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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
Author(s) -
Cuéllar Teresa,
Pascaud François,
Verdeil JeanLuc,
Torregrosa Laurent,
AdamBlondon AnneFrançoise,
Thibaud JeanBaptiste,
Sentenac Hervé,
Gaillard Isabelle
Publication year - 2010
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2009.04029.x
Subject(s) - downregulation and upregulation , aquaporin , berry , heterologous expression , calcineurin , microbiology and biotechnology , bimolecular fluorescence complementation , biology , biophysics , gene , botany , biochemistry , medicine , recombinant dna , surgery , transplantation
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 Ca 2+ ‐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.