Hairy root induction and plant regeneration in Hypericum perforatum L

Hypericum perforatum L. (Family: Clusiaceae) is a medicinal plant well known for its antidepressant and antiviral properties. The blooming aerial part of the plant contains active pharmaceutical metabolites (hypericins, hyperforins, xanthones, flavonoids, etc.). In this work hairy roots have been induced in H perforatum, by infecting in vitro root and leaf tissue with wild type A. rhizogenes, ATCC 15834. Hairy root cultures were established and plant regeneration occurred spontaneously on hormone-free medium. The regenerated plants showed typical morphological characters: shorter internodes, increased branching, small leaves and reduced apical dominance. Molecular analysis (PCR and Southern blot) confirmed the integration of the A. rhizogenes T-DNA rolC gene into the host genome. The ploidy level of the hairy root-regenerated plants remained unchanged by transformation/regeneration procedure. One hairy root-regenerated plant line produced a higher hypericin content than in vitro control plants