Effect of rol genes from Agrobacterium rhizogenes TL-DNA on nicotine production in tobacco root cultures.

摘要

Transgenic root lines were induced by inoculation of Nicotiana tabacum cv. Xanthi leaf sections with a disarmed strain of Agrobacterium tumefaciens harbouring the rolA, rolB and rolC genes either together or singly cloned in the binary vector pPCV002. The transgenic root lines grew in the absence of added phytohormones and their growth pattern and nicotine biosynthesis capacity were followed. Striking differences in nicotine production were shown by the four types (rolABC, rolA, rolB and rolC) of transgenic root lines. While the rolC gene was responsible for a high stimulation of alkaloid production by increasing growth, the rolA gene stimulated this production mainly by a direct effect. The presence of rolA, rolB and rolC together dramatically enhanced the growth rate and nicotine production, which showed that the effect of these three rol genes was synergistic. It is suggested that roots transgenic for rolABC genes could be used to improve the production of secondary metabolites in vitro. The possible advantages of these transgenic roots over roots transformed by a wild strain of Agrobacterium rhizogenes are also considered.