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Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus

Rineau, F.; Shah, Firoz LU ; Smits, M. M.; Persson, Per LU ; Johansson, Tomas LU ; Carleer, R.; Troein, Carl LU and Tunlid, Anders LU (2013) In The Isme Journal 7(10). p.2010-2022
Abstract
The majority of nitrogen in forest soils is found in organic matter-protein complexes. Ectomycorrhizal fungi (EMF) are thought to have a key role in decomposing and mobilizing nitrogen from such complexes. However, little is known about the mechanisms governing these processes, how they are regulated by the carbon in the host plant and the availability of more easily available forms of nitrogen sources. Here we used spectroscopic analyses and transcriptome profiling to examine how the presence or absence of glucose and/or ammonium regulates decomposition of litter material and nitrogen mobilization by the ectomycorrhizal fungus Paxillus involutus. We found that the assimilation of nitrogen and the decomposition of the litter material are... (More)
The majority of nitrogen in forest soils is found in organic matter-protein complexes. Ectomycorrhizal fungi (EMF) are thought to have a key role in decomposing and mobilizing nitrogen from such complexes. However, little is known about the mechanisms governing these processes, how they are regulated by the carbon in the host plant and the availability of more easily available forms of nitrogen sources. Here we used spectroscopic analyses and transcriptome profiling to examine how the presence or absence of glucose and/or ammonium regulates decomposition of litter material and nitrogen mobilization by the ectomycorrhizal fungus Paxillus involutus. We found that the assimilation of nitrogen and the decomposition of the litter material are triggered by the addition of glucose. Glucose addition also resulted in upregulation of the expression of genes encoding enzymes involved in oxidative degradation of polysaccharides and polyphenols, peptidases, nitrogen transporters and enzymes in pathways of the nitrogen and carbon metabolism. In contrast, the addition of ammonium to organic matter had relatively minor effects on the expression of transcripts and the decomposition of litter material, occurring only when glucose was present. On the basis of spectroscopic analyses, three major types of chemical modifications of the litter material were observed, each correlated with the expression of specific sets of genes encoding extracellular enzymes. Our data suggest that the expression of the decomposition and nitrogen assimilation processes of EMF can be tightly regulated by the host carbon supply and that the availability of inorganic nitrogen as such has limited effects on saprotrophic activities. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
carbon and nitrogen cycling, ectomycorrhiza, nitrogen assimilation, organic matter degradation, carbon availability
in
The Isme Journal
volume
7
issue
10
pages
2010 - 2022
publisher
Nature Publishing Group
external identifiers
  • wos:000324869400012
  • scopus:84884670492
ISSN
1751-7362
DOI
10.1038/ismej.2013.91
project
BECC
language
English
LU publication?
yes
id
266ccf51-9f83-44ea-bd9e-443a4d659b28 (old id 4172499)
date added to LUP
2013-11-21 11:14:42
date last changed
2019-07-02 01:14:29
@article{266ccf51-9f83-44ea-bd9e-443a4d659b28,
  abstract     = {The majority of nitrogen in forest soils is found in organic matter-protein complexes. Ectomycorrhizal fungi (EMF) are thought to have a key role in decomposing and mobilizing nitrogen from such complexes. However, little is known about the mechanisms governing these processes, how they are regulated by the carbon in the host plant and the availability of more easily available forms of nitrogen sources. Here we used spectroscopic analyses and transcriptome profiling to examine how the presence or absence of glucose and/or ammonium regulates decomposition of litter material and nitrogen mobilization by the ectomycorrhizal fungus Paxillus involutus. We found that the assimilation of nitrogen and the decomposition of the litter material are triggered by the addition of glucose. Glucose addition also resulted in upregulation of the expression of genes encoding enzymes involved in oxidative degradation of polysaccharides and polyphenols, peptidases, nitrogen transporters and enzymes in pathways of the nitrogen and carbon metabolism. In contrast, the addition of ammonium to organic matter had relatively minor effects on the expression of transcripts and the decomposition of litter material, occurring only when glucose was present. On the basis of spectroscopic analyses, three major types of chemical modifications of the litter material were observed, each correlated with the expression of specific sets of genes encoding extracellular enzymes. Our data suggest that the expression of the decomposition and nitrogen assimilation processes of EMF can be tightly regulated by the host carbon supply and that the availability of inorganic nitrogen as such has limited effects on saprotrophic activities.},
  author       = {Rineau, F. and Shah, Firoz and Smits, M. M. and Persson, Per and Johansson, Tomas and Carleer, R. and Troein, Carl and Tunlid, Anders},
  issn         = {1751-7362},
  keyword      = {carbon and nitrogen cycling,ectomycorrhiza,nitrogen assimilation,organic matter degradation,carbon availability},
  language     = {eng},
  number       = {10},
  pages        = {2010--2022},
  publisher    = {Nature Publishing Group},
  series       = {The Isme Journal},
  title        = {Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus},
  url          = {http://dx.doi.org/10.1038/ismej.2013.91},
  volume       = {7},
  year         = {2013},
}