Regulation of tissue differentiation by plant growth regulators on tTCLs of Panax ginseng adventitious roots

Differentiated tissue in Panax ginseng cultures was found to be very efficacious for saponin production. In order to increase the yield of saponins and preserve culture stability we were testing different plant growth regulators (PGR) and auxin/cytokinin combinations to regulate a level of tissue differentiation. For this purpose we used transverse thin cell layers (tTCLs) of adventitious roots of Panax ginseng. Adventitious roots were cultivated in Shenk and Hildebrand (SH) liquid medium supplemented with IBA (24.6 μM). Callus formation and root multiplication of adventitious root tTCLs was evaluated after 4 and following 12 weeks of cultivation, respectively, on SH basal medium containing various auxins (3 mg l−1) or cytokinins (0.2 or 0.02 mg l−1) or their combinations. We found that kinetin (Kin) in combination with auxin benzo[b]selenienyl acetic acid (BSAA), naphthalene acetic acid or indole-3-butric acidis the best for biomass production and following root multiplication. These combinations were tested in previously selected most suitable large-scale system—a temporary immersion system RITA. The best saponin production (15.94 ± 1.89 mg g−1 dry weight) and growth value (5.62 ± 0.34) was reached on medium containing BSAA and Kin combination.

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► We optimized production of ginsenosides in adventitious roots of Panax ginseng.
► Auxin/cytokinin combinations were tested to regulate level of tissue differentiation.
► Transverse thin cell layers system is an effective tool for fast testing.
► We concluded that BSAA in combination with Kin enhanced biomass growth.
► BSAA/Kin stabilized panaxatriol/panaxadiol ratio in ginseng in vitro cultures.