Publicação
Analysis of functional genes diversity in aquatic fungal species
| Resumo: | Freshwater ecosystems comprise detritus-based food webs, which use allochthonous sources of nonliving organic carbon, such as leaf litter, as their main energy sources. A group of microbial decomposers, known as aquatic hyphomycetes (AQH), have a dominant role in the leaf litter decomposition process. These organisms can produce extracellular enzymes targeting complex molecules involved in this process and are also able to assimilate nutrients from stream water, immobilizing them in the decomposing substrate. However, global alterations, particularly increases in stream water temperatures, are predicted to substantially impact freshwater ecosystems functioning, potentially causing biodiversity losses, which could, in the case of AQH communities, lead to losses of specific enzymatic abilities. AQH diversity has been assessed in some studies, but mostly regarding their taxonomic relationships. Some other studies have assessed degradative potentials of AQH species through qualitative enzymatic assays. Our study is, to the best of our knowledge, the first to evaluate functional gene and protein diversities of an assortment of 16 functional genes involved in leaf litter decomposition in 30 different AQH species. Functional genes assessments were performed resorting to methods such as PCR amplifications, cloning and in silico analyses. Functional diversity was assessed through phylogenetic trees. Our results reveal, for most cases, a correlation between taxonomic and functional gene relatedness. Additionally, we have found intra- and interspecific differences between AQH isolates, for both functional gene and protein partial sequences as well as divergences between nucleotide and amino acid sequences for the same organism and functional gene. No correlation was found between the intensity of the degradative reaction and the degree of phylogenetic relatedness. These results are the kickstart to further assessments on functional diversity across AQH species and the impacts of global change alterations in AQH communities’ survival, interactions and degradative performances. Studies as such will also allow better predictions on how those alterations will affect nutrient cycling and supplying to higher trophic levels and, subsequently, freshwater ecosystems functioning. |
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| Autores principais: | Mariz, Joana da Venda |
| Assunto: | Aquatic hyphomycetes Biodiversity Enzymes Freshwater ecosystems Leaf litter decomposition Hifomicetos aquáticos Biodiversidade Decomposição da folhada Enzimas Ecossistemas ribeirinhos |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Freshwater ecosystems comprise detritus-based food webs, which use allochthonous sources of nonliving organic carbon, such as leaf litter, as their main energy sources. A group of microbial decomposers, known as aquatic hyphomycetes (AQH), have a dominant role in the leaf litter decomposition process. These organisms can produce extracellular enzymes targeting complex molecules involved in this process and are also able to assimilate nutrients from stream water, immobilizing them in the decomposing substrate. However, global alterations, particularly increases in stream water temperatures, are predicted to substantially impact freshwater ecosystems functioning, potentially causing biodiversity losses, which could, in the case of AQH communities, lead to losses of specific enzymatic abilities. AQH diversity has been assessed in some studies, but mostly regarding their taxonomic relationships. Some other studies have assessed degradative potentials of AQH species through qualitative enzymatic assays. Our study is, to the best of our knowledge, the first to evaluate functional gene and protein diversities of an assortment of 16 functional genes involved in leaf litter decomposition in 30 different AQH species. Functional genes assessments were performed resorting to methods such as PCR amplifications, cloning and in silico analyses. Functional diversity was assessed through phylogenetic trees. Our results reveal, for most cases, a correlation between taxonomic and functional gene relatedness. Additionally, we have found intra- and interspecific differences between AQH isolates, for both functional gene and protein partial sequences as well as divergences between nucleotide and amino acid sequences for the same organism and functional gene. No correlation was found between the intensity of the degradative reaction and the degree of phylogenetic relatedness. These results are the kickstart to further assessments on functional diversity across AQH species and the impacts of global change alterations in AQH communities’ survival, interactions and degradative performances. Studies as such will also allow better predictions on how those alterations will affect nutrient cycling and supplying to higher trophic levels and, subsequently, freshwater ecosystems functioning. |
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