Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany.
Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle, Germany.
Elife. 2020 Feb 6;9:e52976. doi: 10.7554/eLife.52976.
Polyploidization, the increase in genome copies, is considered a major driving force for speciation. We have recently provided the first direct in planta evidence for polyspermy induced polyploidization. Capitalizing on a novel -based polyspermy assay, we here show that polyspermy can selectively polyploidize the egg cell, while rendering the genome size of the ploidy-sensitive central cell unaffected. This unprecedented result indicates that polyspermy can bypass the triploid block, which is an established postzygotic polyploidization barrier. In fact, we here show that most polyspermy-derived seeds are insensitive to the triploid block suppressor . The robustness of polyspermy-derived plants is evidenced by the first transcript profiling of triparental plants and our observation that these idiosyncratic organisms segregate tetraploid offspring within a single generation. Polyspermy-derived triparental plants are thus comparable to triploids recovered from interploidy crosses. Our results expand current polyploidization concepts and have important implications for plant breeding.
多倍体化，即基因组拷贝数的增加，被认为是物种形成的主要驱动力。我们最近提供了第一个关于多精受精诱导多倍体化的直接植物体内证据。利用一种基于的多精受精检测方法，我们在这里表明，多精受精可以选择性地使卵细胞多倍体化，而不影响倍性敏感的中央细胞的基因组大小。这一前所未有的结果表明，多精受精可以绕过三倍体阻断，这是一种已建立的合子后多倍体化障碍。事实上，我们在这里表明，大多数多精受精衍生的种子对三倍体阻断抑制剂不敏感。多精受精衍生的植物的稳健性证据是通过对三亲体植物的首次转录谱分析和我们的观察，这些特殊的生物体在单个世代中分离出四倍体后代。因此，多精受精衍生的三亲体植物与从种间杂交中恢复的三倍体相当。我们的研究结果扩展了当前的多倍体化概念，并对植物育种具有重要意义。
