Draft Genome of Triticum urartu (Progenitor of Wheat A Genome) and its Physical Mapping

Triticum urartu is the progenitor of wheat A genome. It plays a central role in wheat evolution, domestication and genetic improvement because the A genome is the basic genome of bread wheat and other polyploidy wheats. We sequenced T. urartu accession G1812 using a whole-genome shotgun strategy on the Illumina HiSequation (2000) platform, and assembled the genome sequence. In total, 34,879 protein-coding gene models were predicted in the T. urartu genome. The large genome size of the wheat A genome (about 5 Gb) was due to enlarged intergenic space with repetitive elements, such as Gypsy and Copia retrotransposons, during the evolution. Compared to the genomes of rice, maize, sorghum and Brachypodium distachyon, 3,425 T. urartu-specific genes, 24 new microRNAs and more abundant disease resistance genes (R genes) were identified in T. urartu genome, suggesting that T. urartu may have distinctive responses to biotic and abiotic stresses and developmental processes, which may enable wheat to adapt to more diverse environments. Additionally, some important genes, such as TuGASR7 involved in control of grain length and weight, and a large number of SSR, ISBP and SNP molecular markers were identified, which should facilitate further functional genomics and molecular breeding studies of wheat and related species. Recently, we collaborated with Keygene, the Netherlands, analyzed more than 450,000 BAC clones using the whole genome profiling technology, and constructed BAC contigs. Further, we integrated the whole genome sequence data and the whole genome profiling data, and constructed the superscaffolds of the wheat A genome.