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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Research » Research » Publications at this Location » Publication #342490
Title: Molecular cytogenetic and genomic analyses reveal new insights into the origin of the wheat B genome

Author
item ZHANG, WEI - North Dakota State University
item ZHANG, MINGYI - North Dakota State University
item ZHU, XIANWEN - North Dakota State University
item CAO, YAPING - North Dakota State University
item SUN, QING - North Dakota State University
item MA, GUOJIA - North Dakota State University
item Chao, Shiaoman
item YAN, CHANGHUI - North Dakota State University
item Xu, Steven
item CAI, XIWEN - North Dakota State University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2017
Publication Date: 11/1/2017
Publication URL: http://handle.nal.usda.gov/10113/5900028
Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Sun, Q., Ma, G., Chao, S., Yan, C., Xu, S.S., Cai, X. 2017. Molecular cytogenetic and genomic analyses reveal new insights into the origin of the wheat B genome. Theoretical and Applied Genetics. 131:365-375. https://doi.org/10.1007/s00122-017-3007-0.
DOI: https://doi.org/10.1007/s00122-017-3007-0

Interpretive Summary: Common wheat, also known as bread wheat, contains three genetically related genomes (A, B, and D). The ancestors for the genomes A and D had been identified. However, the ancestor of the genome B, remains obscure even though intensive efforts have been made to tackle this evolutionary puzzle of wheat over nearly a century. The goatgrass species Aegilops speltoides with S genome has been controversially considered a candidate for the ancestor of the wheat B genome. The present study aimed to trace the footprint of Aegilops speltoides in the B genome by assessing the relationship of the B and S genomes using an integrative genetic and genomic approach. We detected obvious similarity between wheat chromosome 1B and Ae. speltoides chromosome 1S, but not between other chromosomes in the B and S genomes. We detected an Ae. speltoides chromosome segment present on the long arm of wheat chromosome 1B (1BL). Evidently, Ae. speltoides had been involved in the origin of the wheat B genome, but should not be considered an exclusive donor of B genome. The wheat B genome might originate from multiple ancestors, including Ae. speltoides. These novel findings will facilitate genome studies in wheat and its related species.

Technical Abstract: Wheat is a typical allopolyploid with three homoeologous subgenomes (A, B, and D). The donors 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 possible candidate for the donor of the wheat B genome. However, the relationship of the Ae. speltoides S genome with the wheat B genome remains largely obscure. The present study assessed the homology of the B and S genomes using an integrative cytogenetic and genomic approach, and revealed the contribution of Ae. speltoides to the origin of the wheat B genome. We discovered noticeable 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 approximately10.57 Mb was detected 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. Evidently, Ae. speltoides had been involved in the origin of the wheat B genome, but should not be considered an exclusive donor of this genome. The wheat B genome might have a polyphyletic origin with multiple ancestors involved, including Ae. speltoides. These novel findings will facilitate genome studies in wheat and other polyploids.