Maternal Control of Male-Gamete Delivery in Arabidopsis Involves a Putative GPI-Anchored Protein Encoded by the LORELEI Gene
Maternal Control of Male-Gamete Delivery in Arabidopsis Involves a Putative GPI-Anchored Protein Encoded by the LORELEI Gene
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DOI：
10.1105/tpc.108.061713
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发表时间：
2008-11-01
期刊：
影响因子：
11.6
通讯作者：
Sundaresan, Venkatesan
中科院分区：
文献类型：
--
作者：
Capron, Arnaud;Gourgues, Mathieu;Sundaresan, Venkatesan
在被子植物中，雄性配子通过花粉管通过母体生殖组织传递给雌性配子。到达后，花粉管释放两个精细胞，允许双受精发生。虽然雌性配子体在花粉管接收中的关键作用已被证实，但其潜在的机制仍然知之甚少。在这里，我们描述了lorelei，一种精子细胞释放受损的拟南芥突变体，让人想起feronia/sirene突变体。到达球蕾胚囊的花粉管通常不破裂，而是继续在胚囊中生长。此外，在初始花粉管到达后，球蕾胚囊继续吸引额外的花粉管。LORELEI基因在受精前在协同细胞中表达，并编码一种小型植物特异性糖基磷脂酰肌醇锚定蛋白（GAP）。这些结果支持了协同细胞膜信号机制的概念，通过该机制，雌性配子体识别相容花粉管的到来并促进精子释放。尽管gap先前已被证明在哺乳动物的受精起始中起着关键作用，但开花植物似乎在类似的生物学背景下独立进化出了利用这些蛋白质独特特征的生殖机制。
In Angiosperms, the male gametes are delivered to the female gametes through the maternal reproductive tissue by the pollen tube. Upon arrival, the pollen tube releases the two sperm cells, permitting double fertilization to take place. Although the critical role of the female gametophyte in pollen tube reception has been demonstrated, the underlying mechanisms remain poorly understood. Here, we describe lorelei, an Arabidopsis thaliana mutant impaired in sperm cell release, reminiscent of the feronia/sirene mutant. Pollen tubes reaching lorelei embryo sacs frequently do not rupture but continue to grow in the embryo sac. Furthermore, lorelei embryo sacs continue to attract additional pollen tubes after arrival of the initial pollen tube. The LORELEI gene is expressed in the synergid cells prior to fertilization and encodes a small plant-specific putative glucosylphosphatidylinositol-anchored protein (GAP). These results provide support for the concept of signaling mechanisms at the synergid cell membrane by which the female gametophyte recognizes the arrival of a compatible pollen tube and promotes sperm release. Although GAPs have previously been shown to play critical roles in initiation of fertilization in mammals, flowering plants appear to have independently evolved reproductive mechanisms that use the unique features of these proteins within a similar biological context.