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Characterization of the grapevine Shaker K + channel VvK3.1 supports its function in massive potassium fluxes necessary for berry potassium loading and pulvinus‐actuated leaf movements
Author(s) -
NievesCordones Manuel,
Andrianteranagna Mamy,
Cuéllar Teresa,
Chérel Isabelle,
Gibrat Rémy,
Boeglin Martin,
Moreau Bertrand,
Paris Nadine,
Verdeil JeanLuc,
Zimmermann SabineDagmar,
Gaillard Isabelle
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15604
Subject(s) - berry , apoplast , phloem , shaker , potassium channel , ripening , potassium , petiole (insect anatomy) , biophysics , botany , biology , chemistry , horticulture , cell wall , physics , hymenoptera , organic chemistry , quantum mechanics , vibration
Summary In grapevine, climate changes lead to increased berry potassium (K + ) contents that result in must with low acidity. Consequently, wines are becoming ‘flat’ to the taste, with poor organoleptic properties and low potential aging, resulting in significant economic loss. Precise investigation into the molecular determinants controlling berry K + accumulation during its development are only now emerging. Here, we report functional characterization by electrophysiology of a new grapevine Shaker‐type K + channel, VvK3.1. The analysis of VvK3.1 expression patterns was performed by qPCR and in situ hybridization. We found that VvK3.1 belongs to the AKT 2 channel phylogenetic branch and is a weakly rectifying channel, mediating both inward and outward K + currents. We showed that VvK3.1 is highly expressed in the phloem and in a unique structure located at the two ends of the petiole, identified as a pulvinus. From the onset of fruit ripening, all data support the role of the VvK3.1 channel in the massive K + fluxes from the phloem cell cytosol to the berry apoplast during berry K + loading. Moreover, the high amount of VvK3.1 transcripts detected in the pulvinus strongly suggests a role for this Shaker in the swelling and shrinking of motor cells involved in paraheliotropic leaf movements.