Abstract:
Fusarium oxysporum is an asexual fungal species that includes human and animal pathogens and a
diverse range of nonpathogens. Pathogenic and nonpathogenic strains of this species can be
distinguished from each other with pathogenicity tests, but not with morphological analysis or sexual
compatibility studies. Substantial genetic diversity among isolates has led to the realization that F.
oxysporum represents a complex of cryptic species. F. oxysporum f. sp cubense (Foc), causal agent of
Fusariumwilt of banana, is one of the more than 150 plant pathogenic forms of F. oxysporum.Multi-gene
phylogenetic studies of Foc revealed at least eight phylogenetic lineages, a finding that was supported by
random amplified polymorphic DNAs, restriction fragment length polymorphisms and amplified
fragment length polymorphisms. Most of these lineages consist of isolates in closely related vegetative
compatibility groups, some of which possess opposite mating type alleles, MAT-1 and MAT-2; thus, the
evolutionary history of this fungus may have included recent sexual reproduction. The ability to cause
disease on all or some of the current race differential cultivars has evolved convergently in the taxon, as
members of some races appear in different phylogenetic lineages. Therefore, various factors including
co-evolution the plant host and horizontal gene transfer are thought to have shaped the evolutionary
history of Foc. This review discusses the evolution of Foc as a model formae specialis in F. oxysporum in
relation to recent research findings involving DNA-based studies.
