Sequencing and comparative analysis of Aegilops tauschii chromosome arm 3DS revealed rapid evolution of Triticeae genomes

Publication date: Available online 5 October 2016
Source:Journal of Genetics and Genomics
Author(s): Jingzhong Xie, Naxin Huo, Shenghui Zhou, Yi Wang, Guanghao Guo, Karin R. Deal, Shuhong Ouyang, Yong Liang, Zhenzhong Wang, Lichan Xiao, Tingting Zhu, Tiezhu Hu, Vijay Tiwari, Jianwei Zhang, Hongxia Li, Zhongfu Ni, Yingyin Yao, Huiru Peng, Shengli Zhang, Olin D. Anderson, Patrick E. McGuire, Jan Dvorak, Ming-Cheng Luo, Zhiyong Liu, Yong Q. Gu, Qixin Sun
Bread wheat (Triticum aestivum, AABBDD) is an allohexaploid species derived from two rounds of interspecific hybridizations. A high-quality genome sequence assembly of diploid Aegilops tauschii, the donor of the wheat D genome, will provide a useful platform to study polyploid wheat evolution. A combined approach of BAC pooling and next-generation sequencing technology was employed to sequence the minimum tiling path (MTP) of 3176 BAC clones from the short arm of Ae. tauschii chromosome 3 (At3DS). The final assembly of 135 super-scaffolds with an N50 of 4.2 Mb was used to build a 247-Mb pseudomolecule with a total of 2222 predicted protein-coding genes. Compared with the orthologous regions of rice, Brachypodium, and sorghum, At3DS contains 38.67% more genes. In comparison to At3DS, the short arm sequence of wheat chromosome 3B (Ta3BS) is 95-Mb large in size, which is primarily due to the expansion of the non-centromeric region, suggesting that transposable element (TE) bursts in Ta3B likely occurred there. Also, the size increase is accompanied by a proportional increase in gene number in Ta3BS. We found that in the sequence of short arm of wheat chromosome 3D (Ta3DS), there was only less than 0.27% gene loss compared to At3DS. Our study reveals divergent evolution of grass genomes and provides new insights into sequence changes in the polyploid wheat genome.



from Genetics via xlomafota13 on Inoreader http://ift.tt/2dy2mDe
via IFTTT