Influence of KNO3, CaCl2 and MgSO4 Concentrations on Growth and Cichoric Acid Accumulation in Hairy Root Culture of Purple Coneflower (Echinacea purpurea L.)

Background: Purple coneflower (Echinacea purpurea L.) is one of the most important medicinal plants. Hairy root culture of Echinace, represent a valuable alternative to field cultivation for the production of bioactive secondary metabolites. Objective: The present study investigates the effects of KNO3, CaCl2 and MgSO4 concentrations on growth and the biosynthesis of cichoric acid in Echinacea purpurea hairy root culture. Methods: Agrobacterium rhizogenes strain R15834 was used for hairy root induction. The experiment was performed with 0.5 g of fresh hairy roots (about 2 cm long segments) per 100 ml Erlenmeyer flasks containing 30 ml of hormone-free liquid 1/2MS salts with B5 vitamins supplemented with different amounts of KNO3 (3131, 3939, and 4747 mg/l), CaCl2 (85, 170, and 340 mg/l) and MgSO4 (370 (control), 600, and 1600 mg/l). After 4 weeks, growth parameters and cichoric acid amounts were assessed. Results: Results indicated that the highest fresh (99.69 g/l) and dry weight (6.91 g/l) of hairy roots were achieved using 3131 mg/l KNO3. Fresh and dry weights of hairy roots in various CaCl2 and MgSO4 concentrations were not significantly different from those of control. The highest amount of cichoric acid (30.55 mg/g DW) was produced by 1600 mg/l MgSO4 treated hairy roots after 4 weeks. Conclusion: The present work demonstrated the effectiveness of modified 1/2MS salts supplemented with B5 vitamins medium for improving hairy root growth and in vitro production of cichoric acid.