Efficient micropropagation, genetic validation and phytochemical profiling of Rumex hastatus D. Don- an edible medicinal herb of Western Himalayas

Rumex hastatus D. Don commonly known as arrowleaf dock is a traditional medicinal herb of Western Himalayas. In view of its immense demand and overexploitation by the therapeutic and pharmaceutical industries, its natural population is declining at a faster rate. To cope up with industrial needs an efficient micropropagation protocol has been developed using nodal explants via direct organogenesis. Nodal explants were cultured on MS medium augmented with different cytokinins. BAP at 5.0 mu M proved optimum for differentiating multiple shoots in 100% cultures with an average of 5.00 +/- 0.38 shoots per explant having 1.28 +/- 0.08 cm length, after 30 days (d). Of the three auxins (IAA, IBA or NAA) tried in different concentrations (0.1, 1, 5 or 10 mu M), 0.1 mu M IBA proved most effective in inducing an average of 8.25 +/- 1.05 roots per shoot having an average length of 5.39 +/- 0.34 cm after 30 d of transfer. The regenerated plantlets were hardened and acclimatized under greenhouse conditions and their genetic fidelity was evaluated employing start codon targeted (SCoT) and sequence related amplified polymorphism (SRAP) markers, which revealed 98% similarity amongst the regenerants and mother plant. Interestingly, such regenerants showed enhanced levels of photosynthetic pigments and enzymatic antioxidants compared to mother plants. Phytochemical analysis of root extract of R. hastatus using FT-IR revealed the presence of various functional groups, whereas GC-MS and LC-MS analysis unveiled the presence of 32 and 40 pharmacologically important compounds, respectively. The protocol, thus, developed can be gainfully employed for the large-scale production of the genetically uniformed plants of R. hastatus for its conservation and incessant supply to the pharma industries for the extraction of bioactive compounds. To the best of our knowledge, this is the first report pertaining to regeneration through nodal explants in R. hastatus.