title: Bacillus amyloliquefaciens Q-426 as a potential biocontrol agent against Fusarium oxysporum f. sp. spinaciae.
abstract: In recent years, Bacillus species have received considerable attention for the biological control of many fungal diseases. In this study, Bacillus amyloliquefaciens Q-426 was tested for its potential use against a variety of plant pathogens. Our screen for genes involved in the biosynthesis of antifungal agents revealed that the fen and bmy gene clusters are present in the Q-426 genome. Lipopeptides such as bacillomycin D, fengycin A, and fengycin B were purified from the bacterial culture broth and subsequently identified by ESI-mass spectrometry. The minimal inhibitory concentration of fengycin A against Fusarium oxysporum f. sp. spinaciae W.C. Snyder & H.N. Hansen O-27 was determined to be 31.25 μg ml(-1) . However, exposure of fungal cells to 50 μg ml(-1) of fengycin A did not allow permeation of fluorescein diacetate into the cytoplasm through the cell membrane. Moreover, leakage of intracellular inorganic cations, nucleic acid and protein were also not detected, indicating that the fungal cell membrane is not the primary target of action for fengycin A. Profound morphological changes were observed in the F. oxysporum strain and spore germination was completely inhibited, suggesting that 50 μg ml(-1) of fengycin A acts, at least, as a fungistatic agent.
authors.affiliation: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Graduate School of Chinese Academy of Sciences, Beijing, China.
authors.forename: Pengchao
authors.initials: P
authors.lastname: Zhao
authors.forename: Chunshan
authors.initials: C
authors.lastname: Quan
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Wang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.forename: Shengdi
authors.initials: S
authors.lastname: Fan
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D001407:Bacillus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D005670:Fusarium / Q000187:drug effects / Q000254:growth & development*; D055666:Lipopeptides / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D005810:Multigene Family; D010455:Peptides / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D010572:Pest Control, Biological / Q000379:methods*
chemical_list: D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D055666:Lipopeptides; D010455:Peptides; C049972:fengycin; C027845:bacillomycin D
keywords: Antifungal mechanism; Fengycin A; Fungistatic agent; Gene clusters; Lipopeptides