Influence of Agrobacterium rhizogenes strains on hairy root induction and ‘bacoside A’ production from Bacopa monnieri (L.) Wettst.

Abstract

Stable lines of hairy roots were established from leaf explants of Bacopa monnieri using different strains (A4, R1000, SA79, MTCC 532 and MTCC 2364) of Agrobacterium rhizogenes. The efficiency of hairy roots induction of these strains varied significantly and the maximum transformation frequency (75 %) was observed in case of strain SA79 using leaf explants followed by internode (55 %) in the presence of acetosyringone. Different parameters such as cell density of Agrobacterium suspension, co-cultivation period and infection time influenced the root induction frequency. Maximum frequency of root induction was obtained with bacterial density of 0.6 OD 600 , 2 days of co-cultivation period and 10 min of infection time. Integration of T-DNA in the genome of hairy roots was confirmed by PCR amplification of rolB gene. Elimination of Agrobacterium from the established root cultures was ascertained by amplifying the DNA fragment specific to 16S rDNA and virD gene. All lines of hairy roots except strain A4 induced showed higher growth rate and accumulated higher levels of 'bacoside A' than the untransformed roots. Maximum biomass accumulation (6.8 g l -1 ) and 'bacoside A' content (10.02 mg g -1 DW) were recorded in case of the hairy root line induced by strain MTCC 2364.

Advances in Boerhaavia diffusa hairy root technology: a valuable pursuit for identifying strain sensitivity and up-scaling factors to refine metabolite yield and bioactivity potentials

“…In tandem, the prevailing lesser compatibility threshold of the SA79 strain towards B. diffusa substantiated a previous report involving Catharanthus roseus (Batra et al 2004). However, higher virulence of the SA79 strain over other A. rhizogenes strains including the A4 could also be noted in case of Bacopa monnieri (Bansal et al 2014) contradicting our present observation. Host plant-specific receptiveness towards designated A. rhizogenes strain, in combination with the compatibility threshold of certain explants, might primarily be accountable for the presently observed trend, which has already been exemplified in several earlier studies (Zehra et al 1999;Akramian et al 2008;Roychowdhury et al 2013).…”

“…The requirement of an accurate time duration and optimum cell surface area for maximum interaction with metabolically active cells and unsuppressed signal transduction leading to T-DNA transfer/integration necessitates optimization of wounding process and co-cultivation duration, which have already been highlighted earlier in several instances (Swain et al 2012;Bansal et al 2014).…”

RolB gene-induced production of isoflavonoids in transformed Maackia amurensis cells

“…T-DNA carries the rol genes (rolA, rolB, rolC, and rolD), which together or separately cause the hairy root syndrome in host plants at sites of infection (White et al 1985). Transgenic hairy roots were shown to stably produce secondary metabolites at levels comparable to or greater than those of the intact plants (Swain et al 2012;Oksman-Caldentey and Hiltunen 1996;Giri and Narasu 2000;Grzegorczyk et al 2006;Tiwari et al 2008;Sheela 2012;Jiao et al 2014;Bansal et al 2014;Gai et al 2015).…”

Production of bacoside A, a memory enhancer from hairy root cultures of Bacopa monnieri (L.) Wettst

“…Hairy root were established using different strains of Agrobacterium rhizogenes (Bansal et al, 2014a). Based on higher growth and bacoside A content, hairy roots established using A. rhizogenes strain MTCC2364 was selected for the present study and was named as MTCC2364.…”

“…Plant cell and organ cultures have been exploited as an alternative for sustained production of 'bacosides' (Rahman et al, 2002;Majumdar et al, 2011;Bansal et al, 2014a). Hairy root culture, make a significant contribution in the production of secondary metabolites (Flores et al, 1999).…”