Localisation of phosphomonoesterase activity in ectomycorrhizal fungi grown on different phosphorus sources.
Phosphorus (P) is a major limiting nutrient for plants in boreal forest ecosystems where a substantial part of the total P is sequestered in organic compounds. Some ectomycorrhizal (ECM) fungi are known to produce phosphomonoesterases, enzymes that degrade organic P sources. Here, we test 16 ECM species for this enzymatic activity by growing them on media containing orthophosphate, phytic acid or apatite. A method with an overlay gel that determined both phosphomonoesterase activity and its spatial distribution was developed. The phosphomonoesterase activity was not significantly higher when growing on organic P; conversely some isolates only produced measurable enzyme activity when grown on apatite. Species-specific variations with respect to phosphomonoesterase activity as well as growth responses to different substrates were found. The production of phosphomonoesterases was found to be widespread in ECM fungi and the enzyme activity did not need induction by organic P. The enzyme activity was highest in the central parts of the mycelia, potentially reflecting breakdown and recycling of phospholipids from old hyphae or potentially higher mycelial density.
Nygren
C M R
CMR
Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, 750 07, Uppsala, Sweden. Cajsa.Nygren@mykopat.slu.se.
Rosling
A
A
Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, 750 07, Uppsala, Sweden.
D001031:Apatites / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005658:Fungi / Q000737:chemistry* / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D008969:Molecular Sequence Data; D025282:Mycelium / Q000737:chemistry / Q000201:enzymology; D038821:Mycorrhizae; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis*; D010758:Phosphorus / Q000378:metabolism*; D010833:Phytic Acid / Q000378:metabolism; D017422:Sequence Analysis, DNA
D001031:Apatites; D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D010758:Phosphorus; D010833:Phytic Acid; D010744:Phosphoric Monoester Hydrolases