Efficient plant regeneration, genetic fidelity and high-level accumulation of two pharmaceutical compounds in regenerated plants of Valeriana officinalis L.

An efficient regeneration system via adventitious shoot formation was developed in Valeriana officinalis , an important medicinal species. Regeneration response was significantly influenced by the type and concentrations of plant growth regulators as well as callus morphology. Optimum values for adventitious shoot–buds induction in both leaf and petiole explants were obtained when organogenic calli with compact, nodular and yellowish green phenotype was cultured in MS medium supplemented with 9.30 μM Kn and 2.26 μM 2,4-D. Well-developed shoots was achieved on a hormone-free half strength (1/2) MS basal medium. In vitro rooting of elongated shoots was tried on 1/2 MS medium supplemented with various concentrations of α-naphthalene acetic acid (NAA) or indole-3-butyric acid (IBA). IBA at a concentration of 2.46 μM was found to be the best rooting treatment, which promoted the highest frequency of rooting (98%). Successful acclimatization of rooted plantlets was achieved in potting medium containing 5:1 mixture of peat and perlite with 95.34% survival rate. The contents of valtrate and valerenic acid in biomass extracts from petiole-derived plants were significantly ( P < 0.05) higher than leaf-derived plants as well as the seed-raised field-grown plants. Maximum valtrate (6.98 mg g − 1 DW) and valerenic acids (3.02 mg g − 1 DW) contents were quantified in root tissue of petiole-derived plants raised on medium with higher concentration of Kn (9.30 μM) in combination with 2.26 μM 2,4-D. Random amplified polymorphic DNA (RAPD) analysis indicated no evidence of genetic variation in the tissue culture-raised plants. The results suggest that the tissue culture-raised V. officinalis plants are capable of producing higher content of secondary metabolites under optimum in vitro conditions than that under natural wild growth conditions.