Fungos de solos de recuo de geleiras antárticas: avaliação da diversidade e ecologia
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Data
2020-09-16
Autores
Santos, Juliana Aparecida Dos
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Universidade Estadual Paulista (Unesp)
Resumo
A retração frontal de geleiras é frequentemente considerada como um sinal evidente de aquecimento global. Os solos de geleiras abrigam uma comunidade microbiana ativa de decompositores e frente à retração contínua do gelo, o solo passa a representar um gradiente de fatores físicos, químicos e biológicos que refletem as mudanças regionais ao longo do tempo. A micologia antártica é uma ciência relativamente recente e pouco se conhece sobre a natureza biológica desse grupo de micro-organismos. O presente trabalho é parte dos projetos FAPESP 2016/07957-7, PROANTAR/CNPq MICROSFERA e CNPq Universal (407986/2018-9) e teve como objetivo principal conhecer a diversidade de fungos (utilizando métodos dependentes e independentes de cultivo) de amostras de solo de recuo de duas geleiras situadas na Península Fildes (Ilha Rei George), bem como avaliar a estrutura da comunidade de fungos e correlacioná-la à composição dos solos amostrados. Os resultados obtidos no método dependente de cultivo revelaram a diferença na composição das comunidades fúngicas ao longo do recuo da geleira Collins e a presença de isolados ainda não reportados no ambiente Antártico. Foi isolado um total de 309 fungos distribuídos em 19 gêneros. Os representantes dos gêneros Pseudogymnoascus e Mortierella apresentaram alta prevalência e dominância em todas as amostras. Os dados revelaram a presença de fungos filamentosos pertencentes ao Filo Basidiomycota, raramente isolados na Antártica. As variações ambientais demonstraram ter influenciado os gêneros Pseudogymnoascus e Pseudeutorium. A abordagem independente de cultivo (metabarcoding de DNA ITS1) das amostras do transecto das geleiras Collins e Baranowski, forneceu informações sobre a diversidade e composição das comunidades fúngicas desses ecossistemas. As geleiras Baranowski e Collins apresentaram diferenças na composição das comunidades fúngicas, com predominância de fungos pertencentes aos Filos Ascomycota e Basidiomycota. A composição da comunidade foi espacialmente auto-correlacionada e os resultados indicam uma certa relação com diferentes fatores ambientais, tais como, Argila, Ca e Mn. Os dados obtidos pelo método independente de cultivo possibilitaram acessar uma maior diversidade de fungos quando comparado com o método baseado em cultivo utilizado para avaliar as amostras de solos da geleira Collins. Contudo, os dois métodos revelaram a predominância do Filo Ascomycota no ambiente. No método dependente de cultivo o gênero Pseudogymnoascus foi o mais abundante, corroborando os resultados de outros estudos onde este gênero se apresenta como predominante em amostras marinhas e terrestres da Antártica. Porém, no método independente de cultivo representantes do gênero Pseudogymnoascus não foram os prevalentes nas amostras de solo estudadas. Esta abordagem revelou um total de 190 gêneros nas amostras de solos do recuo da geleira Collins e Baranowski. Os gêneros Verrucaria, Mortierella e Peniophora apresentaram alta abundância e prevalência em todas as amostras. Os resultados gerados nesse trabalho contribuem para a elucidação de lacunas no meio científico, trazendo inovação, conhecimento e dados que podem ser futuramente explorados em âmbito ecológico biotecnológico.
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.
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.
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Palavras-chave
Fungos antártico, Recuo de geleira, Ecologia microbiana, Diversidade fúngica, Antarctic fungi, Glacier retreat, Microbial ecology, Fungal diversity