College of Chemistry and Life Science, Hubei University of Education, Wuhan 430205, People's Republic of China.
J Genet. 2021;100.
The aneuploidy chromosome addition lines with individual chromosomes of one species into the whole genome of another species developed from interspecific or intergeneric crosses are ideal for studying the gene expression regulation under asymmetrical genome interactions. Here, we chose two rapeseed-radish addition lines (2=40, AACC+2R) with all chromosomes of rapeseed and one pair of radish chromosomes carrying 25S rDNA loci and both 5S and 25S rDNA loci, respectively. Transcriptome sequencing of these two rapeseed-radish addition lines, together with two parents (, 2=38, AACC; Raphanus sativus, 2=18, RR), was performed to assess gene expression changes due to the aneuploidy effect. Our results showed that the global gene expression perturbations in two addition lines showed asymmetric distributions between A and C subgenomes, for more downregulated genes located in the C subgenome. Moreover, several dysregulated domains occurred in the addition lines and majority of them were clustered in C subgenome, further revealing that C subgenome was more inclined to be repressed by the aneuploidy. Homoeolog expression was slightly biased toward C subgenome in the parent , but had no preference to either of A or C subgenome in the addition lines. The total number of biased genes increased sharply and most of them were shared only by two addition lines, indicating that aneuploidy could change the extent and direction of homoeolog expression. The triplicated subgenomes which were orthologs to the chromosomes of also exhibited dramatic alternations in two additions. Together, our results revealed that the addition of individual radish chromosomes could induce dramatically transcriptomic disturbances and those expression changes gave asymmetric distributions between two subgenomes in . The possible mechanisms including the uniparental expression of rRNA genes in the allopolyploids and additions for the findings are discussed.
将一个物种的全部染色体添加到另一个物种的整个基因组中而形成的非整倍体添加系，来源于种间或属间杂交，非常适合研究不对称基因组互作下的基因表达调控。在这里，我们选择了两个油菜-萝卜添加系（2=40，AACC+2R），它们分别带有油菜的全部染色体和一对携带 25S rDNA 基因座的萝卜染色体，以及同时携带 5S 和 25S rDNA 基因座的一对萝卜染色体。对这两个油菜-萝卜添加系以及两个亲本（2=38，AACC；Raphanus sativus，2=18，RR）进行转录组测序，以评估由于非整倍体效应导致的基因表达变化。我们的结果表明，两个添加系的全局基因表达扰动在 A 和 C 亚基因组之间呈不对称分布，更多的下调基因位于 C 亚基因组。此外，在添加系中发生了几个失调区域，其中大多数聚集在 C 亚基因组中，进一步表明 C 亚基因组更容易受到非整倍体的抑制。在亲本中，同系物表达略有偏向 C 亚基因组，但在添加系中没有偏向 A 或 C 亚基因组。偏向基因的总数急剧增加，大多数基因仅在两个添加系中共享，表明非整倍体可以改变同系物表达的程度和方向。与染色体同源的三倍体亚基因组在两个添加系中也表现出明显的改变。总之，我们的研究结果表明，单个萝卜染色体的添加可以引起转录组的显著紊乱，这些表达变化在中呈现出不对称的分布在两个亚基因组之间。讨论了可能的机制，包括异源多倍体和添加物中 rRNA 基因的单亲表达。
