Genome Sequence of T. uartu

Genome sequencing of Triticum urartu – the progenitor of wheat A genome

Hong-Qing Ling, Hui Liu, Biao Ma¹, Hua Sun¹, Shancen Zhao², ³Michiel van Eijk, Zhensheng Li¹, Aimin Zhang¹, Daowen Wang¹, Chengzhi Liang¹

¹Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China. ²BGI Shenzhen, Shenzhen, China. ³Keygene, Wageningen, The Netherlands, E-mail: hqling@genetics.ac.cn

Bread wheat (Triticum aestivum), one of the most widely cultivated and consumed food crops in the world, is a hexaploid containing A, B and D genomes. Due to its complex polyploidy nature and large genome size (17 Gb), the genetic and functional analysis of bread wheat is extremely challenging. 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. Therefore, we are working on the genome sequencing of T. urartu since 2009.

Two years ago, we have sequenced T. urartu accession G1812 using a whole-genome shotgun strategy on the Illumina HiSequation (2000) platform, and generated a draft genome of wheat A genome (Ling et al., 2013, Nature 496: 87-90). To completely sequence the wheat A genome, we constructed 3 BAC libraries and created BAC contigs using the whole genome profiling technology by collaboration with Keygene, the Netherlands. Based on BAC contig data, we selected 47,223 BACs by MTP approach, and sequenced them. Additionally, we also generated more than 80 G sequence data by whole genome sequencing using the third generation sequencing technology (PacBio RS II). The sequence assembly has been finished and the genome analysis is in progress. For assignment and order of the genome sequences on their corresponding chromosome, we sequenced 480 F2 plants derived from two T. urartu accessions (G1812 and G3146) using RAD-sequencing technology, and identified more than 400,000 SNPs. With them, a high resolution SNP map has been constructed. In conclusion, completing the genome sequence of T. urartu will provide a diploid reference for the analysis of polyploidy wheat genomes, and is a valuable resource for the genetic improvement of wheat to meet the future challenges of global food security and sustainable agriculture.