Root Restriction Improved Anthocyanins Accumulation and Biosynthetic Genes Expression during Berry Development in ‘Kyoho' Grape

Root restriction could significantly  improve grape coloration with increased anthocyanins content, however, less information involved in anthocyanins biosynthesis and related-genes expression in grape berry skin was available. In this study, four-year-old ‘Kyoho’ grapevines were planted in wooden boxes as root restriction and the conventional ground planting as the control. Compositional changes in skin anthocyanins and expression patterns of 15 genes in anthocyanin pathway were investigated. Our results showed that root restriction significantly increased the total and individual anthocyanins levels in berry skin. Gene expression patterns revealed that the increased anthocyanins coincide with the up-regulated expression of 14 genes [except chalcone synthase 1 (CHS1)] investigated, including Phenylalanine ammonia-lyase (PAL); 4-coumarate CoA ligase (4CL);chalcone synthase 2 (CHS2); chalcone synthase 3 (CHS3); flavanone 3-hydroxylase 1 (F3H1); flavanone 3-hydroxylase 2 (F3H2); flavonoid 3’-hydroxylase (F3’H), flavonoid 3’,5’-hydroxylase (F3’5’H), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX), O-methyltransferases (OMT), UDP-glucose:flavonoid 3-O-glucosyl-transferase (3’GT) and UDP-glucose:flavonoid 5-O-glucosyl-transferase (5’GT).