Discovering fungi in the extreme Copahue geothermal region; first comprehensive assessment of cultivable species.

HIPPERDINGER MARCELA; CASTRO CAMILA; URBIETA SOFIA; ASTORECA ANDREA

Quilmes

Congreso; 3er Congreso ISME Latinoamericano; 2023

Copahue geothermal region, in the northwest corner of Neuquén province in Coordillera de los Andes, is a natural extreme environment influenced by the still active Copahue volcano. The area presents two different parts: the geothermal manifestations with ponds and hot springs of diverse temperature and pH conditions (from moderate to more than 90°C and from neutral to highly acidic) and the acidic Río Agrio that originates near the crater of Copahue volcano (pH near 1) and runs down for more than 20 Km maintaining acid waters (pH 2-3), despite receiving many neutral tributary courses. Biodiversity of prokaryotes has been deeply studied at both sites, and even with such harsh environmental conditions both environments present high diversity of acidophilic and thermophilic bacteria and archaea, with many autochthonous novel species. On the other hand, fungal diversity has never been systematically explored. In this work we present the first comprehensive assessment of fungal species in the Copahue geothermal region by cultivation using different isolation strategies. The taxonomical affiliation was made by macroscopic and microscopic observation and confirmed by sequencing of ITS 1-4 and NL 1-4 regions and the beta-tubulin gene.The enrichment and isolation were done from three samples of the geothermal ponds (AL: 82°C pH 2, B9: 49°C pH 2, LMa: 84°C pH 4) and various all through Río Agrio with temperatures from 40 to 20°C and pH from 1 to 4.5. The first attempt was to incubate at temperature and pH close to the environmental, however there was no growth at extreme conditions despite a grate culturing effort. Only one isolate was obtained at 45°C and pH 3 (Aspergillus sp.). At moderate conditions (25-30°C, pH 3 -7) a total of 35 other isolates were obtained from all sampled tested; the most abundant species belonged to Penicillium genus, regardless of the site. Other genera identified were Trichoderma, Cladosporium, Diplococcium, Tolypocladium and some representatives of the zygomycota division.These results highlight the enormous biodiversity of the Copahue region, as well as the flexibility of its fungal community, able to tolerate highly extreme environmental conditions.