Osmoregulation determines sperm cell geometry and integrity for double fertilization in flowering plants.
Osmoregulation determines sperm cell geometry and integrity for double fertilization in flowering plants.
复制标题
渗透调节决定开花植物双受精的精子细胞几何形状和完整性。
DOI：
10.1016/j.molp.2022.07.013
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发表时间：
2022-08
期刊：
影响因子：
--
通讯作者：
Hong-Ju Li
中科院分区：
文献类型：
--
作者：
Shu-Yan Chen;Lan Wang;Peng-Fei Jia;Wei-Cai Yang;Heven Sze;Hong-Ju Li
与动物和早期陆地植物的有鞭毛精子不同，开花植物的无鞭毛精子细胞由花粉粒携带到雌蕊。授粉后，一对精细胞通过花粉管生长和破裂被送入胚囊。与其他具有内部膨压和细胞壁的机械约束之间的平衡的有壁植物细胞不同，包裹在花粉营养细胞的细胞质内的精细胞仅具有薄且不连续的细胞壁。精细胞的形状是独特的椭圆形，尽管目前还不清楚它们如何在花粉管内和释放后保持这种形状。在这项研究中，我们发现，基因破坏三内膜相关的阳离子/H+交换器，特别是导致精子细胞成为球状的水合花粉拟南芥。此外，释放的突变精子细胞是脆弱的，并在双受精前破裂，导致失败的种子集，这可以通过耗尽精子表达的液泡水通道来部分挽救。这些结果表明，在开花植物的成功双受精的精细胞形状的调整中，细胞自主调节的关键作用。
Distinct from the motile flagellated sperm of animals and early land plants, the non-motile sperm cells of flowering plants are carried in the pollen grain to the female pistil. After pollination, a pair of sperm cells are delivered into the embryo sac by pollen tube growth and rupture. Unlike other walled plant cells with an equilibrium between internal turgor pressure and mechanical constraints of the cell walls, sperm cells wrapped inside the cytoplasm of a pollen vegetative cell have only thin and discontinuous cell walls. The sperm cells are uniquely ellipsoid in shape, although it is unclear how they maintain this shape within the pollen tubes and after release. In this study, we found that genetic disruption of three endomembrane-associated cation/H+ exchangers specifically causes sperm cells to become spheroidal in hydrated pollens of Arabidopsis. Moreover, the released mutant sperm cells are vulnerable and rupture before double fertilization, leading to failed seed set, which can be partially rescued by depletion of the sperm-expressed vacuolar water channel. These results suggest a critical role of cell-autonomous osmoregulation in adjusting the sperm cell shape for successful double fertilization in flowering plants.