Elicitors Mediated Enhancement of Picrosides and Their Pathway Precursors in Dedifferentiated Cell Suspension Culture of Picrorhiza kurroa Royle ex Benth

Elicitors trigger complex signaling cascades within plants, enhancing secondary metabolite production. The present study investigated the impact of various elicitors on the augmentation of picrosides (P-I, P-II, P-III) and their precursors (vanillic acid, caffeic acid, cinnamic acid, catalpol, and aucubin) metabolites in Picrorhiza kurroa cell suspension cultures. Four elicitors; methyl jasmonate (Me-JA; 50–150 µM), salicylic acid (SA; 50–150 mg/L), chitosan (CHT; 50–150 mg/L), and yeast extract (YE; 50–150 mg/L) were applied to leaf (LFSC) and rhizome (RHSC) cell suspensions on the 21st day of culture and incubated up to 192 h. In LFSC, the highest contents of P-I (7.90 mg/g DW) and P-III (0.69 mg/g DW) were at Me-JA 150 µM, while P-II (3.99 mg/g DW) was at Me-JA 50 µM. YE 150 mg/L increased vanillic acid (0.29 mg/g DW), and Me-JA 100 µM increased caffeic acid (0.06 mg/g DW) and cinnamic acid (0.19 mg/g DW). CHT 100 mg/L maximized catalpol (5.91 mg/g DW), and aucubin (0.29 mg/g DW) peaked with Me-JA 50 µM, YE 150 mg/L, and CHT 150 mg/L. In RHSC, Me-JA 150 µM yielded the highest levels of P-I (7.74 mg/g DW), P-II (4.59 mg/g DW), cinnamic acid (0.19 mg/g DW), and aucubin (0.29 mg/g DW). The study indicated that Me-JA is particularly effective in enhancing picrosides accumulation in P. kurroa cell cultures. In conclusion, elicitors significantly boost the production of valuable secondary metabolites, particularly in plant cell culture of P. kurroa.