The impact of plant rolC oncogene on ginsenoside production by ginseng hairy root cultures

Plasmid constructions containing rolA, rolB and rolC genes, isolated earlier from the TL-DMA of Agrobacterium rhizogenes were used to transform a cell culture (strain Ic) of Panax ginseng. The levels of ginsenosides were measured in the resulting transgenic tissues to evaluate the possible role of rol genes in ginsenoside formation. The ginsenoside content of the hairy root culture of P. ginseng, transformed by wild type A4 plasmid DNA and containing all vol loci, was higher than that of the control Ic culture (5.12-8.92 mg g(-1) dry wt), being in the range of 13.23-21.27 mg g(-1) dry wt. Ginseng tissue, transgenic for the rolA gene appeared to lose the ability to synthesize ginsenosides since only a trace amount of Re ginsenoside was found in 1c-rolA tissue. 1c-rolB cultures contained at least five times lower ginsenoside levels compared to the initial Ic culture. The ginsenoside content of rolC transgenic roots was about three times higher than that of the respective control. Taking into account the differences in cell differentiation levels in tissues transformed by vol genes, we compared the ginsenoside levels in I rolC roots and tumours. It was found that ginsenoside production in tissues with different levels of differentiation is nearly the same. Wie have concluded that the plant oncogene rolC is responsible for increased ginsenoside formation in ginseng hairy root cultures. (C) 1998 Elsevier Science Ltd. All rights reserved.