Assessment of direct shoot organogenesis and genetic fidelity inSolanum viarumDunal-a commercially important medicinal plant

Solanum viarumDunal is an important medicinal plant with a high quantity of steroidal alkaloids used for the synthesis of contraceptives, corticosteroids, and sex hormones.It is also used by Indian tribal people for the treatment of leprosy, toothache, and diabetes. Therefore, to meet the existing needs for this plant, it is necessary to develop an efficient regeneration system useful for rapid and large-scale clonal propagation with ensured genetic fidelity. An efficient and improved regeneration protocol for prickly and prickleless genotypes ofS. viarumhas been developed using three explants, leaf, petiole, and internodes, under the influence of two plant growth regulators, thidiazuron (TDZ) and 6-benzyladenine (BA). Effects of genotype, explant type, and concentrations of TDZ and BA were studied. A higher percentage of shoot organogenesis (78.25% +/- 2.53) and shoot number per explant (6.79 +/- 1.04) were achieved in the leaf segments of prickly genotype cultured on modified Murashige and Skoog (MS) medium supplemented with TDZ (1.50 mg L-1). Furthermore, basal leaf segments showed 100% regeneration from the prickly genotype. A significantly higher content of total phenolics was quantified in prickleless (3.66 mu g mg(-1)) than prickly genotypes (2.73 mu g mg(-1)). The monomorphic banding pattern of random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) analysis confirmed the genetic fidelity of the regenerated plants. Additionally, flow cytometric analysis of regenerants showed no variation in the ploidy levels when compared to the mother (control) plants. These results clearly depicted the efficiency of developed protocol that can be utilized for generating genetically stable population ofS. viarum.