Production of biomass and useful compounds through elicitation in adventitious root cultures of Fagonia indica

Fagonia indica is an important medicinal plant highly traded for its multitude of potentials against breast cancer. The natural availability of this high-valued herb is not fulfilling the ever-increasing demand. Alternative options should be adopted to balance the supply with demand. Adventitious root culture provides a preferred platform to produce commercially important secondary metabolites. In the present report, adventitious roots (AR) were induced from callus explants in F. indica for the first time. Higher adventitious root induction frequency (88%) and biomass accumulation (6.9 DW g/L) were observed when callus explants were treated with 0.5 mg/L Methyl Jasmonate (Me-J) for 2 h and subsequently incubated on solid Murashige and Skoog (MS) media containing 1.0 mg/L Naphthalene acetic acid (NAA). Variations in growth of roots in suspension cultures were analyzed to estimate the impact of elicitors on adventitious rooting in F. indica. In response to 1.0 mg/L NAA, a lag phase of 6 days, logarithmic (log) phase of 15 days and stationary phase of 6 days were observed in the growth curve of AR in suspension culture. Maximum biomass (9.5 g DW g/L) was recorded on the 27th day in log phase of culture. Analysis of AR samples derived from different growth stages showed that at 0.5 mg/L Me-J, maximum Total Phenolic Content (TPC; 6.0 mg GAE/g of DW) and Total Flavonoid Content (TFC; 5.0 mg QE/g of DW) were produced, respectively in the lag phase compared to other growth lines. Quantification of vital plant secondary metabolites through High-Performance Liquid Chromatography (HPLC) revealed a higher amount of Gallic acid (148.0 ± 4.8 μg/mg of DW) detected in Control (CTR) samples raised in vitro at 1.0 mg/L NAA. This was followed by Rutin (122.3 ± 3.8 μg/mg of DW) in LOG phase and Myricetin (32.3 ± 0.7 μg/mg of DW) in LAG phase during growth of AR suspension cultures. In response to 0.5 mg/L Me-J, more Apigenin (25.3 ± 0.6 μg/mg of DW), Caffeic acid (25.3 ± 0.6 μg/mg of DW) and Catechin (9.4 ± 0.07 μg/mg DW) were accumulated in the LOG phase in comparison to other growth stages. Thus, a feasible protocol was developed for induction and proliferation of adventitious roots with sustainable metabolite profiles through elicitation.