背景回顾：Sexual reproduction in angiosperms relies on precise communications between the pollen and pistil. 

提出问题：The molecular mechanisms underlying these communications remain elusive.

主要发现：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. 

结果：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. 

结论：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.

 摘 要 

被子植物的有性生殖依赖于花粉与柱头之间的精确通讯。但是，这些通讯背后潜在的分子机制还不清楚。本文中，作者发现拟南芥的柱头“守护者”ANJ–FER受体激酶复合物感知快速碱化因子RALF23和RALF33多肽，以诱导柱头乳突产生活性氧物质（ROS），而授粉后会减少柱头的ROS，以确保花粉的水合。一旦授粉后，花粉被膜蛋白B类多肽PCP-Bs会与RALF23/33竞争结合ANJ-FER复合体，导致柱头的ROS减少，从而促进花粉的水合。本文的结果揭示了一种分子门控机制，在该机制中，花粉中不同多肽能够与柱头的多肽竞争，从而与柱头的受体激酶复合体发生相互作用，促进花粉的水合和萌发。