Background and Objectives
Plant pathogens, insects and weeds contribute to more than 30% of crop losses annually. Toxic chemical bactericides have been extensively used to control plant pathogenic bacteria. These chemicals pose a health threat to humans and the environment and eventually lead to resistance of pathogens. Hence, breeding cultivars resistance to bacterial pathogens is a valuable and sustainable solution. Antimicrobial peptides (AMP) are a part of the immune system of all living organisms, including plants, to combat pathogenic bacteria. Hairy roots (HRs) system is a valuable tool to produce and evaluate the activity of AMPs in planta. The aim of this study was to produce a Dermaseptin B1 (Drs-B1) recombinant AMP in transgenic tobacco HRs using Agrobacterium rhizogenes and test its antibacterial activities.
The DNA encoding sequence of a Drs-B1 peptide of a frog was codon optimized based and synthesized in the pGSA1285 expression vector under the control of 35S CaMV promoter (×3). A gene cassette containing the Drs-B1 gene was introduced to tobacco roots by Agrobacterium rhizogenesis mediated transformation.
The transgenic HRs were confirmed by molecular methods. Antimicrobial activity of the protein extracts from transgenic HRs showed that the recombinant protein was able to prevent Pectobacterium carotovorum, Erwinia amylovora and Xanthomonas citri plant pathogenic bacteria growth. The anti-bacterial effects of Drs-B1 peptide against plant pathogenic bacteria were in the order of X. citri> E. amylovora >P. carotovorum.
The peptide present in transgenic DrsB1-expressing HRs clones inhibited devastating plant pathogenic bacteria growth, suggesting that DrsB1 retains its antibacterial activity in plant cells. The results of present study may open promising opportunities to produce transgenic plants expressing antimicrobial peptides resistance to plant pathogens