生物
着丝粒
多倍体
减数分裂
倍性
遗传学
卫星
卫星DNA
同源染色体
染色体
动细胞
进化生物学
基因
工程类
航空航天工程
作者
Handong Su,Yalin Liu,Chang Liu,Qinghua Shi,Yuhong Huang,Fangpu Han
出处
期刊:The Plant Cell
[Oxford University Press]
日期:2019-07-16
卷期号:31 (9): 2035-2051
被引量:72
摘要
Centromeres mediate the pairing of homologous chromosomes during meiosis; this pairing is particularly challenging for polyploid plants such as hexaploid bread wheat (Triticum aestivum), as their meiotic machinery must differentiate homologs from similar homoeologs. However, the sequence compositions (especially functional centromeric satellites) and evolutionary history of wheat centromeres are largely unknown. Here, we mapped T. aestivum centromeres by chromatin immunoprecipitation sequencing using antibodies to the centromeric-specific histone H3 variant (CENH3); this identified two types of functional centromeric satellites that are abundant in two of the three subgenomes. These centromeric satellites had unit sizes greater than 500 bp and contained specific sites with highly phased binding to CENH3 nucleosomes. Phylogenetic analysis revealed that the satellites have diverged in the three T. aestivum subgenomes, and the more homogeneous satellite arrays are associated with CENH3. Satellite signals decreased and the degree of satellites variation increased from diploid to hexaploid wheat. Moreover, several T. aestivum centromeres lack satellite repeats. Rearrangements, including local expansion and satellite variations, inversions, and changes in gene expression, occurred during the evolution from diploid to tetraploid and hexaploid wheat. These results reveal the asymmetry in centromere organization among the wheat subgenomes, which may play a role in proper homolog pairing during meiosis.
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