Enhanced tanshinone production in hairy roots of 'Salvia miltiorrhiza Bunge' under the influence of plant growth regulators in liquid culture

Tanshinone constituents are the most potent diterpene diketones used to treat several diseases. We studied the influence of different plant growth regulators (PGR) on the growth and production of three tanshinone constituents using hairy root culture of Salvia miltiorrhiza Bunge. Leaves of the medicinally-important plant S. miltiorrhiza were infected with Agrobacterium rhizogenes strain BCRC15010, which induced hairy roots in 78% of the explants. The best line of hairy roots was established on B5 liquid medium under dark conditions. The transformed nature of the root lines was confirmed by polymerase chain reaction using 'rol' B and C gene-specific primers. Adding different PGRs i.e., auxins, cytokinins and abscisic acid (ABA), enhanced the production of cryptotanshinone, tanshinone I and IIA. Tanshinone I and cryptotanshinone accumulation was 5- and 7.5-fold higher with the addition of 1.0 mg/l ABA and TDZ, respectively, compared to root of greenhouse-grown plant. Cryptotanshinone content was 6.3-, 5.0- and 3.75-fold higher in hairy roots grown under the influence of TDZ, ABA and BA, respectively, compared to a commercial herb. The devised protocol can be used to enhance tanshinone production.