Both the mevalonate and the non-mevalonate pathways are involved in ginsenoside biosynthesis.

KEY MESSAGE: When one of them was inhibited, the two pathways could compensate with each other to guarantee normal growth. Moreover, the sterol biosynthesis inhibitor miconazole could enhance ginsenoside level. ABSTRACT: Ginsenosides, a kind of triterpenoid saponins derived from isopentenyl pyrophosphate (IPP), represent the main pharmacologically active constituents of ginseng. In plants, two pathways contribute to IPP biosynthesis, namely, the mevalonate pathway in cytosol and the non-mevalonate pathway in plastids. This motivates biologists to clarify the roles of the two pathways in biosynthesis of IPP-derived compounds. Here, we demonstrated that both pathways are involved in ginsenoside biosynthesis, based on the analysis of the effects from suppressing either or both of the pathways on ginsenoside accumulation in Panax ginseng hairy roots with mevinolin and fosmidomycin as specific inhibitors for the mevalonate and the non-mevalonate pathways, respectively. Furthermore, the sterol biosynthesis inhibitor miconazole could enhance ginsenoside levels in the hairy roots. These results shed some light on the way toward better understanding of ginsenoside biosynthesis.