title: The Grapevine Uncharacterized Intrinsic Protein 1 (VvXIP1) Is Regulated by Drought Stress and Transports Glycerol, Hydrogen Peroxide, Heavy Metals but Not Water.
abstract: A MIP (Major Intrinsic Protein) subfamily called Uncharacterized Intrinsic Proteins (XIP) was recently described in several fungi and eudicot plants. In this work, we cloned a XIP from grapevine, VvXIP1, and agrobacterium-mediated transformation studies in Nicotiana benthamiana revealed that the encoded aquaporin shows a preferential localization at the endoplasmic reticulum membrane. Stopped-flow spectrometry in vesicles from the aqy-null yeast strain YSH1172 overexpressing VvXIP1 showed that VvXIP1 is unable to transport water but is permeable to glycerol. Functional studies with the ROS sensitive probe CM-H2DCFDA in intact transformed yeasts showed that VvXIP1 is also able to permeate hydrogen peroxide (H2O2). Drop test growth assays showed that besides glycerol and H2O2, VvXIP1 also transports boric acid, copper, arsenic and nickel. Furthermore, we found that VvXIP1 transcripts were abundant in grapevine leaves from field grown plants and strongly repressed after the imposition of severe water-deficit conditions in potted vines. The observed downregulation of VvXIP1 expression in cultured grape cells in response to ABA and salt, together with the increased sensitivity to osmotic stress displayed by the aqy-null yeast overexpressing VvXIP1, corroborates the role of VvXIP1 in osmotic regulation besides its involvement in H2O2 transport and metal homeostasis.
authors: Centro de Investigação e de Tecnologias Agro-ambientais e Biológicas CITAB, Vila Real, Portugal.|Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors: Henrique
authors: H
authors: Noronha
authors: Centro de Investigação e de Tecnologias Agro-ambientais e Biológicas CITAB, Vila Real, Portugal.
authors: Diogo
authors: D
authors: Araújo
authors: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|IBMC; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors: Carlos
authors: C
authors: Conde
authors: Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL) University of Lisbon, Lisbon, Portugal.
authors: Ana P
authors: AP
authors: Martins
authors: Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL) University of Lisbon, Lisbon, Portugal.
authors: Graça
authors: G
authors: Soveral
authors: Institut des Science de la Vie, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
authors: François
authors: F
authors: Chaumont
authors: INRA, ISVV, Ecophysiologie et Génomique Fonctionnelle de la Vigne, UMR 1287, Université de Bordeaux, Villenave D'Ornon, France.
authors: Serge
authors: S
authors: Delrot
authors: Centro de Investigação e de Tecnologias Agro-ambientais e Biológicas CITAB, Vila Real, Portugal.|Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors: Hernâni
authors: http://orcid.org/0000-0002-3040-4095
authors: H
authors: Gerós
mesh_terms: D001692:Biological Transport; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D005990:Glycerol / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism; D019216:Metals, Heavy / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D013312:Stress, Physiological; D014158:Transcription, Genetic; D027843:Vitis / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014867:Water / Q000378:metabolism
chemical_list: D019216:Metals, Heavy; D010940:Plant Proteins; D014867:Water; D006861:Hydrogen Peroxide; D005990:Glycerol