Rapid in vitro propagation by liquid culture system and genetic homogeneity assessment of Plectranthus bourneae Gamble, an endemic plant species to South India

Abstract

The present investigation describes the in vitro propagation of Plectranthus bourneae via liquid culture system from axillary bud and shoot tip explants. Multiple shoots were initiated from axillary bud and shoot tip explants on Murashige and Skoog (MS) medium supplemented with different concentrations (0.1–2.0 mg/l) and combinations of cytokinins [BA (6-benzyladenine), KN (kinetin), and TDZ (thidizauron)] along with (0.5–2.0 mg/l) auxins [NAA (α-naphthalene acetic acid), IAA (indole-3 acetic acid), IBA (indole-3-butyric acid)]. Maximum shoot multiplication (12.14) was achieved from axillary bud explant followed by shoot tip explant (8.85) at 0.5 mg/l TDZ with 1.0 mg/l NAA. A maximum of 9.71 roots/shoot was observed at 0.7 mg/l IBA. The rooted plantlets successfully hardened and transferred to greenhouse condition with 83% survival. Inter-simple sequence repeat markers exhibited genetic fidelity with 100% monomorphism in regenerants. The authenticated protocol supports rapid production of true-to-type plants by liquid culture in vitro and therefore could supply a valuable target material for genetic transformation study.