Methyl jasmonate elicits the solasodine production and anti-oxidant activity in hairy root cultures of Solanum trilobatum L.

Hairy root cultures of Solanum trilobatum L. were established from leaf explants infected with Agrobacterium rhizogenes strains viz., MTCC 532, MTCC 2364 and ATCC A₄. Initially 27 independent root clones were obtained and 5 clones (ST-02, ST-09, ST-11, ST-13 and ST-17) were scrutinized based on their rapid growth in MS solid medium and exemplified for biomass and solasodine accumulation. MS liquid medium containing 3% sucrose with an initial pH of 5.8 favored the maximum biomass accumulation (27.5 fold increments than initial inoculums) of hairy roots. Amid 5 clones, ST-09 was found to the superior one, producing 2 fold greater biomass (3.85±0.11g FW) and 3.3 fold elevated solasodine content (4.76±0.05mg/g DW) than non transformed roots (control). PCR and southern hybridization analysis revealed the integration of rolA gene in transformed roots. Hairy roots of ST-09 elicited with 4μM methyl jasmonate (MJ) for 2 weeks resulted in 1.9 fold and 6.5 fold enhanced production of solasodine (9.33±0.04mg/g DW) than unelicited and non transformed roots, respectively. This was also corroborated by RT-PCR analysis, showing a considerable upregulation of hmgr (HMGCoA reductase) gene transcripts during 1st 2 weeks of elicitation. A significant increase was noticed in the total phenolics (150.42mg/g DE), total flavonoids (521.09 mg/g DE) and radical scavenging activity (83.3%) of 4μM MJ elicited roots in comparison with control. Thus, the study illustrates that hairy roots of S. trilobatum could be exploited for scaling up in bioreactors for the large-scale production of solasodine.