Abstract:
Extremely acidic soils (pH<3) harbour poorly diversified
mycobiota that are very different from less acidic
habitats. During investigations of the mycobiota from several
highly acidic soils in the Czech Republic and a coastal site in
the Antarctic Peninsula, a group of hyaline fungal isolates was
obtained. Based on phenotype and nuclear ribosomal DNA
sequences (ITS region, SSU, LSU), the isolates belonged to
three phylogenetic lineages within two different classes,
Sordariomycetes and Leotiomycetes (Pezizomycotina,
Ascomycota). The first lineage is described here as a new
genus and species Acidothrix acidophila gen. nov. et sp. nov.
(Amplistromataceae, Sordariomycetes, Ascomycota). The
most closely related species to this new clade are woodinhabiting
fungi. The isolates belonging to the second and
the third lineages are also described as two new genera and
species Acidea extrema gen. nov. et sp. nov. and Soosiella minima gen. nov. et sp. nov. (Helotiales, Leotiomycetes,
Ascomycota). Their position and the relationships within
Helotiales are discussed. Soosiella minima was acidotolerant,
Acidothrix acidophila and Acidea extrema exhibited both
acidotolerant and acidophilic characteristics. All the species
were slightly halophilic. The adaptation of hyaline fungi from
mesophilic lineages to highly acidic environments has been
revealed. The association between highly acidic and Antarctic
habitats is discussed.
