Microbial elicitation in root cultures of Taverniera cuneifolia (Roth) Arn. for elevated glycyrrhizic acid production

• Roots of Taverniera cuneifolia contain exploitable amount of glycyrrhizic acid (GA); current report is about initiation of root culture and in vitro GA production.
• We have shown about sixfold increase in GA through elicitation by live microbial cultures.
• Microbial elicitation is twofold higher than commonly used elicitor, methyl jasmonate.
• Thus the entire system could be translated into a process for harvesting pharmacologically important GA.

Plant secondary metabolites are important phytoconstituents, for pharmaceutical, food and industrial applications. Plant tissue culture plays an important role in conservation and in vitro production of secondary metabolites. However, lower yield and high water content are the major obstacles in realizing these goals. Elicitors can profitably be used to enhance yields of secondary metabolites especially in cultured cells and organs. Roots of Taverniera cuneifolia, contain appreciable amount of glycyrrhizic acid (GA), owing to which it is considered to have potential medicinal properties. The present study demonstrates use of live microbial cultures (5 fungal and 5 bacterial) as elicitors in in vitro production of GA from root culture of T. cuneifolia. Unchallenged roots produced 1.09 ± 0.95 mg/g of GA, which is increased by the use of fungal elicitors, Mucor hiemalis showed maximum (4.90 ± 0.10 mg/g), whereas, Aspergillus tenuis showed minimum (1.50 ± 0.07 mg/g) GA induction. On the other hand, among bacterial elicitors; Rhizobium leguminosarum demonstrated maximum (6.37 ± 0.41 mg/g), whereas, Agrobacterium tumefaciens (1.46 ± 0.06 mg/g) demonstrated minimum GA induction. Methyl jasmonate (MJ) (100 μM), a well known elicitor, accumulated 2.57 ± 0.20 mg/g of GA. The root culture together with the optimized live inducers could be considered as a useful system for production of GA.