Plant & Animal Genomes XIV Conference

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

Brachypodium distachyon As A Potential Genomic ‘Bridge’ To Physically Map Grass Genomes

John Draper¹ , Robert Hasterok² , Agnieszka Marasek³ , Iain S. Donnison⁴ , Ian Armstead⁴ , Ian P. King⁴ , Elzbieta Wolny² , Dominika Idziak² , Glyn Jenkins¹

¹  Institute of Biological Sciences, Edward Llwyd Building, University of Wales Aberystwyth, Penglais, Aberystwyth, Ceredigion SY23 3DA, UK

²  Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia, Jagiellonska 28, 40-032 Katowice, Poland

³  Department of Plant Physiology and Biochemistry, Research Institute of Pomology and Floriculture, Pomologiczna 18, 96-100 Skierniewice, Poland

⁴  Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, SY23 3EB, UK

The large and complex genomes of temperate cereals and forage grasses can contain a large component of repetitive DNA which frustrate the exploitation of large insert DNA library technology. Brachypodium distachyon has been identified as a model diploid grass species closely related to the Triticeae and shown to possess a very small genome contained in 5 chromosome pairs. The physical analysis of this simple genome will be described including initial progress towards developing a functional genomics toolkit to exploit Brachypodium distachyon as a “bridge” species for gene isolation in temperate cereals. As part of this project, a small BAC library has been constructed and preliminary analysis has shown that only around 3% of the clones are of medium to high copy number, reflecting the compact and economical (1C = 355 Mbp) genome of this species. PCR-based screening, using syntenic regions of the rice and wheat genomes controlling agronomically important traits, identified orthologous BACs in the library. Over 30 BAC clones have been anchored by Fluorescence in situ Hybridisation (FISH) to single loci of the somatic and pachytene chromosomes of this species, enabling the discrimination of all of the chromosomes arms of the complement. Future effort will concentrate on the use of ‘BAC landing’ technology to identify BAC clones from Brachypodium which are syntenic to important regions of temperate cereal genomes in order to obtain an ‘tile’ of flanking BAC clones that can be used to ‘bridge’ difficult chromosome walks in crop species.