Investigation of the unculturable fungal diversity of cold environments

Description of the research

Cold habitats (characterized by an average annual temperature <5°C) represent ∼80% of the environments present on Earth: deep seas, cold deserts, ice caps and polar and mountain glaciers. Several studies have documented that these habitats, while exhibiting extreme ecological conditions, host a viable and metabolically active community, composed of both prokaryotic and eukaryotic microorganisms. Psychrophilic microorganisms (obligate and facultative) living in cold habitats are subject to a combination of stress factors that have stimulated the development of multiple physiological adaptations that allow them to colonize these habitats, where they are considered active players of biogeochemical cycles.

The first studies on cold-adapted microbial communities date back to the 1960s and describe the culturable diversity of such environments. As is well known, culturable microorganisms represent only a small percentage of the total microbial biodiversity. This implies that the ecological conclusions based exclusively on the study of culturable diversity depicted a picture very far from the present reality. In recent years and thanks to molecular techniques (e.g. next-generation sequencing, NGS), the investigation of unculturable microbial diversity has finally become possible.

The study of some cold habitats (Alpine glaciers and Antarctica – soil, sediments, ice, melt water and brines) by the researchers of the Department of Agricultural, Food and Environmental Sciences of the University of Perugia (hosting Institution of the DBVPG Collection concerned not only the isolation of yeasts and their conservation, but also the investigation of the unculturable fungal community (yeasts and filamentous fungi) associated to them. This was correlated with the physical and chemical (abiotic) conditions present in the explored environment and also with coexisting prokaryotic communities, generating ecological conclusions on the distribution of specialist and generalist taxa. In addition, some experimental plans have been developed to evaluate the dynamics of microbial communities subjected to different forms of alteration during growth conditions, such as, for example, the increase in temperature or the loss of glacial cover.

Papers published on the subject in the last 5 years

L. Selbmann, S. Onofri, C. Coleine, P. Buzzini, F. Canini, L. Zucconi (2017) Effect of environmental parameters on biodiversity of the fungal component in lithic Antarctic communities. Extremophiles, 21: 1069-1080; DOI: 10.1007/s00792-017-0967-6.

L. Borruso, C. Sannino, L. Selbmann, D. Battistel, L. Zucconi, M Azzaro, B. Turchetti, P. Buzzini, M. Guglielmin (2018). A thin ice layer segregates two distinct fungal communities in Antarctic brines from Tarn Flat (Northern Victoria Land). Scientific Reports 8:6582 DOI: 10.1038/s41598-018-25079-3.

D. Kulikova-Borovikova, S. Lisi, E. Dauss, T. Alamae, P. Buzzini, J.E. Hallsworth, A. Rapoport (2018) Activity of the α-glucoside transporter Agt1 in Saccharomyces cerevisiae cells during dehydration-rehydration events. Fungal Biology, 122:613-620; DOI: 10.1016/j.funbio.2018.03.006.

C. Sannino, L. Borruso, C. Smiraglia, A. Bani, A. Mezzasoma, L. Brusetti, B. Turchetti, P. Buzzini (2020) Dynamics of in situ growth and taxonomic structure of fungal communities in Alpine supraglacial debris. Fungal Ecology 44 (100891); DOI: 10.1016/j.funeco.2019.100891.

B. Turchetti, G. Marconi, C. Sannino, P. Buzzini (2020) DNA Methylation Changes Induced by Cold in Psychrophilic and Psychrotolerant Naganishia Yeast Species. Microorganisms 8, 296; DOI: 10.3390/microorganisms8020296; DOI: 10.3390/microorganisms8020296.

C. Coleine, N. Pombubpa, L. Zucconi, S. Onofri, B. Turchetti, P.Buzzini, J.E. Stajich, L. Selbmann (2020). Uncovered Microbial Diversity in Antarctic Cryptoendolithic Communities Sampling three Representative Locations of the Victoria Land. Microorganisms, 8(6): 942; DOI: 10.3390/microorganisms8060942.

C. Sannino, L. Borruso, A. Mezzasoma, D. Battistel, L. Zucconi, L. Selbmann, M. Azzaro, S. Onofri, B. Turchetti, P. Buzzini, M. Guglielmin (2020). Intra- and inter-cores fungal diversity suggests interconnection of different habitats in an Antarctic frozen lake (Boulder Clay, Northern Victoria Land) Environmental Microbiology, 22(8), 3463-3477; DOI: 10.1111/1462-2920.15117.

A. Franzetti, F. Pittino, I. Gandolfi, R.S. Azzoni, G. Diolaiuti, C. Smiraglia, M. Pelfini, C. Compostella, B. Turchetti, P. Buzzini, R. Ambrosini (2020). Early ecological succession patterns of bacterial, fungal and plant communities along a chronosequence in a recently deglaciated area of Italian Alps FEMS Microbiology Ecology 96 (10), fiaa165; DOI: 10.1093/femsec/fiaa165.

F. Canini, J. Geml, L.P. D’Acqui, P. Buzzini, B. Turchetti, S. Onofri, S. Ventura, L. Zucconi (2021) Fungal diversity and functionality are driven by soil texture in Taylor Valley, Antarctica. Fungal Ecology 50, 101041; DOI: 10.1016/j.funeco.2021.101041.

F. Canini, J. Geml, P. Buzzini, B. Turchetti, S. Onofri, L.P. D’Acqui, C. Ripa, L. Zucconi (2021) Growth Forms and Functional Guilds Distribution of Soil Fungi in Coastal Versus Inland Sites of Victoria Land, Antarctica. Biology Basel, 10(4), 320; DOI:10.3390/biology10040320.

C. Sannino, L. Borruso, A. Mezzasoma, D. Battistel, S. Ponti, B. Turchetti, P. Buzzini, M. Guglielmin (2021) Abiotic factors affecting the bacterial and fungal diversity of permafrost in a rock glacier in the Stelvio Pass (Italian Central Alps). Applied Soil Ecology 166, 104079; DOI: 10.1016/j.apsoil.2021.104079.

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