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| Author(s): |
Juliana Aparecida Dos Santos
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Rio Claro. 2021-03-23. |
| Institution: | Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro |
| Defense date: | 2020-09-16 |
| Advisor: | Lara Durães Sette; Rubens Tadeu Delgado Duarte |
| Abstract | |
Glacial retreat is often considered a clear sign of global warming. Glacier soils harbor an active microbial community of decomposers, and under the continuous retraction of glaciers, the soil starts to represent a gradient of physical, chemical, and biological factors that reflect local changes over time. Antarctic mycology is a relatively recent science and little is known about the biological nature of fungi in this environment. The present work is part of three projects (FAPESP 2016/07957-7, PROANTAR/CNPq MICROSFERA and CNPq Universal (407986/2018-9)) and it aimed at assessing the diversity of fungi (by the use of culture-dependent and -independent methods) from samples of glacier soil collected after glacial retreat of Collins and Baranowski glaciers (Fildes Peninsula, King George Island). Moreover, it also aimed at evaluating the structure of the fungal community and correlating it to the composition of the sampled soils.The results obtained using the culture-dependent approach revealed a difference in the composition of fungal communities along the retreat of Collins glacier. They also showed the presence of isolates that have not been reported in Antarctica yet. A total of 309 fungi distributed in 19 genera were obtained. Representatives of the genera Pseudogymnoascus and Mortierella were the most abundant in all samples. The data revealed the presence of filamentous fungi belonging to the phylum Basidiomycota, rarely found in Antarctica. Environmental variations proved to have influenced the genera Pseudogymnoascus and Pseudeutorium. The culture-independent approach (ITS1 DNA metabarcoding) of the samples from the transect of Collins and Baranowski glaciers provided information on the diversity and composition of fungal communities in those ecosystems. Collins and Baranowski glaciers showed differences in the composition of their fungal communities, with the predominance of fungi belonging to the phyla Ascomycota and Basidiomycota. The composition of the community was spatially auto-correlated and the results indicate a certain relation with different environmental factors, such as, clay, Ca and Mn. The data obtained by the culture-independent approach revealed a higher diversity of fungi in the samples form Collins glacier when compared to the culture-dependent one. Nevertheless, both approaches revealed a predominance of the phylum Ascomycota in the environment. The genus Pseudogymnoascus was the most abundant genus retrieved by the culture-dependent method, which confirms the results of other studies in which Pseudogymnoascus isolates were found to be predominant in terrestrial and marine Antarctic samples. Nonetheless, representatives of that genus were not found to be prevalent in the soil samples when the culture-independent method was applied. This approach revealed a total of 190 fungi genera from all soil samples from Collins and Baranowski glaciers. The genera Verrucaria, Mortierella and Peniophora were highly abundant and prevalent in all samples. The results obtained in this work contribute to the elucidation of gaps in the scientific knowledge, and bring innovation and data that can be explored in the future in the ecological and biotechnological areas. (AU) | |
| FAPESP's process: | 15/25170-1 - Soil fungi of Collins glacier (Antarctica): evaluation of biodiversity and resistance to UV radiation |
| Grantee: | Juliana Aparecida dos Santos |
| Support Opportunities: | Scholarships in Brazil - Doctorate |