Hairy root induction and secondary metabolite production in Perovskia abrotanoides Karel

Induction of hairy roots in Perovskia abrotanoides Karel, a medicinally important member of the Lamiaceae family, was evaluated using different strains of Agrobacterium rhizogenes and various carbon sources. An efficient Agrobacteriummediated transformation system was established for the first time for this plant species using the bacterial strains of ATCC15834, TR105, and R1000. Meanwhile, the effects of acetosyringone and carbon sources on both rooting and root biomass production were investigated and the potential of hairy root cultures for producing tanshinones was explored. Hairy root induction in the nodes of intact seedlings was found to be successful with all the bacterial strains tested but R1000 was found to be more effective than TR105. The highest transformation frequency belonged to the nodes infected with ATCC15834 (47.33%). Moreover, transformation frequency increased by up to 60.99% when 100 µM of acetosyringone was added. The strain ATCC15834 recorded the highest root dry and fresh weights per 50 mL of the nutrient medium (0.149 and 1.996 g, respectively) and root length (34.45 cm) in a medium containing 3% sucrose. However, R1000 induced maximum lateral root density in hairy roots (7.1 branches cm-1) in a medium containing 3% glucose. PCR analysis using rolC specific primer with an amplicon of 612 bp confirmed the transgenic nature of the hairy roots. Finally, HPLC analysis revealed that the cryptotanshinone and tanshinone IIA levels in the hairy roots induced by TR105 (clone T7) were 53.17±0.26 and 14.48±0.30 µg g-1 DW, respectively.