Publicação
Saprotrophic fungi Hypholoma fasciculare effect on the fungal community associated to Castanea sativa
| Resumo: | The European chestnut (Castanea sativa) is a plant species with eminent importance, due to the high gastronomic value attributed to its fruit, as well as for being a high quality wood source. Associated to the chestnut orchards soils of the region of Trás-os-Montes (Bragança, Portugal) is commonly found the saprotrophic fungi, Hypholoma fasciculare. Some preliminary studies have suggested that the presence of this fungus in the soil can damage chestnut trees and reshape the soil microbial community, due to the strong antagonist activity that H. fasciculare displays against soil-borne fungi from orchard. In order to acknowledge the effect of H. fasciculare in soil fungal community, a metabarcoding project was performed by pyrosequencing the ITS1 barcodes of DNA obtained from different soil samples. Chestnut orchard soil was collected and used for chestnut plant growing. Two months after transplantation, plants were inoculated with H. fasciculare, being harvested after six-months or one-year upon inoculation. As controls, noninoculated plants were used. In order to study the effect of the well-established fungal community on H. fasciculare constraints, sterile orchard soils were use in a parallel assay. In this study, 458 OTUs (operational taxonomic units) were identified comprising 78,029 reads. The richest phylum was the Ascomycota (58.9%), followed by the Basidiomycota (38.9%). However, the Basidiomycota was the most abundant phylum (57.4%), followed by the Ascomycota (40.9%). In order to evaluate the habitat quality, alpha and beta diversity were evaluated, which allowed to determine the richness in species within each soil sample and the species turnover between conditions, respectively. Sterile soil samples were less rich and diverse than non-sterile soil samples, but non-sterile soil samples were more homogeneous among them. The variation of functional groups of the most well-represented OTUs was also analyzed, being the parasites the most rich and abundant, followed by saprotrophic and mycorrhizal functional groups. Correlations between functional groups were also computed and the most positive correlation was found between saprotrophs and parasites. At the end, a clear effect of H. fasciculare was not detected, although specific microbial interactions could have taken place. The use of sterile soils allowed the recognition of a buffering-like effect, in which microbial community is not so easily affected in its equilibrium, neither by the fungal inoculation nor by the chestnut growing. This effect could be of major importance from the agronomic point of view. |
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| Autores principais: | Soares, Ângela Moreira |
| Assunto: | Chestnut orchard soils Castanea sativa Hypholoma fasciculare Metagenomics Ecological Diversity Fungal community Solos de soutos Castanea sativa Hypholoma fasciculare Metagenómica Ecológico Diversidade Comunidade microbiana |
| Ano: | 2015 |
| 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: | The European chestnut (Castanea sativa) is a plant species with eminent importance, due to the high gastronomic value attributed to its fruit, as well as for being a high quality wood source. Associated to the chestnut orchards soils of the region of Trás-os-Montes (Bragança, Portugal) is commonly found the saprotrophic fungi, Hypholoma fasciculare. Some preliminary studies have suggested that the presence of this fungus in the soil can damage chestnut trees and reshape the soil microbial community, due to the strong antagonist activity that H. fasciculare displays against soil-borne fungi from orchard. In order to acknowledge the effect of H. fasciculare in soil fungal community, a metabarcoding project was performed by pyrosequencing the ITS1 barcodes of DNA obtained from different soil samples. Chestnut orchard soil was collected and used for chestnut plant growing. Two months after transplantation, plants were inoculated with H. fasciculare, being harvested after six-months or one-year upon inoculation. As controls, noninoculated plants were used. In order to study the effect of the well-established fungal community on H. fasciculare constraints, sterile orchard soils were use in a parallel assay. In this study, 458 OTUs (operational taxonomic units) were identified comprising 78,029 reads. The richest phylum was the Ascomycota (58.9%), followed by the Basidiomycota (38.9%). However, the Basidiomycota was the most abundant phylum (57.4%), followed by the Ascomycota (40.9%). In order to evaluate the habitat quality, alpha and beta diversity were evaluated, which allowed to determine the richness in species within each soil sample and the species turnover between conditions, respectively. Sterile soil samples were less rich and diverse than non-sterile soil samples, but non-sterile soil samples were more homogeneous among them. The variation of functional groups of the most well-represented OTUs was also analyzed, being the parasites the most rich and abundant, followed by saprotrophic and mycorrhizal functional groups. Correlations between functional groups were also computed and the most positive correlation was found between saprotrophs and parasites. At the end, a clear effect of H. fasciculare was not detected, although specific microbial interactions could have taken place. The use of sterile soils allowed the recognition of a buffering-like effect, in which microbial community is not so easily affected in its equilibrium, neither by the fungal inoculation nor by the chestnut growing. This effect could be of major importance from the agronomic point of view. |
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