Phylogeny of some Fusarium species, as determined by large-subunit rRNA sequence comparison

Fifty-two strains from eight species of Fusarium were analyzed by rapidrRNA sequencing. Two highly variable stretches (138 and 214 nucleotides) ofthe 5' end of the 28S-like rRNA molecule were sequenced. Such stretchespermit evaluation of the divergence between closely related species andeven between varieties within a species. The phylogenetic tree computedfrom the number of nucleotide differences shows seven Fusarium species tobe more closely related to one another than the eighth species, F. nivale,is to them. On the basis of these data, we discuss both the phylogeneticvalue of taxonomical criteria and the impact of our findings on thedemarcation of the genus Fusarium. We conclude that this method is suitablefor establishing a precise phylogeny between closely related species withina genus.