Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Construction And Characterization Of Two BAC Libraries For Brachypodium distachyon, A New Model For Grass Genomics

Yong Q. Gu¹ , Naxin Huo¹ , John Vogel¹ , David F. Garvin² , Gerard R. Lazo¹ , Olin D. Anderson¹

¹  Genomcis and Gene Discovery Research Unit, USDA-ARS, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710

²  Dept. of Agronomy and Plant Genetics, 411 Borlaug Hall, University of Minnesota, 1991 Upper Buford Circle, St. Paul, MN 55108

Due to its small genome size (~360Mb), short life cycle (2 months), and small stature, Brachypodium distachyon is well suited to study grass functional genomics. High efficiency-genetic transformation of Brachypodium distachyon via microprojectile bombardment and Agrobacterial has been reported (Christiansen et al., 2005, Vogel et al., 2005). To further develop genome resources and initiate our understanding of the structure and organization of its small genome, we recently generated 20,000 expressed sequence tags (ESTs) derived from five Brachypodium cDNA libraries. Here, we report the construction of HindIII- and BamHI-digested BAC libraries from high molecular weight genomic DNA isolated from a diploid Brachypodium distachyon species. 36,864 BAC clones were picked and arrayed onto two high-density colony filters for each library. The average insert size was estimated to be 105 kb and 115 kb for the HindIII- and BamHI-digested libraries, respectively. The two libraries represent over 20X genome coverage. Various EST probes from rice, wheat, barley, and Brachypodium were used to screen the libraries to study synthetic relationship among these species. Sample sequencing of BAC ends from the libraries reveals low percentage of repetitive DNA elements and high number of single copy DNA in the Brachypodium genome. The two BAC libraries constructed with different restriction enzymes provide valuable resources for many uses including map-based cloning, comparative studies to other grass genomes, and construction of BAC-based physical map for this new model species.