Induction and Optimization of Hairy Root Growth Condition for Valeriana officinalis L. Through Inoculation by Agrobacterium rhizogenes

In this study, with the aim of optimizing hairy root growth conditions, leaf, hypocotyl and root explants were inoculated by strain ‘A13’ of Agrobacterium rhizogenes. Then effect of four basal MS liquid media was considered with different combinations and temperature on rate of hairy roots growth. In order to hairy root induction via spary and leaf disc methods, two strains of Agrobacterium rhizogenes (A13 and 9534) were used. For confirmation of transformation but not infection of hairy roots, PCR reaction was performed through specific amplification of rolB and virD genes. Obtained hairy roots in a basal liquid MS medium were cultured under different treatments in based on completely randomized design (CRD) with three replicates and dry weight of hairy roots was measured after two months. Hairy roots were observed in root, hypocotyl and leaf explants after 8 days. The highest percentage of transformation was found in leaf explants. The obtained results showed that the highest (0.19 gr) and the lowest(0.05 gr) rate of hairy root dry weight related to basal liquid MS medium containing 30 g/l sucrose in 35°C and basal MS liquid medium containing 0.2 gr ∕ l NAA hormone,respectively,. The results indicate the main role of culture medium compounds and temperature in enhancing of hairy root biomass.