title: Thirteen novel deoxynivalenol-degrading bacteria are classified within two genera with distinct degradation mechanisms.
abstract: The mycotoxin deoxynivalenol (DON), a secondary metabolite produced by species of the plant pathogen Fusarium, causes serious problems in cereal crop production because of its toxicity towards humans and livestock. A biological approach for the degradation of DON using a DON-degrading bacterium (DDB) appears to be promising, although information about DDBs is limited. We isolated 13 aerobic DDBs from a variety of environmental samples, including field soils and wheat leaves. Of these 13 strains, nine belonged to the Gram-positive genus Nocardioides and other four to the Gram-negative genus Devosia. The degradation phenotypes of the two Gram types were clearly different; all washed cells of the 13 strains degraded 100 μg mL(-1) DON to below the detection limit (0.5 μg mL(-1)), but the conditions inducing the DON-degrading activities differed between the two Gram types. The HPLC profiles of the DON metabolites were also distinct between the two genera, although all strains produced 3-epi-deoxynivalenol. The Gram-positive strains showed DON assimilation in media containing DON as a carbon source, whereas the Gram-negatives did not. Our results suggest that aerobic DDBs are distributed within at least two phylogenetically restricted genera, suggesting independent evolution of the DON-degradation mechanisms.
authors.affiliation: National Institute for Agro-Environmental Sciences, Tsukuba, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Sato
authors.forename: Michihiro
authors.initials: M
authors.lastname: Ito
authors.forename: Masumi
authors.initials: M
authors.lastname: Ishizaka
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ikunaga
authors.forename: Yukari
authors.initials: Y
authors.lastname: Sato
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Yoshida
authors.forename: Motoo
authors.initials: M
authors.lastname: Koitabashi
authors.forename: Seiya
authors.initials: S
authors.lastname: Tsushima
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005670:Fusarium / Q000378:metabolism; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000378:metabolism*; D010802:Phylogeny; D012988:Soil Microbiology; D014255:Trichothecenes / Q000378:metabolism*; D014908:Triticum / Q000382:microbiology
chemical_list: D009183:Mycotoxins; D014255:Trichothecenes; C007262:deoxynivalenol