Polyspermy in angiosperms: Its contribution to polyploid formation and speciation
Polyspermy in angiosperms: Its contribution to polyploid formation and speciation
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DOI：
10.1002/mrd.23295
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发表时间：
2019-11
影响因子：
2.5
通讯作者：
Erika Toda;T. Okamoto
中科院分区：
文献类型：
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作者：
Erika Toda;T. Okamoto
多倍化在被子植物的长期多样化和进化成功中发挥了重要作用。二倍体植物间的三倍体形成通常被认为是通过未减数配子与减数配子受精实现的，已被认为是一种多倍体生产手段。此外，在玉米、小麦和一些兰花中，多精受精也有助于三倍体的形成；然而，这种机制一直被认为是罕见的，因为复制多精受精的情况和明确地研究多精受精卵的发育特征是困难的。为了克服这些问题，通过一个卵细胞和两个精子细胞的电融合成功地产生了水稻多精受精卵，并对它们的发育情况进行了监测。三倍体受精卵通过核受精进行，通过典型的有丝分裂形成二细胞胚胎；二细胞胚胎进一步发育成三倍体植物，这表明多精子植物受精卵与动物受精卵不同，可以正常发育。此外，通过两种不同类型的父本与母本授粉，已在拟南芥中成功地获得了由三亲遗传物质组成的后代。这些关于多精受精卵在体外和植物中发育和出现的不同证据表明，多精受精是多倍化和物种多样化的关键事件。
Polyploidization has played a major role in the long‐term diversification and evolutionary success of angiosperms. Triploid formation among diploid plants, which is generally considered to be achieved by fertilization of an unreduced gamete with a reduced one, has been accepted as a means of polyploid production. In addition, it has been supposed that polyspermy also contributes to the triploid formation in maize, wheat, and some orchids; however, such a mechanism has been considered uncommon because reproducing the polyspermic situation and unambiguously investigating developmental profiles of polyspermic zygotes are difficult. To overcome these problems, rice polyspermic zygotes have been successfully produced by electrofusion of an egg cell with two sperm cells, and their developmental profiles have been monitored. The triploid zygotes progress through karyogamy and divide into two‐celled embryos via a typical bipolar mitotic division; the two‐celled embryos further develop into triploid plants, indicating that polyspermic plant zygotes, unlike those of animals, can develop normally. Furthermore, progenies consisting of triparental genetic materials have been successfully obtained in Arabidopsis through the pollination of two different kinds of male parents with a female parent. These different pieces of evidence for development and emergence of polyspermic zygotes in vitro and in planta suggest that polyspermy is a key event in polyploidization and species diversification.