We characterized the fungal community found in the winter seasonal snow of the Antarctic Peninsula. From the samples of snow, 234 fungal isolates were obtained and could be assigned to 51 taxa of 26 genera. Eleven yeast species displayed the highest densities; among them, Phenoliferia glacialis showed a broad distribution and was detected at all sites that were sampled. Fungi known to be opportunistic in humans were subjected to antifungal minimal inhibition concentration. Debaryomyces hansenii, Rhodotorula mucilaginosa, Penicillium chrysogenum, Penicillium sp. 3, and Penicillium sp. 4 displayed resistance against the antifungals benomyl and fluconazole. Among them, R. mucilaginosa isolates were able to grow at 37 °C. Our results show that the winter seasonal snow of the Antarctic Peninsula contains a diverse fungal community dominated by cosmopolitan ubiquitous fungal species previously found in tropical, temperate, and polar ecosystems. The high densities of these cosmopolitan fungi suggest that they could be present in the air that arrives at the Antarctic Peninsula by air masses from outside Antarctica. Additionally, we detected environmental fungal isolates that were resistant to agricultural and clinical antifungals and able to grow at 37 °C. Further studies will be needed to characterize the virulence potential of these fungi in humans and animals.

We studied the fungal diversity present in soils sampled along a deglaciated chronosequence from para- to periglacial conditions on James Ross Island, north-east Antarctic Peninsula, using DNA metabarcoding. A total of 88 amplicon sequence variants (ASVs) were detected, dominated by the phyla Ascomycota, Basidiomycota and Mortierellomycota. The uncommon phyla Chytridiomycota, Rozellomycota, Monoblepharomycota, Zoopagomycota and Basidiobolomycota were detected. Unknown fungi identified at higher hierarchical taxonomic levels (Fungal sp. 1, Fungal sp. 2, Spizellomycetales sp. and Rozellomycotina sp.) and taxa identified at generic and specific levels (Mortierella sp., Pseudogymnoascus sp., Mortierella alpina, M. turficola, Neoascochyta paspali, Penicillium sp. and Betamyces sp.) dominated the assemblages. In general, the assemblages displayed high diversity and richness, and moderate dominance. Only 12 of the fungal ASVs were detected in all chronosequence soils sampled. Sequences representing saprophytic, pathogenic and symbiotic fungi were detected. Based on the sequence diversity obtained, Clearwater Mesa soils contain a complex fungal community, including the presence of fungal groups generally considered rare in Antarctica, with dominant taxa recognized as cold-adapted cosmopolitan, endemic, saprotrophic and phytopathogenic fungi. Clearwater Mesa ecosystems are impacted by the effects of regional climatic changes, and may provide a natural observatory to understand climate change effects over time.

In this study, we evaluated the fungal diversity present associated with cores of Oligocene rocks using a DNA metabarcoding approach. We detected 940,969 DNA reads grouped into 198 amplicon sequence variants (ASVs) representing the phyla Ascomycota, Basidiomycota, Mortierellomycota, Chytridiomycota, Mucoromycota, Rozellomycota, Blastocladiomycota, Monoblepharomycota, Zoopagomycota, Aphelidiomycota (Fungi) and the fungal-like Oomycota (Stramenopila), in rank abundance order. Pseudogymnoascus pannorum, Penicillium sp., Aspergillus sp., Cladosporium sp., Aspergillaceae sp. and Diaporthaceae sp. were assessed to be dominant taxa, with 22 fungal ASVs displaying intermediate abundance and 170 being minor components of the assigned fungal diversity. The data obtained displayed high diversity indices, while rarefaction indicated that the majority of the diversity was detected. However, the diversity indices varied between the cores analysed. The endolithic fungal community detected using a metabarcoding approach in the Oligocene rock samples examined contains a rich and complex mycobiome comprising taxa with different lifestyles, comparable with the diversity reported in recent studies of a range of Antarctic habitats. Due to the high fungal diversity detected, our results suggest the necessity of further research to develop strategies to isolate these fungi in culture for evolutionary, physiological, and biogeochemical studies, and to assess their potential role in biotechnological applications.

The use of yeasts has been explored as an efficient alternative to fungicide application in the treatment and prevention of post-harvest fruit deterioration. Here, we evaluated the biocontrol abilities of the Antarctic yeast strain Debaryomyces hansenii UFT8244 against the post-harvest phytopathogenic fungi Botrytis cinerea and Rhizopus stolonifer for the protection and preservation of strawberry fruit. The strongest inhibition of germination of B. cinerea (57%) was observed at 0 °C, followed by 40% at 25 °C. In addition, germ tubes and hyphae of B. cinerea were strongly surrounded and colonized by D. hansenii. Production of the enzymes β-1,3-glucanase, chitinase and protease by D. hansenii was detected in the presence of phytopathogenic fungus cell walls. The activity of β-1,3-glucanase was highest on day 12 of incubation and remained high until day 15. Chitinase and protease activities reached their highest levels on the day 15 of incubation. D. hansenii additionally demonstrated the ability to resist oxidative stress. Our data demonstrated that the main biocontrol mechanisms displayed by D. hansenii were the control of phytopathogenic fungal spore germination, production of antifungal enzymes and resistance to oxidative stress. We conclude that isolate D. hansenii UFT8422 should be further investigated for use at commercial scales at low temperatures.

Background/Objectives: We evaluated eukaryotic diversity in two cores obtained from abyssal sediments collected at depths of 4280 m and 4444 m in the equatorial Atlantic, between the Fernando de Noronha and São Pedro and São Paulo archipelagos, using a DNA metabarcoding approach applied to environmental DNA (eDNA) samples. Results: In total, we detected 248,905 DNA reads that were assigned to 65 amplicon sequence variants (ASVs) in the two core sediments (176,073 DNA reads and 59 ASVs were detected in sediment obtained at 4280 m depth, and 72,832 DNA reads and 14 ASVs were detected in the core at 4444 m). These represented three Kingdoms and five phyla: Fungi (Ascomycota and Basidiomycota), Viridiplantae (Chlorophyta and Streptophyta) and Chromista (Ciliophora), in rank abundance order. Ascomycota was the dominant phylum, followed by Basidiomycota. Didymella sp., Cladosporium sp., Scopulariopsis sp., Alternaria eichhorniae, Curvularia sp., Hortaea werneckii, Penicillium sp. (Ascomycota) and Malassezia globosa (Basidiomycota) were the most abundant taxa. Pseudochlorella pyrenoidosa (Chlorophyta) was the most abundant representative of Viridiplantae detected, and Spirotrachelostyla tani (Ciliophora) was the only Chromista detected, both present as minor components of the assigned eukaryotic diversity and only in the 4280 m core. The eukaryotic assemblages displayed moderate diversity indices, and those from the deeper core (4444 m depth) displayed the highest diversity values. Few assigned taxa were present in both samples. The two cores differed in their geological characteristics, consistent with their location in different depositional basins. The core obtained at 4280 m depth, located further north and more isolated from the adjacent continent by two fracture zones, appears to receive less terrigenous sediment input. In contrast, the core obtained at 4444 m depth is under greater continental influence and receives more terrigenous input from the continent. These geological and geographic differences may contribute to the varying eukaryotic eDNA diversities found. Results: Our metabarcoding study revealed the presence of a sediment eukaryotic community dominated by fungi. This included assigned ASVs representing groups with different ecological roles, such as cosmopolitan and phytopathogenic members and extremophiles, some of which may be able to survive and function in the polyextreme deep-sea abyssal conditions. Abyssal sediments present a potential habitat for studying organisms at the edge of viable conditions for life on Earth. eDNA metabarcoding provides a promising technique for detecting cryptic and uncultured biodiversity compared to traditional approaches, opening avenues for further ecological, evolutionary and biotechnological studies.

Microorganisms often occur in association with macroalgae, with the term “phycosphere” referring to the seaweed surface where they may be present. Phycosphere represents a poorly explored niche of marine diversity, especially in the polar regions. DNA metabarcoding provides a new and accessible method for the detection of DNA from different organisms, especially applicable for poorly known groups where taxonomic expertise is limited or unavailable. In this study we used DNA metabarcoding to provide an initial survey of eukaryotic communities associated with marine macroalgae obtained from the shores of Svalbard. Samples of Ulvaria obscura were sequenced and the DNA reads found were assigned to 75 taxa of six Kingdoms and 17 phyla: Chromista (Ciliophora, Haptophyta, Ochrophyta, Oomycota and Chrysophyta), Fungi (Ascomycota, Basidiomycota, Chytridiomycota, Mortierellomycota and Rozellomycota), Holozoa (Ichthyosporia), Metazoa (Cnidaria), Protozoa (Cercozoa, Discosea and Heterolobosea) and Viridiplantae (Bryophyta and Chlorophyta). The most abundant group was Viridiplantae, followed by Fungi. Our environmental DNA study confirmed that the phycosphere of U. obscura shelters a rich and complex microbiome, suggesting that Arctic macroalgae provide a hotspot of currently undescribed polar biodiversity. Additionally, our results were obtained during the first official Brazilian Arctic expedition, representing a historic step for the Brazilian Antarctic Program (PROANTAR).