Intercellular Signaling in Pollen Tube Reception

细胞如何感知和建立与其他细胞的通信，以便允许有益或兼容的相互作用，而不是有害的相互作用？植物授粉是了解这一问题的一个很好的系统，因为雄性和雌性组织之间的细胞间通讯对于识别相容的花粉至关重要。在植物中，花粉管(PT)从落在花的雌性生殖组织表面的花粉粒中生长出来。管子穿过组织延伸到含卵的卵巢。一旦进入卵巢，输卵管就停止生长并破裂，释放精子使卵子受精，卵子继而发育成种子。为了将精子细胞输送到卵巢，PT必须感觉到它已经到达了正确的位置，并从顶端生长转变为它所包含的精子的爆炸性释放。这个项目试图确定传递给PT的分子信号，即它已经进入卵巢，必须停止生长并释放其精子。费洛尼亚(FER)和NORTIA(NTA)是7-跨膜蛋白中抗霉菌基因O(MLO)家族的成员，它们的雌性配子体突变导致PT继续生长在接受性助细胞内，而不是破裂释放精子，这表明这些基因构成了信号网络的一部分。本项目以NTA为锚分子，旨在进一步阐明PT接受过程中助细胞与PT之间通讯的分子机制。助细胞是高度专门化的细胞，其唯一功能是与PTS通信。将进行实验，以确定在接受PT之前、期间和之后助细胞的细胞生物学，确定NTA定位和功能所必需的结构域，并确定NTA如何适应在接受PT期间发生的动态细胞变化。该项目的第二个目标是确定PT接收途径的新成员，并确定他们在信号途径中的作用。NTA基因的增强子和抑制子突变体将被鉴定为在PT接受中的作用，NTA将被用作酵母-2杂交筛选的诱饵，以识别该途径的其他成员。这个项目的结果将提供一个更清晰的关于PT接收的信号通路的图景，也可能改变我们对自我/非我识别如何发生的理解。在这个项目中，一名研究生、博士后和本科生将接受植物遗传学和细胞生物学领域的培训。由首席研究员教授的细胞生物学实验室的学生将在基于探究的实验室模块中研究预测参与PT接收的蛋白质，并将实施一项外联计划，以鼓励俄克拉荷马州农村高中将植物科学研究纳入他们的课程。

How do cells sense and establish communication with other cells in order to allow for beneficial or compatible interactions as opposed to harmful interactions? Plant pollination is an excellent system for gaining insight into this question because intercellular communication between male and female tissues is critical for the recognition of compatible pollen. In plants a pollen tube (PT) grows from a pollen grain that has landed on the surface of a flower's female reproductive tissue. The tube extends through that tissue towards the egg-containing ovary. Upon entering the ovary the tube stops growing and bursts open, releasing sperm that fertilize an egg, which in turn develops into a seed. In order to deliver the sperm cells to the ovary, the PT must sense that it has arrived at the right place and change from tip-growth to explosive release of the sperm it contains. This project seeks to determine the molecular signals that communicate to a PT that it has entered the ovary and must stop growing and release its sperm. Female gametophytic mutations in FERONIA (FER), a receptor-like kinase, and NORTIA (NTA), a member of the MILDEW RESISTANCE LOCUS O (MLO) family of 7-transmembrane proteins, cause PTs to continue growing inside of the receptive synergid instead of rupturing to release the sperm, indicating that these genes form part of a signaling network. This project is aimed at further elucidation of the molecular mechanisms used for communication between the synergid and PT during PT reception, using NTA as the anchor molecule. Synergids are highly specialized cells whose sole function is to communicate with PTs. Experiments will be performed to define the cell biology of the synergid cells before, during and after PT reception and to determine which domains are necessary for NTA localization and function and to determine how NTA fits into the dynamic cellular changes that occur during PT reception. The second goal of the project is to identify new members of the PT reception pathway and determine how they act in the signaling pathway. Enhancer and suppressor mutants of the gene nta will be characterized for roles in PT reception and NTA will be used as bait in yeast-2-hybrid screens to identify other members of the pathway. The results of this project will provide a clearer picture of the signaling pathway involved in PT reception and may also be transformative in our understanding of how self/non-self recognition takes place. A graduate student, post-doc, and undergraduate student will be trained in the fields of plant genetics and cell biology during this project. Students in a cell biology lab taught by the Principal Investigator will investigate proteins that are predicted to be involved in PT reception in an inquiry-based lab module and an outreach program will be conducted to encourage rural Oklahoma high schools to incorporate plant science research in their curricula.