Global fungal diversity is estimated to range in the millions, yet it remains severely underexplored, especially in extreme environments. Fewer than 5% of species have been officially identified and characterised. Estimates suggest that 70%–90% of soil fungi remain uncultivable, often referred to as ‘fungal dark taxa’. This study shows a comprehensive assessment of the fungal diversity in Robinson Ridge, East Antarctica using both culturing and non-culture dependent methods. The soil community was assessed by ITS gene sequencing of 93 subsoil and 93 surface soils collected along 3 × 300 m long transects. Strains were isolated from soil following enrichment cultivation under oligotrophic conditions supplemented with excess hydrogen gas. Landscape heterogeneity significantly influenced the composition, diversity, and functionality of the communities. A high relative abundance of lichen-associated fungi was recorded in areas with low levels of nutrients and moisture. One hundred and thirty fungal strains were isolated, mainly comprising the classes Eurotiomycetes and Dothideomycetes. A large proportion of fungal ASVs were not shared between techniques, with an overlap of only 1.9% of the total produced sequences. Our study underscores the value of integrating culture-dependent and independent approaches to gain a more comprehensive understanding of fungal distribution, diversity, and functional potential.

A new fungal species, Penicillium psychrofluorescens sp. nov. is described as a member of section Torulomyces. The new species is sister to P. catalonicum, and was isolated from soil collected from Robinson Ridge, East Antarctica, following enrichment cultivation under oligotrophic conditions supplemented with excess hydrogen gas. Penicillium psychrofluorescens is named for its intense autofluorescence derived from a combination of compounds that may include NADPH, porphyrins, and secondary metabolites, such as polyketides. Comparative genomics with both Antarctic and mesophilic Penicillium spp. shows that Penicillium psychrofluorescens has a wide repertoire of glycoside hydrolases, but almost no polysaccharide lyases, has comparably large effector proteins, lacks the machinery to use nitrate as an N-source, but has the genes for the assimilation of phosphorus from phosphonates via oxidative pathway. The strain was found to have 30 biosynthetic gene clusters (BGCs), the majority of which were unrelated to known compound BGCs. Given the remarkable diversity of natural products already characterised from Penicillium spp. and the presence of >30 BGCs with low similarity to known genes, there is biotechnological potential within this novel species that is yet to be explored.