Low Expression of Flavonoid 3′,5′-Hydroxylase (F3′,5′H) Associated with Cyanidin-based Anthocyanins in Grape Leaf

The aim of this study was to clarify anthocyanin composition and transcription profiles of anthocyanin-synthesis-related genes in grape (Vitis vinifera L.) leaf during development. Berry skin accumulated both cyanidin-based anthocyanins and delphinidin-based anthocyanins during development and showed up-regulation of flavonoid 3′,5′-hydroxylase gene (F3′,5′H) expression. Grape leaf, in contrast, accumulated a large amount of cyanidin-based anthocyanins during development. This result was supported by the low expression of F3′,5′H in developing grape leaf. The low expression of F3′,5′H and the low level of delphinidin-based anthocyanins in grape leaf were consistent in green-yellow-, purple-, and black-colored skin cultivars. Flavonoid 3′-hydroxylase gene (F3′H) expression increased in grape leaf during development. Since F3′,5′H regulates the synthesis of delphinidin-based anthocyanins and F3′H regulates the synthesis of cyanidin-based anthocyanins in plants, it is possible that grape leaf accumulates large amount of cyanidin-based anthocyanins through the cyanidin synthesis pathway regulated by F3′H.