Disfunctions in the anthocyanin accumulation of Vitis vinifera L. varieties studied by a targeted resequencing approach

BACKGROUND: The pathway of anthocyanin biosynthesis, and its alterations leading to berry colour modification, are well known in grape skin. This variability could affect both quantity and quality of pigment accumulation. OBJECTIVE: The present work is focused on 15 grapevine cultivars selected to represent a high variability in the phenotypical colour traits in order to highlight new polymorphisms related to the flavonoid pathway. METHODS: Twenty-one genes involved in the biosynthetic pathway of anthocyanins were studied via targeted resequencing and were correlated with phenotypic data (anthocyanin profiles and spectroscopy indices). RESULTS: Single nucleotide polymorphism (SNP) and InDel (insertion/deletion) polymorphisms were detected. Out of 1751 polymorphic loci, 68% were SNPs and 32% were InDels (568). Cluster analysis and SPLS-DA were used to investigate the genetic relationships among the cultivars, confirming the large range of phenotypical variability. Statistically significant correlations were detected between accumulation of cyanidin-based anthocyanins and genetic polymorphisms in two structural genes and one transcription factor putatively involved in the anthocyanin biosynthetic pathway. CONCLUSIONS: The understanding of the polymorphisms related to the anthocyanin accumulation could support future selection of new pink table grape varieties with increased appeal on the consumers.