Polyspermy Block in the Central Cell During Double Fertilization of Arabidopsis thaliana.
Polyspermy Block in the Central Cell During Double Fertilization of Arabidopsis thaliana.
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DOI：
10.3389/fpls.2020.588700
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发表时间：
2020
影响因子：
5.6
通讯作者：
Higashiyama T
中科院分区：
文献类型：
--
作者：
Nagahara S;Takeuchi H;Higashiyama T
在被子植物的双受精过程中，两个雄配子（精细胞）从花粉管中释放到两个雌配子之间的接受区;卵细胞和胚珠的中央细胞。精细胞以一对一的方式使卵细胞和中央细胞受精，分别产生合子和胚乳。精子细胞一对一地分配给两个雌性配子是严格控制的，可能是通过四个配子之间的交流。多精受精阻滞是受精的雌性配子阻止次级精子受精的机制，并且被认为在卵细胞而不是中央细胞中起作用。然而，中央细胞是否也有能力在双受精过程中避免多精受精仍然不清楚。在这里，我们评估了一对一的受精机制的中央细胞的雌性配子的激光照射和受精过程中的活细胞成像在拟南芥。我们成功地打破了一个卵细胞内的胚珠照射使用飞秒脉冲激光。在卵破裂的胚珠中，中央细胞主要显示一个精子细胞的单受精，这表明卵细胞及其与一个精子细胞的融合对于一对一受精是不必要的（即，单精生殖）。此外，使用在一个花粉中具有多个精子细胞对的四孢子突变体，我们证明了正常的双受精，即使当多余的精子被释放到雌配子之间的接受区域。在接受四个精细胞的胚珠中，卵细胞从不与一个以上的精细胞融合，而一半的中央细胞与一个以上的精细胞融合（即，多精受精）甚至1小时后。我们的研究结果表明，在双受精过程中，中央细胞可以阻止多精受精，虽然中央细胞比卵细胞更允许多精受精。中央细胞的多精受精块的潜在贡献进行了讨论，它是如何参与一对一的分配的精子细胞两个不同的女性配子。
During double fertilization in angiosperms, two male gametes (sperm cells), are released from a pollen tube into the receptive region between two female gametes; the egg cell and the central cell of the ovule. The sperm cells fertilize the egg cell and the central cell in a one-to-one manner to yield a zygote and an endosperm, respectively. The one-to-one distribution of the sperm cells to the two female gametes is strictly regulated, possibly via communication among the four gametes. Polyspermy block is the mechanism by which fertilized female gametes prevent fertilization by a secondary sperm cell, and has been suggested to operate in the egg cell rather than the central cell. However, whether the central cell also has the ability to avoid polyspermy during double fertilization remains unclear. Here, we assessed the one-to-one fertilization mechanism of the central cell by laser irradiation of the female gametes and live cell imaging of the fertilization process in Arabidopsis thaliana. We successfully disrupted an egg cell within the ovules by irradiation using a femtosecond pulse laser. In the egg-disrupted ovules, the central cell predominantly showed single fertilization by one sperm cell, suggesting that neither the egg cell nor its fusion with one sperm cell is necessary for one-to-one fertilization (i.e., monospermy) of the central cell. In addition, using tetraspore mutants possessing multiple sperm cell pairs in one pollen, we demonstrated that normal double fertilization was observed even when excess sperm cells were released into the receptive region between the female gametes. In ovules accepting four sperm cells, the egg cell never fused with more than one sperm cell, whereas half of the central cells fused with more than one sperm cell (i.e., polyspermy) even 1 h later. Our results suggest that the central cell can block polyspermy during double fertilization, although the central cell is more permissive to polyspermy than the egg cell. The potential contribution of polyspermy block by the central cell is discussed in terms of how it is involved in the one-to-one distribution of the sperm cells to two distinct female gametes.
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影响因子：
9.2
作者：
Beale, Kristin M.;Leydon, Alexander R.;Johnson, Mark A.
通讯作者：
Johnson, Mark A.
影响因子：
56.9
作者：
Higashiyama, T;Yabe, S;Kuroiwa, T
通讯作者：
Kuroiwa, T
影响因子：
56.9
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FAURE, JE;DIGONNET, C;DUMAS, C
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DUMAS, C
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11.8
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Maruyama, Daisuke;Hamamura, Yuki;Higashiyama, Tetsuya
通讯作者：
Higashiyama, Tetsuya
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7.2
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KRANZ, E;VONWIEGEN, P;LORZ, H
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LORZ, H