Characterization of a Grapevine R2R3-MYB Transcription Factor That Regulates the Phenylpropanoid Pathway1[W]

The ripening of grape (Vitis vinifera) berry is characterized by dramatic changes in gene expression, enzymatic activities, and metabolism that lead to the production of compounds essential for berry quality. The phenylpropanoid metabolic pathway is one of the components involved in these changes. I...

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Published inPlant physiology (Bethesda) Vol. 140; no. 2; pp. 499 - 511
Main Authors Deluc, Laurent, Barrieu, François, Marchive, Chloé, Lauvergeat, Virginie
Format Journal Article
LanguageEnglish
Published Rockville American Society of Plant Biologists 01.02.2006
Subjects
Biosynthesis
Cloning
Enzymatic activity
Fruits
Phenols
Tannins
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Summary:The ripening of grape (Vitis vinifera) berry is characterized by dramatic changes in gene expression, enzymatic activities, and metabolism that lead to the production of compounds essential for berry quality. The phenylpropanoid metabolic pathway is one of the components involved in these changes. In this study, we describe the cloning and functional characterization of VvMYB5a, a cDNA isolated from a grape L. cv Cabernet Sauvignon berry library. VvMYB5a encodes a protein belonging to a small subfamily of R2R3-MYB transcription factors. Expression studies in grapevine indicate that the VvMYB5a gene is mainly expressed during the early steps of berry development in skin, flesh, and seeds. Overexpression of VvMYB5a in tobacco (Nicotiana tabacum) affects the expression of structural genes controlling the synthesis of phenylpropanoid and impacts on the metabolism of anthocyanins, flavonols, tannins, and lignins. Overexpressing VvMYB5a induces a strong accumulation of several phenolic compounds, including keracyanin (cyanidin-3-rhamnoglucoside) and quercetin-3-rhamnoglucoside, which are the main anthocyanin and flavonol compounds in tobacco. In addition, VvMYB5a overexpression increases the biosynthesis of condensed tannins and alters lignin metabolism. These findings suggest that VvMYB5a may be involved in the control of different branches of the phenylpropanoid pathway in grapevine.
Bibliography:Corresponding author; e-mail said.hamdi@bordeaux.inra.fr; fax 33–5–57–12–25–41.
This work was supported by grants from the Conseil Interprofessionnel du Vin de Bordeaux.
The online version of this article contains Web-only data.
Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.067231.
Present address: Department of Biochemistry, University of Nevada, Reno, NV 89557.
The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Saïd Hamdi (said.hamdi@bordeaux.inra.fr).
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.105.067231