conference schedule and program with abstracts - Horticulture ...

P-9
A molecular marker system for the identification of the colour-locus
in different tissues of grapevine (Vitis vinifera L.)
N. Ruh*, E. Bleser, E. Rühl, O. Bitz
Geisenheim Research Centre, Geisenheim, German
*Presenting author: natascha.ruh@fa-gm.de
Anthocyanins are red- or purple-coloured secondary metabolites present in many tissues of many
plants and are a subgroup of flavonoids. Most grapevine cultivars can be divided in red and
white although the colour spectrum goes from white over red and grey to blue and black. The
composition from about 20 different anthocyanins and their concentration in the berry skin
determine this colour-variation in grape. Each cultivar has a unique set of anthocyanins. The
anthocyanin biosynthetic pathway starts from L-phenylalanin and from the important
intermediate product, dihydrokaempferol two similar pathways leading either to cyanidin or
delphinidin respectively. These products are subsequent glycosylized through UDP-Glc-
Flavonoid-3-O-Glucosyltransferase (UFGT). The expression of the UFGT gene is much lower in
white grapes than in red or black but no significant differences can be found in the sequence of
the gene from white to red/black cultivars. The expression of the gene UFGT is controlled by
transcription-factors VvMYBA1 and VvMYBA3. The two paralogous genes are adjacent,
building a single locus inherited with berry colour. The VvMYBA1 gene is not expressed in white
berries mainly to an insertion-mutation of Gret1 (Grape retrotransposon 1) in the promoter of
VvMYBA1.Based on this locus we used PCR-primer, both published and self designed, to
develop an “easy-to-use” marker system to determine the potential berry skin colour from
wooden material. But the application of the system to different tissues: wood, roots, anthers,
leaves and grape skin leads to different results. Especially in the grey variety Pinot gris, which is
prone for colour chimaera, has shown great differences in various tissues and white and grey
coloured sectors of berry skin. The system is now used in “In vitro-Culture” experiments for
developing a test for separating chimaeras. PCR-analyses showed interesting results in red
Riesling, a colour mutation of white Riesling. A secondary DNA-band slightly larger than
expected was found. Also Chardonnay rosé showed similar results.
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