Department of Biotechnology, Faculty of Agriculture, Tarbiat Modares University, Tehran, 1497713111, Iran.
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, 06466, Seeland, Germany.
Plant Mol Biol. 2024 Jun 14;114(4):74. doi: 10.1007/s11103-024-01474-5.
Centromeric nucleosomes are determined by the replacement of the canonical histone H3 with the centromere-specific histone H3 (CENH3) variant. Little is known about the centromere organization in allopolyploid species where different subgenome-specific CENH3s and subgenome-specific centromeric sequences coexist. Here, we analyzed the transcription and centromeric localization of subgenome-specific CENH3 variants in the allopolyploid species Arabidopsis suecica. Synthetic A. thaliana x A. arenosa hybrids were generated and analyzed to mimic the early evolution of A. suecica. Our expression analyses indicated that CENH3 has generally higher expression levels in A. arenosa compared to A. thaliana, and this pattern persists in the hybrids. We also demonstrated that despite a different centromere DNA composition, the centromeres of both subgenomes incorporate CENH3 encoded by both subgenomes, but with a positive bias towards the A. arenosa-type CENH3. The intermingled arrangement of both CENH3 variants demonstrates centromere plasticity and may be an evolutionary adaption to handle more than one CENH3 variant in the process of allopolyploidization.
着丝粒核小体由经典组蛋白 H3 被着丝粒特异性组蛋白 H3（CENH3）变体取代决定。在不同亚基因组特异性 CENH3 和亚基因组特异性着丝粒序列共存的异源多倍体物种中，对着丝粒组织知之甚少。在这里，我们分析了异源多倍体物种拟南芥瑞典亚种中亚基因组特异性 CENH3 变体的转录和着丝粒定位。生成并分析了拟南芥和拟南芥的合成杂种，以模拟瑞典拟南芥的早期进化。我们的表达分析表明，与拟南芥相比，CENH3 在拟南芥中通常具有更高的表达水平，这种模式在杂种中仍然存在。我们还表明，尽管着丝粒 DNA 组成不同，但两个亚基因组的着丝粒都包含由两个亚基因组编码的 CENH3，但对拟南芥型 CENH3 有正向偏倚。两种 CENH3 变体的交织排列显示出着丝粒的可塑性，这可能是一种进化适应，以在异源多倍体化过程中处理不止一种 CENH3 变体。
