Cytological karyotyping of Fusarium oxysporum by the germ tube burst method (GTBM)

Abstract

Fusarium oxysporum is an ascomycete fungus including plant pathogenic and nonpathogenic strains. Genome analyses have indicated that the karyotype of F. oxysporum is diverse among isolates. Here we used the germ tube burst method (GTBM), a more reliable method than conventional cytology or pulsed field gel electrophoretis, to karyotype isolates of F. oxysporum ff. spp. lycopersici and conglutinans and nonpathogenic F. oxysporum. In this first application of GTBM for F. oxysporum, pathogenic isolates were found to have more chromosomes than in nonpathogenic isolates. We also used a ribosomal DNA probe and fluorescence in situ hybridization (FISH) to analyze chromosome structure.