Jung J D, Park H-W, Hahn Y, Hur C-G, In D S, Chung H-J, Liu J R, Choi D-W
Eugentech Inc, 52-Oun Dong, Yusong, 305-333 Daejon, Korea.
Plant Cell Rep. 2003 Oct;22(3):224-30. doi: 10.1007/s00299-003-0678-6. Epub 2003 Aug 13.
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.
表达序列标签（ESTs）提供了一种有价值的工具，可用于鉴定次生代谢物生物合成中的基因。人参（Panax ginseng C.A Meyer）是一种在根中积累人参皂苷的药用植物。我们对来自五个人参文库的11,636个ESTs进行了测序，以便为人参皂苷的生物合成创建一个基因资源，人参皂苷被认为是根中的主要活性成分。只有59%的人参ESTs与先前已知的多肽序列表现出显著的同源性。应激和病原体反应蛋白在4年生人参根中最为丰富。通过对BLASTX结果的关键词搜索和人参ESTs的结构域搜索，鉴定了参与人参皂苷生物合成的ESTs。我们鉴定出4个可能参与2,3-氧化鲨烯环化反应的氧化鲨烯环化酶候选物、9个细胞色素P450和12个糖基转移酶候选物，它们可能参与三萜骨架的修饰。
