Plant & Animal Genomes XV Conference

January 13-17, 2007
Town & Country Convention Center
San Diego, CA

EST-SSR-Based Phylogenetic Analysis Of USDA Brachypodium distachyon Collection

Yiqun Weng¹ , Perumal Azhaguvel¹ , Wanlong Li² , Bikram S. Gill² , Jackie C. Rudd¹

¹  Texas A&M University Agricultural Research & Extension Center, 6500 Amarillo Blvd. W., Amarillo, TX 79106, USA

²  Wheat Genetic and Genomic Resources Center, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA

Brachypodium distachyon (2n = 2x = 10) has been proposed as a model species of the temperate grasses for genomics research. However, much basic information is lacking in this species. In this study, genetic diversity of B. distachyon was investigated using six accessions (Bd1-1, Bd2-3, Bd3-1, Bd18-1, Bd21 and BD29) from the USDA collection and 160 SSR (simple sequence repeats) markers developed from B. distachyon ESTs. The effect of inbreeding on diversity in B. distachyon was also evaluated by comparison of three inbred lines (Bd2-3, Bd3-1, and Bd18-1) that have undergone five or six cycles of selfing with their respective original parental line. Three grass species, rice (Oryza sativa cv. Nipponbare), perennial ryegrass (Lolium perenne cv. Palmer), and Aegilops tauschii (accession AL8/78) were included as outliers in phylogenetic analysis. No polymorphism was detected between each of the three inbred lines and their respective parental line. While polymorphisms among different B. distachyon accessions were generally low, Bd1-1 and Bd21 were more diverse than the other lines examined. The genetic divergence was correlated with geographical distances. In the phylogenetic tree, L. perenne was closer to B. distachyon than Ae. tauschii, and rice was the most distant. Information from this study should be useful in selecting parents for linkage mapping in B. distachyon.