Effects of explant age and strain of Agrobacterium rhizogenes on hairy roots induction in Fenugreek (Trigonella foenum– graecum L.)

Induced hairy roots by Agrobacterium rhizogenes are suitable organs for the production of secondary metabolites, due to the stability and high production of roots without phyhormones in a short time. Fenugreek (Trigonella foenum– graecum L.) is one of the most important medicinal plants with valuable medicinal compounds. For optimizing the hairy root induction of T. foenum-graecum L., six strains of A. rhizogenes ATCC15834, ATCC11325, K599, A7, A4 and A13 (MAFF-02- 10266) and three explant ages (7, 14 and 21 day old seedlings) were tested. The explants were cultured in B5 in a completely randomized design with 4 replications. Hairy roots appeared after 3 to 4 weeks. Transgenic status of the roots was confirmed by PCR using rolB specific primers. The results revealed that all strains were able to induce hairy roots after 3-4 weeks. The maximum percentage of hairy root induction (87.5%) was obtained from A7 and ATCC11325 strains and 7-day-old explants. Among the strains, ATCC11325 strain showed the highest hairy root number (4.25) and root length (2.1 cm) using 14-day-old explant. Also, the highest fresh (0.203 g) and dry weights (0.029 g) were observed in the A4, A7 and ATCC11325 strains. The highest total phenolic and flavonoid contents were found at 74.05 mg g-1 DW and 11.80 μg g-1 DW in hairy roots induced by A7 strain.