Tissue-specific Accumulation of Flavonoids in Grape Berries is Related to Transcriptional Expression of VvF3′H and VvF3′5′H

Abstract

The products and the related gene expression of flavonoid metabolism were examined in the skin and pulp
of Yan73 (Vitis vinifera L. cv.) grapes, a teinturier variety cultivated in China, and the data were compared
with those in the skin and pulp of Cabernet Sauvignon (Vitis vinifera L. cv.) grapes, a well-known red
variety. The results showed that, in comparison with the skins of Cabernet Sauvignon, the skins of Yan73
berries were characterised by fewer types of flavonols and anthocyanins, a higher level of flavonoids,
and a much lower percentage of 3′-hydroxylated flavonols. Flavonoid metabolism was also present in the
pulp of Yan73, and the percentages of 3′-hydroxylated flavonols and 3′-hydroxylated flavan-3-ols were
significantly higher than the percentages of their corresponding 3′,5′-hydroxylated forms. Only flavan-3-
ols were found in the pulp of Cabernet Sauvignon. The expression of VvmybA1 exhibited a co-ordination
with the accumulation of anthocyanins in the pulp of the teinturier cultivar, which showed great similarity
to that in the skin. A good correlation was found between the expression of VvF3′H and 3′-hydroxylated
flavonoids, as well as between the expression of VvF3′5′H and 3′,5′-hydroxylated flavonoids in the skin and
pulp of the grape berries. It is suggested that tissue-specific accumulation of flavonoids in grape berries is
related to the transcriptional expression of VvF3′H and VvF3′5′H.