RT Journal Article
SR Electronic
T1 Genome-wide homology analysis reveals new insights into the origin of the wheat B genome
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 197640
DO 10.1101/197640
A1 Wei Zhang
A1 Mingyi Zhang
A1 Xianwen Zhu
A1 Yaping Cao
A1 Qing Sun
A1 Guojia Ma
A1 Shiaoman Chao
A1 Changhui Yan
A1 Steven S. Xu
A1 Xiwen Cai
YR 2017
UL http://biorxiv.org/content/early/2017/10/02/197640.abstract
AB Wheat is a typical allopolyploid with three homoeologous subgenomes (A, B, and D). The ancestors of the subgenomes A and D had been identified, but not for the subgenome B. The goatgrass Aegilops speltoides (genome SS) has been controversially considered a candidate for the ancestor of the wheat B genome. However, the relationship of the Ae. speltoides S genome with the wheat B genome remains largely obscure, which has puzzled the wheat research community for nearly a century. In the present study, the genome-wide homology analysis identified perceptible homology between wheat chromosome 1B and Ae. speltoides chromosome 1S, but not between other chromosomes in the B and S genomes. An Ae. speltoides-originated segment spanning a genomic region of approximately 10.46 Mb was identified on the long arm of wheat chromosome 1B (1BL). The Ae. speltoides-originated segment on 1BL was found to co-evolve with the rest of the B genome in wheat species. Thereby, we conclude that Ae. speltoides had been involved in the origin of the wheat B genome, but should not be considered an exclusive ancestor of this genome. The wheat B genome might have a polyphyletic origin with multiple ancestors involved, including Ae. speltoides. These novel findings provide significant insights into the origin and evolution of the wheat B genome, and will facilitate polyploid genome studies in wheat and other plants as well.