Live-Cell Imaging Reveals the Dynamics of Two Sperm Cells during Double Fertilization in Arabidopsis thaliana
Live-Cell Imaging Reveals the Dynamics of Two Sperm Cells during Double Fertilization in Arabidopsis thaliana
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DOI：
10.1016/j.cub.2011.02.013
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发表时间：
2011-03-22
期刊：
影响因子：
9.2
通讯作者：
Higashiyama, Tetsuya
中科院分区：
文献类型：
--
作者：
Hamamura, Yuki;Saito, Chieko;Higashiyama, Tetsuya
有花植物进化出一种独特的生殖过程，称为双受精，即两个二型雌性配子由花粉管运送的两个不动的精子受精[1，2]。两个精细胞与一个领先的花粉管核串联排列，形成雄性生殖单位，并处于相同的遗传控制下[3]。控制双受精的基因已经被确定[4-6]，但每个精子细胞是否能够使任一雌性配子受精仍不清楚[7-9]。单个精子细胞在释放到雌性组织中后的动力学在很大程度上仍然未知。在这项研究中，我们光标记的个人同构精子细胞之前，他们的释放和分析他们的命运在双受精拟南芥。我们发现，精子的传递由三个步骤组成。精子细胞一起投射到两个雌性配子之间的边界。在长时间的静止之后，每个精子细胞与任一雌性配子融合，没有特定的顺序，也没有观察到对任一雌性配子的偏好。我们的研究结果表明，在男性生殖单位的前面和后面的两个精子细胞的功能是等同的，并建议意想不到的细胞-细胞通信所需的精子细胞，以协调双受精的两个女性配子。
Flowering plants have evolved a unique reproductive process called double fertilization, whereby two dimorphic female gametes are fertilized by two immotile sperm cells conveyed by the pollen tube [1, 2]. The two sperm cells are arranged in tandem with a leading pollen tube nucleus to form the male germ unit and are placed under the same genetic controls [3]. Genes controlling double fertilization have been identified [4-6], but whether each sperm cell is able to fertilize either female gamete is still unclear [7-9]. The dynamics of individual sperm cells after their release in the female tissue remain largely unknown. In this study, we photolabeled individual isomorphic sperm cells before their release and analyzed their fate during double fertilization in Arabidopsis thaliana. We found that sperm delivery was composed of three steps. Sperm cells were projected together to the boundary between the two female gametes. After a long period of immobility, each sperm cell fused with either female gamete in no particular order, and no preference was observed for either female gamete. Our results suggest that the two sperm cells at the front and back of the male germ unit are functionally equivalent and suggest unexpected cell-cell communications required for sperm cells to coordinate double fertilization of the two female gametes.