Deciphering Male- and Female-coordinated Gating Mechanisms that Ensure Plant Reproductive Success

项目摘要 开花植物的繁殖取决于多个雄性（花粉）-雌性（雌蕊）相互作用的步骤， 传递精子，精子是不动的，作为细胞质货物由花粉管通过 雌蕊的几个专门的雌蕊组织的女性目标受精，导致种子生产。的 提出的研究解决了三个不同的前合子（即之前）中的关键细胞-细胞通信事件。 精卵融合）阶段，在雌蕊中的花粉/花粉管旅程期间，以使受精。长- 我们实验室的长期努力为该领域设定了发现里程碑，最近阐明了关键分子 这些阶段中的每一个阶段都有重要的参与者，为发展中国家提供了关键的进步和前所未有的机会。 这里提出的机械解剖。雌蕊在其感受器表面支持花粉萌发， 柱头，以产生花粉管，花粉管在传递组织内生长，到达目标产卵器 室，位于胚珠内的雌配子体。一旦到达雌配子体， 花粉管破裂，释放精子受精，产生种子。雌蕊也设置了屏障， 去除不需要的配偶或入侵性疾病因子，并有效地防止多个花粉管 穿透同一雌配子体以抑制多精受精并确保后代健康。我们 发现了三个相关的信号模块，每一个都对三个前合子阶段中的一个至关重要。1期 支持柱头上的花粉萌发。第二阶段实现了两个目标，一个是确保花粉管的完整性 直到它到达它的目标，另一个确保单个花粉管进入胚珠。第三阶段发生在 花粉管/胚珠界面和花粉管/雌配子体界面。这里的相互作用引起 雌配子体中最先到达的花粉管，并触发了局部多精受精的机制 阻断，以进一步确保多余的花粉管进入已经穿透的雌性 配子体这些信号模块由雌蕊表达的受体激酶FERONIA锚定 或花粉表达的同源物，每个与GPI锚定蛋白（GPI-AP）LORELEI（LRE） 或LRE样GPI-AP 1，2，3（LLG 1，2，3）作为称为RALF的肽配体的共受体（Rapid 碱化因子）。在这里，我们提出实验来阐明这些信号模块和 另外的调节因子影响分子相互作用、生物化学过程和细胞生物学特性。 条件在雌蕊细胞介导这些前合子阶段的成功，使受精， 防止不必要的入侵。植物已经进化，但隐藏在最受保护的地方，这些高度 复杂的细胞间通讯策略，以确保自身的增殖。我们的专业职位 我们唯一能够实现这些目标，这将填补一个完整的机械空白， 范例，以指导许多生态和农业重要植物的研究，并告知合理的 设计以保障生殖成功，确保粮食安全，以满足全球营养需求。

Project Summary Reproduction in flowering plants depends on multiple male (pollen)-female (pistil) interactive steps to deliver sperm, which are non-motile and transported as cytoplasmic cargos by the pollen tube through several specialized pistil tissues to the female target for fertilization, leading to seed production. The proposed research addresses key cell-cell communicative events in three distinct prezygotic (i.e. prior to sperm-egg fusion) phases during the pollen/pollen tube journey in the pistil to enable fertilization. Long- term efforts in our lab have set discovery milestones for the field and recently elucidated key molecular players in each of these phases, providing critical advances and unprecedented opportunities for the mechanistic dissection proposed here. The pistil supports pollen germination on its receptive surface, the stigma, to produce a pollen tube that grows inside the transmitting tissue to reach the target egg-bearing chamber, the female gametophyte located inside an ovule. Once arriving at the female gametophyte, the pollen tube burst, releasing sperm for fertilization, producing seed. The pistil also set up barriers to ward off unwanted mates or invasive disease agents, and to effectively prevent multiple pollen tubes from penetrating the same female gametophyte to suppress polyspermy and ensure progeny health. We discovered three related signaling modules, each critical for one the three prezygotic phases. Phase 1 supports pollen germination on the stigma. Phase 2 achieves two goals, one ensuring pollen tube integrity until it reaches its target, the other ensuring single pollen tube entry into an ovule. Phase 3 occurs at the pollen tube/ovule and pollen tube/female gametophyte interfaces. Interactions here induce bursting of the first-arriving pollen tube in the female gametophyte and trigger a mechanism for a local polyspermy block to further ensure against supernumerary pollen tube entry into an already penetrated female gametophyte. These signaling modules are anchored by the pistil-expressed receptor kinase FERONIA or pollen-expressed homologs, each partnering with a GPI-anchored protein (GPI-AP) LORELEI (LRE) or LRE-like GPI-AP1,2,3 (LLG1,2,3) to serve as coreceptors for peptide ligands called RALFs (Rapid Alkalinization Factors). Here we propose experiments to elucidate how these signaling modules and additional regulatory factors impact the molecular interactions, biochemical processes and cellular conditions in pistillate cells to mediate success for these prezygotic phases, enabling fertilization, and to prevent unwanted intrusions. Plants have evolved but hidden in the most protected location these highly sophisticated cell-cell communication strategies to ensure their own proliferation. Our expertise positions us uniquely capable of achieving these goals, which will fill a complete mechanistic void, setting paradigms to guide studies in many ecologically and agriculturally important plants, and inform rational designs to safe-guard reproductive success, ensuring food security to provide for global nutritional needs.