Population structure of Serpula lacrymans in Europe with an outlook to the French population

Abstract

In this study the genetic variation and population structure in a French population of the dry rot fungus S. lacrymans was investigated using 14 microsatellites markers and compared to the rest of Europe. In that comparison the French population possessed the same allelic diversity as rest of Europe. A weak geographic structuring of the genetic variation was observed across Europe, where the French isolates to some extent separated from the rest of Europe, indicating that weak barriers to gene flow exists. Eighty percent of the isolates had unique multilocus microsatellite genotypes, which corresponds to high recombination and dispersal by sexual spores. Deviations from Hardy-Weinberg expectations were observed in multiple loci. In most loci there was an excess of heterozygotes, which could be due to either non-random mating, presence of more than two nuclei in the secondary mycelia or another unrecognized process. A total of six vegetative compatibility (VC) groups were present in Europe, out of which four were sampled in France. One VC group was over-represented in France while two others were underrepresented, as compared to the rest of Europe.

• dry rot fungi
• heterozygosity excess
• population genetics
• Serpulaceae
• vegetative compatibility

Acknowledgments

This research was financially supported by the Région Bretagne, Brest Métropole Océane, the Norwegian Research Council and the University of Oslo. SM thanks members of MERG and CEES at the University of Biology of Oslo for their warm welcome during her research stay. Unni Vik is acknowledged for technical advice during the microsatellite analyses and Ingeborg Engh for fruitful discussions.

Notes

Competing interests

The authors declare no competing interests.

Author contributions

HK and GB designed the study. SM carried out the experiments. SM and IS performed the population genetic analyses. SM, IS and HK wrote the paper. All authors read and approved the final manuscript.