWEET17 is the first vacuolar fructose transporter to be characterized in plants. Physiological studies in planta provide evidence that SWEET17 acts to export fructose out of the vacuole. Overall, our results suggest that natural variation in leaf fructose levels is controlled by the vacuolar fructose transporter SWEET17. SWEET17 is highly conserved across the plant kingdom; thus, these findings offer future possibilities to modify carbohydrate partitioning in crops.
authors.affiliation: INRA AgroParisTech, UMR1318 Institut Jean-Pierre Bourgin, RD10, 78026 Versailles Cedex, France. fabien.chardon@versailles.inra.fr
authors.forename: Fabien
authors.initials: F
authors.lastname: Chardon
authors.forename: Magali
authors.initials: M
authors.lastname: Bedu
authors.forename: Fanny
authors.initials: F
authors.lastname: Calenge
authors.forename: Patrick A W
authors.initials: PA
authors.lastname: Klemens
authors.forename: Lara
authors.initials: L
authors.lastname: Spinner
authors.forename: Gilles
authors.initials: G
authors.lastname: Clement
authors.forename: Giorgiana
authors.initials: G
authors.lastname: Chietera
authors.forename: Sophie
authors.initials: S
authors.lastname: Léran
authors.forename: Marina
authors.initials: M
authors.lastname: Ferrand
authors.forename: Benoit
authors.initials: B
authors.lastname: Lacombe
authors.forename: Olivier
authors.initials: O
authors.lastname: Loudet
authors.forename: Sylvie
authors.initials: S
authors.lastname: Dinant
authors.forename: Catherine
authors.initials: C
authors.lastname: Bellini
authors.forename: H Ekkehard
authors.initials: HE
authors.lastname: Neuhaus
authors.forename: Françoise
authors.initials: F
authors.lastname: Daniel-Vedele
authors.forename: Anne
authors.initials: A
authors.lastname: Krapp
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D003001:Cloning, Molecular; D005632:Fructose / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D016133:Polymerase Chain Reaction; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological; D014981:Xenopus
chemical_list: D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C584524:SWEET17 protein, Arabidopsis; D005632:Fructose