Differential resistance to arsenate (AsO43-) is demonstrated here among pop
ulations of the ericoid mycorrhizal fungus Hymenoscyphus ericae isolated fr
om Calluna vulgaris in natural heathland soils and soils contaminated with
AsO43-.
Isolates (c. 25) of the fungus from each of two As and Cu mine sites, and a
natural heathland site, were screened for AsO43- and Cu2+ resistance by gr
owing isolates in media containing a range of AsO43- and Cu2+ concentration
s.
H. ericae populations from the mine sites demonstrated resistance to AsO43-
compared with the heathland population; the mine-site populations producin
g significant growth at the highest AsO43- concentration (4.67 mol m(-3)),
whereas growth of the heathland population was almost completely inhibited.
EC50 values for mine-site isolates were estimated to be 5-41-times higher
than the heathland population. All isolates produced identical responses to
increasing Cu2+ concentrations, with no differences observed between mine-
site and heathland isolates.
Populations of H. ericae on the contaminated mine sites have developed adap
tive resistance to AsO43-. By contrast, Cu2+ resistance appears to be const
itutive. (C) New Phytologist (2001) 151: 265-270.