Abstract
Recent insights into lignin biosynthesis have shown phenylpropanoid ester such as chlorogenic acid (CGA) plays prominent roles in monolignol biosynthesis. However, there is active debate about the biosynthetic pathway for generating phenolic esters. The two different pathways in CGA biosynthesis are known. Generally accepted pathway shown in tobacco and tomato cells used for hydroxycinnamoyl CoA thioester as precursor, and other pathway that used for hydroxycinnamoyl glucose ester is known in sweet potato. We characterized the relationship between both phenylpropanoid pathways involved in CGA biosynthesis in sweet potato cells in suspension culture. Most of enzymes and substrates involved in the glucose ester-derived biosynthesis were detected in vacuole not protoplast fraction, on the other hand, the monolignol biosynthesis used for caffeoyl CoA was detected in cytosol. These results show metabolic channeling by two different phenylpropanoid pathways is probably involved in chlorogenic acid biosynthesis in sweet potato cells.
