Inheritance and mutations are important factors affecting grape phenolic composition. To investigate the inter- and intra-varietal differences in polyphenolic compounds among grapes and wines, 27 clones belonging to eight varieties of Vitis vinifera L. were studied over two consecutive years. A total of 24 polyphenols (nine anthocyanins, three flavanols, five flavonols, and seven phenolic acids) were analyzed, and the physicochemical parameters of the grapes and wines were determined. Polyphenol profiles showed significant varietal and clonal polymorphisms, and malvidin-3-O-glucoside, peonidin-3-O- glucoside, and epicatechin were identified as key biomarkers distinguishing different grapes and wines when using an orthogonal partial least squares discriminant analysis. Further multivariate analysis classified these genotypes into three subclasses, and a somatic variant of \'Malbec\', MBVCR6, had the most abundant polyphenolic compounds that were related to the titratable acid content. The current results reveal that varietal and clonal variations are important for obtaining wines with high polyphenol content.

The grapevine (Vitis vinifera L.) berry coloring mechanism in response to seasonal rain during grape ripening remains poorly understood. Therefore, anthocyanin biosynthesis regulation, dynamic changes in anthocyanin accumulation, biosynthetic enzyme activities, and related gene expression patterns were investigated in Cabernet Sauvignon grown under rain-shelter cultivation and open-field cultivation. Results showed that anthocyanin biosynthesis was strongly repressed during the rainy season. Environmental fluctuation from seasonal rain provoked metabolic responses in grapes, and there was a significantly greater accumulation of most of the anthocyanins, mainly the compositions of non-acylated and non-methylated, under rain-shelter cultivation; these findings indicate that rain-shelter cultivation may help improve tolerance to seasonal rain-induced stresses. Obvious resilience was observed in anthocyanins of open-field-cultivated grapes at harvest. Hierarchical cluster analysis indicated strong correlations between anthocyanin contents, CHI and DFR activities, and VvMYB5b transcriptional level. These findings provide novel insight into the crucial factors that directly modulate anthocyanin biosynthesis and consequently control grape coloration.