Extensive homoeologous genome exchanges in allopolyploid crops revealed by mRNAseq-based visualization.
Extensive homoeologous genome exchanges in allopolyploid crops revealed by mRNAseq-based visualization.
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DOI：
10.1111/pbi.12657
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发表时间：
2017-05
影响因子：
13.8
通讯作者：
Bancroft I
中科院分区：
文献类型：
--
作者：
He Z;Wang L;Harper AL;Havlickova L;Pradhan AK;Parkin IAP;Bancroft I
多倍性，即拥有多套染色体，是被子植物进化和成功的主要因素。虽然人工形成的异源多倍体显示出很高的基因组重排率，但用于作物育种的品种和种质的基因组被假定为稳定的，并且在商业育种的人工选择过程中基因组结构变异的研究仍然很少。在这里，我们显示，使用基于转录组序列数据的重新设计的可视化方法，基因组结构重排经常发生在三种多倍体作物（油菜，芥菜油菜和面包小麦）的品种中，这意味着经济作物中存在的基因组结构变异的程度远高于预期。交换被发现最频繁地发生在同源染色体片段与端粒共线的地方，并且在作为加倍的单倍体产生的材料中。对基因组结构进化的新见解使我们能够重新解释最近的研究结果，并暗示同源交换，而不是缺失，是负责控制油菜重要种子品质性状的变异。在开始确定多倍体作物基因组结构变异的程度之后，我们可以设想应对扩大作物遗传多样性和加速适应的全球挑战的新策略，例如分子鉴定和选择基因组缺失或重复，包括具有性状控制剂量效应的基因。
Polyploidy, the possession of multiple sets of chromosomes, has been a predominant factor in the evolution and success of the angiosperms. Although artificially formed allopolyploids show a high rate of genome rearrangement, the genomes of cultivars and germplasm used for crop breeding were assumed stable and genome structural variation under the artificial selection process of commercial breeding has remained little studied. Here, we show, using a repurposed visualization method based on transcriptome sequence data, that genome structural rearrangement occurs frequently in varieties of three polyploid crops (oilseed rape, mustard rape and bread wheat), meaning that the extent of genome structural variation present in commercial crops is much higher than expected. Exchanges were found to occur most frequently where homoeologous chromosome segments are collinear to telomeres and in material produced as doubled haploids. The new insights into genome structural evolution enable us to reinterpret the results of recent studies and implicate homoeologous exchanges, not deletions, as being responsible for variation controlling important seed quality traits in rapeseed. Having begun to identify the extent of genome structural variation in polyploid crops, we can envisage new strategies for the global challenge of broadening crop genetic diversity and accelerating adaptation, such as the molecular identification and selection of genome deletions or duplications encompassing genes with trait‐controlling dosage effects.