Construction of plant cell factory for biosynthesis of ginsenoside Rh2 in tobacco

Ginsenoside Rh2, a kind of rare triterpene saponin isolated from Panax plants, has high medicinal values. But the extremely low content of ginsenoside Rh2 in ginseng herbs has limited its clinical application. In this work, we achieved a plant cell factory for biosynthesis of rare ginsenoside Rh2 in an industrial crop, tobacco, by metabolic engineering. Three enzyme genes (PnDDS, CYP12H and UGTPn3) isolated from Panax notoginseng were introduced into tobacco. Thus, a biosynthetic pathway for ginsenoside Rh2 synthesis was artificially constructed in tobacco, moreover, the three exogenous genes could be expressed in the roots, stems and leaves of transgenic plants. Consequently, ginsenoside Rh2 and its precursors were successfully synthesized in transgenic tobacco. Based on these results, a sustainable and efficient approach was established to produce ginsenoside Rh2, meanwhile, such strategy could also be employed for the heterologous synthesis of other important or rare natural products in plant hosts.