Genetic Variability of Two Populations of the Ectomycorrhizal Fungus Xerocomus Chrysenteron Associated with European Beech (Fagus sylvatica L.)

2000

8 Abb., 12 Tab., 29 Lit. Ang.

Unselbständiges Werk

13343

200069722

The intra- and interpopulation genetic variablity of the ectomycorrhizal fungus Xerocomus chrysenteron (Bull. Ex. St. Amans) Quél, infecting European beech (Fagus sylvatica L.), was studied in two populations in central Germany (Bingen und Heppenheim). The allele and genotype frequencies of the polymorphic enzyme loci Acp-B, Dia-B, Dia-C, Gópdh-A, Lap-B, Mdh-C, Me-B, Pepl-B and Pep2-B served as genetic markers. The total number of alleles of the nine gene loci was 23 (allele/polymorhic locus = 2.4). The alleles 1 of the loci Me-B and Dia-Be were observed only in one of the populations (Heppenheim). The average number of alleles per polymorphic locus was a little higher in one stand (Heppenheim: 2.55) than in the other (Bingen: 2.33). the number of effective alleles was calculated to be ne = 1.56 (Heppenheim) and ne = 1.53 (Bingen) in both populations. The genotypes Dia-B 1/1, Gópdh-A 1/2, Lap-B 1/3, Mdh-C 1/2 and Me-B 1/1, 1/2, 1/3 were found only in one population (Heppenheim),hile they were missing in Bingen. On the other hand, the Bingen population showed the genotypes Gópdh-A 1/1 and Lap-B 1/1 which were missing in Heppenheim population. Relative allelic frequencies varied little (3 to 5 %) at the loci Dia-C, Gópdh-A, Lap-B, Mdh-C, Pel-B and Pep2-B whereas the frequency differences of the alleles 1 and 2 at the locus Acp-B were considerable in both populations (allele 1:46 %(Heppenheim), 82 % (Bingen)). As a consequence, a low genetic distance (D = 3 %, do = 0.9 %) was observed among the two populations studied. Also, the average heterozygosity was not significantly different in both populations (HE = 33 %). An excess of heterozygous genotypes was observed in both populations at the loci Me-B and Pep2-B. The total genetic diversity was Hr = 0.3455, the genetic diversity within populations was Hs = 0.3381 and the amount of genetic differentiation of the total diversity was Gsr = 2.5 %. These data are compared with known population genetic data of Europea beech and similarities and differences are discussed.