title: Overexpression of squalene synthase in Eleutherococcus senticosus increases phytosterol and triterpene accumulation.
abstract: Squalene synthase (SS) catalyzes the first committed step in sterol and triterpenoid biosynthesis. Transgenic Eleutherococcus senticosus Rupr. and Maxim. plants were generated by introducing an SS-encoding gene derived from Panax ginseng (PgSS1) together with genes expressing hygromycin phosphotransferase and green fluorescent protein (GFP) through Agrobacterium-mediated transformation. Early globular embryo clusters developing from the embryogenic callus were used for Agrobacterium-mediated transformation. Transformants were selected on Murashige Skoog medium containing 25 mg/L hygromycin. Hygromycin-resistant somatic embryos developed into plants after the cotyledonary embryos were treated with 14.4 microM gibberellic acid. Transformation was confirmed by polymerase chain reaction, Southern, and GFP analyses. The SS enzyme activity of the transgenic plants was up to 3-fold higher than that of wild-type plants. In addition, GC-MS and HPLC analysis revealed that phytosterols (beta-sitosterol and stigmasterol) as well as triterpene saponins (ciwujianosides B (1), C(1) (2), C(2) (3), C(3) (4), C(4) (5), D(1) (6) and D(2) (7)) levels in transgenic E. senticosus were increased by 2- to 2.5-fold. These results suggest that the metabolic engineering of E. senticosus to enhance production of phytosterols and triterpenoids by introducing the PgSS1 gene was successfully achieved by Agrobacterium-mediated genetic transformation.
authors.affiliation: Department of Biotechnology, Chung-Ang University, Ansung, Korea.
authors.forename: Jin-Wook
authors.initials: JW
authors.lastname: Seo
authors.forename: Jae-Hun
authors.initials: JH
authors.lastname: Jeong
authors.forename: Cha-Gyun
authors.initials: CG
authors.lastname: Shin
authors.forename: Seog-Cho
authors.initials: SC
authors.lastname: Lo
authors.forename: Seong-Soo
authors.initials: SS
authors.lastname: Han
authors.forename: Ki-Won
authors.initials: KW
authors.lastname: Yu
authors.forename: Emiko
authors.initials: E
authors.lastname: Harada
authors.forename: Jeong-Yeon
authors.initials: JY
authors.lastname: Han
authors.forename: Yong-Eui
authors.initials: YE
authors.lastname: Choi
mesh_terms: D028001:Eleutherococcus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D013186:Farnesyl-Diphosphate Farnesyltransferase / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D015394:Molecular Structure; D010840:Phytosterols / Q000096:biosynthesis* / Q000737:chemistry; D030821:Plants, Genetically Modified; D014315:Triterpenes / Q000737:chemistry / Q000378:metabolism*
chemical_list: D010840:Phytosterols; D014315:Triterpenes; D013186:Farnesyl-Diphosphate Farnesyltransferase