Abstract
Fraxinus excelsior is currently suffering from ash dieback disease caused by the fungus Hymenoscyphus fraxineus. Co-occurrence of large numbers of other fungi with endophytic as well as pathogenic
lifestyles has been observed on F. excelsior. In this study, new endophytic Fusarium spp. isolate Fraxinus excelsior Fusarium from Slovak territory, associated with F. excelsior, was characterised. Using morphology-based approaches, the fungus was assigned to
the genus Fusarium. The isolate formed thick-walled hyaline, fusiform, slightly curved macroconidia,
produced from monophialides in sporodochia, pointed at the tip, mostly 3 – 5 septate,
occasionally 6 septate, and 40 – 68 × 3.8 – 5.0 µm in size with basal pedicellate
cells. For more accurate taxonomic affiliation, molecular sequence analyses of the
internal transcribed spacer, translation elongation factor 1-alpha sequences, and
partial β-tubulin gene were performed.
While the internal transcribed spacer sequence of the isolate showed the highest
similarity to the Fraxinus oxysporum species, translation elongation factor 1-alpha and partial β-tubulin sequences were distantly related to the Fraxinus avenaceum species. Based on these data, the Fraxinus excelsior Fusarium isolate could probably be considered a new species of the Fusarium genus.
Key words
Oleaceae -
Fusarium
- endophyte - morphology - new species - phylogenetic analyses
