Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany.
Institute of Functional Genomics, University of Regensburg, 93053 Regensburg, Germany.
Plant Cell. 2017 Sep;29(9):2106-2125. doi: 10.1105/tpc.17.00099. Epub 2017 Aug 16.
The formation of a zygote via the fusion of an egg and sperm cell and its subsequent asymmetric division herald the start of the plant's life cycle. Zygotic genome activation (ZGA) is thought to occur gradually, with the initial steps of zygote and embryo development being primarily maternally controlled, and subsequent steps being governed by the zygotic genome. Here, using maize () as a model plant system, we determined the timing of zygote development and generated RNA-seq transcriptome profiles of gametes, zygotes, and apical and basal daughter cells. ZGA occurs shortly after fertilization and involves ∼10% of the genome being activated in a highly dynamic pattern. In particular, genes encoding transcriptional regulators of various families are activated shortly after fertilization. Further analyses suggested that chromatin assembly is strongly modified after fertilization, that the egg cell is primed to activate the translational machinery, and that hormones likely play a minor role in the initial steps of early embryo development in maize. Our findings provide important insights into gamete and zygote activity in plants, and our RNA-seq transcriptome profiles represent a comprehensive, unique RNA-seq data set that can be used by the research community.
通过卵子和精子细胞融合形成受精卵，并随后进行不对称分裂，标志着植物生命周期的开始。人们认为合子基因组激活（ZGA）是逐渐发生的，受精卵和胚胎发育的初始步骤主要受母源控制，随后的步骤则受合子基因组控制。在这里，我们以玉米（）为模式植物系统，确定了受精卵的发育时间，并生成了配子、受精卵和顶端及基部子细胞的 RNA-seq 转录组图谱。ZGA 发生在受精后不久，涉及大约 10%的基因组以高度动态的模式被激活。特别是，各种家族的转录调控因子的基因在受精后不久就被激活了。进一步的分析表明，受精后染色质组装被强烈修饰，卵细胞被预先激活翻译机制，激素可能在玉米早期胚胎发育的初始步骤中只发挥较小的作用。我们的研究结果为植物的配子和受精卵活动提供了重要的见解，并且我们的 RNA-seq 转录组图谱代表了一个全面的、独特的 RNA-seq 数据集，可供研究界使用。
