|MACCAFERRI, MARCO - University Of Bologna|
|HARRIS, NEIL - University Of Alberta|
|TWARDZIOK, SVAN - Helmholtz Centre|
|GUNDLACH, HEIDRUN - Helmholtz Centre|
|SPANNAGL, MANUEL - Helmholtz Centre|
|ORMANBEKOVA, DANARA - University Of Bologna|
|LUX, THOMAS - Helmholtz Centre|
|PRADE, VERENA - Helmholtz Centre|
|MILNER, SARA - Leibniz Institute|
|HIMMELBACH, AXEL - Leibniz Institute|
Submitted to: Nature Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2019
Publication Date: 5/1/2019
Citation: Maccaferri, M., Harris, N.S., Twardziok, S.O., Gundlach, H., Spannagl, M., Ormanbekova, D., Lux, T., Prade, V., Milner, S., Himmelbach, A., Chao, S., Faris, J.D., Xu, S.S. 2019. Durum wheat genome highlights past domestication signatures and future improvement targets. Nature Genetics. 51(5):885-895. https://doi.org/10.1038/s41588-019-0381-3.
Interpretive Summary: Durum wheat is a widely grown cereal crop mainly for making pasta products. It originated from the taming of wild emmer wheat, a primitive wheat species whose genome was recently sequenced. In this study, an international team has generated a genome sequence of the modern durum wheat cultivar ‘Svevo’, which enabled an in-depth comparison between modern durum and its ancestor wild emmer. This comparative analysis revealed that the chromosomal regions exhibiting genetic changes associated with formation of durum wheat and facilitated by human selection were widely present in the durum genome. One such region carries a gene (TdHMA3-B1) causing high levels of dietary cadmium (Cd) in grain. This gene is widespread among modern durum cultivars but undetected in wild emmer germplasm collections. The rapid analysis of the structure and function of this gene allowed the effective recovery of the beneficial gene for low Cd uptake, thus demonstrating the practical utility of the durum genome sequence reported in this study for wheat improvement.
Technical Abstract: The domestication of wild emmer wheat led to the selection of modern durum wheat widely grown mainly for pasta production. The 10.45 Gb assembly of the genome of durum wheat cv. Svevo enabled a genome-wide comparison between wild and cultivated forms of tetraploid wheat. Regions exhibiting strong signatures of genetic divergence associated with speciation, genetic drift, and selection events were widespread. One such region carries a gene coding for a metal transporter (TdHMA3-B1) with a non-functional variant causing high levels of dietary cadmium (Cd) in grain. We demonstrate that the high Cd allele, widespread among durum cultivars but undetected in wild emmer accessions, increased in frequency from domesticated emmer to durum landraces and ultimately to modern durum wheat. The rapid dissection of TdHMA3-B1 allowed to reach back through wheat's domestication bottleneck and rescue a wild beneficial allele, thus demonstrating the practical utility of this new genomic resource for wheat improvement.