Discovery of genes for ginsenoside biosynthesis by analysis of ginseng expressed sequence tags.
Expressed sequence tags (ESTs) provide a valuable tool that can be used to identify genes in secondary metabolite biosynthesis. Ginseng (Panax ginseng C.A Meyer) is a medicinal plant that accumulates ginsenosides in roots. We sequenced 11,636 ESTs from five ginseng libraries in order to create a gene resource for biosynthesis of ginsenosides, which are thought to be the major active component in roots. Only 59% of the ginseng ESTs exhibited significant homology to previously known polypeptide sequences. Stress- and pathogen-response proteins were most abundant in 4-year-old ginseng roots. ESTs involved in ginsenoside biosynthesis were identified by a keyword search of BLASTX results and a domain search of ginseng ESTs. We identified 4 oxidosqualene cyclase candidates involved in the cyclization reaction of 2,3-oxidosqualene, 9 nine cytochrome P450 and 12 glycosyltransferse candidates, which may be involved in modification of the triterpene backbone.
Jung
J D
JD
Eugentech Inc, 52-Oun Dong, Yusong, 305-333 Daejon, Korea.
Park
H-W
HW
Hahn
Y
Y
Hur
C-G
CG
In
D S
DS
Chung
H-J
HJ
Liu
J R
JR
Choi
D-W
DW
D018744:DNA, Plant / Q000235:genetics; D020224:Expressed Sequence Tags; D015723:Gene Library; D036145:Ginsenosides / Q000235:genetics*; D005894:Panax / Q000235:genetics*; D018517:Plant Roots / Q000235:genetics; D012639:Seeds / Q000235:genetics
D018744:DNA, Plant; D036145:Ginsenosides