Tryptophan metabolism and evaluation of morphological, biochemical and molecular variations in a field grown plant population derived via direct adventitious shoot bud regeneration from pre-plasmolysed leaves of Catharanthus roseus

Sixty six plants raised via direct shoot bud organogenesis from pre-plasmolysed leaf explants of Catharanthus roseus were assessed under in vivo conditions for their physio-morpho traits, tryptophan metabolism, genetic fidelity and alkaloid profile. Morphologically all plants were parent like except the three morpho-types i.e. broad cup-shaped leaves, dwarf phenotype and enlarged pink corona. Vindoline was detected in most of the plants in substantial amount while ajmalicine, ajmaline and catharanthine were detected in few plants only. More than eightfold increased vindoline (0.08 % dry wt.) was showed by plant no. 1, 4 and 39. Except plant no. 54, which accumulated the highest alkaloid content of 3.09 % dry wt. with tryptophan content of 0.0283 % dry wt., majority of the plants showed a negative correlation between total alkaloid content and tryptophan accumulation and strong positive correlation between tryptophan content and 5-methyltryptophan tolerance. ISSR and RAPD profile of seventeen randomly selected, field established plants was generated by using 10 ISSR and 60 RAPD primers. In RAPD, a total of 753 bands were detected, out of which 624 (82.87 %) were monomorphic. In ISSR profiling, a total of 205 bands were detected out of which 200 bands were monomorphic (97.56 %) and only 5 bands were found to be polymorphic. Highly significant data for the monomorphic banding pattern across all the three genotypes (p < 0.01) was observed. Principal components, AMOVA analysis and multivariate analysis using Nei and Li’s coefficient further validate the monomorphism. Thirteen plants having superior traits were grown in Random Block Design in field. The relevance of physiological and epigenetic changes occurred in the light of morpho-types and alkaloid profile of directly regenerated plants during in vitro to in vivo acclimatization in C. roseus is discussed.