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Molecular genetic studies of Armillaria species: Application of molecular genetic tools toward understanding ecological relationships in forest ecosystems
Abstract
Armillaria species cause root and butt rots of woody plants throughout the world. Molecular genetic techniques were used to augment species identification, determine nuclear status, address issues of gene flow, and analyze mating of Armillaria isolates. Twenty-six isolates representing nine North American Armillaria species were investigated with flow cytometry and restriction fragment length polymorphism (RFLP) analyses to determine their genome size and RFLP profile. Putatively diploid isolates of A. ostoyae, A. gemina, A. calvescens, A. sinapina, A. mellea, A. gallica, A. nabsnona, North American Biological Species (NABS) X, and NABS XI were analyzed. Genome sizes of Armillaria species ranged from 0.11 pg to 0.17 pg per diploid nucleus, depending on species. A. ostoyae, A. gemina, and A. mellea possessed relatively small genome sizes (0.11 pg–0.12 pg per diploid nucleus), whereas A. gallica possessed a relatively large genome size (0.17 pg per diploid nucleus). Polymerase chain reaction (PCR) and RFLP of the intergenic spacer region-1 (IGS-1) generated characteristic banding patterns for nine Armillaria species. Thirty-five Armillaria isolates were collected from northern Idaho and eleven isolates were collected from northern Nebraska. Based on RFLP patterns of northern Idaho isolates, fifteen were identified as A. ostoyae, fourteen were identified as NABS X, and six were identified as A. sinapina or A. calvescens. All isolates from northern Nebraska were identified as A. gallica . Genome sizes of 46 Armillaria isolates ranged from 0.11 pg to 0.18 pg per diploid nucleus, depending on species. For assessments of intraspecific mating using flow cytometry and fluorescence microscopy, two compatible basidiospore-derived isolates were selected from each of four parental basidiomata of NABS X. Seven basidiospore isolates were specifically selected to assess rare, interspecific mating among A. cepistipes, A. sinapina, NABS X, and NABS XI. Flow cytometry and fluorescence microscopic analyses provided evidence of intraspecific mating within NABS X and interspecific mating among A. cepistipes, A. sinapina , NABS X, and NABS XI isolates. In addition, PCR-RFLP analysis of IGS-1 showed combined banding patterns from interspecifically mated cultures.
Subject Area
Plant pathology|Molecular biology|Forestry
Recommended Citation
Kim, Mee-Sook, "Molecular genetic studies of Armillaria species: Application of molecular genetic tools toward understanding ecological relationships in forest ecosystems" (1999). ETD collection for University of Nebraska-Lincoln. AAI9942132.
https://digitalcommons.unl.edu/dissertations/AAI9942132