Hanna, J.W., Klopfenstein, N.B., Kim, M.-S., McDonald, G.I., and Moore, J.A. 2003. Intraspecific and intragenomic variation of Armillaria ostoyae within the western United States. Proceedings of the annual meeting of the American Phytopathological Society. 9-13 August 2003, Charlotte, NC. Phytopathology 93: S33. (Offered poster paper by Hanna)

Intraspecific and intragenomic variation of Armillaria ostoyae were observed through sequencing of ribosomal DNA (rDNA) including nuclear large ribosomal subunit (nLSU), internal transcribed spacer (ITS), 5.8S rDNA, and intergenic spacer (IGS-1). Many of the A. ostoyae genets contained heterogeneous sequences, an indication of intragenomic variation/intraspecific hybridization. Intragenomic variation was verified by visual analysis of sequence chromatograms and PCR with specific internal primers. Intraspecific and intragenomic variation was found to exist in all rDNA regions analyzed, with the exception of the 5.8S rDNA. Variation will be further analyzed using Parsimony and Neighbor-Joining methods for phylogenetic analysis. Genetic diversity within A. ostoyae can be examined for relationships to ecological function (e.g., pathogenicity, host specificity, habitat type), geographic origin, forest management practices (e.g., fertilization), and interactions among Armillaria genotypes.