Overexpression of squalene synthase in Eleutherococcus senticosus increases phytosterol and triterpene accumulation.
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.
Seo
Jin-Wook
JW
Department of Biotechnology, Chung-Ang University, Ansung, Korea.
Jeong
Jae-Hun
JH
Shin
Cha-Gyun
CG
Lo
Seog-Cho
SC
Han
Seong-Soo
SS
Yu
Ki-Won
KW
Harada
Emiko
E
Han
Jeong-Yeon
JY
Choi
Yong-Eui
YE
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*
D010840:Phytosterols; D014315:Triterpenes; D013186:Farnesyl-Diphosphate Farnesyltransferase