Caracterização e identificação taxonômica de fungos do gênero Cladosporium isolados de amostras marinhas e terrestres da Antártica
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Data
2023-03-02
Autores
Simonetti, Flávio Lourenção
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Universidade Estadual Paulista (Unesp)
Resumo
O reino Fungi apresenta uma ampla diversidade de organismos, encontrados em praticamente todos os ecossistemas conhecidos do planeta. De acordo com especialistas, o número de espécies conhecidas é apenas uma fração do número estipulado de espécies existentes. Os fungos desenvolvem adaptações para colonizarem e lidarem com as condições adversas dos ambientes considerados extremos, como o ambiente antártico. Algumas dessas adaptações possuem potencial para aplicação biotecnológica, incluindo enzimas que são adaptadas ao frio e substâncias bioativas, como a melanina, que protege esses organismos contra uma alta incidência de radiação UV. O presente estudo teve como objetivo avaliar o crescimento em diferentes temperaturas (5, 10, 15, 20, 25 e 30°C), salinidade (5, 10, 15, 20 e 25% NaCl), meios de cultura (MA2%, BDA, BDA1% e SNA) e sob radiação UV (UVB e UVC) de oito fungos do gênero Cladosporium (L.564; L.595; L.598; L.616; L.1345; L.1369; L.1800 e L.2541) isolados de amostras marinhas e terrestres do ambiente antártico, bem como a caracterização e a taxonômica molecular. Os isolados L.595, L.616 e L.1369 cresceram em uma ampla faixa de temperatura (de 5 a 30°C), podendo ser explorados quanto a produção de enzimas adaptadas ao frio. Esses mesmos isolados apresentaram uma boa tolerância a concentrações elevadas de NaCl (15%). Em adição, os isolados L.564, L.595 e L.1800 apresentaram uma alta resistência contra os dois tipos de radiação UV testados e são promissores quanto a produção de substâncias fotoprotetoras. Dentre todos os Cladosporium estudados, o isolado L.595 se destacou, apresentando um bom crescimento em todas as temperaturas testadas, todos os meios de cultura avaliados, uma boa tolerância quando exposto a elevadas concentrações salinas e uma maior resistência contra radiação UVB e UVC. Com base nos estudos de taxonomia molecular (sequenciamento do gene marcador act e análises filogenéticas deste gene concatenado com a região ITS) foi possível avaliar as relações entre os isolados antárticos e as espécies mais próximas. Os isolados L.595 e L.616 são filogeneticamente próximos e fisiologicamente semelhantes podendo pertencer à mesma espécie de Cladosporium. O mesmo ocorreu para os isolados L.564 e L.1800. Os isolados L.598 e L.1369 se mostraram filogeneticamente próximos, porém, divergiram quanto ao crescimento nos diferentes parâmetros testados. Por outro lado, os isolados L.1345 e L.2541 não se assemelharam com nenhum dos outros isolados antárticos, apresentando proximidade filogenética com espécies distintas de Cladosporium. Análises moleculares adicionais (usando o marcador tef1) são necessárias para a caracterização taxonômica mais acurada desses isolados. Os resultados desse estudo destacam os Cladosporium antárticos como novos recursos microbianos com potencial aplicação biotecnológica e abrem novas perspectivas no campo da microbiologia aplicada de fungos extremófilos.
The fungi kingdom harbors a huge diversity of organisms, which can be found in virtually all environments on the planet. According to experts, the number of known species is just a fraction of the estimated existing species. Fungus developed many different adaptations to colonize and resist environments considered extreme, like the Antarctic environment. Some of these adaptations have the potential to be exploited for biotechnology purposes, including cold-adapted enzymes and bioactive substances, such as melanin, which is able to protect these microorganisms against high dosages of UV radiation. The present study aimed at the evaluation of growth at different temperatures (5, 10, 15, 20, 25 and 30°C), salinity (5, 10, 15, 20 and 25% NaCl), culture media (MA2%, BDA, BDA1% and SNA), and under UV radiation (UVB and UVC) of eight fungi belonging to the genus Cladosporium (L.564; L.595; L.598; L.616; L.1345; L.1369; L.1800 e L.2541) isolated from marine and terrestrial samples from the Antarctic environment, as well as the molecular taxonomic characterization. The isolates L.595, L.616 and L.1369 were able to grow in a wide range of temperatures (5 to 30°C), showing promising results for the bioprospection of cold-adapted enzymes. These same isolates showed good tolerance to high concentrations of NaCl (15%). In addition, isolates L.564, L.595 and L.1800 showed high resistance against the two types of UV radiation tested, being promising for the production of photoprotective substances. Among all Cladosporium studied, isolate L.595 stood out, growing at all temperatures tested, showing good growth in all culture media evaluated, tolerance when exposed to high saline concentrations, in addition to having demonstrated the highest resistance against radiation UVB and UVC. Based on molecular taxonomy (sequencing of the act marker gene and phylogenetic analyzes of this gene concatenated with the ITS region) it was possible to assess the relationships between the Antarctic isolates and the closest species. Isolates L.595 and L.616 are phylogenetically close and physiologically similar, and may be from the same species of Cladosporium. The same occurred for isolates L.564 and L.1800. The isolates L.598 and L.1369 were phylogenetically similar, however, they differed in terms of growth in the different parameters tested. Furthermore, isolates L.1345 and L.2541 did not resemble any of the other Antarctic isolates, showing phylogenetic proximity to different species of Cladosporium. Additional molecular analyzes (using the marker tef1) are necessary for more accurate taxonomic characterization of these isolates. The results of the present study highlight Antarctic Cladosporium as new microbial resources with potential biotechnological application and open new perspectives in the field of applied microbiology of extremophile fungi.
The fungi kingdom harbors a huge diversity of organisms, which can be found in virtually all environments on the planet. According to experts, the number of known species is just a fraction of the estimated existing species. Fungus developed many different adaptations to colonize and resist environments considered extreme, like the Antarctic environment. Some of these adaptations have the potential to be exploited for biotechnology purposes, including cold-adapted enzymes and bioactive substances, such as melanin, which is able to protect these microorganisms against high dosages of UV radiation. The present study aimed at the evaluation of growth at different temperatures (5, 10, 15, 20, 25 and 30°C), salinity (5, 10, 15, 20 and 25% NaCl), culture media (MA2%, BDA, BDA1% and SNA), and under UV radiation (UVB and UVC) of eight fungi belonging to the genus Cladosporium (L.564; L.595; L.598; L.616; L.1345; L.1369; L.1800 e L.2541) isolated from marine and terrestrial samples from the Antarctic environment, as well as the molecular taxonomic characterization. The isolates L.595, L.616 and L.1369 were able to grow in a wide range of temperatures (5 to 30°C), showing promising results for the bioprospection of cold-adapted enzymes. These same isolates showed good tolerance to high concentrations of NaCl (15%). In addition, isolates L.564, L.595 and L.1800 showed high resistance against the two types of UV radiation tested, being promising for the production of photoprotective substances. Among all Cladosporium studied, isolate L.595 stood out, growing at all temperatures tested, showing good growth in all culture media evaluated, tolerance when exposed to high saline concentrations, in addition to having demonstrated the highest resistance against radiation UVB and UVC. Based on molecular taxonomy (sequencing of the act marker gene and phylogenetic analyzes of this gene concatenated with the ITS region) it was possible to assess the relationships between the Antarctic isolates and the closest species. Isolates L.595 and L.616 are phylogenetically close and physiologically similar, and may be from the same species of Cladosporium. The same occurred for isolates L.564 and L.1800. The isolates L.598 and L.1369 were phylogenetically similar, however, they differed in terms of growth in the different parameters tested. Furthermore, isolates L.1345 and L.2541 did not resemble any of the other Antarctic isolates, showing phylogenetic proximity to different species of Cladosporium. Additional molecular analyzes (using the marker tef1) are necessary for more accurate taxonomic characterization of these isolates. The results of the present study highlight Antarctic Cladosporium as new microbial resources with potential biotechnological application and open new perspectives in the field of applied microbiology of extremophile fungi.
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Palavras-chave
Antártica, Cladosporium, Taxonomia, Biomoléculas, Resistência, Antarctica, Taxonomy, Biomolecules, Resistance