Double fertilization in Arabidopsis thaliana involves a polyspermy block on the egg but not the central cell
Double fertilization in Arabidopsis thaliana involves a polyspermy block on the egg but not the central cell
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DOI：
10.1093/mp/ssn016
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发表时间：
2008-07-01
期刊：
影响因子：
27.5
通讯作者：
Spielman, Melissa
中科院分区：
文献类型：
--
作者：
Scott, Rod J.;Armstrong, Susan J.;Spielman, Melissa
在动物繁殖中，成千上万的精子可能会竞争使一个卵子受精，但多精受精阻止了多次受精，否则会导致胚胎死亡。在开花植物中，成功的种子发育需要只有两个精子被输送到胚囊，每个精子必须使雌性配子（卵或中央细胞）受精以产生胚和胚乳。因此，必须避免多精受精，这不仅是为了防止后代畸形，而且是为了确保双受精。目前还不清楚每个精子如何只使一个雌性配子受精，也没有在体内直接测试多精受精障碍的存在。在这里，我们寻求证据的多精生殖块在被子植物中使用的多精四孢子（TES）突变体的拟南芥，它允许在体内挑战卵和中央细胞与多个雄性配子。我们发现tes突变体的花粉管可以将一对以上的精子传递到胚囊中，并且来自一对以上的精子可以参与受精。我们检测到胚乳，但没有胚的倍性，只能导致多次受精。因此，我们的研究结果表明，在体内多精受精块的鸡蛋，但不是中央细胞的开花植物。
In animal reproduction, thousands of sperm may compete to fertilize a single egg, but polyspermy blocks prevent multiple fertilization that would otherwise lead to death of the embryo. In flowering plants, successful seed development requires that only two sperm are delivered to the embryo sac, where each must fertilize a female gamete (egg or central cell) to produce the embryo and endosperm. Therefore, polyspermy must be avoided, not only to prevent abnormalities in offspring, but to ensure double fertilization. It is not understood how each sperm fertilizes only one female gamete, nor has the existence of polyspermy barriers been directly tested in vivo. Here, we sought evidence for polyspermy blocks in angiosperms using the polyspermic tetraspore (tes) mutant of Arabidopsis, which allows in-vivo challenge of egg and central cell with multiple male gametes. We show that tes mutant pollen tubes can transmit more than one sperm pair to an embryo sac, and that sperm from more than one pair can participate in fertilization. We detected endosperms but not embryos with ploidies that could only result from multiple fertilization. Our results therefore demonstrate an in-vivo polyspermy block on the egg, but not the central cell of a flowering plant.