Cloning and expression of an omiganan pentahydrochloride (MBI226) antimicrobial peptide in tobacco (Nicotiana tabacum) confers resist to bacterial pathogens

Antimicrobial peptides are ancient and conserved molecules which are found in defense mechanisms of almost all living organisms from bacteria to animal and plant species. Identification and introduction of novel antimicrobial peptides, is a cost-effective way to improve crop plants resistance to pathogens by using recombinant DNA technology. Therefore, an expression construct containing omiganan antimicrobial encoding gene from the cytoplasmic granules of bovine neutrophils, was cloned and transferred to the tobacco leaf disk using Agrobacterium tumefaciens mediated-transformation. The presence of the antimicrobial peptide encoding gene in the genome of transgenic plants was confirmed by PCR analysis. Six putative transgenic lines and a non-transgenic control plant were selected for further molecular analysis. Total protein was extract from transgenic and nontransgenic control plants and used for antimicrobial activity assay against some human; E. coli, Salmonella, Staphylococcus, Bacillus, and plant: Xanthomonas and Pseudomonas pathogens by disc diffusion method. Results of this experiment showed that total protein extract from transgenic lines, as compared to non-transgenic plant, was significantly (P0.05) on gram-positive pathogenic bacteria. Therefore, it is possible to express and purify omiganan peptide from transgenic and used it in pharmacology formulations as an anti-bacterial medicine. Furthermore, this approach may offer an opportunity to generate transgenic crop plants expressing omiganan peptide resistance to some devastating plant bacteria pathogens.