A library of linear undecapeptides with bactericidal activity against phytopathogenic bacteria.
A 125-member library of synthetic linear undecapeptides was prepared based on a previously described peptide H-K(1)KLFKKILKF(10)L-NH(2) (BP76) that inhibited in vitro growth of the plant pathogenic bacteria Erwinia amylovora, Xanthomonas axonopodis pv. vesicatoria, and Pseudomonas syringae pv. syringae at low micromolar concentrations. Peptides were designed using a combinatorial chemistry approach by incorporating amino acids possessing various degrees of hydrophobicity and hydrophilicity at positions 1 and 10 and by varying the N-terminus. Library screening for in vitro growth inhibition identified 27, 40 and 113 sequences with MIC values below 7.5 microM against E. amylovora, P. syringae and X. axonopodis, respectively. Cytotoxicity, bactericidal activity and stability towards protease degradation of the most active peptides were also determined. Seven peptides with a good balance between antibacterial and hemolytic activities were identified. Several analogues displayed a bactericidal effect and low susceptibility to protease degradation. The most promising peptides were tested in vivo by evaluating their preventive effect of inhibition of E. amylovora infection in detached apple and pear flowers. The peptide H-KKLFKKILKYL-NH(2) (BP100) showed efficacies in flowers of 63-76% at 100 microM, being more potent than BP76 and only less effective than streptomycin, currently used for fire blight control.
Badosa
Esther
E
Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-CeRTA, University of Girona, Campus Montilivi, 17071 Girona, Spain.
Ferre
Rafael
R
Planas
Marta
M
Feliu
Lidia
L
Besalú
Emili
E
Cabrefiga
Jordi
J
Bardají
Eduard
E
Montesinos
Emilio
E
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000472:pathogenicity*; D015195:Drug Design; D019286:Endopeptidase K; D044084:Erwinia amylovora / Q000187:drug effects / Q000472:pathogenicity; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology*; D019151:Peptide Library; D010935:Plant Diseases / Q000382:microbiology; D010944:Plants / Q000382:microbiology*; D044224:Pseudomonas syringae / Q000187:drug effects / Q000472:pathogenicity; D053532:Xanthomonas axonopodis / Q000187:drug effects / Q000472:pathogenicity
D000900:Anti-Bacterial Agents; D009842:Oligopeptides; D019151:Peptide Library; D019286:Endopeptidase K