In angiosperms, successful sexual reproduction relies on complicated communications between male and female organs. We previously disclose a molecular gating mechanism in which distinct peptide classes from pollen PCP-B peptides compete with stigma RALF peptides for interaction with a stigmatic receptor kinase complex, repressing the stigmatic ROS generation and allowing the pollen to hydrate and germinate. Through PCP-Bγ-induced phosphoproteomic and functional studies of the downstream pathways, we found that PCP-Bs trigger FER/ANJ-receptor controlled compatible responses, particularly the opening of aquaporins via H+-ATPase-mediated pH changes, thereby facilitating pollen hydration. Moreover, we found that the PP2C phosphatases act as negative regulators of FER kinase activity, thereby modulating ROS accumulation in the stigma. Exploring downstream signaling of CrRLK1L–ROS pathway, we found that auxin activates the FER–ROS pathway in root hair cells, results in the oxidative modifications of TIR1/AFB2 and in turn their transport from cytoplasm to nucleus for transcriptional auxin responses.  Furthermore, we developed a small-molecule inhibitor that specifically disrupts FER kinase activity, namely FRV. Assisted by the FRV tool and quantitative phosphoproteomics, we characterized a series of signaling pathways and network regulated by RALF1 and FER, which leads to apoplastic alkalinization and regulates cell expansion in root meristem. Given the conservation of FRV binding sites in FER proteins across land plant species, FRV could serve as valuable tool for dissecting FER signaling mechanisms as well as facilitating agricultural applications.

李超博士，华东师范大学生命科学学院二级教授、植物学科主任、现代农业科学与技术研究所所长。获国家自然科学基金杰青、重点项目、上海市青年英才计划拔尖项目、中国植物生理与植物分子生物学学会“卫志明青年创新奖”和上海生化学会“青年新锐奖”等。2002年于中国农业大学获学士学位，同年进入中科院遗传与发育生物学研究所硕博连读，2005-2008年在北京生命科学研究所联合培养，2008年获博士学位后到美国马萨诸塞大学开展博士后研究。2016年回国在华东师范大学工作至今，围绕小肽-受体激酶调控植物发育的分子机理开展研究，主要成果发表在Science、Dev Cell、Mol Plant、PNAS、eLife等国际知名期刊。