Tracing the genetic diversity of the bread wheat D genome

Wang, Z.; Wang, W.; He, Y.; Xie, X.; Yang, Z.; Zhang, X.; Niu, J.; Peng, H.; Yao, Y.; Xie, C.; Xin, M.; Hu, Z.; Sun, Q.; Ni, Z.; Guo, W.

doi:10.1101/2024.08.23.609385

bioRxiv · 10.1101/2024.08.23.609385

Tracing the genetic diversity of the bread wheat D genome

Wang, Z.·Wang, W.·He, Y.·Xie, X.·Yang, Z.·Zhang, X.·Niu, J.·Peng, H.·Yao, Y.·Xie, C.·Xin, M.·Hu, Z.·Sun, Q.·Ni, Z.·Guo, W.

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Abstract

Bread wheat (Triticum aestivum) became a globally dominant crop after incorporating the D genome from donor species Aegilops tauschii, while evolutionary history shaping the D genome during this process remains elusive. Here, we proposed a renewed evolutionary model linking Ae. tauschii and hexaploid wheat D genome, based on an ancestral haplotype map covering a total of 762 Ae. tauschii and hexaploid wheat accessions. We dissected the evolutionary process of Ae. tauschii lineages and clarified L3 as the most ancient lineage. A few independent intermediate accessions were reported, demonstrating the low-frequent inter-sublineage geneflow enriched the diversity of Ae. tauschii. We discovered that the D genome of hexaploid wheat inherited from a unified ancestral template, but with a mosaic composition that is highly mixed by three Ae. tauschii L2 sublineages located in the Caspian coastal region, suggesting the early agricultural activities facilitate the innovation of D genome compositions that finalized the success of hexaploidization. We further found that the majority (65.6%) of polymorphisms were attributed to novel mutations absent during the spreading of bread wheat, and also identified large Ae. tauschii introgressions from wild Aegilops lineages, expanding the diversity of wheat D genome and introducing beneficial alleles. This work decoded the mystery of the wheat hexaploidization process and the evolutionary significance of the multi-layered origins of the genetic diversity of the bread wheat D genome.

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Wang, Z., Wang, W., He, Y., Xie, X., Yang, Z., Zhang, X., Niu, J., Peng, H., Yao, Y., Xie, C., Xin, M., Hu, Z., Sun, Q., Ni, Z., Guo, W.. 2024-08-24. Tracing the genetic diversity of the bread wheat D genome. https://doi.org/10.1101/2024.08.23.609385

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