Abstract

Anthocyanidin synthase (ANS) catalyzes the biosynthesis of anthocyanidin, which is a late gene for anthocyanin biosynthesis. In order to investigate the role of anthocyanidin synthase in anthocyanin biosynthesis, we cloned and characterized the anthocyanidin synthase gene from purple-flesh sweet potato (Ipomoea batatas(L.) Lam) Yuzi 263, which was designated as IbANS. The cDNA fragment of the ANS gene of sweet potato was 1375-bp in length which contained a 1086-bp open reading frame that encoded a 362-amino acid polypeptide. Comparative analysis showed that IbANS had a high similarity to other plant ANSs. The tissue expression profiles of IbANS indicated that it could be expressed in all tissues but at different levels. The higher expression level of IbANS was found in diameter (3.0 cm) of tuberous roots and periderms, while the lower expression level of IbANS was found in other tissues just coinciding with the anthocyanin content distribution.

Key words: Sweet potato, purple-fleshed, anthocyanidin synthase, cloning, characterization, expression profile.