title: Improvement of the efficacy of linear undecapeptides against plant-pathogenic bacteria by incorporation of D-amino acids.
abstract: A set of 31 undecapeptides, incorporating 1 to 11 d-amino acids and derived from the antimicrobial peptide BP100 (KKLFKKILKYL-NH(2)), was designed and synthesized. This set was evaluated for inhibition of growth of the plant-pathogenic bacteria Erwinia amylovora, Pseudomonas syringae pv. syringae, and Xanthomonas axonopodis pv. vesicatoria, hemolysis, and protease degradation. Two derivatives were as active as BP100, and 10 peptides displayed improved activity, with the all-d isomer being the most active. Twenty-six peptides were less hemolytic than BP100, and all peptides were more stable against protease degradation. Plant extracts inhibited the activity of BP100 as well as that of the d-isomers. Ten derivatives incorporating one d-amino acid each were tested in an infectivity inhibition assay with the three plant-pathogenic bacteria by using detached pear and pepper leaves and pear fruits. All 10 peptides studied were active against E. amylovora, 6 displayed activity against P. syringae pv. syringae, and 2 displayed activity against X. axonopodis pv. vesicatoria. Peptides BP143 (KKLFKKILKYL-NH(2)) and BP145 (KKLFKKILKYL-NH(2)), containing one d-amino acid at positions 4 and 2 (underlined), respectively, were evaluated in whole-plant assays for the control of bacterial blight of pepper and pear and fire blight of pear. Peptide BP143 was as effective as streptomycin in the three pathosystems, was more effective than BP100 against bacterial blight of pepper and pear, and equally effective against fire blight of pear.
authors.affiliation: LIPPSO, Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona, Spain.
authors.forename: Imma
authors.initials: I
authors.lastname: Güell
authors.forename: Jordi
authors.initials: J
authors.lastname: Cabrefiga
authors.forename: Esther
authors.initials: E
authors.lastname: Badosa
authors.forename: Rafael
authors.initials: R
authors.lastname: Ferre
authors.forename: Montserrat
authors.initials: M
authors.lastname: Talleda
authors.forename: Eduard
authors.initials: E
authors.lastname: Bardají
authors.forename: Marta
authors.initials: M
authors.lastname: Planas
authors.forename: Lidia
authors.initials: L
authors.lastname: Feliu
authors.forename: Emilio
authors.initials: E
authors.lastname: Montesinos
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000494:pharmacology*; D044084:Erwinia amylovora / Q000187:drug effects*; D006461:Hemolysis; D010447:Peptide Hydrolases / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology; D044224:Pseudomonas syringae / Q000187:drug effects*; D031989:Pyrus / Q000382:microbiology*; D013237:Stereoisomerism; D053532:Xanthomonas axonopodis / Q000187:drug effects*
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D010447:Peptide Hydrolases