Growth on nitrate and occurrence of nitrate reductase-encoding genes in a phylogenetically diverse range of ectomycorrhizal fungi

Cajsa M. R. Nygren*, Ursula Eberhardt, Magnus Karlsson, Jeri L. Parrent, Bjoern D. Lindahl, Andy F. S. Taylor

*Corresponding author for this work

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

Ectomycorrhizal (ECM) fungi are often considered to be most prevalent under conditions where organic sources of N predominate. However, ECM fungi are increasingly exposed to nitrate from anthropogenic sources. Currently, the ability of ECM fungi to metabolize this nitrate is poorly understood.

Here, growth was examined among 106 isolates, representing 68 species, of ECM fungi on nitrate as the sole N source. In addition, the occurrence of genes coding for the nitrate reductase enzyme (nar gene) in a broad range of ectomycorrhizal fungi was investigated.

All isolates grew on nitrate, but there was a strong taxonomic signature in the biomass production, with the Russulaceae and Amanita showing the lowest growth. Thirty-five partial nar sequences were obtained from 43 tested strains comprising 31 species and 10 genera. These taxa represent three out of the four clades of the Agaricales within which ECM fungi occur. No nar sequences were recovered from the Russulaceae and Amanita, but Southern hybridization showed that the genes were present.

The results demonstrate that the ability to utilize nitrate as an N source is widespread in ECM fungi, even in those fungi from boreal forests where the supply of nitrate may be very low.

New Phytologist (2008) 180: 875-889

(c) The Authors (2008). Journal compilation (c) New Phytologist (2008) doi: 10.1111/j.1469-8137.2008.02618.x.

Original languageEnglish
Pages (from-to)875-889
Number of pages15
JournalNew Phytologist
Volume180
Issue number4
Early online date9 Sep 2008
DOIs
Publication statusPublished - Dec 2008

Keywords

  • nitrate assimilation
  • nitrate reductase
  • nitrogen deposition gradient
  • community change
  • nitrogen nutrition
  • nitrite
  • assimilation
  • nar1
  • nitrogen fertilization
  • basidiomycete
  • ectomycorrhizal fungi
  • paxillus-involutus
  • hebeloma-cylindrosporum
  • boreal forest
  • forest
  • nitrate reductase-encoding genes
  • mycorrhizal fungi
  • ammonium

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