Per Persson
Dekan
Nitrogen acquisition from mineral-associated proteins by an ectomycorrhizal fungus
Författare
Summary, in English
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.
Avdelning/ar
- BECC: Biodiversity and Ecosystem services in a Changing Climate
- Mikrobiologisk ekologi
- Centrum för miljö- och klimatvetenskap (CEC)
Publiceringsår
2020-10
Språk
Engelska
Sidor
697-711
Publikation/Tidskrift/Serie
New Phytologist
Volym
228
Issue
2
Dokumenttyp
Artikel i tidskrift
Förlag
Wiley-Blackwell
Ämne
- Biochemistry and Molecular Biology
Nyckelord
- boreal forests
- decomposition and N acquisition
- ectomycorrhizal (ECM) fungi
- iron oxides
- mineral-associated organic nitrogen
- Paxillus involutus
- secondary metabolites
- soil proteins
Status
Published
Forskningsgrupp
- Microbial Ecology
ISBN/ISSN/Övrigt
- ISSN: 0028-646X