title: Morphological, chemical and molecular differentiation of Fusarium equiseti isolated from Norwegian cereals.
abstract: The morphological variation, secondary metabolite profiles and restriction fragment length polymorphisms (RFLPs) of PCR amplified intergenic spacer (IGS) ribosomal DNA (rDNA) were studied in 27 isolates of Fusarium equiseti, 25 isolated from Norwegian cereals and 2 from soil obtained from the IBT culture collection (BioCentrum, Technical University of Denmark). All 27 isolates were tested for production of fusarochromanone (FUSCHR), zearalenone (ZEA) and the trichothecenes: 15-monoacetoxy-scirpentriol (MAS), diacetoxy-scirpenol (DAS), T-2 and HT-2 toxins, T2-triol, neosolaniol (NEO), deoxynivalenol (DON), nivalenol (NIV) and 4-acetylnivalenol (Fus-X). The trichothecenes were analysed by GC-MS in a selected ion monitoring mode, while FUSCHR was determined by ion pair HPLC with fluorometric detection and production of ZEA by TLC. For amplification of IGS rDNA primers CNL12 and CNS1 were applied. IGS rDNA was digested with the four restriction enzymes: AvaII, CfoI, EcoRI and Sau3A. In addition, we sequenced the IGS rDNA region of three of the Norwegian isolates. There were two morphological types among the Norwegian strains of F. equiseti, type I with short apical cells (dominating) and type II with long apical cells, with four haplotypes identified based on the RFLP data. Variation in secondary metabolite profiles within and between the morphological groups was observed and the levels of produced toxins were: FUSCHR 3000-42,500 and 25-30 ng/g, NIV 20-2500 and 120-700 ng/g, FUS-X 20-15,000 and 0 ng/g, DAS 30-7500 and 0-600 ng/g, and MAS 10-600 and 0-500 ng/g, for strains with short and long apical cells, respectively. NEO was detected in 16/27 strains tested (all morphotype I). All but four strains of type I (these four lacked a restriction site for EcoRI) had identical RFLP profiles. The isolates of type II had two haplotypes. The IGS sequence similarity data indicated differences between these morphotypes corresponding to two separate lineages apparently at the species level.
authors.affiliation: National Veterinary Institute, Department of Feed and Food Hygiene, P.O. Box 8156 Dep., N-0033 Oslo, Norway. barbara.kosiak@vetinst.no
authors.forename: Elzbieta Barbara
authors.initials: EB
authors.lastname: Kosiak
authors.forename: Arne
authors.initials: A
authors.lastname: Holst-Jensen
authors.forename: Thomas
authors.initials: T
authors.lastname: Rundberget
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Gonzalez Jaen
authors.forename: Mona
authors.initials: M
authors.lastname: Torp
mesh_terms: D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis* / Q000737:chemistry; D021903:DNA, Ribosomal Spacer / Q000032:analysis; D002523:Edible Grain / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis; D005670:Fusarium / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000032:analysis*; D009664:Norway; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D009183:Mycotoxins