In vitro induction of hairy root from isoflavones-producing Korean wild arrowroot Pueraria lobata

Pueraria lobata is a perennial legume plant, widely distributed in the countries of East Asia. It is a medicinally important leguminous plant and produces various isoflavones such as puerarin, daidzein etc which have potential for preventing several chronic diseases including osteoporosis, cardiovascular disease and cancer. In this study, we tried to induce hairy roots in vitro from Korean wild arrowroot P. lobata and investigated the effects of hormones and light conditions. Initially leaf and stem segments were infected with Agrobacterium rhizogenes and incubated in different conditions. Hairy roots were induced from only stem segments and the induction was best at dark condition and the presence of IBA during incubation. Secondary roots were also significantly much more induced at the dark condition than at the 16 hours light condition. Among plant growth regulators of auxin, IBA was best for secondary root formation while 2,4-D, IAA and NAA produced callus or less hairy roots. The presence of the foreign gene rolC transferred by A. rhizogenes that plays a major role in hairy root induction was confirmed by PCR. The accumulation of isoflavones such as puerarin and daidzin was also confirmed. These results will facilitate mass production of hairy root and can be used for the production of functional substances from wild arrowroots.