Fungal genotyping, Cu-tolerance and host protection in ectomycorrhizal strains of the "Hymenoscyphus ericae aggregate" (Ascomycota).

Human activities as mining, melting, metal-processing and other industrial activities result in soils with toxic concentrations of heavy metals. Even though heavy metals significantly affect plant health, several higher plants grow in metalliferous enviro nments. All these plants are mycorrhizal, and the expressed metal tolerance may be influenced by their fungal partners underground, some of which effectively assimilate, bind or block high metal concentrations. Understanding the physiology, ecology, evol ution and co-evolution of metal tolerance in mycorrhizal fungi and their hosts is an intriguing research area, and is of significant importance for further knowledge of ecosystem function. In an applied setting it is important in relation to forest health improvements and metal-removal using hyper-accumulating organisms. Linking the fields of physiology, ecology and genetics is a novel approach to answer questions concerning heavy metal tolerance and host protection in ectomycorrhizal fungi. The objectiv es of this study is firstly to characterize genotypic variation in populations of ectomycorrhizal strains of the "Hymenoscyphus ericae aggregate" (Ascomycota) from non-polluted and metal polluted soils, secondly to study their Cu-tolerance in relat ion to origin and genotypic patterns and thirdly to investigate whether "H. ericae aggregate" strains protect pine seedlings of non-polluted and metal-polluted origins against Cu-toxicity. Aspects of co-evolution will be addressed.