Panax ginseng C.A Meyer is commonly used in Asian traditional medicine to treat a variety of diseases. Ginsenosides are glycosylated triterpenes, referred to saponins, have been especially noted as active compounds contributing to the various efficacy of ginseng. In this study, we are trying to select high saponin content of ginseng lines from the gamma irradiated adventitious roots. Recently, we have generated several mutant ginseng lines improving ginseniside content by gamma radiation. The mutant lines were selected by phenotypes and ginsenoside content (HPLC analysis) of the irradiated adventitious root lines. However, the ginsenoside content of the mutant lines was not sufficient for commercial use and the selection method was not suitable for large scale of mutant line selection. In this study, we are testing Fourier transfer infrared spectroscopy (FT-IR) as a new selection method of mutant lines in Panax ginseng. About 5,000 pieces of Panax ginseng adventitious roots were exposed to gamma radiation (60Co). Irradiation dosages were 0, 25, 50 and 70Gy. Survival rate of the irradiated samples was evaluated by counting the number of survival main roots after 5 weeks culture in the solid MS medium with NAA, IAA and 5% sucrose. In present, we are collecting the survived adventitious root lines (about 900 lines) from the gamma irradiated ginseng roots for FT-IR and HPLC analysis. After analysis of FT-IR and HPLC, we will assess the suitability of the FT-IR as a screening method for the preparation of mutant lines in ginseng.

With the purpose of improving ginsenoside production in Korean wild ginseng (Panax ginseng Meyer) mutant adventitious root lines, a synthetic gene encoding squalene synthase (PgSS2) was placed under the control of 35S promoter and transferred to Panax ginseng. Embryogenic callus obtained from ginseng adventitious root lines were transformed by infection with A. tumefaciens strain EHA105 containing the PgSS2 gene. Ten phosphinothricin-resistant plants were generated on selection medium, and the transgene integration and expression in these plants were confirmed by PAT test strip, RT-PCR and Southern hybridization. Ginsenoside analysis by HPLC revealed that the total contents of the 8 ginsenoside types (Rg1, Re, Rf, Rh1, Rb1, Rc, Rb2, Rd) in transgenic adventitious root lines were about 1.6-fold higher than that of the mutant control line (MCL1). This transformation method may facilitate the improvement of Panax ginseng in terms of the accumulation levels of ginsenoside.