Fig. 1: The proposed pathway for de novo biosynthesis of ginsenosides Rg2 and Re in engineered yeast strains.

Bluish green arrows represent glycosylation steps using UDP-glucose as a sugar donor, blue arrows represent the biosynthetic pathway of UDP-rhamnose and glycosylation steps using UDP-rhamnose as a sugar donor. Multi-step conversions were presented as multi arrows. Bluish green marked genes represented previous reported genes and the bule marked gene represented the identified one in this study. PPD protopanaxadiol, PPT protopanaxatriol.