Somatic embryogenesis and subsequent plant regeneration were established from hypocotyl and internode explants collected from in vitro-grown seedlings and in vitroproliferated shoots, respectively. Somatic embryogenesis was significantly influenced by the types of auxin and cytokinin. Friable calluses with somatic embryos developed well in Murashige and Skoog basal (MS) medium supplemented with 0.8-8.8 μM 6-benzylaminopurine (BA) and 2.0-8.0 μM 2,4-dichlorophexoxyacetic acid (2,4-D) or α-naphthaleneacetic acid (NAA). The maximal frequency of embryogenic callus and somatic embryo formation were obtained when the MS medium was amended with 8.8 μM BA and 4.0 μM 2,4-D. The best embryo germination occurred in a hormone-free 1/2-MS medium. The highest percentage of shoot proliferation was observed in embryogenic calluses in MS medium containing 2.0 μM BA and 1.0 μM NAA. In vitro-grown shoots were rooted in MS medium with 0.5-2.0 μM indole-3-butyric acid. Regenerants were transferred to vermiculite and successfully established under an ex vitro environment in garden soil.

Dimeric indole alkaloids are used extensively for cancer therapy. Agrobacterium tumefaciens C58 strain was used for induction of shooty teratoma in Catharanthus roseus using epicotyl and stem node explants. The transformed nature of shooty teratomas was confirmed by nopaline assay. Growth kinetics of shooty teratomas depicted maximum growth during 21-24 days of culture. Dimeric alkaloid vincristine in the transformed cultures was present at a concentration of 0.011 that was tenfold higher compared to untransformed control cultures.