ClassII peroxidase-encoding genes are present in a phylogenetically wide range of ectomycorrhizal fungi.
Fungal peroxidases (ClassII) have a key role in degrading recalcitrant polyphenolic compounds in boreal forest wood, litter and humus. To date, their occurrence and activity have mainly been studied in a small number of white-rot wood decomposers. However, peroxidase activity is commonly measured in boreal forest humus and mineral soils, in which ectomycorrhizal fungi predominate. Here, we used degenerate PCR primers to investigate whether peroxidase-encoding genes are present in the genomes of a wide phylogenetic range of ectomycorrhizal taxa. Cloning and sequencing of PCR products showed that ectomycorrhizal fungi from several different genera possess peroxidase genes. The new sequences represent four major homobasidiomycete lineages, but the majority is derived from Cortinarius, Russula and Lactarius. These genera are ecologically important, but consist mainly of non-culturable species from which little ecophysiological information is available. The amplified sequences contain conserved active sites, both for folding and substrate oxidation. In some Cortinarius spp., there is evidence for gene duplications during the evolution of the genus. ClassII peroxidases seem to be an ancient and a common feature of most homobasidiomycetes, including ectomycorrhizal fungi. Production of extracellular peroxidases may provide ectomycorrhizal fungi with access to nitrogen sequestered in complex polyphenolic sources.
Bödeker
Inga T M
IT
Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden. inga.bodeker@mykopat.slu.se
Nygren
Cajsa M R
CM
Taylor
Andy F S
AF
Olson
Ake
A
Lindahl
Björn D
BD
D020134:Catalytic Domain; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000201:enzymology* / Q000235:genetics; D009195:Peroxidase / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D004271:DNA, Fungal; D005656:Fungal Proteins; D009195:Peroxidase