Fertilization Recovery after Defective Sperm Cell Release in Arabidopsis
Fertilization Recovery after Defective Sperm Cell Release in Arabidopsis
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DOI：
10.1016/j.cub.2012.03.069
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发表时间：
2012-06-19
期刊：
影响因子：
9.2
通讯作者：
Higashiyama, Tetsuya
中科院分区：
文献类型：
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作者：
Kasahara, Ryushiro D.;Maruyama, Daisuke;Higashiyama, Tetsuya
在动物受精过程中，多个精子通常会到达一个卵细胞以“赢得竞争”受精。然而，在开花植物中，通常只有一个花粉管到达每个胚珠，胚珠含有一个卵细胞[1,2]。因此，植物的受精被认为依赖于单个花粉管的生育能力。在这里，我们报道了开花植物中的一种受精恢复现象，通过吸引第二个功能正常的花粉管，积极地挽救了第一个突变花粉管的受精失败。拟南芥野生型（WT）胚珠在配子育性缺陷的突变花粉进入时，通常（约80%）接受两个花粉管。在典型的开花植物中，卵细胞一侧的两个协同细胞吸引花粉管[3-5]，其中一个在花粉管排出后退化[3,6]。通过半离体活细胞成像[7,8]，我们观察到当第二个辅助细胞接受WT花粉管时，受精得以恢复。我们的研究结果表明，开花植物精确控制到达每个胚珠的花粉管数量，并采用受精恢复机制来最大化成功定子的可能性。
In animal fertilization, multiple sperms typically arrive at an egg cell to "win the race" for fertilization. However, in flowering plants, only one of many pollen tubes, conveying plant sperm cells, usually arrives at each ovule that harbors an egg cell [1, 2]. Plant fertilization has thus been thought to depend on the fertility of a single pollen tube [1]. Here we report a fertilization recovery phenomenon in flowering plants that actively rescues the failure of fertilization of the first mutant pollen tube by attracting a second, functional pollen tube. Wild-type (WT) ovules of Arabidopsis thaliana frequently (similar to 80%) accepted two pollen tubes when entered by mutant pollen defective in gamete fertility. In typical flowering plants, two synergid cells on the side of the egg cell attract pollen tubes [3-5], one of which degenerates upon pollen tube discharge [3, 6]. By semi-in vitro live-cell imaging [7, 8] we observed that fertilization was rescued when the second synergid cell accepted a WT pollen tube. Our results suggest that flowering plants precisely control the number of pollen tubes that arrive at each ovule and employ a fertilization recovery mechanism to maximize the likelihood of successful seed set.