The health benefits of purple sweetpotato, which is used as an edible food in its natural state and in processed foods and as a natural color pigment, have been recognized. In Japan, sweetpotato has been economically produced in regions below 36°4′N latitude, however, cultivation areas are beginning to expand further north. The anthocyanin and polyphenolics in purple sweetpotatoes cultivated in different locations; I (42°92′ N, 143°04′ E), II (35°99′ N, 140°01′ E), and III (31°72′ N, 131°03′ E), were compared over two years. Total anthocyanin and polyphenolic contents in purple sweetpotatoes tended to be high in location I. Their contents significantly differed over the two years in locations I and III and was dependent on temperature during cultivation. The anthocyanin and polyphenolic compositions differed between locations. The peonidin/cyanidin ratios were higher in location III compared with I and II in all varieties. The relative amount of chlorogenic acid was higher in location I, while the amount of 3,4- and 4,5-dicaffeoyolquinic acids were higher in location III, suggesting that the variability of the anthocyanin and polyphenolic content and composition was dependent on cultivation conditions. This study suggested that northern areas in Japan are an alternative production area and may yield higher amounts of anthocyanin and polyphenolics.

The phenylpropanoid pathway is a major secondary metabolite pathway that helps plants overcome biotic and abiotic stress and produces various by-products that promote human health. Its byproduct, chloroquinic acid (CQA), is a soluble phenolic compound present in many angiosperms. Hy-droxycinnamate-CoA shikimate/quinate transferase(BAHDs superfamily enzyme) is a significant en-zyme that plays a role in accumulating CQA biosynthesis. This study analyzed transcriptome-wide identification of the phenylpropanoid to chloroquinic acid biosynthesis candidate genes in A. spathulifolius flowers and leaves. Transcriptomic analyses of the flowers and leaves showed a differential expression of the PPP and CQA biosynthesis regulated unigenes. An analysis of PPP captive unigenes revealed the following: the major duplication of the key enzyme, PAL, 120 unigenes in leaves and 76 in flowers; the gene encoding C3’H, 169 unigenes in leaves and 140 unigenes in flowers; duplicated unigenes of 4CL, 41 in leaves and 27 in flowers. In addition, C4H unigenes had 12 unigenes in the leaves of A. spathulifolius and four in the flowers. The characterization of the BAHDs superfamily members identified 82 in leaves and 72 in flowers. Among them, phylogenetic analysis showed that five unigenes encoded HQT and three en-coded HCT in A. spathulifolius. The three HQT are common to both leaves and flowers, whereas the two HQT were specialized for leaves. The pattern of HQT synthesis was upregulated in flowers, whereas HCT was expressed strongly in the leaves of A. spathulifolius. Overall, 4CL, C4H, and HQT are expressed strongly in flowers, and caffeic acid and HCT show more expression in leaves. Therefore, CQA biosynthesis occurs in the flowers of A. spathulifolius rather than leaves.