title: Detection of extracellular protease activity in different species and genera of ectomycorrhizal fungi.
abstract: In northern forest ecosystems, most soil nitrogen (N) is in organic form and forest trees are largely dependent on ectomycorrhizal (ECM) fungi and their degradative abilities for N uptake. The ability of ECM fungi to acquire N from organic substrates should, therefore, be a widespread trait given its ecological importance. However, little is known about the degradative abilities of most ECM fungi as they remain untested due to problems of isolation or extremely slow growth in pure culture. In this paper, we present data on extracellular protease activity of 32 species of ECM fungi, most of which have not previously been cultured. Milk powder plates and zymograms were compared for detecting protease activity in these intractable species. In total, 29/32 of the species produced extracellular protease activity, but detection was method dependent. Growth on milk powder plates detected protease activity in 28 of 32 species, while zymograms only detected proteases in Amanita muscaria, Russula chloroides, Lactarius deterrimus and Lactarius quieticolor. The study supports the hypothesis that protease excretion is a widespread physiological trait in ECM fungi and that this ability is of considerable significance for nitrogen uptake in forest ecosystems.
authors.affiliation: Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07, Uppsala, Sweden. Cajsa.Nygren@mykopat.slu.se.
authors.forename: Cajsa M R
authors.initials: CMR
authors.lastname: Nygren
authors.affiliation: Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, P.O. Box 7080, SE-750 07, Uppsala, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Edqvist
authors.affiliation: Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07, Uppsala, Sweden.
authors.forename: Malin
authors.initials: M
authors.lastname: Elfstrand
authors.affiliation: Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07, Uppsala, Sweden.
authors.forename: Gregory
authors.initials: G
authors.lastname: Heller
authors.affiliation: Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-750 07, Uppsala, Sweden.
authors.forename: Andy F S
authors.initials: AFS
authors.lastname: Taylor
mesh_terms: D017753:Ecosystem; D038821:Mycorrhizae / Q000145:classification / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D010447:Peptide Hydrolases / Q000378:metabolism*; D013045:Species Specificity; D013559:Symbiosis; D014197:Trees / Q000382:microbiology
chemical_list: D010447:Peptide Hydrolases