Population structure of the wood decay fungus Fomitopsis pinicola.

Three populations of the wood decay fungus Fomitopsis pinicola, one from each of three countries (Sweden, Russia and Lithuania), were studied by means of arbitrary primed PCR. The genetic structure of the populations was assessed by inferring the genotype of the genets by studying the haplotypes of several single-spore isolates from one sporocarp for each individual. Heterozygotes could therefore be detected with a dominant genetic marker. The amplified band and the null allele of all loci segregated in a way that was in agreement with a 50:50 ratio. Genetic analysis showed that the total population as well as the subpopulations had heterozygote frequencies in agreement with Hardy-Weinberg expectations. No population differentiation was detected in spite of large geographical distances among the populations studied. We also compared the methods of somatic incompatibility and AP-PCR in terms of their value in detecting fungal genets. This was tested for a sample of dikaryotic mycelia from Switzerland. For the tested material the two methods gave congruent results.