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United States Department of Agriculture

Agricultural Research Service


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Title: A 4-gigbase physical map unlocks the structure and evolution of the complex genome of Aegilop tauschii, the wheat D-genome progenitor

item Luo, M-c
item Gu, Yong
item You, Frank
item Deal, K
item Ma, Y
item Hu, N
item Huo, N
item Wang, Y
item Wang, J
item Chen, S
item Jorgensen, C
item Zhang, Y
item Mcguire, P
item Pastrnak, S
item Stein, J
item Ware, D
item Mccombie, W
item Juanuan, S
item Martis, M
item Mayer, K
item Sehgal, S
item Gill, B
item Bevan, M
item Dolezel, J
item Lazo, Gerard
item Anderson, Olin
item Dvorak, J

Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2013
Publication Date: 5/7/2013
Citation: Luo, M., Gu, Y.Q., You, F., Deal, K.R., Ma, Y., Hu, N., Huo, N., Wang, Y., Wang, J., Chen, S., Jorgensen, C.M., Zhang, Y., Mcguire, P.E., Pastrnak, S., Stein, J.C., Ware, D.H., Mccombie, W.R., Juanuan, S.F., Martis, M.M., Mayer, K.F., Sehgal, S., Gill, B.S., Bevan, M.W., Dolezel, J., Lazo, G.R., Anderson, O.D., Dvorak, J. 2013. A 4-gigbase physical map unlocks the structure and evolution of the complex genome of Aegilop tauschii, the wheat D-genome progenitor. Proceedings of the National Academy of Sciences. 110:7940-7945.

Interpretive Summary: Bread wheat is one of the most important staple food crop worldwide. However, genomics research in wheat is often hindered by the complexity of wheat genome. Bread wheat is hexaploid species containing three highly related genomes termed A, B, and D. The wheat genome is extremely larger (17 Gb) and contain nearly 90% repetitive DNA. Aegilop tauschii is the diploid grass species which contributed the D genome to the hexaploid wheat during wheat evolution. Agronomically, important genes present in Aegilop tauschii gene pool can therefore be transferred into wheat using conventional breeding techniques. Therefore, the knowledge gained from genomics research on this species can be directly applied to bread wheat for crop improvement. In addition, Aegilop tauschii has been recognized as a model system to study wheat genetics and evolution. In this work, an integrated high-resolution physical and genetic map was developed by fingerprinting 400,000 large insert bacterial clones and mapping 1200 recombinant lines using 7,000 molecular markers. In addition, random shotgun genomics sequences representing over 50X genome coverage were generated to facilitate data analyses in this research project. The research result here represents a major breakthrough in wheat genomics research and will render unprecedented impacts on wheat research for crop improvement.

Technical Abstract: The genomes of wheat and its relatives in the tribe Triticeae are large, containing nearly 90% repetitive DNA, and some are polyploid. These genomes can currently be completely sequenced only by the ordered-clone genome sequencing approach, which reduces the complexity of sequence assembly from the level of the entire genome to the level of small pools of bacterial artificial chromosome clones. Ordered-clone sequencing requires the construction of a physical map of the genome. Here we report the physical map of Aegilops tauschii, the progenitor of the wheat D genome, and the largest and most complex genome for which a global physical map has been assembled, and use it for ordering Ae. tauschii gene sequences. We illustrate the utility of the map and associated gene sequences for advancing wheat genomics and the knowledge of grass genome structure and evolution.

Last Modified: 10/17/2017
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