RESUMO
BACKGROUND: Anthocyanins, a major flavonoid class, determine the color and quality of wine. Recent research revealed that basal leaf removal can increase the content of these compounds. This study determined the effects of basal leaf removal on the anthocyanin profiles of Cabernet Sauvignon grapes. RESULTS: The effects of basal leaf removal on anthocyanin composition in Cabernet Sauvignon grapes were investigated over two growing seasons. Leaf removal at 5% veraison (VB6) and at 100% veraison (VC6) was compared with a control. Reducing sugar and total anthocyanin contents in the leaf removal group were significantly higher than in the control group at harvest for both vintages. Leaf removal increased the content of individual anthocyanins and significantly improved the malvidin-3-O-glucoside (Mv-3-glc), peonidin-3-O-glucoside (Pn-3-glc), and malvidin-3-O-(6-acetyl)-glucoside (Mv-3-acglc) content of the VB6 group. At harvest, VB6 treatment increased the transcript abundance of structural and regulator genes in the anthocyanin pathway, especially VvF3'5'H, VvLDOX, and VvDFR. CONCLUSIONS: Our results suggest that leaf removal at 5% veraison may be useful for improving the anthocyanin content in grapes. © 2020 Society of Chemical Industry.
Assuntos
Antocianinas/biossíntese , Produção Agrícola/métodos , Frutas/química , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Vitis/crescimento & desenvolvimento , Antocianinas/análise , Cromatografia Líquida de Alta Pressão , Frutas/genética , Frutas/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Vitis/química , Vitis/genética , Vitis/metabolismoRESUMO
Monoterpenes contribute to the varietal aromas of grapes and wines. We determined the effects of cluster zone leaf removal on the monoterpene profiles of Sauvignon Blanc grape berries and wines, and on the expression of key genes in the terpenoid pathway. Leaf removal at two intensities (half basic, 50%; full basic, 100%) was conducted at two weeks before veraison, veraison, and two weeks after veraison. Half basic leaf removal increased the pH and decreased the tartaric acid content in grapes and wines. The concentrations of most free- and bound-form monoterpenes in grapes were increased by early leaf removal. The total monoterpene contents were increased in wines in the defoliation treatments, but were significantly lower in wines from the full basic leaf removal treatments than in wines from the half basic leaf removal treatments. The defoliation treatments resulted in increased transcript levels of some key genes in terpene biosynthesis (VvPNLinNer1, VvPNLinNer2, VvPNLNGl1, VvPNLNGl2, and VvUGT88A1L1).
