RAPD-PCR, isozyme, rDNA RFLP and rDNA sequence analyses in identification of Finnish Fusarium oxysporum isolates

Twenty-seven Fusarium oxysporum isolates were studied by RAPD-PCR and isozy me analyses. Thirteen isolates were from barley and the rest from different hosts, most of which were dicotyledonous plants. All isolates could be dis tinguished from each other by RAPD-PCR analysis, and clustered into seven g roups in NJ and parsimony consensus trees. Isozyme analysis detected polymo rphism in five of the six enzymes and the isolates could be divided into 26 different electrophoretic groups. Five groups were supported by high branc h support and bootstrap values in the approximate support tree of combined RAPD-PCR and isozyme data. These five groups were found also in NJ and pars imony consensus trees. The matrices from RAPD-PCR and isozyme data proved t o be incongruent, but they did not totally disprove each other. Some correl ation was found between geographical origin and phylogenetic relationships of isolates collected from barley. Representatives of the main clades of ph ylogenetic trees, were further studied by rDNA RFLP and rDNA sequence analy ses, together with isolates of other Fusarium species. Isolates of F. oxysp orum and F. avenaceum formed distinct groups in the phylogenetic analyses, except for two isolates of F. oxysporum which were grouped with isolates of F. redolens.