2017年12月15日Science文章，该文章为北京大学瞿礼嘉课题组发表，文章揭示了植物调控花粉管细胞完整性与精细胞释放的分子机制，即：在花粉管抵达胚囊之前的生长过程中，花粉管膜上的BUPS-ANX受体复合体接收到花粉管自己分泌的小肽信号RALF4/19，维持花粉管细胞的完整性；当花粉管到达胚囊后，雌方分泌的小肽信号RALF34竞争性取代掉原先结合在BUPS-ANX受体复合体上的信号RALF4/19，从而促使花粉管发生破裂、释放出精细胞，从而完成双受精。

原题目为：

Arabidopsis pollen tube integrity and sperm release are regulated by RALF-mediated signaling

在开花植物中，受精需要花粉管和雌性生殖组织之间复杂的细胞间交流，这种交流是受细胞间信号分子与花粉管表面的受体相互作用所控制的。我们在拟南芥中发现这样的两种受体，BUPS1和BUPS2以及它们的肽配体RALF4和RALF19，它们在花粉管中表达，并且是维持花粉管完整性所必需的。BUPS1和BUPS2通过它们的胞外域与受体ANXUR1和ANXUR2相互作用，并且这两组受体结合于RALF4和RALF19。这些受体-配体相互作用与雌性衍生的配体RALF34竞争，其以纳摩尔浓度诱导花粉管爆裂。我们推测RALF34在花粉管-雌配子体接触的表面替代RALF4和RALF19，从而释放BUPS-ANXUR信号，反过来导致花粉管破裂和精子释放。

In flowering plants, fertilization requires complex cell-to-cell communication events between the pollen tube and the female reproductive tissues, which are controlled by extracellular signaling molecules interacting with receptors at the pollen tube surface. We found that two such receptors in Arabidopsis, BUPS1 and BUPS2, and their peptide ligands, RALF4 and RALF19, are pollen tube–expressed and are required to maintain pollen tube integrity. BUPS1 and BUPS2 interact with receptors ANXUR1 and ANXUR2 via their ectodomains, and both sets of receptors bind RALF4 and RALF19. These receptor-ligand interactions are in competition with the female-derived ligand RALF34, which induces pollen tube bursting at nanomolar concentrations. We propose that RALF34 replaces RALF4 and RALF19 at the interface of pollen tube–female gametophyte contact, thereby deregulating BUPS-ANXUR signaling and in turn leading to pollen tube rupture and sperm release.

每日一词

integrity

英[ɪnˈtegrəti]

美[ɪnˈtɛɡrɪti]

n. 完整; 正直，诚实; [计算机] 保存; 健全;

[例句]I have always regarded him as a man of integrity

我一直认为他正直诚实。

[其他] 复数：integrities