Search

Simple Summary: We characterized the fungal organisms present in soils at James Ross Island, north-east Antarctic Peninsula, using DNA metabarcoding. Taxa detected included members of the widespread phyla Ascomycota, Basidiomycota and Mortierellomycota. Additionally, the uncommon phyla Chytridiomycota, Rozellomycota, Monoblepharomycota, Zoopagomycota and Basidiobolomycota were detected. Unknown fungi and taxa identified at generic and specific levels dominated the assemblages. The fungal sequence assemblages displayed high diversity and richness, and moderate dominance, and included taxa known to play saprophytic, pathogenic and symbiotic functions. Soils of Clearwater Mesa contain a complex fungal community, including fungal groups considered rare in Antarctica, dominated by cold-adapted cosmopolitan, endemic, saprotrophic and phytopathogenic taxa. 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. [ABSTRACT FROM AUTHOR]

We assessed fungal diversity in deep-sea sediments obtained from different depths in the Southern Ocean using the internal transcribed spacer 2 (ITS2) region of nuclear ribosomal DNA by metabarcoding through high-throughput sequencing (HTS). We detected 655,991 DNA reads representing 263 fungal amplicon sequence variants (ASVs), dominated by Ascomycota, Basidiomycota, Mortierellomycota, Mucoromycota, Chytridiomycota and Rozellomycota, confirming that deep-sea sediments can represent a hotspot of fungal diversity in Antarctica. The community diversity detected included 17 dominant fungal ASVs, 62 intermediate and 213 rare. The dominant fungi included taxa of Mortierella, Penicillium, Cladosporium, Pseudogymnoascus, Phaeosphaeria and Torula. Despite the extreme conditions of the Southern Ocean benthos, the total fungal community detected in these marine sediments displayed high indices of diversity and richness, and moderate dominance, which varied between the different depths sampled. The highest diversity indices were obtained in sediments from 550 m and 250 m depths. Only 49 ASVs (18.63%) were detected at all the depths sampled, while 16 ASVs were detected only in the deepest sediment sampled at 1463 m. Based on sequence identities, the fungal community included some globally distributed taxa, primarily recorded otherwise from terrestrial environments, suggesting transport from these to deep marine sediments. The assigned taxa included symbionts, decomposers and plant-, animal- and human-pathogenic fungi, suggesting that deep-sea sediments host a complex fungal diversity, although metabarcoding does not itself confirm that living or viable organisms are present. [ABSTRACT FROM AUTHOR]

We studied the molecular taxonomy and diversity of cultivable rock fungi from Antarctic islands. From 50 rock samples, 386 fungal isolates were obtained and identified as 33 taxa of 20 genera. The genera Cladophialophora, Cladosporium, Cyphellophora, Eichleriella, Paracladophialophora, and Penicillium displayed the highest densities. Ecological diversity indices showed that the fungal assemblages are diverse and rich with low dominance. The genera Cladophialophora, Cladosporium, and Penicillium showed a broad distribution from rocks of the various islands. One hundred and fifty-nine fungi, grown at 37 °C, were identified as Penicillium chrysogenum, Fusarium sp., and Rhodotorula mucilaginosa. One hundred and three fungi displayed haemolytic activity, 81 produced proteinase, 9 produced phospholipase, and 25 presented dimorphism and a spore diameter ≤ 4 µm. The Antarctic Peninsula region appears to be under the effects of global climate changes, which may expose and accelerate the rock's weathering processes, and expose and release cryptic fungi and other microbes, especially those with innate pathogenic potential, previously arrested in rocks. Consequently, these rocks and their particles may represent a vehicle for the dispersal of microbial propagules, including those able to spread pathogens, along, across, and out of Antarctica. [ABSTRACT FROM AUTHOR]

The interest in the diversity of yeasts in the Antarctic environment has increased in recent years, mainly because Antarctic microbiology is a recent science, and little is known about the biodiversity and genetic resources of the microorganisms that inhabit this ecosystem. This study aimed to determine the diversity of epiphytic yeasts in samples of Deschampsia antarctica, Colobanthus quitensis, and bryophytes, as well yeasts present in biofilms collected from Antarctic meltwater. Samples were collected in the summer of 2014 and 2015 during expeditions organized by the Brazilian Antarctic Program. A total of 310 yeasts were isolated, and 34 species were identified by sequencing the D1/D2 domains of the rDNA region belonging to 18 genera. The species Vishniacozyma victoriae and Mrakia gelida were the most abundant. Dioszegia antarctica and Leucosporidium creatinivorum were found only in plant substrates. Most psychrophilic yeasts were isolated from biofilms, including Glaciozyma antarctica, Glaciozyma martinii, Mrakia gelida, Mrakia frigida, Mrakia robertii, Phenoliferia glacialis, and Phenoliferia psychrophenolica, suggesting that the substrates examined in this study represented an interesting habitat for the isolation and characterization of epiphytic and non-epiphytic yeasts that colonize the Antarctic region. [ABSTRACT FROM AUTHOR]

A novel actinobacterium, designated strain CMAA 1533T, was isolated from the rhizosphere of Deschampsia antarctica collected at King George Island, Antarctic Peninsula. Strain CMAA 1533T was found to grow over a wide range of temperatures (4-28 °C) and pH (4-10). Macroscopically, the colonies were observed to be circular shaped, smooth, brittle and opaque-cream on most of the culture media tested. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CMAA 1533T belongs to the family Nocardiaceae and forms a distinct phyletic line within the genus Rhodococcus. Sequence similarity calculations indicated that the novel strain is closely related to Rhodococcus degradans CCM 4446T, Rhodococcus erythropolis NBRC 15567T and Rhodococcus triatomae DSM 44892T (≤ 96.9%). The organism was found to contain meso-diaminopimelic acid, galactose and arabinose in whole cell hydrolysates. Its predominant isoprenologue was identified as MK-8(H2) and the polar lipids as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The major fatty acids were identified as Summed feature (C16:1 ω6c and/or C16:1 ω7c), C16:0, C18:1 ω9c and 10-methyl C18:0. The G+C content of genomic DNA was determined to be 65.5 mol%. Unlike the closely related type strains, CMAA 1533T can grow at 4 °C but not at 37 °C and was able to utilise adonitol and galactose as sole carbon sources. Based on phylogenetic, chemotaxonomic and physiological data, it is concluded that strain CMAA 1533T (= NRRL B-65465T = DSM 104532T) represents a new species of the genus Rhodococcus, for which the name Rhodococcus psychrotolerans sp. nov. is proposed. [ABSTRACT FROM AUTHOR]

Species of Leucosporidiales are a group of psychrotolerant yeasts with biotechnological potential. In the present work, we studied the phenotypic, genetic and sexual characteristics of three species of this genus (Leucosporidium scottii, Leucosporidiella creatinivora and Le. yakutica) to clarify the evolutionary relationship among these closely related taxa. From the results obtained, it becomes clear that these yeasts can interbreed. Although genetic delimitation is possible for the three species, the extent of nucleotide substitutions and phenotypic differences observed between them are lower than that expected for species that have ended the speciation process. Our taxonomic conclusion is to maintain the three taxa until further genomic data are gathered. However, the concept of L. scottii species complex is proposed for this group of species. Finally, we transfer all Leucosporidiella and Mastigobasidium species to Leucosporidium (Leucosporidiales), and, in order to end the polyphyly condition of these taxa, we propose the new genus Pseudoleucosporidium gen. nov. and the new combination Peudoleucosporidium fasciculatum comb. nov. [ABSTRACT FROM AUTHOR]

Few studies have addressed the diversity of cultivable fungi from marine sediments, especially those from Antarctica. In the present study, we evaluated the presence and distribution of cultivable fungi in marine core sediments obtained from 100, 500, 700 and 1,100 m below the Antarctic Ocean surface. Fifty-two fungal isolates were identified as Penicillium solitum by their physiological and morphological characteristics, and the identity of 12 representative isolates was further confirmed by sequencing of the ITS1-5.8S-ITS2 and β-tubulin genes. P. solitum displayed high sequence similarity to Penicillium taxa that have been described from other marine habitats. Conidial germination of P. solitum occurred at low temperatures and high salinities. In addition, P. solitum displayed extracellular amylasic and esterasic activities. The isolation of P. solitum from marine sediments in Antarctica and its survival at low temperatures and high salt concentrations suggest that it is adapted to the cold and halophilic environment of the Antarctic oceans. Because P. solitum produces extracellular enzymes, it is an interesting eukaryotic model for the study of structure–function relationships during enzymatic biocatalysis and biotransformation under extreme conditions. Marine sediments from Antarctica may represent a unique source for obtaining extremophilic fungi. New studies using different culture media, temperatures ranges and pressure conditions as well as metagenomic techniques can assist in understanding the extremophilic fungal communities in marine sediments across the Antarctic Ocean. [ABSTRACT FROM AUTHOR]

• The endophytic fungi of Copaifera langsdorffii and Copaifera pubiflora and their antimicrobial activities were characterized. • A total of 668 fungal isolates of the 64 taxa and 22 genera were obtained. • Extracts of Alternaria and Diaporthe displayed antibacterial activities. Medicinal plants represent a promising reservoir of diverse endophytic fungi, including taxa that are able to produce bioactive metabolites. In Brazil, the genus Copaifera includes species that are well known in folk medicine mainly due to their ability to produce oleoresin. In this study, we characterized the endophytic fungal communities associated with Copaifera langsdorffii and Copaifera pubiflora and investigated their ability to produce antimicrobial agents. We obtained 668 fungal isolates from the leaves, stems, and seeds of both plants, which were later classified into 64 taxa and 22 genera. Diaporthe sp. 6, Xylariaceae sp. 1, Diaporthales sp. 1, and Diaporthales sp. 2 were the most abundant taxa in C. langsdorffii , while Phyllosticta sp., Diaporthe sp. 7, Diaporthales sp. 3, and Diaporthe miriciae were the most abundant taxa in C. pubiflora. Diaporthe sp. 4, Phyllosticta sp., Diaporthe sp. 1, Diaporthe sp. 7, and Neopestalotiopsis sp. were the only taxa common between the two plants. Both plants were found to have high fungal diversity, especially C. langsdorffii. Six extracts displayed antibacterial, being Alternaria sp., Diaporthe sp. 1, D. miriciae , and Diaporthe sp. 14. Our results showed that different tissues of the ethnomedicinal plants C. langsdorffii and C. pubiflora are systematically colonized by rich and diverse endophytic fungal communities, and that some of the fungi are able to produce antimicrobial compounds, which may be explored in further studies as potential candidates for the development of new drugs. [ABSTRACT FROM AUTHOR]

We recovered 195 fungal isolates from the sediments of different lakes in the Antarctic Peninsula, which were screened to detect bioactive compounds. Forty-two taxa belonging to the phyla Ascomycota , Basidiomycota , and Mortierellomycota were identified. Thelebolus globosus , Antarctomyces psychrotrophicus , Pseudogymnoascus verrucosus , Vishniacozyma victoriae , and Phenoliferia sp. were found to be the most prevalent. The fungal assemblages showed high diversity and richness, but low dominance values. However, the diversity indices and fungal distribution ranged according to the different lake sediments. Sixty fungal extracts displayed at least one biological activity against the evaluated targets. Among them, Pseudogymnoascus destructans showed selective trypanocidal activity, Cladosporium sp. 1 and Trichoderma polysporum showed antifungal activity, and Pseudogymnoascus appendiculatus and Helotiales sp. showed high herbicidal activity. We detected a rich and diverse fungal community composed of cold cosmopolitan and psychrophilic endemic taxa recognized as decomposers, symbiotics, pathogens, and potential new species, in the sediments of Antarctic lakes. The dynamics and balance of this fungal community represents an interesting aquatic web model for further ecological and evolutionary studies under extreme conditions and potential climate changes in the regions. In addition, we detected fungal taxa and isolates able to produce bioactive compounds that may represent the source of prototype molecules for applications in medicine and agriculture. Image 1 • We access fungi present in the sediments of lakes of Antarctica. • Taxa belonging to cold cosmopolitan and psychrophilic endemic taxa. • Fungi demonstrated trypanocidal, herbicidal, and antifungal activities. • Decomposers, symbiotics, pathogens, and potential new species were detected. [ABSTRACT FROM AUTHOR]

In the present study, we surveyed the distribution and diversity of fungal assemblages associated with 10 species of marine animals from Antarctica. The collections yielded 83 taxa from 27 distinct genera, which were identified using molecular biology methods. The most abundant taxa were Cladosporium sp. 1, Debaryomyces hansenii, Glaciozyma martinii , Metschnikowia australis , Pseudogymnoascus destructans , Thelebolus cf. globosus , Pseudogymnoascus pannorum , Tolypocladium tundrense , Metschnikowia australis , and different Penicillium species. The diversity, richness, and dominance of fungal assemblages ranged among the host; however, in general, the fungal community, which was composed of endemic and cold-adapted cosmopolitan taxa distributed across the different sites of Antarctic Peninsula, displayed high diversity, richness, and dominance indices. Our results contribute to knowledge about fungal diversity in the marine environment across the Antarctic Peninsula and their phylogenetic relationships with species that occur in other cold, temperate, and tropical regions of the World. Additionally, despite their extreme habitats, marine Antarctic animals shelter cryptic and complex fungal assemblages represented by endemic and cosmopolitan cold-adapted taxa, which may represent interesting models to study different symbiotic associations between fungi and their animal hosts in the extreme conditions of Antarctica. Image 1 • We surveyed the distribution and diversity of fungi associated with marine animals from Antarctica. • The collections yielded 83 taxa from 27 distinct genera. • The fungal community was composed of endemic and cold-adapted cosmopolitan taxa. [ABSTRACT FROM AUTHOR]

This study focused on the taxonomy and diversity of the endophytic fungi associated with Vellozia gigantea , an endemic, ancient, and endangered plant species that occurs only in the rupestrian grasslands of Brazil. A total of 285 fungal isolates were recovered from leaves and roots of the V. gigantea , which were identified in 27 genera and 87 different taxa using molecular taxonomy methods. Xylaria berteri , Diaporthe sp. 1, Nigrospora oryzae , Muscodor sp. 1, Colletotrichum aeschynomene , and Trichoderma viride occurred in the highest frequency in both the leaf and root. Diaporthe was the most abundant genus, with 70 endophytic isolates recovered from the leaves and roots. Among all the taxa identified, 62 occurred as singlets, including those of the genera Clonostachys , Coccomyces , Crucellisporiopsis , Daldinia , Myxotrichum , Pallidocercospora , Pezicula , Peyronellaea , and Pseudocercospora . The diversity indices displayed high values, showing that V. gigantea shelters a diverse and rich mycobiota. Our results indicate that V. gigantea shelters in its tissues a highly diverse and cryptic mycobiota, including several rare species previously unreported as endophytes, but that are reported to have different ecological functions, which might be an important biological component contributing to the fitness of the plants living in the rupestrian grassland. [ABSTRACT FROM AUTHOR]