Genetic diversity of an ectomycorrhizal fungus Tricholoma terreum in a Larix principis-rupprechtii stand assessed using random amplified polymorphic DNA

The genetic variation and spatial distribution of the ectomycorrhizal fungus Tricholoma terreum was studied in an artificial Larix principis-rupprechtii stand in China. The 33 sporophores studied belonged to distinct genotypes, based on analysis of random amplified polymorphic DNA (RAPD) markers. The genets of T. terreum were small and no larger than 0.5 m. Two major phenetic groups, i.e. eight individuals in group 1 and 25 in group 2, were identified by principal component analysis and the unweighted pair group method with arithmetic means of simple matching coefficients, respectively. The genetic diversity as determined by the Shannon-Weaver diversity index was 4.52 for these 33 sporophores. Furthermore, there was a slightly lower diversity index in group 1 (4.28) than in group 2 (4.46). It is suggested that sexual spore propagation is very important in the life history of T. terreum in this larch forest.