Reichman, Jay R. , Smith, Bonnie M. , Londo, Jason P. , Bollman, Michael A. , Auer, Carol , Watrud, Lidia S. .
Diallelic microsatellites developed for Agrostis stolonifera L. population analyses provide evidence for A. transcaspica Litv. as the source of the bentgrass A3 subgenome.
Little is known about the genetic connectivity between creeping bentgrass (Agrostis stolonifera L.) populations. A fundamental challenge to DNA fragment-based population structure analyses of allopolyploid species like creeping bentgrass (2n=4x=28, A2A2A3A3) is scoring individuals as homozygous or heterozygous for loci that are present in multiple genomes of the species. Thus, our primary objective was to develop genome-specific, co-dominant simple sequence repeat (SSR) markers that are diallelic, producing one or two alleles per A. stolonifera individual per locus, in order to obtain greater certainty of the heterozygosity, hybridization and admixture measured within populations. While planning our development strategy, we considered previous inferences about the genomic organization and evolutionary history of A. stolonifera and its close relatives. Polymorphic microsatellite loci were isolated from three genomic libraries; four markers were identified from a wild-collected creeping bentgrass population, three from a commercial creeping bentgrass cultivar and two from an accession of A. transcaspica Litv. (2n=2x=14, putative A3A3). These nine SSR markers were characterized in 87 A. stolonifera individuals sampled from six distinct sources. Bayesian population structure analyses and groupings based on Rogersí modified genetic distance resolved wild from commercial genotypes. Each method assigned individuals to clusters that corresponded to their sources. The markers correctly identified known intraspecific creeping bentgrass F1 hybrids. Contrasting patterns of amplification of orthologs in other Agrostis species with different but overlapping genomic compliments suggest that at least six of our SSRs are A3 genome specific and that one was derived from the A2 subgenome of A. stolonifera. Furthermore, our results support the hypothesis that A. transcaspica Litv. is the ancestral source of the A3 subgenome found in A. stolonifera and A. gigantea R. (2n=6x=42, A1A1A2A2A3A3).
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1 - US Environmental Protection Agency, Western Ecology Division, 200 SW 35th Street, Corvallis, Oregon, 97333, USA
2 - National Research Council , 200 SW 35th Street, Corvallis, OR, 97333, USA
3 - US Environmental Protection Agency, Western Ecology Division, 200 SW 35th Street, Corvallis, OR, 97333, USA
4 - University of Connecticut, Plant Science, Box U-4163, Storrs, Connecticut, 06269, United States
Presentation Type: Oral Paper:Papers for Topics
Location: 556A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 11:30 AM