A male-expressed rice embryogenic trigger redirected for asexual propagation through seeds
A male-expressed rice embryogenic trigger redirected for asexual propagation through seeds
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DOI：
10.1038/s41586-018-0785-8
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发表时间：
2019-01-03
期刊：
影响因子：
64.8
通讯作者：
Sundaresan, Venkatesan
中科院分区：
文献类型：
--
作者：
Khanday, Imtiyaz;Skinner, Debra;Sundaresan, Venkatesan
开花植物受精后触发胚胎发生并在未受精的情况下阻止其发生的分子途径尚不清楚(1)。在这里，我们在水稻 (Oryza sativa) 中证明，在精子细胞中表达的转录因子 AP2 家族 (2) 的成员 BABY BOOM1 (BBM1) 在此过程中发挥着关键作用。卵细胞中 BBM1 的异位表达足以进行孤雌生殖，这表明单个野生型基因可以绕过雌配子中的受精检查点。 BBM1 的合子表达最初是雄性等位基因特异的，但随后是双亲的，这与其观察到的自动激活一致。 BBM1、BBM2 和 BBM3 基因的三重敲除会导致胚胎停滞和流产，而男性传播的 BBM1 可以完全挽救这种现象。这些发现表明胚胎发生中受精的要求是由多能因子的雄性基因组传递介导的。当用有丝分裂代替减数分裂 (MiMe)(3,4) 的基因组编辑与卵细胞中 BBM1 的表达相结合时，可以获得保留全基因组亲本杂合性的克隆后代。合成的无性繁殖特征可通过多代克隆遗传。杂交作物提供了更高的产量，但由于基因隔离，其后代无法维持这种产量。这项工作确立了作物无性繁殖的可行性，并且可以通过种子繁殖来无性系地维持杂交种(5,6)。
The molecular pathways that trigger the initiation of embryogenesis after fertilization in flowering plants, and prevent its occurrence without fertilization, are not well understood(1). Here we show in rice (Oryza sativa) that BABY BOOM1 (BBM1), a member of the AP2 family(2) of transcription factors that is expressed in sperm cells, has a key role in this process. Ectopic expression of BBM1 in the egg cell is sufficient for parthenogenesis, which indicates that a single wild-type gene can bypass the fertilization checkpoint in the female gamete. Zygotic expression of BBM1 is initially specific to the male allele but is subsequently biparental, and this is consistent with its observed auto-activation. Triple knockout of the genes BBM1, BBM2 and BBM3 causes embryo arrest and abortion, which are fully rescued by male-transmitted BBM1. These findings suggest that the requirement for fertilization in embryogenesis is mediated by male-genome transmission of pluripotency factors. When genome editing to substitute mitosis for meiosis (MiMe)(3,4) is combined with the expression of BBM1 in the egg cell, clonal progeny can be obtained that retain genome-wide parental heterozygosity. The synthetic asexual-propagation trait is heritable through multiple generations of clones. Hybrid crops provide increased yields that cannot be maintained by their progeny owing to genetic segregation. This work establishes the feasibility of asexual reproduction in crops, and could enable the maintenance of hybrids clonally through seed propagation(5,6).