Two invasive populations of the dry rot fungus Serpula lacrymans show divergent population genetic structures

Authors

  • INGEBORG BJORVAND ENGH,

    1. Microbial Evolution Research Group (MERG), Department of Biology, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway
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  • TOR CARLSEN,

    1. Microbial Evolution Research Group (MERG), Department of Biology, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway
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  • GLENN-PETER SÆTRE,

    1. Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway
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  • NILS HÖGBERG,

    1. Department of Forest Mycology & Pathology, Box 7026, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden
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  • SHUICHI DOI,

    1. Division of Appropriate Technology & Science for Sustainable Development, Graduate School of Life & Environmental Sciences, University of Tsukuba, 305-8572 Tsukuba, Japan
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  • HÅVARD KAUSERUD

    1. Microbial Evolution Research Group (MERG), Department of Biology, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway
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Ingeborg Bjorvand Engh, Fax: 22 85 47 26; E-mail: ingebbj@bio.uio.no

Abstract

The dry rot fungus Serpula lacrymans is a devastating basidiomycete occurring in wooden constructions in temperate regions worldwide. In this study, we compare the genetic structures of two invasive populations from Europe and Japan. Microsatellite data from 14 loci and DNA sequences from four loci demonstrated that the two populations were highly differentiated. Significant isolation by distance effect was observed in Europe and Japan. Higher genetic variation was observed within the Japanese population than within the European population, corresponding with the observed higher richness of vegetative compatibility types in Japan, indicating that there has been a higher level of gene flow from the Asian source populations to Japan than to Europe. The European population is genetically more homogenous with only six detected vegetative compatibility types. Various tests indicate that both the European and the Japanese populations have gone through population bottlenecks prior to population expansion. No identical multi-locus genotypes were observed within Japan and very few within Europe, indicating limited clonal dispersal. Deviations from Hardy Weinberg expectations were observed both in Europe and Japan and heterozygote excess were observed at several loci, especially in Europe. Possible explanations for this pattern are discussed.

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