Differentiation of Fusarium verticillioides from banana fruits by IGS and EF-1α sequence analyses

Fusarium verticillioides (Gibberella moniliformis, G. fujikuroi mating population A) is an important pathogen of maize and produces several mycotoxins, including fumonisins, which cause diseases in humans and animals. The partial sequences of the IGS region (Intergenic Spacer of rDNA units) and the translation elongation factor EF-1α gene of a representative sample (48 strains) of F. verticillioides isolated from diverse hosts, geographical origins and with different levels of fumonisin production were analyzed. A phylogenetic approach by PAUP was used to evaluate the genetic variability in this species and to detect the occurrence of lineages which could be associated with different hosts or produced different toxin profiles within this species. Genetic variability detected by both sequences was high, especially with the IGS sequence which showed a high number of parsimony-informative sites and nucleotide diversity. The results of the phylogenetic analysis indicated that F. verticillioides occurs as (i) a major fumonisin-producing population with a wide geographical distribution, wide host preferences (cereals), showing variability and considerable incidence of sexual reproduction and (ii) a minor fumonisin non-producing population, with restricted host preference (banana), low variability and clonal reproductive strategy.