Effect of Different Agrobacterium rhizogenes Strains on In-vitro Hairy Root Induction for Cucurbitacin E Production in Citrullus colocynthis

Abstract

In the present study, we have examined the responses of different Agrobacterium rhizogenes strains for the hairy root production and evaluated the concentration of bioactive compound Cucurbitacin E in hairy roots and normal in vitro root cultures. Leaf explants were more suitable for production of hairy roots through A. rhizogenes. This protocol facilitates mass production of bioactive compounds from medicinal plant roots. Hairy root cultures of C. colocynthis were established after infecting cotyledon, leaf, stem and callus segments with Agrobacterium rhizogenes strains-A4, Ar532, ARqua1 and R1000 were cultured on Murashige and Skoog phytohormone-free media. Among all the Agrobacterium- strains used, R1000 induced hairy roots more effectively with a frequency of transformation of 80.1% in leaf explants. Addition of 150 μM acetosyringone to the co-cultivation medium resulted in a two-fold induction of root hairs from leaf explants infected with strain R1000, followed by 20 min and three days of co-cultivation also demonstrated to increase the percentage of infection. Cefotaxime at a concentration of 300 mg/L was found to be optimum for the hairy root production without any damage to explants and control the growth of bacterial culture.