Functional analysis of β-amyrin synthase gene in ginsenoside biosynthesis by RNA interference

• Published in: Plant cell reports 2015-08, Vol.34 (8), p.1307-1315
• Main Authors: Zhao, Che, Xu, Tianhui, Liang, Yanlong, Zhao, Shoujing, Ren, Luquan, Wang, Qian, Dou, Bo
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Biotechnology; Cell Biology; Dammaranes; Down-Regulation - genetics; Down-Regulation - physiology; Gene Expression Regulation, Plant - physiology; Genes, Plant - physiology; Ginsenosides - biosynthesis; Intramolecular Transferases - genetics; Intramolecular Transferases - physiology; Life Sciences; Oleanolic Acid - analogs & derivatives; Oleanolic Acid - biosynthesis; Original Paper; Panax - enzymology; Panax - genetics; Panax - metabolism; Panax ginseng; Plant Biochemistry; Plant Sciences; Polymerase Chain Reaction; RNA Interference - physiology; Triterpenes - metabolism; Up-Regulation - genetics; Up-Regulation - physiology
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-015-1788-7

Key message Down-regulation of β-amyrin synthase gene expression by RNA interference led to reduced levels of β-amyrin and oleanane-type ginsenoside as well as up-regulation of dammarane-type ginsenoside level. In the biosynthetic pathway of ginsenosides, β-amyrin synthase catalyzes the reaction from oxidosqualene to β-amyrin, the proposed aglycone of oleanane-type saponins. Here, RNAi was employed to evaluate the role of this gene in ginsenoside biosynthesis of Panax ginseng hairy roots. The results showed that RNAi-mediated down-regulation of this gene led to reduced levels of β-amyrin and oleanane-type ginsenoside R o as well as increased level of total ginsenosides, indicating an important role of this gene in biosynthesis of ginsenoside. Expression of key genes involved in dammarane-type ginsenoside including genes of dammarenediol synthase and protopanaxadiol and protopanaxatriol synthases were up-regulated in RNAi lines. While expression of squalene synthase genes was not significantly changed, β-amyrin oxidase gene was down-regulated. This work will be helpful for further understanding ginsenoside biosynthesis pathway.