The IWGSC: Strategies & Activities to Sequence the Bread Wheat Genome

Bread wheat, the staple food for 35% of the world’s population and the most widely produced crop, is one of the most important crop species. Genomics offers powerful tools for understanding the molecular basis of phenotypic variation as well as accelerating gene cloning, marker assisted selection, and more efficient exploitation of genetic diversity. In 2005, a group of growers, breeders, and plant scientists launched the International Wheat Genome Sequencing Consortium (IWGSC) with the goal of securing a high quality, reference sequence of the bread wheat genome. A milestone-based strategy coupled with short and long-term roadmaps provides breeders and plant scientists access to an increasing array of tools and resources without having to wait for the completed sequence. To reduce the complexity of the allohexaploid, highly repetitive, 17Gb bread wheat genome, the IWGSC follows a chromosome-specific approach to develop physical maps, survey sequencing, and high quality sequencing of the Minimum Tiling Paths before moving towards a gold standard reference sequence.  Physical maps have been completed or are underway for all 21 chromosomes of the reference cultivar, Chinese Spring. To facilitate anchoring, marker development, and to gain a first insight into the gene space composition, the IWGSC launched an internationally coordinated survey sequencing initiative that will provide breeders with gene modeling, virtual ordering, annotation, functional, and structural analyses of all 21 chromosomes.  High quality, BAC-by-BAC sequencing of chromosome 3B was completed in 2012 by INRA/Genoscope and is underway for 7B at the Norwegian University of Life Sciences/BGI.  An overview of the IWGSC strategies and activities as well as results from the physical mapping, survey sequencing, and high quality sequencing will be presented.