Influence of different cytokinins on micropropagation of an important medicinal plant, Solanum erianthum D. Don, and assessment of the genetic fidelity of the regenerants

The present study describes the first successful report on an efficient in vitro protocol for direct and indirect organogenesis of an important medicinal and anticancerous plant, Solanum erianthum D. Don. An optimal response using leaf explants was achieved in half-strength Murashige and Skoog (MS)-medium supplemented with 5 mg L-1 naphthalene acetic acid for friable callus formation and 2 mg L-1 naphthaleneacetic acid and 0.5 mg L-1 6-benzylaminopurine amino purine for induction of compact callus. The maximum number of shoot buds (20.33 +/- 11.55) was obtained from compact callus using indirect shoot organogenesis in MS medium supplemented with 0.5 mg L-1 thidiazuron among the four cytokinins tested, which included 6-benzyl amino purine, kinetin, 6-gamma,gamma-dimethylallylamino purine, and thidiazuron. Supplements of 3 mg L-1 6-benzyl amino purine played a crucial role in direct shoot bud formation from a leaf. The buds appeared as small protuberances, and finally developed into leafy shoots as the culture period progressed. Regenerated shoot buds were transferred to MS media that contained four cytokinins for shoot tip culture, in which 8 mg L-1 6-gamma,gamma-dimethylallylamino purine exhibited the best response (15 +/- 2.52). Although efficient plant regeneration was achieved in the presence of all four tested cytokinins in the three organogenetic pathways, distinct differences exist in terms of shoot regeneration potential. Half-strength MS basal medium is recommended for root induction. An approximate 70% survival rate of regenerated plantlets was recorded following sequential transfer from culture conditions to the field. The genetic fidelity of the regenerated plants was evaluated using random amplified polymorphic DNA molecular markers, which showed a high number of uniform monomorphic bands.