Transgenic tobacco expressing Medicago sativa Defensin (Msdef1) confers resistance to various phyto-pathogens

This study was performed to evaluate the competency of transgenic plants expressing Medicago sativa defensin (MsDef1) towards developing self-resistance against the attack of pathogens. We raised fifteen lines of T2 transgenic tobacco plants expressing MsDef1 under the control of a strong constitutive promoter (M24) and transgene integration was confirmed. Plant-derived enriched MsDef1 at a concentration of 0.6 μg/μl showed 78, 53 and 71% anti-bacterial activities against Pseudomonas aeruginosa, Ralstonia solanacearum and Xanthomonas campestris respectively; alongside it demonstrated 53, 65 and 52% anti-fungal activity against Aspergillus niger, Pyricularia oryzae and Rhizoctonia solani respectively, at a concentration of 0.8 μg/μl in vitro. In addition, plant-derived MsDef1 showed significant anti-bacterial activity against Pseudomonas syringae pv tabaci. The LD50 values obtained from in vitro analyses clearly indicated the efficacy of MsDef1 against the above mentioned phyto-pathogens. The in vivo studies employing R. solanacearum and A. niger showed that transgenic plants could withstand the invasion of these virulent pathogens. Under this nascent study, we demonstrated the activity of plant-derived MsDef1 against plant pathogens; both in vitro and in vivo.