Diversity and ecology of fungal assemblages present in lake sediments at Clearwater Mesa, James Ross Island, Antarctica, assessed using metabarcoding of environmental DNA

We detected the fungal assemblages present in lake sediments on James Ross Island, Antarctica, using DNA metabarcoding. A total of 132 amplicon sequence variants (ASVs) were assigned, dominated by taxa of the phyla Ascomycota, Basidiomycota, Mortierellomycota and Mucoromycota. However, the less common phyla Chytridiomycota, Rozellomycota, Monoblepharomycota, Basidiobolomycota, Aphelidiomycota and the fungus-like Straminopila were also detected. Fungal sp. 1, Fungal sp. 2, Spizellomycetales sp. 1, Rozellomycotina sp. 1, Talaromyces rubicundus and Betamyces sp. dominated the assemblages. In general, the assemblages displayed high diversity and richness, and moderate dominance. Saprophytic, pathogenic and symbiotic fungi were detected. The metabarcoding data indicated that Antarctic lakes may represent a hotspot of fungal diversity in Antarctica. The sediments of these lakes may accumulate different fungal fragments and active fungal mycelia and their propagules, deposited over long periods of time. Lakes in the Antarctic Peninsula region are sensitive environments threatened by the effects of regional climatic changes. The abundance of sequences of little-known Rozellomycota and Chytridiomycota (Spizellomycetales) taxa in these ecosystems highlights the need for further studies to identify if they are metabolically active in the sediments and whether they have potentially pathogenic capabilities.

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