Metabarcoding of Soil Fungal Communities in Rupestrian Grassland Areas Preserved and Degraded by Mining: Implications for Restoration.

Rupestrian grasslands are vegetation complexes of the Cerrado biome (Brazilian savanna), exhibiting simultaneously great biodiversity and important open-pit mining areas. There is a strong demand for the conservation of remaining areas and restoration of degraded. This study evaluated, using next-generation sequencing, the diversity and ecological aspects of soil fungal communities in ferruginous rupestrian grassland areas preserved and degraded by bauxite mining in Brazil. In the preserved and degraded area, respectively, 565 and 478 amplicon sequence variants (ASVs) were detected. Basidiomycota and Ascomycota comprised nearly 72% of the DNA, but Ascomycota showed greater abundance than Basidiomycota in the degraded area (64% and 10%, respectively). In the preserved area, taxa of different hierarchical levels (Agaromycetes, Agaricales, Mortierelaceae, and Mortierella) associated with symbiosis and decomposition were predominant. However, taxa that colonize environments under extreme conditions and pathogens (Dothideomycetes, Pleoporales, Pleosporaceae, and Curvularia) prevailed in the degraded area. The degradation reduced the diversity, and modified the composition of taxa and predominant ecological functions in the community. The lack of fungi that facilitate plant establishment and development in the degraded area suggests the importance of seeking the restoration of this community to ensure the success of the ecological restoration of the environment. The topsoil of preserved area can be a source of inocula of several groups of fungi important for the restoration process but which occur in low abundance or are absent in the degraded area.

Does maritime Antarctic permafrost harbor environmental fungi with pathogenic potential?

We assessed the potentially pathogenic fungi present in Antarctic permafrost and the overlying active layer on King George, Robert, Livingston and Deception Islands in the South Shetland Islands archipelago, maritime Antarctica. Permafrost and active layer sub-samples were incubated at 37 °C to select fungi able to grow inside the human body. A total of 67 fungal isolates were obtained, 27 from the permafrost and 40 from the active layer. These represented 18 taxa of the genera Alternaria, Aspergillus, Curvularia, Penicillium, Rhodotorula and Talaromyces. The majority of fungi detected occurred exclusively either in the permafrost or the active layer at each site. Only Aspergillus thermomutatus, Penicillium cf. chrysogenum and Rhodotorula cf. mucilaginosa were present in both permafrost and active layer samples from the same site. The yeast R. cf. mucilaginosa was recovered from both in at least two sites. The genus Penicillium was the most abundant and widely distributed genus in both permafrost and active layer samples across the sites sampled. All fungal isolates were screened using enzymatic, pH and antifungal assays to identify their virulence potential. Aspergillus hiratsukae, A. thermomutatus and R. cf. mucilaginosa, known human opportunistic fungi, were identified, displayed phospholipase, esterase, proteinase and hemolytic activities. All three also displayed the ability to grow at 40°, 45° and/or 50 °C and resistance to fluconazole and itraconazole; additionally, R. cf. mucilaginosa showed resistance to amphotericin B and viability after 100 d at -80 °C. A. thermomutatus UFMGCB 17415 killed the entire larvae of Tenebrio molitor in six days and R. cf. mucilaginosa UFMGCB 17448 and 17473 in three and four days, respectively. The melting of maritime Antarctic permafrost as a result of climate change may threaten the release of wild strains of pathogenic fungi geographically isolated for long time, which may in turn be transported within and beyond Antarctica by different biological and non-biological vectors.

Diversity of Fungi Present in Permafrost in the South Shetland Islands, Maritime Antarctic.

We assess the fungal diversity present in permafrost from different islands in the South Shetland Islands archipelago, maritime Antarctic, using next-generation sequencing (NGS). We detected 1,003,637 fungal DNA reads representing, in rank abundance order, the phyla Ascomycota, Mortierellomycota, Basidiomycota, Chytridiomycota, Rozellomycota, Mucoromycota, Calcarisporiellomycota and Zoopagomycota. Ten taxa were dominant these being, in order of abundance, Pseudogymnoascus appendiculatus, Penicillium sp., Pseudogymnoascus roseus, Penicillium herquei, Curvularia lunata, Leotiomycetes sp., Mortierella sp. 1, Mortierella fimbricystis, Fungal sp. 1 and Fungal sp. 2. A further 38 taxa had intermediate abundance and 345 were classified as rare. The total fungal community detected in the permafrost showed high indices of diversity, richness and dominance, although these varied between the sampling locations. The use of a metabarcoding approach revealed the presence of DNA of a complex fungal assemblage in the permafrost of the South Shetland Islands including taxa with a range of ecological functions among which were multiple animal, human and plant pathogenic fungi. Further studies are required to determine whether the taxa identified are present in the form of viable cells or propagules and which might be released from melting permafrost to other Antarctic habitats and potentially dispersed more widely.

Diversity and Ecology of Chlorophyta (Viridiplantae) Assemblages in Protected and Non-protected Sites in Deception Island (Antarctica, South Shetland Islands) Assessed Using an NGS Approach.

Assessment of the diversity of algal assemblages in Antarctica has until now largely relied on traditional microbiological culture approaches. Here we used DNA metabarcoding through high-throughput sequencing (HTS) to assess the uncultured algal diversity at two sites on Deception Island, Antarctica. The first was a relatively undisturbed site within an Antarctic Specially Protected Area (ASPA 140), and the second was a site heavily impacted by human visitation, the Whalers Bay historic site. We detected 65 distinct algal taxa, 50 from within ASPA 140 and 61 from Whalers Bay. Of these taxa, 46 were common to both sites, and 19 only occurred at one site. Algal richness was about six times greater than reported in previous studies using culture methods. A high proportion of DNA reads obtained was assigned to the highly invasive species Caulerpa webbiana at Whalers Bay, and the potentially pathogenic genus Desmodesmus was found at both sites. Our data demonstrate that important differences exist between these two protected and human-impacted sites on Deception Island in terms of algal diversity, richness, and abundance. The South Shetland Islands have experienced considerable effects of climate change in recent decades, while warming through geothermal activity on Deception Island itself makes this island one of the most vulnerable to colonization by non-native species. The detection of DNA of non-native taxa highlights concerns about how human impacts, which take place primarily through tourism and national research operations, may influence future biological colonization processes in Antarctica.

DNA metabarcoding uncovers fungal diversity in soils of protected and non-protected areas on Deception Island, Antarctica.

We assessed soil fungal diversity at two sites on Deception Island, South Shetland Islands, Antarctica using DNA metabarcoding analysis. The first site was a relatively undisturbed area, and the second was much more heavily impacted by research and tourism. We detected 346 fungal amplicon sequence variants dominated by the phyla Ascomycota, Basidiomycota, Mortierellomycota and Chytridiomycota. We also detected taxa belonging to the rare phyla Mucoromycota and Rozellomycota, which have been difficult to detect in Antarctica by traditional isolation methods. Cladosporium sp., Pseudogymnoascus roseus, Leotiomycetes sp. 2, Penicillium sp., Mortierella sp. 1, Mortierella sp. 2, Pseudogymnoascus appendiculatus and Pseudogymnoascus sp. were the most dominant fungi. In addition, 440,153 of the total of 1,214,875 reads detected could be classified only at the level of Fungi. In both sampling areas the DNA of opportunistic, phytopathogenic and symbiotic fungi were detected, which might have been introduced by human activities, transported by birds or wind, and/or represent resident fungi not previously reported from Antarctica. Further long-term studies are required to elucidate how biological colonization in the island may be affected by climatic changes and/or other anthropogenic influences.

Diversity and distribution of cultivable fungi present in acid sulphate soils in chronosequence under para-periglacial conditions in King George Island, Antarctica.

We recovered 85 fungal isolates from the acid sulphate soils in chronosequence under para-periglacial conditions in King George Island, Antarctica. Thirty-two taxa belonging to the phylum Ascomycota, Basidiomycota and Mortierellomycota were identified. Mortierella amoeboidea, Mortierella sp. 2, Mortierella sp. 3, Penicillium sp. 2 and Penicillium sp. 3 dominated the sulphite soils. Despite the multi-extreme physic-chemical conditions of the sulphate soils (low pH, variable content of macro and micronutrients and organic matter), the fungal assemblages exhibited moderate diversity indices, which ranged according to the degree of soil development. Soils with more weathered and, consequently, with highest values of organic carbon shelter the most diverse fungal assemblages, which can be associated with the occurrence of sulphurisation and sulphide oxidation. Different taxa of Mortierella and Penicillium displayed broad pH (3-9) and temperature (5-35 °C) plasticity. The multi-extreme sulphite soils of Antarctica revealed the presence of moderate fungal diversity comprising cold cosmopolitan and psychrophilic endemic taxa. Among these, Mortierella and Penicillium, known to survive in extreme conditions such as low temperature and available organic matter, low pH and high concentrations of metals, might represent interesting techniques to be used in biotechnological processes such as bioleaching in metallurgy and phosphate solubilisation in agriculture.

Diversity, distribution, and ecology of viable fungi in permafrost and active layer of Maritime Antarctica.

We evaluated the diversity and distribution of viable fungi present in permafrost and active layers obtained from three islands of Maritime Antarctica. A total of 213 fungal isolates were recovered from the permafrost, and 351 from the active layer, which were identified in 58 taxa; 27 from permafrost and 31 from the active layer. Oidiodendron, Penicillium, and Pseudogymnoascus taxa were the most abundant in permafrost. Bionectriaceae, Helotiales, Mortierellaceae, and Pseudeurotium were the most abundant in the active layer. Only five shared both substrates. The yeast Mrakia blollopis represented is the first reported on Antarctic permafrost. The fungal diversity detected was moderate to high, and composed of cosmopolitan, cold-adapted, and endemic taxa, reported as saprobic, mutualistic, and parasitic species. Our results demonstrate that permafrost shelters viable fungi across the Maritime Antarctica, and that they are contrasting to the overlying active layer. We detected important fungal taxa represented by potential new species, particularly, those genetically close to Pseudogymnoascus destructans, which can cause extinction of bats in North America and Eurasia. The detection of viable fungi trapped in permafrost deserves further studies on the extension of its fungal diversity and its capability to expand from permafrost to other habitats in Antarctica, and elsewhere.