ARS | Publication request: Microsatellite markers for the diploid Basidiomycete fungus, Armillaria mellea

Submitted to: Molecular Ecology Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 27, 2008
Publication Date: January 22, 2009
Citation: Baumgartner, K., Grubisha, L.C., Fujiyoshi, P.T., Garbelloto, M., Bergemann, S.E. 2009. Microsatellite markers for the diploid Basidiomycete fungus, Armillaria mellea. Molecular Ecology Resources. 9:943-946.

Interpretive Summary: Armillaria root disease is a serious threat to fruit crops, timber trees, and ornamentals worldwide. The causal pathogen--the fungus Armillaria mellea--decomposes roots, which decreases crop yield and, eventually, kills the plant. Comparisons of DNA sequences between collections of the pathogen from North America, Europe, and Asia suggest that there are divergent populations in eastern and western North America. It is even possible that these divergent populations represent different species, given that there have been no comparisons of the pathogen’s fruiting bodies between easterna dn and western North America (mushrooms). Consequently, the goal of this research was to develop and characterize species-specific molecular markers, known as ‘microsatellite loci’, that can be used to determine if eastern and western collections of the pathogen are indeed representative of the same species. We isolated and characterized 13 microsatellite markers for eastern (Pennsylvania) and western (California) populations. Of the 13 loci, nine and eight loci were polymorphic in the California and Pennsylvania populations, respectively, and showed no evidence of heterozygote deficiencies. Our results suggest that we have isolated and characterized variable loci to estimate genotypic diversity, gene flow, and migration, and to determine population structure among North American A. mellea populations.

Technical Abstract: We isolated and characterized 13 microsatellite markers for two North American populations (California and Pennsylvania) of Armillaria mellea, a fungal root pathogen responsible for Armillaria root disease of numerous horticultural crops and forest trees. The frequency of alleles ranged from two to 7 alleles per locus, and gene diversity ranged from 0.15 to 0.93 in California and Pennsylvania. Of the 13 loci, nine and eight loci were polymorphic in the California and Pennsylvania populations, respectively, and showed no evidence of heterozygote deficiencies. Our results suggest that we have isolated and characterized variable loci to estimate genotypic diversity, gene flow, and migration, and to determine population structure among North American A. mellea populations.