Generation of Composite Plants in Licorice (Glycyrhiza glabra L.) Using Agrobacterium rhizogenes

Licorice is one of the most important medicinal plants in the world. Licorice root contains active triterpene saponins. Glycyrrhizin and its hydrolysis products are important in the pharmaceutical industry and food products. Many higher plants are sensitive to Agrobacterium rhizogenes and their inoculation lead to hairy roots induction. Plant secondary metabolite levels may be enhanced by hairy root culture. Composite plants are an alternative to tissue culture-derived hairy roots cultures for transgenic studies. In this study, licorice composite plants using Agrobacteriumrhizogenes strain AR15834 carrying the binary vector PBI121 with GUS reporter gene were obtained. 14-day-old seedlings grown in pots and sterile seedlings 3-5 days of Glycyrrhiza glabra were cut from internodes and were inoculated with bacterial suspensions. 50-60% of 14-day pot seedlings and 80-90% of 3-5 day seedlings produced hairy roots. Hairy roots of appeared from Rock wool pieces 3-4 weeks after inoculation. The hairy roots were tested using a histochemical GUS assay. GUS gene expression was demonstrated in some of hairy roots but in non-transgenic hairy root GUS gene activity was not observed.