Alteration of Panax ginseng saponin composition by overexpression and RNA interference of the protopanaxadiol 6-hydroxylase gene (CYP716A53v2)

Abstract

BackgroundThe roots of Panax ginseng contain noble tetracyclic triterpenoid saponins derived from dammarenediol-II. Dammarene-type ginsenosides are classified into the protopanaxadiol (PPD) and protopanaxatriol (PPT) groups based on their triterpene aglycone structures. Two cytochrome P450 (CYP) genes (CYP716A47 and CYP716A53v2) are critical for the production of PPD and PPT aglycones, respectively. CYP716A53v2 is a protopanaxadiol 6-hydroxylase that catalyzes PPT production from PPD in P. ginseng.MethodsWe constructed transgenic P. ginseng lines overexpressing or silencing (via RNA interference) the CYP716A53v2 gene and analyzed changes in their ginsenoside profiles.ResultOverexpression of CYP716A53v2 led to increased accumulation of CYP716A53v2 mRNA in all transgenic roots compared to nontransgenic roots. Conversely, silencing of CYP716A53v2 mRNA in RNAi transgenic roots resulted in reduced CYP716A53v2 transcription. HPLC analysis revealed that transgenic roots overexpressing CYP716A53v2 contained higher levels of PPT-group ginsenosides (Rg1, Re, and Rf) but lower levels of PPD-group ginsenosides (Rb1, Rc, Rb2, and Rd). By contrast, RNAi transgenic roots contained lower levels of PPT-group compounds and higher levels of PPD-group compounds.ConclusionThe production of PPD- and PPT-group ginsenosides can be altered by changing the expression of CYP716A53v2 in transgenic P. ginseng. The biological activities of PPD-group ginsenosides are known to differ from those of the PPT group. Thus, increasing or decreasing the levels of PPT-group ginsenosides in transgenic P. ginseng may yield new medicinal uses for transgenic P. ginseng.

Functional regulation of ginsenoside biosynthesis by RNA interferences of a UDP-glycosyltransferase gene in Panax ginseng and Panax quinquefolius

“…The RNAi-mediated inhibition of β-Amyrin synthase decreased levels of oleanane-type ginsenoside Ro and increased the level of total ginsenosides in P. ginseng (Zhao et al, 2015). Silencing of CYP716A53v2 mRNA in RNAi transgenic roots resulted in lower levels of protopanaxatriol-group ginsenosides and higher levels of protopanaxadiol-group ginsenosides in P. ginseng (Park et al, 2016). RNAi of dammarenediol synthase gene in transgenic P. ginseng hairy roots caused silencing of DDS expression which leads to a reduction of ginsenoside production to 84.5% (Han et al, 2006).…”

“…However, little is known about the UGTs participating in ginsenoside biosynthesis in P. quinquefolius. In the present study, we isolated and regulated a (Kim et al, 2014;Park et al, 2016;Rahimi et al, 2015;Wang et al, 2014b;Zhao et al, 2015). Moreover, RNAi has been used for the identification or validation of biological function of the targeted transcripts of individual genes in planta (Han et al, 2010;Sun et al, 2013).…”

Advances in ginsenoside biosynthesis and metabolic regulation

“…Silencing of CYP716A53v2 mRNA in RNAi transgenic roots resulted in reduction of CYP716A53v2 transcription. RNAi transgenic roots contained lower levels of PPT group compounds and higher levels of PPD group compounds . In the studies on P. notoginseng cell, the cells with simultaneously overexpressed FPS and silenced CAS showed higher triterpene contents since metabolic flux for triterpene skeleton formation was enhanced by the overexpression of FPS and the RNAi of CAS .…”

Ascertaining the Paradigm of Secondary Metabolism Enhancement through Gene Level Modification in Therapeutic Plants

“…PgSS1 gene Agrobacterium-mediated transformation Seo et al 2005 [56] Panax ginseng Ginsenoside and phytosterol biosynthesis Squalene epoxidase gene RNA interference Han et al 2010 [57] Panax ginseng Triterpenoid saponins Protopanaxadiol 6-hydroxylase gene RNA interference Park et al 2016 [58] Panax notoginseng triterpenoid saponins biosynthesis. 3-hydroxy-3-methylglutaryl CoA reductase (PnHMGR) and squalene synthase (PnSS)…”