Hanna, J.W., Kim, M.-S., Klopfenstein, N.B., Zambino, P.J., and McDonald, G.I. 2003. Characterization of North American Armillaria species: Phylogenetic relationships from IGS, ITS, and nuclear large subunit ribosomal DNA sequences. Proceedings of the annual meeting of the American Phytopathological Society. 9-13 August 2003, Charlotte, NC. Phytopathology 93: S33. (Offered poster paper by Hanna)

Phylogenetic relationships among nine North American Armillaria spp. were analyzed using ribosomal DNA (rDNA) sequences from intergenic spacer 1 (IGS-1), internal transcribed spacer (including 5.8S rDNA) (ITS+5.8S), and nuclear large subunit rDNA (nLSU) regions. Phylogenetic trees were generated using Neighbor-Joining analysis. Armillaria ostoyae and A. gemina were well separated from the other Armillaria spp. Several Armillaria spp. (A. calvescens, A. sinapina, A. gallica, NABS X, and A. cepistipes) clustered together, despite their previous separation based on in vitro compatibility and/or morphology. The nLSU sequence data indicate that A. mellea is distant from other Armillaria spp. A more detailed phylogenetic analysis and an examination of hybridization among Armillaria spp. are underway.