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The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus
Proteins contribute to a major part of the organic nitrogen (N) in forest soils. This N is mobilized and becomes available to trees as a result of the depolymerizing activities of symbiotic ectomycorrhizal fungi. The mechanisms by which these fungi depolymerize proteins and assimilate the released N...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BlackWell Publishing Ltd
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282482/ https://www.ncbi.nlm.nih.gov/pubmed/23902518 http://dx.doi.org/10.1111/nph.12425 |
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author | Shah, Firoz Rineau, Francois Canbäck, Björn Johansson, Tomas Tunlid, Anders |
author_facet | Shah, Firoz Rineau, Francois Canbäck, Björn Johansson, Tomas Tunlid, Anders |
author_sort | Shah, Firoz |
collection | PubMed |
description | Proteins contribute to a major part of the organic nitrogen (N) in forest soils. This N is mobilized and becomes available to trees as a result of the depolymerizing activities of symbiotic ectomycorrhizal fungi. The mechanisms by which these fungi depolymerize proteins and assimilate the released N are poorly characterized. Biochemical analysis and transcriptome profiling were performed to examine the proteolytic machinery and the uptake system of the ectomycorrhizal basidiomycete Paxillus involutus during the assimilation of organic N from various protein sources and extracts of organic matter. All substrates induced secretion of peptidase activity with an acidic pH optimum, mostly contributed by aspartic peptidases. The peptidase activity was transiently repressed by ammonium. Transcriptional analysis revealed a large number of extracellular endo- and exopeptidases. The expression levels of these peptidases were regulated in parallel with transporters and enzymes involved in the assimilation and metabolism of the released peptides and amino acids. For the first time the molecular components of the protein degradation pathways of an ectomycorrhizal fungus are described. The data suggest that the transcripts encoding these components are regulated in response to the chemical properties and the availability of the protein substrates. |
format | Online Article Text |
id | pubmed-4282482 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | BlackWell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-42824822015-01-15 The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus Shah, Firoz Rineau, Francois Canbäck, Björn Johansson, Tomas Tunlid, Anders New Phytol Research Proteins contribute to a major part of the organic nitrogen (N) in forest soils. This N is mobilized and becomes available to trees as a result of the depolymerizing activities of symbiotic ectomycorrhizal fungi. The mechanisms by which these fungi depolymerize proteins and assimilate the released N are poorly characterized. Biochemical analysis and transcriptome profiling were performed to examine the proteolytic machinery and the uptake system of the ectomycorrhizal basidiomycete Paxillus involutus during the assimilation of organic N from various protein sources and extracts of organic matter. All substrates induced secretion of peptidase activity with an acidic pH optimum, mostly contributed by aspartic peptidases. The peptidase activity was transiently repressed by ammonium. Transcriptional analysis revealed a large number of extracellular endo- and exopeptidases. The expression levels of these peptidases were regulated in parallel with transporters and enzymes involved in the assimilation and metabolism of the released peptides and amino acids. For the first time the molecular components of the protein degradation pathways of an ectomycorrhizal fungus are described. The data suggest that the transcripts encoding these components are regulated in response to the chemical properties and the availability of the protein substrates. BlackWell Publishing Ltd 2013-11 2013-07-31 /pmc/articles/PMC4282482/ /pubmed/23902518 http://dx.doi.org/10.1111/nph.12425 Text en © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust http://creativecommons.org/licenses/by/3.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Shah, Firoz Rineau, Francois Canbäck, Björn Johansson, Tomas Tunlid, Anders The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus |
title | The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus |
title_full | The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus |
title_fullStr | The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus |
title_full_unstemmed | The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus |
title_short | The molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus Paxillus involutus |
title_sort | molecular components of the extracellular protein-degradation pathways of the ectomycorrhizal fungus paxillus involutus |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282482/ https://www.ncbi.nlm.nih.gov/pubmed/23902518 http://dx.doi.org/10.1111/nph.12425 |
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