title: VvBOR1, the grapevine ortholog of AtBOR1, encodes an efflux boron transporter that is differentially expressed throughout reproductive development of Vitis vinifera L.
abstract: Boron (B) is an essential micronutrient for normal development of roots, shoots and reproductive tissues in plants. Due to its role in the structure of rhamnogalacturonan II, a polysaccharide required for pollen tube growth, B deficiency has been associated with the occurrence of parthenocarpic seedless grapes in some varieties of Vitis vinifera L. Despite that, it is unclear how B is mobilized and accumulated in reproductive tissues. Here we describe the characterization of an efflux B transporter, VvBOR1, homolog to AtBOR1, which is involved in B xylem loading in Arabidopsis thaliana roots. VvBOR1-green fluorescent protein (GFP) fusion protein expressed in A. thaliana localizes in the proximal plasma membrane domain in root pericycle cells, and VvBOR1 overexpression restores the wild-type phenotype in A. thaliana bor1-3 mutant plants exposed to B deficiency. Complementation of a mutant yeast strain indicates that VvBOR1 corresponds to a B efflux transporter. Transcriptional analyses during grapevine reproductive development show that the VvBOR1 gene is preferentially expressed in flowers at anthesis and a direct correlation between the expression pattern and B content in grapes was established, suggesting the involvement of this transporter in B accumulation in grapevine berries.
authors.affiliation: Instituto de Biología Vegetal y Biotecnología, Universidad de Talca, Talca, Chile.
authors.forename: Ramón
authors.initials: R
authors.lastname: Pérez-Castro
authors.forename: Koji
authors.initials: K
authors.lastname: Kasai
authors.forename: Felipe
authors.initials: F
authors.lastname: Gainza-Cortés
authors.forename: Simón
authors.initials: S
authors.lastname: Ruiz-Lara
authors.forename: José A
authors.initials: JA
authors.lastname: Casaretto
authors.forename: Hugo
authors.initials: H
authors.lastname: Peña-Cortés
authors.forename: Jaime
authors.initials: J
authors.lastname: Tapia
authors.forename: Toru
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Enrique
authors.initials: E
authors.lastname: González
mesh_terms: D000595:Amino Acid Sequence; D017920:Antiporters / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001895:Boron / Q000378:metabolism*; D035264:Flowers / Q000378:metabolism; D005638:Fruit / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D027843:Vitis / Q000235:genetics* / Q000378:metabolism
chemical_list: D017920:Antiporters; D010940:Plant Proteins; D049452:Green Fluorescent Proteins; D001895:Boron