Yao Xiaozhen, Yang Huidan, Zhu Yingxiu, Xue Jingshi, Wang Tianhua, Song Teng, Yang Zhongnan, Wang Shui
College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China.
Front Plant Sci. 2018 May 15;9:638. doi: 10.3389/fpls.2018.00638. eCollection 2018.
A number of cell fate determinations, including cell division, cell differentiation, and programmed cell death, intensely occur during plant germline development. How these cell fate determinations are regulated remains largely unclear. The transcription factor E2F is a core cell cycle regulator. Here we show that the Arabidopsis canonical E2Fs, including E2Fa, E2Fb, and E2Fc, play a redundant role in plant germline development. The () triple mutant is sterile, although its vegetative development appears normal. On the one hand, the microspores undergo cell death during pollen mitosis. Microspores start to die at the bicellular stage. By the tricellular stage, the majority of the microspores are degenerated. On the other hand, a wild type ovule often has one megaspore mother cell (MMC), whereas the majority of ovules have two to three MMCs. The subsequent female gametogenesis of mutant is aborted and the vacuole is severely impaired in the embryo sac. Analysis of transmission efficiency showed that the canonical E2Fs from both male and female gametophyte are essential for plant gametogenesis. Our study reveals that the canonical E2Fs are required for plant germline development, especially the pollen mitosis and the archesporial cell (AC)-MMC transition.
包括细胞分裂、细胞分化和程序性细胞死亡在内的许多细胞命运决定过程，在植物生殖系发育过程中强烈发生。这些细胞命运决定是如何被调控的，目前仍 largely 不清楚。转录因子 E2F 是核心细胞周期调节因子。在这里我们表明，拟南芥中的典型 E2F，包括 E2Fa、E2Fb 和 E2Fc，在植物生殖系发育中发挥冗余作用。（）三重突变体是不育的，尽管其营养发育看起来正常。一方面，（）小孢子在花粉有丝分裂期间经历细胞死亡。小孢子在二细胞阶段开始死亡。到三细胞阶段时，大多数（）小孢子已经退化。另一方面，野生型胚珠通常有一个大孢子母细胞（MMC），而大多数（）胚珠有两到三个 MMC。（）突变体随后的雌配子发生过程中止，并且胚囊中液泡严重受损。传递效率分析表明，来自雄配子体和雌配子体的典型 E2F 对植物配子发生都是必不可少的。我们的研究揭示，典型 E2F 是植物生殖系发育所必需的，特别是花粉有丝分裂和孢原细胞（AC）-MMC 转变。
