Sexual reproduction in angiosperms relies on precise communications between the pollen and pistil. The molecular mechanisms underlying these communications remain elusive. We established that in Arabidopsis, a stigmatic gatekeeper, the ANJEA–FERONIA (ANJ–FER) receptor kinase complex, perceives the RAPID ALKALINIZATION FACTOR peptides RALF23 and RALF33 to induce reactive oxygen species (ROS) production in the stigma papillae, whereas pollination reduces stigmatic ROS, allowing pollen hydration. Upon pollination, the POLLEN COAT PROTEIN B-class peptides (PCP-Bs) compete with RALF23/33 for binding to the ANJ–FER complex, leading to a decline of stigmatic ROS that facilitates pollen hydration. Our results elucidate a molecular gating mechanism in which distinct peptide classes from pollen compete with stigma peptides for interaction with a stigmatic receptor kinase complex, allowing the pollen to hydrate and germinate.

被子植物的有性繁殖依赖于花粉和雌蕊之间的精确交流。这些通信背后的分子机制仍然难以捉摸。我们在拟南芥中确定，一种柱头看门人，ANJEA-FERONIA (ANJ-FER) 受体激酶复合物，感知快速碱化因子肽 RALF23 和 RALF33 以诱导柱头乳头中活性氧 (ROS) 的产生，而授粉减少柱头 ROS，允许花粉水合作用. 授粉后，花粉涂层蛋白 B 类肽 (PCP-Bs) 与 RALF23/33 竞争结合 ANJ-FER 复合物，导致促进花粉水合作用的柱头 ROS 减少。我们的结果阐明了一种分子门控机制，其中来自花粉的不同肽类与柱头肽竞争与柱头受体激酶复合物的相互作用，使花粉水合和发芽。