Abstract
Antimicrobial peptides (AMPs) are components of immune defense in many organisms, including plants. They combat pathogens due to their antiviral, antifungal and antibacterial properties, and are considered potential therapeutic agents. An example of AMP is Epsilon-Poly-l-lysine (EPL), a polypeptide formed by ~ 25 lysine residues with known antimicrobial activity against several human microbial pathogens. EPL presents some advantages such as good water solubility, thermal stability, biodegradability, and low toxicity, being a candidate for the control of phytopathogens. Our aim was to evaluate the antimicrobial activity of EPL against four phytobacterial species spanning different classes within the Gram-negative phylum Proteobacteria: Agrobacterium tumefaciens (syn. Rhizobium radiobacter), Ralstonia solanacearum, Xanthomonas citri subsp. citri (X. citri), and Xanthomonas euvesicatoria. The minimum inhibitory concentration (MIC) of the peptide ranged from 80 μg/ml for X. citri to 600 μg/ml for R. solanacearum and X. euvesicatoria. Two hours of MIC exposure led to pathogen death due to cell lysis and was enough for pathogen clearance. The protective and curative effects of EPL were demonstrated on tomato plants inoculated with X. euvesicatoria. Plants showed less disease severity when sprayed with EPL solution, making it a promising natural product for the control of plant diseases caused by diverse Proteobacteria.
Highlights
Antimicrobial peptides (AMPs) are components of immune defense in many organisms, including plants
The minimum inhibitory concentration (MIC) of EPL varied between 80 μg/ml to inhibit X. citri growth, 400 μg/ml for A. tumefaciens and 600 μg/ml for R. solanacearum and X. euvesicatoria
Incubating the cells with the determined MICs of EPL confirmed the antibacterial activity of the peptide in the first 30 min, when the quantity of colony forming units (CFUs) in the treatment group was already statistically different from the water-treated control (Fig. 2)
Summary
Antimicrobial peptides (AMPs) are components of immune defense in many organisms, including plants. Phytobacteria constitute an important group of plant pathogens that reduce yields of valuable crops They are disseminated and can spread quickly, causing severe bacterial infections that are difficult to control[1]. Crop rotation can suppress some diseases, but is not always feasible and some pathogens can survive for many years in the soil or unnoticed in asymptomatic hosts This scenario warrants an urgent need for agents that effectively control phytobacteria without selecting for resistance such as when conventional antibiotics are used. The aim of this work was to investigate the in vitro antimicrobial potential of EPL against the phytopathogens R. solanacearum, X. euvesicatoria, X. citri and A. tumefaciens and to verify the in vivo action in the control of bacterial spot on tomato plants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
