Improving hairy root induction of Urena lobata L. by Agrobacterium rhizogenes ATCC 15834 by some factors

Introduction: Our previous study showed that Urena lobata L. hairy root is a potential pharmaceutical source for type 2 diabetes treatment. In order to improve the transformation efficacy and the quality of hairy roots, this study examined the effects of several factors including age, parts of plants, infection time and culture medium in inducing hairy roots in Urena lobata L. Methods: In this study, we investigated four factors to improve the hairy root induction in Urena lobata L. These factors include: age of plant (15-day-old in vitro plants, 45-day-old in vitro plants and after two subculture generations plants), different parts of plant (roots, stems, and leaves), infection time (10, 20 and 30 minutes), and culture medium (Murashige and Skoog (MS), Gamborg B5 medium (GB5) and Woody plant medium (WPM)). All experiments were repeated three times, with uninfected leaf explants of 15-day-old in vitro as the negative control. The transformation frequency and the fresh biomass of hairy roots were recorded at four weeks after infection. Results: The results showed that the optimized procedure which used 15-day-old in vitro plants, the leafy part, the infection time of 10 minutes and culture in the WPM medium was better than the original procedure. The optimized procedure achieved a transformation frequency of 100%. In addition, the fresh biomass of hairy roots formed on an explant in the optimized procedure was 3.2 times higher than the ones induced by the original procedure. Conclusion: The results showed that the optimized procedure was more effective than the original procedure in inducing Urena lobata hairy roots.