Reduced chromatin accessibility underlies gene expression differences in homologous chromosome arms of hexaploid wheat and diploid Aegilops tauschii
Reduced chromatin accessibility underlies gene expression differences in homologous chromosome arms of hexaploid wheat and diploid Aegilops tauschii
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DOI：
10.1101/571133
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发表时间：
2019-03
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通讯作者：
Fu-Hao Lu;N. McKenzie;Laura-Jayne Gardiner;M. Luo;Anthony Hall;M. Bevan
中科院分区：
文献类型：
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作者：
Fu-Hao Lu;N. McKenzie;Laura-Jayne Gardiner;M. Luo;Anthony Hall;M. Bevan
多倍体在推动植物进化中起着核心作用，并导致基因表达的变化，这被认为是新性状出现的基础。尽管在多倍体中普遍存在这些改变基因表达的全球模式，但其中涉及的机制尚不清楚。利用六倍体小麦染色体3d1及其祖先二倍体节节麦3L染色体臂上高度保守的同线基因的精确框架，我们发现这些基因中有70%的基因表达比例降低，其中3d1基因在六倍体背景下的表达水平约为二倍体Ae的40%。陶斯奇。与Ae相比，许多基因在小麦籽粒发育后期表现出高表达。陶斯奇。基因序列和甲基化的差异只是基因表达差异的几个例子。相比之下，与其二倍体祖先相比，六倍体染色体臂中基因染色质可及性降低的大规模模式与观察到的基因表达总体减少和差异基因表达相关。因此，可及染色质的总体减少是多倍化导致的基因表达的主要差异的基础。
Polyploidy has been centrally important in driving the evolution of plants, and leads to alterations in gene expression that are thought to underlie the emergence of new traits. Despite the common occurrence of these global patterns of altered gene expression in polyploids, the mechanisms involved are not well understood. Using a precise framework of highly conserved syntenic genes on hexaploid wheat chromosome 3DL and its progenitor 3L chromosome arm of diploid Aegilops tauschii, we show that 70% of these genes exhibited proportionally reduced gene expression, in which expression in the hexaploid context of the 3DL genes was approximately 40% of the levels observed in diploid Ae. tauschii. Many genes showing elevated expression during later stages of grain development in wheat compared to Ae. tauschii. Gene sequence and methylation differences accounted for only a few cases of differences in gene expression. In contrast, large scale patterns of reduced chromatin accessibility of genes in the hexaploid chromosome arm compared to its diploid progenitor were correlated with observed overall reduction in gene expression and differential gene expression. Therefore, that an overall reduction in accessible chromatin underlies the major differences in gene expression that results from polyploidization.