Synthesis and Accumulation of Phytocompounds in Field-, Tissue-Culture Grown (Stress) Root Tissues and Simultaneous Defense Response Activity in Glycyrrhiza glabra L.

Harsh climates, i.e., drought, extreme temperatures, and toxic gases, pose issues to agriculture by altering plants' growth and yield. Biotechnology with biochemical defense approaches is beneficial for generating new plants/varieties with extra resilience to adverse conditions. In response to stress, cultures show an enriched level of secondary metabolite synthesis. Here, an efficient in vitro propagation method using axillary shoot proliferation, along with callus formation, was established in Glycyrrhiza glabra L. The phytochemical composition of in vitro and in vivo grown tissues was analyzed using a gas chromatography-mass spectrometry (GC-MS) technique, and the biochemical attributes were measured and compared in different investigated tissues. Callus formation from root explants was achieved with a frequency of 88.89% on MS medium containing 2.0 mg/L BAP and 0.5 mg/L 2,4-D. Axillary shoot proliferation was obtained from dormant buds when cultured onto MS supplemented with BAP alone, or in combination with, IAA. The maximum shoot proliferation (94.44%) was recorded on MS with 1.0 mg/L BAP with an average shoot length of 10.5 cm. The regenerated shoots were subcultured and transferred to the root induction medium, supplemented with various concentrations of IAA/IBA, wherein 2.0 mg/L IBA resulted in the best rooting frequency (88.89%). The GC-MS-based phytocompounds analysis of the methanolic extracts of root-derived callus and in vivo- and in vitro- grown root tissues was conducted. These samples revealed the presence of more than 35 therapeutically important bioactive compounds, such as methylglabridin, sitosterol, lupeol, squalene, stearic acid, linoleic acid, etc. The biochemical parameters, like total phenolic content, flavonoid content, DPPH scavenging activity, superoxide dismutase, and peroxidase activity were also measured. All the biochemical attributes were found to be higher in in vitro derived roots than the callus and in vivo grown root (donor) samples. These findings demonstrated that callus (root derived) and in vitro roots are a stable and potent source of multiple phytocompounds, encompassing medical significance with wide applications. This study may serve as an alternative opportunity in the sustained and continuous synthesis of important compounds without harming natural vegetation and normal environment.