• Plant Biotechnology Reports
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• 제5권1호
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• pp.79-88
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• 2011

Vitis vinifera cv. Koshu is a traditional grape cultivar that has been grown for centuries in Japan. The Koshu grape has pink-colored skin and Koshu wines have slight astringency. We demonstrated for the first time the characterization of hydroxycinnamic acids, flavan-3-ols, and flavonoids in Koshu grape using high-performance liquid chromatography and liquid chromatography-mass spectrometry. The gross weight of phenolic compounds excluding anthocyanins and proanthocyanidins in Koshu grape at harvest was higher than those in Sauvignon Blanc, Chardonnay, and Merlot grapes. In addition, hydroxycinnamic acid and monomeric flavonol contents in Koshu grape were also higher than those in the other grape cultivars. Transcription analysis of cinnamic acid 4-hydroxylase, p-coumarate 3-hydroxylase, caffeate methyltransferase, and flavonol synthase genes indicated high accumulation of hydroxycinnamic acids and flavonols in Koshu grape skin compared with the other cultivars. These findings obtained by chemical and molecular approaches partially explained the phenolic characteristics and the peculiar astringency of Koshu grape.

• Plant Biotechnology Reports
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• 제3권3호
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• pp.225-241
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• 2009

We investigated the transcriptional profiles of Japanese indigenous grape cultivar 'Koshu' (Vitis vinifera) leaf and berry skin during ripening. In leaf, 64 genes were abundantly transcribed at the end of $v{\acute{e}}raison$ (14 weeks post-flowering), whereas the expression of 61 genes was upregulated at the end of ripening (20 weeks post-flowering). In berry skin, 67 genes were abundantly transcribed at the end of $v{\acute{e}}raison$, whereas the expression of 86 genes was upregulated at the end of ripening. Gene expression associated with biological processes was activated in both tissues at the end of ripening. The expression of genes associated with photosynthesis, sugar synthesis, anthocyanin synthesis, cinnamic acid synthesis, and amino acid metabolism was observed in leaf and berry skin during ripening, together with the accumulation of sugars, anthocyanins, cinnamic acids, and amino acids. Transcripts of AUX/IAA family proteins that repress the activities of auxin-induced proteins were expressed in berry skin at the end of $v{\acute{e}}raison$. Transcripts of genes related to the ubiquitin-proteasome system that degrades AUX/IAA family proteins were abundantly expressed in berry skin at the end of ripening, suggesting that the expansion of skin cells at $v{\acute{e}}raison$ is suppressed by AUX/IAA family proteins, and that the ubiquitin-proteasome system induces the expansion of skin cells during ripening by degrading AUX/IAA family proteins. These transcriptional profiles, which provide new information on the characteristics of 'Koshu' grapevine during ripening, may explain the unique characteristics of 'Koshu' grape in comparison with those of European grapes used for winemaking, and may contribute to the improvement of 'Koshu' grape quality.