Cloning and accumulation of anthocyanin biosynthesis genes in developing tubers

Anthocyanins are a class of flavonoids that are responsible for the pigmentation of red potato periderm. The cDNAs of two genes were cloned from 'Norland' periderm and, based on their sequence similarity to genes in various databases, were identified as the anthocyanin biosynthetic genes for leucoanthocyanidin dioxygenase (EC 1.14.11.19) and UDP glucose: flavonoid 3-O-glucosyI transferase (EC 2.4.1.91). The mRNA accumulation of these genes in periderm during the development of tubers was determined using RNA gel blot analyses. The mRNA of the putative LDOX was detected in cortex tissue and microtubers, but not in periderm. While mRNA of the putative UFGT was detected in cortex tissue and periderm of young tubers, but not in periderm of tubers weighing more than 25 g. These data suggest that accumulation of LDOX and UFGT mRNA may limit anthocyanin synthesis as Norland tubers develop.