Phylogenetic relationships of Fusarium poae based on EF-1α and mtSSU sequences

Abstract

A molecular phylogenetic analysis of Fusarium poae isolates from South America (Argentina) and Europe (mainly England, Germany, Italy) was performed using 98 F. poae, four Fusarium culmorum, two Fusarium sporotrichioides and one Fusarium langsethiae isolates. Phylogenetic analyses were performed using nuclear (translation elongation factor 1-alpha, EF-1a) and mitochondrial (mitochondrial small subunit rDNA, mtSSU ) sequences. Partitioned (each dataset separately) and combined (EF-1a þ mtSSU ) analyses did not reveal any clear correlations from the inferred branching topology, between the distribution of observed haplotypes and the geographic origin and/or host species. Results from the present study confirmed that isolates from F. poae form a monophyletic group, and the low variability within isolates from a broad geographic range suggests a common lineage history. Among F. poae isolates from Argentina, however, some were found to possess an insert within mtSSU with structural similarities to group IC2 introns. F. poae isolates differing by the presence/absence of a mtSSU insertion were characterized further by analysis of a portion of the Tri5 gene, but this sequence was unable to reveal variability. The presence of this insert only within isolates from Argentina suggests that evolutionary events (insertions/deletions) are probably taking place within the Argentinian F. poae isolates, and that the acquisition of this insert occurred after geographic isolation of the Argentinian and European populations.