Taxonomic novelties in Aspergillus section Fumigati: A. tasmanicus sp. nov., induction of sexual state in A. turcosus and overview of related species

Vit Hubka, Zuzana Dudová, Alena Kubátová, Jens Christian Frisvad, Takashi Yaguchi, Yoshikazu Horie, Željko Jurjević, Seung-Beom Hong, Miroslav Kolařík

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The phylogenetic position of two Aspergillus strains isolated from Australian soil and phenotypically resembling A. unilateralis was investigated by using multigene phylogeny based on β-tubulin (benA), calmodulin (CaM), actin (act), and RNA polymerase II second largest subunit (RPB2) genes. The analysis supported their placement into a separate lineage within a well-supported clade containing 10 other members of section Fumigati (“A. unilateralis clade”). Comparisons of extrolite profiles, taxonomically informative morphological and physiological characters were made, and it was discovered that the two strains can be differentiated from all relatives by their low maximum growth temperature, short stipes, and ornamentation of conidia. The data justified the proposal of a new species, A. tasmanius sp. nov. Amplification of mating-type genes showed that the A. unilateralis clade contains five heterothallic species. Only the MAT1-1-1 idiomorph was detected among isolates of A. unilateralis, A. tasmanicus, and A. marvanovae, while isolates having both opposite mating types were detected in A. turcosus and A. nishimurae. The sexual state of A. turcosus was induced by mating experiments and is described in this study. Ascospores of this species were unique by their smooth to finely verrucose convex surface and two well-visible equatorial crests. Some exometabolites detected in A. marvanovae and A. tasmanicus are also indicative of a perfect state, thus supporting the hypothesis that these species have cryptic sexual cycles. The epitype and ex-epitype culture is designated for A. nishimurae to facilitate further taxonomic work with this species.
Original languageEnglish
JournalPlant Systematics and Evolution
Volume303
Issue number6
Pages (from-to)787-806
ISSN0378-2697
DOIs
Publication statusPublished - 2017

Keywords

  • Aspergillus fumigatus
  • Aspergillus unilateralis
  • Mating experiments
  • Mating-type genes
  • Multigene phylogeny
  • Scanning electron microscopy
  • Secondary metabolites

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