A Genome-Wide Sequence-Indexed Collection of Brachypodium Mutants to Accelerate Grain and Biomass Crop Breeding

Brachypodium distachyon emerged recently as model plant for grass crops. With its simple sequenced genome, short life cycle and expanding array of genetic tools, B. distachyon is an excellent system to elucidate the molecular basis of important traits in grasses (e.g. development, grain and biomass producton). Chemical or radiation mutagenesis are commonly used to assign function to specific genes. As a low-cost method to create genetic variation, we used fast-neutron radiation, sodium azide, and ethyl methanesulfonate to mutagenize B. distachyon inbred line Bd21-3. The difficulty in identifying the causal mutation in chemically mutagenized populations has been a limitation of these types of mutants. However, the small genome size of B. distachyoncombined with the decreasing cost of DNA sequencing has made it feasible to sequence thousands of mutants to establish a genome-wide sequence-indexed collection of grass mutants. In order to select the best mutant population for sequencing, we sequenced the genomes of mutants produced by all three mutagens. The collection was extensively validated and characterized by looking for and characterizing mutations in several genes involved in several traits such as flower development, cell wall composition, and grain quality. To date, 430 mutant lines have been sequenced and over 300,000 mutations identified. For more information or to access the collection please contact us or visit http://jgi.doe.gov/our-science/science-programs/plant-genomics/brachypodium/