Construction and Characterization of a cDNA Expression Library for the North American Ginseng Root Tissues

The root of Panax ginseng plant undergoes a specific developmental process to become a biosynthesis and accumulation tissue for ginsenosides. To identify and analyze genes involved in the biosynthesis of ginsenoside, we constructed and characterized a full-length cDNA library for 6-year-old North American ginseng. The titer of primary cDNA library is 1. 2 × 106 pfu/mL, the titer of amplified library is 2. 6 × 1010 pfu/mL and the rate of recombinant is above 86%. The insert size ranges from 0. 3 to 2. 0 kb. Sequencing results show that 18 of 58 genes are high homologous to the genes (GBR5, GBR3 and GBR1) known in GenBank, which are involved in biosynthesis of ginsenoside in North American ginseng plant; 16 of 58 genes are novel genes. The full-length cDNA library of North American ginseng root tissues is essential for the cloning of genes known and it is also an initial key for the screening and cloning of new genes.