Heavy metal pollution and genetic adaptations in ectomycorrhizal fungi

Abstract

Heavy metal toxicity is a strong trigger for evolutionary adaptation in terrestrial biota that colonise metalliferous soils. Here, I will focus on the occurrence of metal tolerance in ectomycorrhizal fungi, the predominant group of root symbionts of pioneer trees that try to colonise severely polluted sites. A considerable amount of literature exists on metal-tolerant plants, which is in sharp contrast to what we know about the tolerance in the fungal symbiotic partners that associate with these plants on metal-polluted soils. I will deal with the ecological and evolutionary processes that drive plant and fungal communities and populations on metal-contaminated sites. The few examples of true metal tolerance in ectomycorrhizal fungi are described and mechanisms possibly involved in this tolerance are briefly summarised. How true metal tolerance in ectomycorrhizal fungi can affect a host plant is discussed in a final paragraph.