A grapevine Shaker inward K+ channel activated by the calcineurin B-like calcium sensor 1–protein kinase CIPK23 network is expressed in grape berries under drought stress conditions

Authors

  • Teresa Cuéllar,

    1. UMR1083, Sciences pour l’Œnologie, INRA, 2 Place Viala, 34060 Montpellier Cedex 1, France
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    • Present address: UPR28 Génetique Palmier, CIRAD, Avenue Agropolis, 34398 Montpellier Cedex 5, France.

  • François Pascaud,

    1. Biochimie et Physiologie Moléculaire des Plantes, CNRS-INRA-SupAgro Montpellier-Université de Montpellier, 2 place Viala, 34060 Montpellier Cedex 1, France
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  • Jean-Luc Verdeil,

    1. Développement et Amélioriation des Plantes. CIRAD, TA 80 / 03, Avenue Agropolis, 34398 Montpellier Cedex 5, France
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  • Laurent Torregrosa,

    1. Diversité et Adaptation des Plantes Pérennes Cultivées, INRA-Supagro Montpellier, 34060 Montpellier Cedex 01, France
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  • Anne-Françoise Adam-Blondon,

    1. Génomique Végétale, CNRS-INRA-UEVE, 2, Rue Gaston Crémieux, CP5708, 91057 Evry Cedex, France
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  • Jean-Baptiste Thibaud,

    1. Biochimie et Physiologie Moléculaire des Plantes, CNRS-INRA-SupAgro Montpellier-Université de Montpellier, 2 place Viala, 34060 Montpellier Cedex 1, France
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  • Hervé Sentenac,

    1. Biochimie et Physiologie Moléculaire des Plantes, CNRS-INRA-SupAgro Montpellier-Université de Montpellier, 2 place Viala, 34060 Montpellier Cedex 1, France
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  • Isabelle Gaillard

    Corresponding author
    1. UMR1083, Sciences pour l’Œnologie, INRA, 2 Place Viala, 34060 Montpellier Cedex 1, France
    2. Biochimie et Physiologie Moléculaire des Plantes, CNRS-INRA-SupAgro Montpellier-Université de Montpellier, 2 place Viala, 34060 Montpellier Cedex 1, France
      For correspondence (fax +33 4 67 52 57 37; e-mail gaillard@supagro.inra.fr).
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For correspondence (fax +33 4 67 52 57 37; e-mail gaillard@supagro.inra.fr).

Summary

Grapevine (Vitis vinifera), the genome sequence of which has recently been reported, is considered as a model species to study fleshy fruit development and acid fruit physiology. Grape berry acidity is quantitatively and qualitatively affected upon increased K+ accumulation, resulting in deleterious effects on fruit (and wine) quality. Aiming at identifying molecular determinants of K+ transport in grapevine, we have identified a K+ channel, named VvK1.1, from the Shaker family. In silico analyses indicated that VvK1.1 is the grapevine counterpart of the Arabidopsis AKT1 channel, known to dominate the plasma membrane inward conductance to K+ in root periphery cells, and to play a major role in K+ uptake from the soil solution. VvK1.1 shares common functional properties with AKT1, such as inward rectification (resulting from voltage sensitivity) or regulation by calcineurin B-like (CBL)-interacting protein kinase (CIPK) and Ca2+-sensing CBL partners (shown upon heterologous expression in Xenopus oocytes). It also displays distinctive features such as activation at much more negative membrane voltages or expression strongly sensitive to drought stress and ABA (upregulation in aerial parts, downregulation in roots). In roots, VvK1.1 is mainly expressed in cortical cells, like AKT1. In aerial parts, VvK1.1 transcripts were detected in most organs, with expression levels being the highest in the berries. VvK1.1 expression in the berry is localized in the phloem vasculature and pip teguments, and displays strong upregulation upon drought stress, by about 10-fold.VvK1.1 could thus play a major role in K+ loading into berry tissues, especially upon drought stress.

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