Synergid Cell Development and Function in Arabidopsis

这项工作的长期目标是了解控制协同细胞发育和功能的调控过程。这两个辅助细胞位于7个细胞的雌性配子体中，在开花植物的生殖过程中是必不可少的。在受精过程中，花粉管生长为其中一个协同细胞，停止生长，破裂，并将两个精子细胞释放到这个细胞中。结构和遗传学研究表明，协同细胞产生一种引诱剂，引导花粉管向雌配子体生长，并含有控制花粉管生长阻滞和释放花粉管内容物的因子；然而，这些调控步骤尚未在分子水平上得到理解。这项工作的重点是分析MYB98基因，该基因编码MYB转录因子，在协同细胞中特异性表达，并且是花粉管引导所必需的。为了确定花粉管引导所需的因子，我们将对MYB98下游的基因进行鉴定和分析。为了深入了解协同细胞基因调控网络，我们将鉴定MYB98直接调控的基因，并剖析协同细胞中控制MYB98表达的调控序列。这些研究结果将为研究雌配子体发育过程中协同细胞分化的调控机制以及成熟协同细胞对花粉管的引导作用提供新的思路。了解这些过程可能有助于操纵生殖过程以提高作物产量。拟议的工作将为本科生和研究生的研究人员提供培训，并包括一个向附近社区学院的学生以及少数民族学生提供研究经验的推广项目。

The long-term goal of the proposed work is to understand the regulatory processes controlling development and function of the synergid cells. The two synergid cells are located within the seven-celled female gametophyte and are essential for the reproductive process in flowering plants. During the fertilization process, the pollen tube grows into one of the synergid cells, ceases growth, ruptures, and releases its two sperm cells into this cell. Structural and genetic studies indicate that the synergid cells produce an attractant that guides growth of the pollen tube to the female gametophyte and that they contain factors that control arrest of pollen tube growth and release of pollen tube contents; however, these regulatory steps are not understood at the molecular level. The proposed work focuses on analysis of the MYB98 gene that encodes a MYB transcription factor, is expressed specifically in the synergid cells, and is required for pollen tube guidance. To identify factors required for pollen tube guidance, genes acting downstream of MYB98 will be identified and analyzed. To gain insight into the synergid cell gene regulatory network, genes regulated directly by MYB98 will be identified and the regulatory sequences controlling MYB98 expression in the synergid cells will be dissected. These studies should provide new insights into the mechanisms controlling synergid cell differentiation during female gametophyte development and pollen tube guidance by the mature synergid cells. Understanding these processes may allow manipulation of the reproductive process to improve crop yield. The proposed work will provide training to undergraduate and graduate investigators and includes an outreach program to provide research experience to students from the nearby community college, as well as to minority students.