Deschampsia antarctica Desv. (Poaceae) represents one of the two vascular plants that have colonized the Antarctic continent, which is usually exposed to extreme environmental conditions. In this work, we have characterized the endophytic fungi associated with the leaves of D. antarctica. Endophytic fungi were recovered from 91 individual plants from diVerent points of Admiralty Bay at King George Island, Antarctica. A total of 26 fungal isolates were obtained from 273 leaf fragments. All isolates were identiWed by analysis of the sequences of the internal transcribed spacer region (ITS) of the rDNA. Alternaria and Phaeosphaeria were the most frequent genera associated with the plant. Other fungal isolates were identi-Wed as Entrophospora sp. and several undescribed Ascomycete species. An interesting result was obtained for the isolates UFMGCB 215 and UFMGCB 262, which were related to fungi associated with bryophytes present in boreal ecosystems. Some isolates showed low identity in the ITS sequences to sequences of fungal species deposited in GenBank, suggesting that these fungi could be new species. This work is the Wrst report on fungal endophytes associated with leaves of the Antarctic grass D. antarctica.

BackgroundFungi are among the most abundant and diverse organisms on Earth. However, a substantial amount of the species diversity, relationships, habitats, and life strategies of these microorganisms remain to be discovered and characterized. One important factor hindering progress is the difficulty in correctly identifying fungi. Morphological and molecular characteristics have been applied in such tasks. Later, DNA barcoding has emerged as a new method for the rapid and reliable identification of species. The nrITS region is considered the universal barcode of Fungi, and the ITS1 and ITS2 sub-regions have been applied as metabarcoding markers. In this study, we performed a large-scale analysis of all the available Basidiomycota sequences from GenBank. We carried out a rigorous trimming of the initial dataset based in methodological principals of DNA Barcoding. Two different approaches (PCI and barcode gap) were used to determine the performance of the complete ITS region and sub-regions.ResultsFor most of the Basidiomycota genera, the three genomic markers performed similarly, i.e., when one was considered a good marker for the identification of a genus, the others were also; the same results were observed when the performance was insufficient. However, based on barcode gap analyses, we identified genomic markers that had a superior identification performance than the others and genomic markers that were not indicated for the identification of some genera. Notably, neither the complete ITS nor the sub-regions were useful in identifying 11 of the 113 Basidiomycota genera. The complex phylogenetic relationships and the presence of cryptic species in some genera are possible explanations of this limitation and are discussed.ConclusionsKnowledge regarding the efficiency and limitations of the barcode markers that are currently used for the identification of organisms is crucial because it benefits research in many areas. Our study provides information that may guide researchers in choosing the most suitable genomic markers for identifying Basidiomycota species.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-017-0958-x) contains supplementary material, which is available to authorized users.

The diversity of yeasts collected from different sites in Antarctica (Admiralty Bay, King George Island and Port Foster Bay and Deception Island) and their ability to produce extracellular enzymes and mycosporines were studied.

This study assessed the diversity and distribution of filamentous fungi obtained from water sampled from six lakes in the Antarctic Peninsula. One hundred and twenty-eight fungal isolates were purified and identified by analysis of nuclear rDNA ITS region sequences as belonging to 31 fungal different operational taxonomic units (OTUs). The most frequently isolated fungi were Geomyces pannorum and Mortierella sp.; these species occurred in six and three of the lakes sampled, respectively, and displayed the highest total colony-forming unit per L. Different species that have not been found to these lakes and/or had adapted to cold conditions were found. In general, the fungal community displayed low richness and high dominance indices. The species Cadophora cf. luteo-olivacea, Cadophora malorum, Davidiella tassiana, G. pannorum, Mortierella cf. alpina and Thelebolus cf. microsporus that were found in the lakes in question were also previously found in other cold ecosystems, such as Arctic, temperate and Alpine regions. The results of this study suggest the presence of an interesting aquatic fungal web, including symbionts, weak and strong saprophytes and parasite/pathogen fungal species. This aquatic web fungal may be a useful community model for further ecological and evolutionary studies of extreme habitats.

The diversity and antimicrobial activity of endophytic fungi associated with the Brazilian medicinal plant Solanum cernuum Vell. were studied during summer and winter seasons. A total of 246 fungal isolates were obtained, including 225 filamentous fungi and 21 yeasts. They were identified by morphological, physiological, and molecular methods. Fifty-five different taxa represented by the phyla Ascomycota (33 taxa), Basidiomycota (21 taxa), and Zygomycota (one taxon) were identified. The most abundant taxa were closely related to Arthrobotrys foliicola , Colletotrichum gloeosporioides , Coprinellus radians , Glomerella acutata , Diatrypella frostii , Phoma glomerata , Mucor sp., Phlebia subserialis , Phoma moricola , Phanerochaete sordida , and Colletotrichum sp. A total of 265 fungal extracts were screened and 64 (26.01%) displayed antimicrobial activities. Among these extracts, 18 (28.12%) presented antibacterial and antifungal activities, 42 (65.62%) displayed selective antibacterial activity, and four (6.25%) exhibited only antifungal activity. The best values of minimum inhibitory concentration were obtained from extracts of Cryptococcus rajasthanensis , Glomerella acutata, Leptosphaeria sp., and Phoma glomerata ranging from 7.8 to 15.62 µg/mL. This study is the first survey of the endophytic fungi community associated with S. cernuum, and our results show that they can represent a promising source of bioactive compounds.

Nahuel Huapi (NH) Lake is an oligotrophic temperate lake of glacial origin with high transparency, surrounded by well-developed forests and located at San Carlos de Bariloche, Nahuel Huapi National Park, in Patagonia, Argentina. In this lake, we characterized yeast distribution and diversity along a south-to-north transect and established a relationship between the ability to produce photoprotective compounds (PPCs) (carotenoid pigments and mycosporines) and the occurrence of yeast at different collection points. Subsurface water samples were filtered for yeast isolation. Total yeast counts ranged between 22 and 141 CFU L(-1) , and the highest values corresponded to the most impacted sites. Littoral sites had a low proportion of yeast-producing PPCs and this group prevailed in pelagic sites. This is probably a result of the high transparency of the water and the increased UV exposure. The yeast community from NH Lake showed a high species richness and a uniform distribution of taxa between pelagic and border collection points. Yeasts were identified as belonging to 14 genera and 34 species. Rhodotorula mucilaginosa and Cryptococcus victoriae were the most frequently found species, representing 14.4% and 13.6% of the total yeast isolates, respectively. Most of the yeast isolates demonstrated at least one extracellular enzymatic activity (mainly cellulase and lipase activities), which suggested that these microorganisms are metabolically active in the lake.

The purpose of this study was to examine antimicrobial activity of endophytic fungi isolated from the leaves, stems, and roots of 54 species of Orchidaceae collected in a Brazilian tropical ecosystem. In total, 382 filamentous fungi and 13 yeast isolates were obtained and cultured to examine the production of crude extracts. Thirty-three percent of the isolates displayed antimicrobial activity against at least one target microorganism. The multivariate statistical analyses conducted indicate that the extracts of endophytic fungi isolated from leaves of terrestrial orchids in semideciduous forest were more active against Escherichia coli, whereas extracts of endophytic fungi from roots of rupicolous orchids collected in rock fields were more active against Candida krusei and Candida albicans. Among the fungi that were screened in the study, 22 isolates held their antimicrobial activities after replication and were therefore selected for assessment of the minimum inhibitory concentration (MIC), which ranged from 62.5 to 250 microg/mL and 7.8 to 250 microg/mL against bacteria and fungi, respectively. One isolate of Alternaria sp. and one isolate of Fusarium oxysporum presented the strongest antibacterial activity. Three Fusarium isolates, Epicoccum nigrum, and Sclerostagonospora opuntiae showed the greatest MIC values against the pathogenic yeasts. This study is the first survey investigating the bioactive potential of endophytic fungi associated with tropical Orchidaceae species present in Brazilian ecosystems.

The mangrove ecosystem harbors a complex microbial community that plays crucial role in biogeochemical cycles. In this study, we analyzed mangrove sediments from India using de novo whole metagenome next generation sequencing (NGS) and compared their taxonomic and functional community structures to mangrove metagenomics samples from Brazil and Saudi Arabia. The most abundant phyla in the mangroves of all three countries was Proteobacteria, followed by Firmicutes and Bacteroidetes. A total of 1,942 genes were found to be common across all the mangrove sediments from each of the three countries. The mangrove resistome consistently showed high resistance to fluoroquinolone and acriflavine. A comparative study of the mangrove resistome with other ecosystems shows a higher frequency of heavy metal resistance in mangrove and terrestrial samples. Ocean samples had a higher abundance of drug resistance genes with fluoroquinolone and methicillin resistance genes being as high as 28.178% ± 3.619 and 10.776% ± 1.823. Genes involved in cobalt-zinc-cadmium resistance were higher in the mangrove (23.495% ± 4.701) and terrestrial (27.479% ± 4.605) ecosystems. Our comparative analysis of samples collected from a variety of habitats shows that genes involved in resistance to both heavy metals and antibiotics are ubiquitous, irrespective of the ecosystem examined.