Genetic Homogeneity Revealed Using SCoT, ISSR and RAPD Markers in Micropropagated Pittosporum eriocarpum Royle- An Endemic and Endangered Medicinal Plant.

Abstract

Pittosporum eriocarpum Royle, a medicinally important taxon, is endemic to Uttarakhand region of Himalaya. It has become endangered due to over-collection and the loss of habitats. As raising plants through seeds in this plant is problematic, a reliable protocol for micropropagation using nodal explants has been developed. High shoot regeneration (95%) occurred in MS medium augmented with BA 0.4mg/l in combination IBA 0.6mg/l. In vitro regenerated shoots were rooted in MS medium supplemented with three auxins, of which 0.6 mg/l indole butyric acid proved to be the best for rooting (90%) with maximum number of roots per shoot. Thereafter, rooted plants were hardened and nearly 73% of rooted shoots were successfully acclimatized and established in the field. Start codon targeted (SCoT), inter simple sequence repeats (ISSR) and random amplified polymorphic DNA (RAPD) markers were used to validate the genetic homogeneity amongst nine in vitro raised plantlets with mother plant. DNA fingerprints of in vitro regenerated plantlets displayed monomorphic bands similar to mother plant, indicating homogeneity among the micropropagated plants with donor mother plant. The similarity values were calculated based on SCoT, ISSR and RAPD profiles which ranged from 0.89 to 1.00, 0.91 to 1.00 and 0.95 to 1.00 respectively. The dendrograms generated through Unweighted Pair Group Method with arithmetic mean (UPGMA) analysis revealed 97% similarity amongst micropropagated plants with donor mother plant, thus confirming genetic homogeneity of micropropagated clones. This is the first report on micropropagation and genetic homogeneity assessment of P. eriocarpum. The protocol would be useful for the conservation and large scale production of P. eriocarpum to meet the demand for medicinal formulations and also for the re-introduction of in vitro grown plants in the suitable natural habitats to restore the populations.