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 Rg1 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 Rg1 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 Rg1 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 Rg1 up to 3.6 mg g(-1) dry weight.

Conclusion: BbRha gene selectively enhances the production of ginsenoside Rg1 in P. ginseng hairy roots.