Duplication and partitioning in evolution and function of homoeologous Q loci governing domestication characters in polyploid wheat
Duplication and partitioning in evolution and function of homoeologous Q loci governing domestication characters in polyploid wheat
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DOI：
10.1073/pnas.1110552108
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发表时间：
2011-11-15
影响因子：
11.1
通讯作者：
Chalhoub, Boulos
中科院分区：
文献类型：
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作者：
Zhang, Zengcui;Belcram, Harry;Chalhoub, Boulos
Q基因编码一个AP 2类转录因子，在多倍体小麦的驯化过程中发挥了重要作用。小麦5A染色体上的Q等位基因（5AQ和5Aq）已被研究得很好，但对小麦同源染色体5 B（5 Bq）和5D（5Dq）上的q等位基因的研究却很少。我们研究了六倍体小麦（Triticum aestivum L.）中Q/q同源等位基因的组织、进化和功能。Q/q基因序列在六倍体小麦的A、B和D基因组、四倍体小麦的A和B基因组以及二倍体祖先的A、S和D基因组内和之间是高度保守的，但Q/q基因座的基因间区域在同源染色体组之间是高度分化的。q基因5.8 Mya的复制很可能随后选择性丢失来自A基因组祖先的一个拷贝和来自B、D和S基因组的另一个拷贝。A谱系中最近的V-329-to-I突变与Q表型相关。异源四倍化后，5 Bq等位基因变为假基因。表达分析表明，同源等位基因以复杂的方式共调控。结合表型和表达分析表明，而5AQ在赋予驯化相关性状中起着重要作用，5Dq直接贡献，5 Bq间接抑制speltoid表型。多倍体小麦Q/q基因座的进化导致5AQ的超功能化、5 Bq的假基因化和5Dq的亚功能化，这些都有助于驯化性状。
The Q gene encodes an AP2-like transcription factor that played an important role in domestication of polyploid wheat. The chromosome 5A Q alleles (5AQ and 5Aq) have been well studied, but much less is known about the q alleles on wheat homoeologous chromosomes 5B (5Bq) and 5D (5Dq). We investigated the organization, evolution, and function of the Q/q homoeoalleles in hexaploid wheat (Triticum aestivum L.). Q/q gene sequences are highly conserved within and among the A, B, and D genomes of hexaploid wheat, the A and B genomes of tetraploid wheat, and the A, S, and D genomes of the diploid progenitors, but the intergenic regions of the Q/q locus are highly divergent among homoeologous genomes. Duplication of the q gene 5.8 Mya was likely followed by selective loss of one of the copies from the A genome progenitor and the other copy from the B, D, and S genomes. A recent V-329-to-I mutation in the A lineage is correlated with the Q phenotype. The 5Bq homoeoalleles became a pseudogene after allotetraploidization. Expression analysis indicated that the homoeoalleles are coregulated in a complex manner. Combined phenotypic and expression analysis indicated that, whereas 5AQ plays a major role in conferring domestication-related traits, 5Dq contributes directly and 5Bq indirectly to suppression of the speltoid phenotype. The evolution of the Q/q loci in polyploid wheat resulted in the hyperfunctionalization of 5AQ, pseudogenization of 5Bq, and subfunctionalization of 5Dq, all contributing to the domestication traits.