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.

We surveyed the distribution and diversity of fungi associated with eight macroalgae from Antarctica and their capability to produce bioactive compounds. The collections yielded 148 fungal isolates, which were identified using molecular methods as belonging to 21 genera and 50 taxa. The most frequent taxa were Geomyces species (sp.), Penicillium sp. and Metschnikowia australis. Seven fungal isolates associated with the endemic Antarctic macroalgae Monostroma hariotii (Chlorophyte) displayed high internal transcribed spacer sequences similarities with the psychrophilic pathogenic fungus Geomyces destructans. Thirty-three fungal singletons (66%) were identified, representing rare components of the fungal communities. The fungal communities displayed high diversity, richness and dominance indices; however, rarefaction curves indicated that not all of the fungal diversity present was recovered. Penicillium sp. UFMGCB 6034 and Penicillium sp. UFMGCB 6120, recovered from the endemic species Palmaria decipiens (Rhodophyte) and M. hariotii, respectively, yielded extracts with high and selective antifungal and/or trypanocidal activities, in which a preliminary spectral analysis using proton nuclear magnetic resonance spectroscopy indicated the presence of highly functionalised aromatic compounds. These results suggest that the endemic and cold-adapted macroalgae of Antarctica shelter a rich, diversity and complex fungal communities consisting of a few dominant indigenous or mesophilic cold-adapted species, and a large number of rare and/or endemic taxa, which may provide an interesting model of algal-fungal interactions under extreme conditions as well as a potential source of bioactive compounds.

This work describes the distribution and diversity of fungal endophytes associated with leaves of Colobanthus quitensis, a dicotyledonous plant that lives in Antarctica. A total of 188 fungal isolates were obtained from six different sites located across a 25.5-km transect through Admiralty Bay, at King George Island. The ITS1-5.8S-ITS2 nuclear ribosomal gene was sequenced and the endophytic fungi were identified as species belonging to the genera Aspergillus, Cadophora, Davidiella, Entrophospora, Fusarium, Geomyces, Gyoerffyella, Microdochium, Mycocentrospora, and Phaeosphaeria. Davidiella tassiana was the prevalent species with 20.2% abundance. The endophytic fungal community showed low richness and high dominance indexes. Eleven endophytic taxa (58%) were fungi able to produce melanin in their hyphae, which may confer resistance against freezing temperatures and high rates of UV radiation and may increase their fitness in the extreme conditions of the Antarctic environment. In addition, phytopathogenic and decomposer species associated with healthy leaves of C. quitensis were found. The results obtained in this work show that C. quitensis is an interesting reservoir of saprobic and pathogenic fungal species, and could be a community model for further ecological and evolutionary studies, as well as studies of the adaptation mechanisms these microorganisms have to the extreme conditions in Antarctica.

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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.

Bioassay-guided fractionation of Cladosporium cladosporioides (Fresen.) de Vries extracts led to the isolation of four compounds, including cladosporin, 1, isocladosporin, 2, 5′-hydroxyasperentin, 3, and cladosporin-8-methyl ether, 4. An additional compound 5′,6-diacetyl cladosporin, 5, was synthesized by acetylation of compound 3. Compounds 1-5 were evaluated for antifungal activity against plant pathogens. Phomopsis viticola was the most sensitive fungus to the tested compounds. At 30 μM, compound 1 exhibited 92.7%, 90.1%, 95.4% and 79.9% growth inhibition against Colletotrichum acutatum, Co. fragariae, Co. gloeosporioides and Phomopsis viticola, respectively. Compound 2 showed 50.4%, 60.2% and 83.0% growth inhibition at 30 μM against Co. fragariae, Co. gloeosporioides and P. viticola, respectively. Compounds 3 and 4 were isolated for the first time from Cladosporium cladosporioides. Moreover, the identification of essential structural features of the cladosporin nuclei has also been evaluated. These structures provide new templates for the potential treatment and management of plant diseases.

The endophytic fungal community associated with the native cactus Opuntia humifusa in the United States was investigated and its potential for providing antifungal compounds. A hundred-eight endophytic fungal isolates were obtained and identified by molecular methods into 17 different taxa of the genera Alternaria, Aureobasidium, Biscogniauxia, Cladosporium, Cryptococcus, Curvularia, Diaporthe, Epicoccum, Paraconiothyrium, Pestalotiopsis and Phoma. The most frequent species associated with O. humifusa were Alternaria sp. 3, Aureobasidium pullulans and Diaporthe sp. The fungal community of O. humifusa had a high richness and diversity; additionally, the species richness obtained indicates that the sample effort was enough to recover the diversity pattern obtained. Six extracts of endophytes showed antifungal properties and (1)H NMR analyses of the extracts of Alternaria sp. 5 Ohu 8B2, Alternaria sp. 3 Ohu 30A, Cladosporium funiculosum Ohu 17C1 and Paraconiothyrium sp. Ohu 17A indicated the presence of functional groups associated with unsaturated fatty-acid olefinic protons and fatty acid methylene and methyl protons. GC-FID analysis of these extracts confirmed the presence of a mixture of different fatty acids. The (1)H NMR analyses of Biscogniauxia mediterranea Ohu 19B extracts showed the presence of aromatic compounds. From the extract of B. mediterranea we isolated the compound 5-methylmellein that displayed moderate antifungal activity against the phytopathogenic fungi Phomopsis obscurans. Our results suggest that native medicinal cacti of the United States can live symbiotically with rich and diverse endophytic communities and may be a source of bioactive molecules, including those able to inhibit or control plant disease pathogens.