Agrobacterium rhizogenes-mediated transformation of a multi-medicinal herb, Boerhaavia diffusa L.: Optimization of the process and anti-microbial activity against bacterial pathogens causing urinary tract infections

Abstract

Hairy root cultures (HRCs) of Boerhaavia diffusa L., an ethno-medicinally important herb, were established via explant co-cultivation with Agrobacterium rhizogenes. Several key factors influencing transformation efficiency were optimized. Rhizoclones showing prolific growth were maintained through successive subcultures in solidified Murashige & Skoog's medium without growth regulators (MS0) under diffused illumination. PCR analysis of the rhizoclones demonstrated positive amplification of rolB and rolC genes of pRi TL-DNA. Reverse transcription-PCR (RT-PCR) and opine assay revealed the presence and expression of the pRi TR-DNA borne ags gene. The methanol and dichloromethane (M:DM) extracts of hairy roots (HRs) and natural roots (NRs) were screened against a wide range of bacterial pathogens causing human urinary tract infections (UTIs). The MIC and MBC values of HRs were markedly lower when compared to NRs against microorganisms causing UTIs. Extracts of HRs were more effective than those of NRs not only against wild type strains but also, and more importantly, against multi-drug resistant strains. Establishment of fast-proliferating renewable HRCs of B. diffusa would provide a direct source of anti-microbial phytocompounds against several pathogenic bacteria, including resistant strains, causing UTIs. © 2014 Taylor & Francis.