Dissecting the mechanisms of FERONIA and related receptor kinase-mediated pollen-pistil interactions

该项目研究开花植物如何实现受精从而产生种子。实现这一目标需要雄性（花粉）和雌性（雌蕊）之间的密切互动，以使花粉管的生长将精子输送到胚珠（种子的前体）内的胚囊中进行受精。该项目利用模式植物拟南芥来了解这些相互作用背后的分子设计和生化反应。重点是两类分子，一类是被称为快速烷化因子的低分子量蛋白质家族，另一类是被称为受体激酶的蛋白质，包括一种被称为FERONIA的分子和相关蛋白质。快速烷化因子被认为是指示这些受体激酶在成功授粉和受精过程中如何反应的信号。目的是确定同源化因子和受体激酶的相互作用对，了解它们如何相互作用及其对生殖过程的重要性。鉴于繁殖是农业产量和物种生存的基础，本研究的结果应有助于旨在保护植物物种和确保食物供应的合理设计。该项目将为本科生、研究生和博士后提供培训机会。研究结果和材料将通过出版物与科学界分享，并作为高中教师STEM研讨会的主题与更广泛的公众分享。花粉粒在雌蕊的受体表面发芽，每粒产生一个管状物，将两个精子细胞运送到胚囊中，胚囊中卵细胞位于胚珠内（种子的前体器官）。胚囊诱导穿透性花粉管破裂，释放出精子，使其可用于受精。该项目将依靠生物化学和遗传学方法来研究RALF-FER和RALF-FER相关受体激酶相互作用如何影响花粉管生长和破裂。本研究选择了几种花粉或胚珠表达的快速烷化因子（ralf）、雌性表达的FERONIA （FER）和三种相关的花粉表达受体激酶进行研究。生物化学方面的努力将集中在生产纯的和活性的ralf，以测试它们在确定的培养基中花粉管生长行为的活性。遗传学方面的努力将集中在确定ralf的精确时间和空间表达模式，并在单个ralf中产生突变，或在多个ralf中组合，以确定其丧失对授粉和受精的影响。尽管ralf和FER蛋白家族的一些功能作用正在出现，例如在生长、发育、繁殖、防御和共生中，但大多数功能作用仍然未知。虽然其本身很重要，特别是考虑到农业生产对社会的影响，但这里建立的功能关系可以为从花粉-雌蕊和植物繁殖扩展到植物生长、发育和生存的几乎所有方面的研究提供一个模型。

This project addresses how flowering plants achieve fertilization so seeds are produced. Achieving this requires intimate interactions between male (pollen) and female (pistil) to enable growth of a pollen tube to deliver sperm to the embryo sac inside an ovule (the precursor of a seed) for fertilization. The project utilizes the model plant Arabidopsis to understand the molecular designs and biochemical reactions behind these interactions. The focus is on two classes of molecules, one is a family of low molecular weight proteins called, Rapid Alkanization Factors, the other is a class of proteins called receptor kinases and includes a molecule called FERONIA and related proteins. Rapid Alkanization Factors are believed to serve as signals to instruct how these receptor kinases should react in successful pollination and fertilization processes. The goal is to identify the interacting pairs of the Alikinazation Factor and receptor kinase, understand how they interact and their importance to the reproductive process. Given reproduction underlies agricultural yields as well as survival of the species, results from this study should contribute to rational designs aiming at protecting plant species as well as ensuring food supply. The project will provide training opportunities for undergraduates, graduate and postdoctoral students. Findings and materials produced will be shared with the scientific community through publications, with the broader public by being introduced as topics in STEM workshops for high school teachers. Pollen grains germinate on the receptive surface of the pistil, each producing a tube to transport two sperm cells to an embryo sac where the egg cell is located inside an ovule (the precursor organ for a seed). The embryo sac induces rupture of the penetrating pollen tube to release sperm rendering them available for fertilization. This project will rely on biochemical and genetic approaches to examine how RALF-FER and RALF-FER related receptor kinase interactions underlie pollen tube growth and rupture. Several pollen- or ovule-expressed Rapid Alkanization Factors (RALFs), the female-expressed FERONIA (FER) and three related pollen-expressed receptor kinases are selected for the study here. Biochemical efforts will focus on producing pure and active RALFs for testing their activity in pollen tube growth behavior in defined culture medium. Genetic efforts will center on determining the precise temporal and spatial expression pattern of the RALFs and generating mutations in individual RALFs, or combinatorially in multiple RALFs, to determine the impact of their loss on pollination and fertilization. Though some functional roles are emerging for RALFs and the FER family of proteins, e.g. in growth, development, reproduction, defense and symbiosis, most remain unknown. While important in its own right, especially given the impact agricultural production to society, the functional relationship established here could provide a model for studies that extend beyond pollen-pistil and plant reproduction to almost all aspects of plant growth, development and survival.