Conservation of the endangered medicinal plant Picrorhiza kurroa through in vitro multiple shoot regeneration

Picrorhiza kurroa, a well-known medicinal plant found in the vicinity of Himalayas, has become critically endangered over the years owing to its overexploitation for medicinal purposes. In this study, we cultured nodal segments onto MS (Murashige and Skoog) medium fortified with different concentrations of kinetin (Kn) and indole3-acetic acid (IAA). For enhanced multiple shooting, the regenerated shoots and callus were subcultured on a similar media combination (utilized for shoot bud initiation). Shoot bud induction was achieved in all media combinations with a maximum of 66.8% cultures exhibiting shoot bud regeneration in MS supplemented with 6 μM Kn and 10 μM IAA with the average number of 4.2 ± 0.4 shoots per culture; moreover, the regeneration of callus was reported. A subculture of regenerated shoots using similar media combinations (utilized for shoot bud induction) resulted in extensive induction and proliferation of multiple shoots. On an average, we obtained 18.6 ± 0.4 shoots in an MS medium supplemented with 6 μM Kn and 4 μM IAA. Similarly, a subculture of callus with preformed shoot buds resulted in a multiple shoot regeneration with a maximum of 20 shoots in an MS medium supplied with 4 μM Kn and 10 μM IAA. The proliferation of callus was achieved in all media combinations and half-strength MS supplemented with IAA (12 μM) was found to be the most appropriate medium for in vitro rooting. Note that, during the process of acclimatization, -62.4% plants survived. Thus, this study provides an effective method for the mass propagation of P. kurroa, which can further be worked out for establishing cell suspension cultures to analyze variations in the synthesis of bioactive metabolites under controlled conditions and in the presence of additives.