Plant Nutrition, Environmental Science and Technology Department, Risø National Laboratory, P.O. Box 49, DK-4000, Roskilde, Denmark.
Nitrogen metabolism of external hyphae of the arbuscular mycorrhizal fungus Glornus intraradices
Article first published online: 28 APR 2006
Volume 133, Issue 4, pages 705–712, August 1996
How to Cite
JOHANSEN, A., FINLAY, R. D. and OLSSON, P. A. (1996), Nitrogen metabolism of external hyphae of the arbuscular mycorrhizal fungus Glornus intraradices. New Phytologist, 133: 705–712. doi: 10.1111/j.1469-8137.1996.tb01939.x
- Issue published online: 28 APR 2006
- Article first published online: 28 APR 2006
- (Received 24 January 1996; accepted 26 March 1996)
- Arbuscular mycorrhiza;
- external hyphae;
- fatty acids;
- N assimilation;
The arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck and Smith was grown in symbiosis with Cucumis sativus L. ev. Aminex (Fl hybrid) in mesh bags surrounded by a sand-filled hyphal compartment (HC), allowing only the fungal hyphae to protrude into the HC. The hyphae in the HC were supplied with 15N-labelled NH4+ or NO3− after 60 d (expt 1). Following a 48 h labelling period, the sand was removed from the HC and the hyphae extracted. In another experiment (expt 2), the hyphae were extracted from the sand before being incubated in vitro in a nutrient solution containing 15N-labelled NH4+ for 15 h. The hyphal material was incubated in a 0 or 2.5 mM solution of the GOGAT-inhibitor albizzine prior to labelling. In both experiments the hyphal content of free amino acids and fatty acids were measured as well as the ammo acid l5N enrichment.
Asparagine was the hyphal amino acid measured in highest concentration followed by glutamine, glutamate, aspartate and alanine. Ornithine, serine and glycine were detected in lower concentrations, but γ-aminobutyric acid and citrulline were not detectable. This pattern was the same in both experiments and was unaffected by the type of N applied to the hyphae or by preincubation with albizzine, although the amino-acid concentration decreased considerably in expt 2 compared with expt 1. Both NH4+-N and NO3−-N were assimilated into amino acids but the levels of l0N enrichment following application of NO3− were much lower than those following application of NH4+ indicating that the latter was more readily assimilated. Albizzine decreased the hyphal amino acid concentration by c. 30% (without affecting the 15N enrichment of the individual amino acids) indicating that the AM-fungal hyphae might possess a GS-GOGAT enzyme system for assimilation of inorganic N. The fatty-acid profiles (especially phospholipid fatty acids 16: 1ω5 and 20:5) obtained from the hyphae of G. intraradices showed that contamination of the samples by fungi other than G. intraradices and bacteria was insignificant, and confirmed the usefulness of specific fatty-acid measurement to estimate soil AM-fungal content.
- 1981 Infectivity and effectiveness of five endomycorrhizal fungi in field soils. Australian Journal of Agricultural Research 32: 621–630. , .
- 1983 Hyphal uptake and transport of nitrogen from two 15N-labelled sources by. Glomus mosseae, a vesicular–arbuscular mycorrhizal fungus. New Phytologist 95: 381–396. , , ,
- 1979 A micromethod for the analysis of free amino acids by gas chromatography and its application to biological systems. Analytical Biochemistry 92: 426–443. ,
- 1974 Incorporation and dilution values - their calculation in mass spectrally assayed stable isotope labelling experiments. Bio-organic Chemistry 3: 386–397. .
- 1990 Occurrence and distribution of aspartate aminotransferases in spruce and beech ectomycorrhizas. Canadian Journal of Botany 68: 1756–1762. , , , , ,
- 1993 Ammonia assimilation in. Zea mays L. infected with a vesicular–arbuscular mycorrhizal fungus Glomus fasciculatum. Plant Physiology 101: 865–871. , .
- 1993 a. Chemical constituents of some higher fungi. I. Fatty acid and phospholipid composition of Basidiomycetes. Cryptogamic Botany 3: 373–377. , , .
- 1993 Chemical constituents of some higher fungi. II. Fatty acid and phospholipid composition of. Ascomycetes. Cryptogamic Botany 3: 378–382. , , .
- 1986 Phospholipid ester-linked fatty acid biomarkers of acetate-oxidizing sulphate-reducers and other sulphide-forming bacteria. Journal of General Microbiology 132: 1815–1825. , , .
- 1994 Growth and assimilation of NH4+ and NO3 by. Paxillus involutus in association with. Betula pendula and. Picea abies as affected by substrate pH. New Phytologist 128: 629–637. , , ,
- 1988 Mycelial uptake, translocation and assimilation of nitrogen from 15N-labelled ammonium by. Pinus sylvestris plants infected with four different ectomycorrhizal fungi. New Phytologist 110: 59–66. , , ,
- 1989 Uptake, translocation and assimilation of nitrogen from 15N-labelled ammonium and nitrate sources by intact ectomycorrhizal systems of. Fagus sylvatica infected with Paxillus involutus. New Phytologist 113: 47–55. , , ,
- 1993 Acquisition of nitrogen by external hyphae of arbuscular mycorrhizal fungi associated with. Zea mays L. New Phytologist 124: 221–230. ,
- 1994 Chitin and ergosterol content of extraradical and intraradical mycelium of the vesicular-arbuscular mycorrhizal fungus Glomus intraradices. Soil Biology and Biochemistry 26: 711–717. , , ,
- 1993 Phospholipid fatty acid composition, biomass, and activity of microbial communities from two soil types experimentally exposed to different heavy metals. Applied and Environmental Microbiology 59: 3605–3617. , ,
- 1996 The use of phospholipid fatty acid analysis to estimate bacterial and fungal biomass in soil. Biology and Fertility in Soil 28: 55–63. ,
- 1995 Fatty acid methyl ester profiles for characterization of Glomalean fungi and their endomycorrhizae. Applied and Environmental Microbiology 61: 58–64. , , .
- 1984 Lipids in plant and microbes, London : George Allen & Unwin. , .
- 1975 Nitrate reducing capacity of two vesicular-arbuscular mycorrhizal fungi. Mycologia 67: 886–888. , .
- 1995 The physiology of fungal nutrition. New York : Cambridge University Press. .
- 1992 Hyphal transport of 15N-labelled nitrogen by a vesicular-arbuscular mycorrhizal fungus and its effect on depletion of inorganic soil N. New Phytologist 122: 281–288. , , .
- 1993 Hyphal transport by a vesicular-arbuscular mycorrhizal fungus of N applied to the soil as ammonium or nitrate. Biology and Fertility of Soils 16: 66–70. , , .
- 1994 Hyphal N transport by a vesicular–arbuscular mycorrhizal fungus associated with cucumber grown at three nitrogen levels. Plant and Soil 160: 1–9. , , .
- 1994 Genetic evidence for the occurrence of assimilatory nitrate reductase in arbuscular mycorrhizal and other fungi. Mycorrhiza 5: 23–28. , ,
- 1986 Assimilation of 15NH4+ by beech (Fagus sylvatica L.) ectomycorrhizas. New Phytologist 102: 85–94. , , ,
- 1987 Carbon and nitrogen metabolism in ectomycorrhizal fungi and ectomycorrhizas. Biochimie 69: 569–581. , ,
- 1986 Analysis of amino acids as their. tert-butyldimethylsilyl derivates by gas-liquid chromatography and mass spectrometry. Journal of Chromatography 358: 231–242. , , , .
- 1980 Ammonia assimilation. In: MiflinBJ, ed.. The Biochemistry of Plants: A Comprehensive Tretise, vol. 5, Amino Acids and Derivatives. London : Academic Press, 169–223. , .
- 1994 Combining sterol and fatty acid profiles for the characterization of fungi. Mycological Research 98: 593–603. , ,
- 1983 Activity of nitrate reductase in. Trifolium subterraneum: effects of mycorrhizal infection and phosphate nutrition. New Phytologist 94: 63–79. , , ,
- 1995 The use of phospholipid and neutral lipid fatty acids to estimate biomass of arbuscular mycorrhizal fungi in soil. Mycological Research 99: 623–629. , , ,
- 1973 Uptake, assimilation and transport of nitrogen compounds by plants. Soil. Biology and Biochemistry 5: 109–119. .
- 1976 Nitrogen metabolism. In: SmithJE, BerryDR. eds.. The Filamentous Fungi : Biosynthesis and Metabolism, vol. 2. London : Edward Arnold, 159–223. , .
- 1990 Microbial immobilization of ammonium and nitrate in cultivated soils. Soil Biology and Biochemistry 22: 913–922. , ,
- 1989 Regulation of nitrate assimilation by ammonium in soil and in isolated soil microorganisms. Soil Biology and Biochemistry 21: 597–602. , .
- 1985 Activity of glutamine synthetase and glutamate dehydrogenase in. Trifolium subterraneum L. and. Allium cepa L.: effects of mycorrhizal infection and phosphate nutrition. New Phytologist 99: 211–227. , , , .
- 1986 Growth and sporulation of vesicular-arbuscular mycorrhizal fungi in aerobic and membrane systems. Symbiosis 1: 259–267. , .
- 1994 Improved nitrogen uptake and transport from 15N-labelled nitrate by external hyphae of arbuscular mycorrhiza under water-stressed conditions. New Phytologist 126: 119–122. , , .
- 1992 Biochemical analysis of biomass, community structure, nutritional status, and metabolic activity of microbial communities in soil. In: StotzkyG, BollagJ-M, eds.. Soil Biochemistry, vol. 7. New York : Marcel Dekker, 229–262. , .