Fusarium neoglobosum, a novel species within the Asian clade of Fusarium fujikuroi complex.

Abstract

From 2017 to 2024, 10 strains morphologically similar to Fusarium globosum were obtained from cereals in West Siberia, the Urals, and the Central European region of Russia. This study was conducted to confirm the species identity of the strains morphologically assigned to F. cf. globosum. For this purpose, comparison with F. globosum strain KSU 11554 from South Africa was performed using multilocus analysis, morphological features, growth tests, and production of secondary metabolites. In order to determine phylogenetic relationships, the translation elongation factor 1α, β-tubulin, RNA polymerase II second largest subunit, and histone H3 genes were used. Strains from Japan and Russia formed a separate and well-supported lineage, representing a single, previously undescribed species, described here as F. neoglobosum. Both F. globosum and F. neoglobosum are deeply nested within the Asian clade in the molecular phylogeny of Fusarium fujikuroi species complex. The key character in both species is a formation of globose microconidia in the dark. Opposite mating type idiomorphs was detected in F. globosum and F. neoglobosum, which is indicative of the heterothallic nature of sexual reproduction. Strains described as F. neoglobosum exhibit two mycotoxin-related phenotypes: mycotoxin-producing and non-mycotoxin-producing. Five F. neoglobosum strains and a F. globosum strain were capable of producing a wide range of fumonisins. None of the strains of either species produced moniliformin, and only 2 of 10 F. neoglobosum strains produced detectable beauvericin. The data presented confirm the distribution of F. neoglobosum in East and North Asia, with only one strain isolated from European Russia.