Arsenate sensitivity in ericoid and ectomycorrhizal fungi

Jade M. Sharples, Andrew A. Meharg, Susan M. Chambers, John W G Cairney*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Isolates of the endomycorrhizal fungus Hymenoscyphus ericae and the ectomycorrhizal fungus Hebeloma crustuliniforme from soils uncontaminated with AsO4/3-, were compared with regard to their sensitivity to AsO4/3- in solution culture. When grown in liquid media amended with a range of AsO4/3- concentrations, H. ericae demonstrated reduced sensitivity to AsO4/3- compared to H. crustuliniforme. The concentrations causing 50% inhibition of growth (EC50) were 1.33 mol/m3 and 0.33 mol/m3, respectively, for H. ericae and H. crustuliniforme. The compound AsO4/3- is a PO4/3- analogue for the plasmalemma PO4/3- transporter. The presence of PO4/3- in the media at high concentrations ameliorated the toxic effects of AsO4/3- in both the ericoid and ectomycorrhizal fungi. This could be due to both suppression of the PO4/3- transporter under high phosporus status and competition of PO4/3- with AsO4/3- for the transport protein. The kinetics of AsO4/3- influx in H. ericae and H. crustuliniforme were also investigated. Hymenoscyphus ericae demonstrated a high K(m) value, 0.071 mol/m3, consistent with values obtained for AsO4/3- -tolerant plants. We suggest that the high K(m) value may be a mechanism used by H. ericae to express reduced AsO4/3- sensitivity. The ecological significance of this reduced sensitivity is also discussed.

Original languageEnglish
Pages (from-to)1848-1855
Number of pages8
JournalEnvironmental toxicology and chemistry
Volume18
Issue number8
DOIs
Publication statusPublished - 1999

Keywords

  • Arsenate
  • Hebeloma crustuliniforme
  • Hymenoscyphus ericae
  • Phosphate
  • Sensitivity

ASJC Scopus subject areas

  • Environmental Science(all)
  • Environmental Chemistry
  • Toxicology
  • Health, Toxicology and Mutagenesis

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