A trial for chemotaxonomic analysis of toxigenic Fusarium species was performed by an introduction of restriction fragment length polymorphisms based on the selected DNA probes of Fusarium sp. Fn 2B strain, a well-known producer of trichothecene mycotoxins nivalenol and fusarenon-X. A total DNA of F. Fn 2B was prepared from the protoplast suspension of mycelia, digested with BamHI, and ligated into BamHI site of plasmid vector pUC19. Two clones harboring inserts in sizes of approximately 1.1 and 1.7 kb were randomly selected for probes. Hybridization patterns of 32P-labeled 1.1 and 1.7 kb fragments of Fn 2B with BamHI, EcoRI or HindIII-digested DNAs from F, sporotrichioides (4 isolates), F, graminearum (6 isolates), F, tricinctum (4 isolates), F. poae (4 isolates), F. crookwellense (3 isolates) and others, were compared by Southern blots. The data obtained with the 1.1 kb fragment have revealed a similar pattern of restriction fragment profiles among the isolates of same Fusarium species such as F. sporotrichioides, F, tricinctum or F. graminearum. While, the fragment profile of Fn 2B strain did not correspond to that of all the other Fusarium spp. tested. This suggested that F. sp. Fn 2B, originally reported as F. nivale by Dr. Tsunoda and later cited as F. tricinctum at NRRL by J. J. Ellis and to F. sporotrichioides at the Medical Research Council Collection (MRC, Tygerberg, South Africa) by Marasas et al., may be unidentified Fusarium species.
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