Search

PNS (Panax notoginseng saponins) is the main medical bioactive component in Panax notoginseng. The medical value of PNS cannot be extended because of its low production. With the deep study of saponins biosynthetic pathway, the control of PNS biosynthesis through metabolic engineering has gradually become possible. In this study, the Squalene synthase (SS) over-expression vector was established. By the way of agrobacterium-mediated method, the vector was transfered and integrated into the Panax notoginseng genome. The result of the PCR detection and the saponin content detection shows that over-expression SS is able to produce high level of Panax notoginseng saponins, and confirms the regulatory function of SS in the biosynthesis of ginsenosides in Panax notoginseng. It provides a theoretical basis and technical basis for the construction of PNS homologous or heterologous efficient expression system in the future.

The recombinant plasmid pBIBSa containing the HBsAg DNA fragment was transferred into Agrobacterium tumefaciens strain LBA4404 directly. Ginseng cells were co-cultivated with Agrobacterium tumefaciens carrying pBIBSa. The ginseng cell lines carrying HBsAg-S gene were obtained. Transgenic cells were checked for the presence of target gene using PCR and RT-PCR. Samples containing the target gene showed a clear band at the site of 700 bp by agarose electrophoresis analysis (Figs. 2, 3). Expression levels determined by ELISA showed maximum expression levels of 184 ng HBsAg/g FW and 0.009% of the total soluble protein. HBsAg in ginseng cells were located both on the membrane and in the nuclei (Fig. 4).