title: Functional analysis of β-amyrin synthase gene in ginsenoside biosynthesis by RNA interference.
abstract: 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 Ro 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.
authors.affiliation: College of Biological and Agricultural Engineering, Jilin University, Changchun, 130022, China.
authors.forename: Che
authors.initials: C
authors.lastname: Zhao
authors.forename: Tianhui
authors.initials: T
authors.lastname: Xu
authors.forename: Yanlong
authors.initials: Y
authors.lastname: Liang
authors.forename: Shoujing
authors.initials: S
authors.lastname: Zhao
authors.forename: Luquan
authors.initials: L
authors.lastname: Ren
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Bo
authors.initials: B
authors.lastname: Dou
mesh_terms: D015536:Down-Regulation / Q000235:genetics / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D017343:Genes, Plant / Q000502:physiology*; D036145:Ginsenosides / Q000096:biosynthesis*; D019751:Intramolecular Transferases / Q000235:genetics* / Q000502:physiology; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000096:biosynthesis; D005894:Panax / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D034622:RNA Interference / Q000502:physiology*; D014315:Triterpenes / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics / Q000502:physiology; D000097669:Dammaranes
chemical_list: D036145:Ginsenosides; D019751:Intramolecular Transferases; D009828:Oleanolic Acid; D014315:Triterpenes; D000097669:Dammaranes; C413246:oleanane; C039924:2,3-oxidosqualene-beta-amyrin-cyclase