Nitrogen acquisition from mineral-associated proteins by an ectomycorrhizal fungus
(2020) In New Phytologist 228(2). p.697-711- Abstract
In nitrogen (N)-limited boreal forests, trees depend on the decomposing activity of their ectomycorrhizal (ECM) fungal symbionts to access soil N. A large fraction of this N exists as proteinaceous compounds associated with mineral particles. However, it is not known if ECM fungi can access these mineral-associated proteins; accordingly, possible acquisition mechanisms have not been investigated. With tightly controlled isotopic, spectroscopic, and chromatographic experiments, we quantified and analyzed the mechanisms of N acquisition from iron oxide mineral-associated proteins by Paxillus involutus, a widespread ECM fungus in boreal forests. The fungus acquired N from the mineral-associated proteins. The collective results indicated a... (More)
In nitrogen (N)-limited boreal forests, trees depend on the decomposing activity of their ectomycorrhizal (ECM) fungal symbionts to access soil N. A large fraction of this N exists as proteinaceous compounds associated with mineral particles. However, it is not known if ECM fungi can access these mineral-associated proteins; accordingly, possible acquisition mechanisms have not been investigated. With tightly controlled isotopic, spectroscopic, and chromatographic experiments, we quantified and analyzed the mechanisms of N acquisition from iron oxide mineral-associated proteins by Paxillus involutus, a widespread ECM fungus in boreal forests. The fungus acquired N from the mineral-associated proteins. The collective results indicated a proteolytic mechanism involving formation of the crucial enzyme–substrate complexes at the mineral surfaces. Hence, the enzymes hydrolyzed the mineral-associated proteins without initial desorption of the proteins. The proteolytic activity was suppressed by adsorption of proteases to the mineral particles. This process was counteracted by fungal secretion of mineral-surface-reactive compounds that decreased the protease–mineral interactions and thereby promoted the formation of enzyme–substrate complexes. The ability of ECM fungi to simultaneously generate extracellular proteases and surface-reactive metabolites suggests that they can play an important role in unlocking the large N pool of mineral-associated proteins to trees in boreal forests.
(Less)
- author
- Wang, Tao LU ; Tian, Zhaomo LU ; Tunlid, Anders LU and Persson, Per LU
- organization
- publishing date
- 2020-10
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- boreal forests, decomposition and N acquisition, ectomycorrhizal (ECM) fungi, iron oxides, mineral-associated organic nitrogen, Paxillus involutus, secondary metabolites, soil proteins
- in
- New Phytologist
- volume
- 228
- issue
- 2
- pages
- 15 pages
- publisher
- Wiley-Blackwell
- external identifiers
-
- scopus:85084488124
- pmid:32279319
- ISSN
- 0028-646X
- DOI
- 10.1111/nph.16596
- language
- English
- LU publication?
- yes
- id
- 0cbc4e2a-1df4-4cfd-be21-4c582c0bfa53
- date added to LUP
- 2020-06-10 15:35:57
- date last changed
- 2024-05-29 13:46:49
@article{0cbc4e2a-1df4-4cfd-be21-4c582c0bfa53,
abstract = {{<p>In nitrogen (N)-limited boreal forests, trees depend on the decomposing activity of their ectomycorrhizal (ECM) fungal symbionts to access soil N. A large fraction of this N exists as proteinaceous compounds associated with mineral particles. However, it is not known if ECM fungi can access these mineral-associated proteins; accordingly, possible acquisition mechanisms have not been investigated. With tightly controlled isotopic, spectroscopic, and chromatographic experiments, we quantified and analyzed the mechanisms of N acquisition from iron oxide mineral-associated proteins by Paxillus involutus, a widespread ECM fungus in boreal forests. The fungus acquired N from the mineral-associated proteins. The collective results indicated a proteolytic mechanism involving formation of the crucial enzyme–substrate complexes at the mineral surfaces. Hence, the enzymes hydrolyzed the mineral-associated proteins without initial desorption of the proteins. The proteolytic activity was suppressed by adsorption of proteases to the mineral particles. This process was counteracted by fungal secretion of mineral-surface-reactive compounds that decreased the protease–mineral interactions and thereby promoted the formation of enzyme–substrate complexes. The ability of ECM fungi to simultaneously generate extracellular proteases and surface-reactive metabolites suggests that they can play an important role in unlocking the large N pool of mineral-associated proteins to trees in boreal forests.</p>}},
author = {{Wang, Tao and Tian, Zhaomo and Tunlid, Anders and Persson, Per}},
issn = {{0028-646X}},
keywords = {{boreal forests; decomposition and N acquisition; ectomycorrhizal (ECM) fungi; iron oxides; mineral-associated organic nitrogen; Paxillus involutus; secondary metabolites; soil proteins}},
language = {{eng}},
number = {{2}},
pages = {{697--711}},
publisher = {{Wiley-Blackwell}},
series = {{New Phytologist}},
title = {{Nitrogen acquisition from mineral-associated proteins by an ectomycorrhizal fungus}},
url = {{http://dx.doi.org/10.1111/nph.16596}},
doi = {{10.1111/nph.16596}},
volume = {{228}},
year = {{2020}},
}