Ginseng Research Today is a free monthly online journal that collates and summarizes the latest research about Ginseng, including details on american ginseng, panax, benefits, side effects. | ||||||||
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Overexpression of squalene synthase in Eleutherococcus senticosus increases phytosterol and triterpene accumulation.Seo JW, Jeong JH, Shin CG, Lo SC, Han SS, Yu KW, Harada E, Han JY, Choi YE Department of Biotechnology, Chung-Ang University, Ansung, Korea. 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. Published 22 April 2005 in Phytochemistry, 66(8): 869-77.
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