Establishment of root to root culture and evaluation of phytochemicals in Rhizobium rhizogenes transformed roots of Stevia rebaudiana

Abstract

Hairy roots provide an efficient way of biomass production due to fast growth and displays high biosynthetic capabilities that are comparable to those of natural roots. For the establishment of root to root culture of Stevia rebaudiana L. Bertoni , hairy roots obtained from infection of S. rebaudiana with Rhizobium rhizogenes strain ATCC 15834 and MTCC 532 were inoculated on MS solid and MS solid medium supplemented with different concentration of Indole-3-acetic acid (IAA), Indole-3-butyric acid (IBA), α-Napthalenacetic acid (NAA). After 3 weeks of culture, well established roots (20.44) were observed in hormone free MS basal media. Lower concentration of IAA and IBA of 1mg L-1 resulted in comparable root growth and multiplication (25.1 and 19.6 respectively). NAA proved detrimental for root multiplication. The developed root culture, when further cultured on growth regulator free MS liquid medium, exhibited fast growth and high lateral branching. Complete dark culture was more effective for the production of roots than light illumination culture. Evaluation of phytochemicals of the transformed hairy roots of S. rebaudiana through High- Performance Thin Layer Chromatography (HPTLC) revealed the presence of Stevioside in vivo and MTCC 532 infected roots and Stevioside and Rebudioside in ATCC 15834 infected roots.