Enhancement of ginsenoside Rg 1 in Panax ginseng hairy root by overexpressing the α- l -rhamnosidase gene from Bifidobacterium breve

Objectives To improve the production of ginsenoside Rg 1 in Panax ginseng . Results The α- l -rhamnosidase gene from Bifidobacterium breve ( BbRha ) was overexpressed into hairy root culture system using Agrobacterium rhizogenes A4. Ginsenoside Rg 1 in hairy roots was obtained following transformation via overexpressed gene representing 2.2-fold higher than those of control lines. Several overexpression transgenic hairy root lines were obtained exhibiting markedly increased levels of the corresponding α- l -rhamnosidase enzymatic activity relative to control. Ginsenoside Rg 1 levels in the transgenic lines were higher (2.2-fold) than those of control after following 30 days culturing, while ginsenoside Re contents in tested transgenic lines were found to be lower. The transgenic hairy roots harboring α- l -rhamnosidase gene improved the accumulation of ginsenoside Rg 1 up to 3.6 mg g −1 dry weight. Conclusion BbRha gene selectively enhances the production of ginsenoside Rg 1 in P. ginseng hairy roots.