Influence of different strains of Agrobacterium rhizogenes, culture medium, age and type of explant on hairy root induction in Echinacea angustifolia

Hairy roots culture is a potential system for secondary metabolite production in medicinal plants. In this research, hairy root induction in Echinacea angustifolia was established using Agrobacterium rhizogenes. The effects of dif-ferent A. rhizogenes strains (AR15834, A4, K599 and MSU440) in two solid growth regula-tor-free culture media, half strength MS salts with B5 vitamins and WPM, were evaluated on hairy root induction in 60-day-old explants. The highest percentage of root induction was ob-tained by AR15834 strain in the WPM medium (46.6%). Also, the effects of age (20, 40 and 60 day-old) and type (leaf, leaf lamina and petiole) of explant on hairy root induction were investi-gated by AR15834 strain in the WPM medium. The high frequency of hairy root induction was obtained in leaf explants (52.4%) and 40 day-old leaf explants (62.3%).Transgenic hairy roots were confirmed by PCR analysis with specific primers of rolB gene.