title: Lysozyme enhances the bactericidal effect of BP100 peptide against Erwinia amylovora, the causal agent of fire blight of rosaceous plants.
abstract: BACKGROUND
  Fire blight is an important disease affecting rosaceous plants. The causal agent is the bacteria Erwinia amylovora which is poorly controlled with the use of conventional bactericides and biopesticides. Antimicrobial peptides (AMPs) have been proposed as a new compounds suitable for plant disease control. BP100, a synthetic linear undecapeptide (KKLFKKILKYL-NH2), has been reported to be effective against E. amylovora infections. Moreover, BP100 showed bacteriolytic activity, moderate susceptibility to protease degradation and low toxicity. However, the peptide concentration required for an effective control of infections in planta is too high due to some inactivation by tissue components. This is a limitation beause of the high cost of synthesis of this compound. We expected that the combination of BP100 with lysozyme may produce a synergistic effect, enhancing its activity and reducing the effective concentration needed for fire blight control.
  
  
  RESULTS
  The combination of a synhetic multifunctional undecapeptide (BP100) with lysozyme produces a synergistic effect. We showed a significant increase of the antimicrobial activity against E. amylovora that was associated to the increase of cell membrane damage and to the reduction of cell metabolism. Combination of BP100 with lysozyme reduced the time required to achieve cell death and the minimal inhibitory concentration (MIC), and increased the activity of BP100 in the presence of leaf extracts even when the peptide was applied at low doses. The results obtained in vitro were confirmed in leaf infection bioassays.
  
  
  CONCLUSIONS
  The combination of BP100 with lysozyme showed synergism on the bactericidal activity against E. amylovora and provide the basis for developing better formulations of antibacterial peptides for plant protection.
authors.affiliation: Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, 17003, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Cabrefiga
authors.affiliation: Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, 17003, Spain. emilio.montesinos@udg.edu.
authors.forename: Emilio
authors.initials: E
authors.lastname: Montesinos
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004338:Drug Combinations; D004357:Drug Synergism; D044084:Erwinia amylovora / Q000187:drug effects* / Q000378:metabolism / Q000472:pathogenicity; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D009113:Muramidase / Q000187:drug effects / Q000494:pharmacology*; D009842:Oligopeptides / Q000008:administration & dosage / Q000187:drug effects / Q000494:pharmacology*; D010935:Plant Diseases / Q000382:microbiology; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000382:microbiology; D031989:Pyrus / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D009842:Oligopeptides; D010936:Plant Extracts; C540525:lysyl-lysyl-leucyl-phenylalanyl-lysyl-lysyl-isoleucyl-leucyl-lysyl-tyrosyl-leucinamide; D009113:Muramidase
keywords: Antimicrobial-peptide; BP100; Erwinia amylovora; Fire blight; Lysozyme; Membrane permeabilization