Characterization of Pollen Tube Repulsion in Arabidopsis thaliana

Ravishankar PalaniveluProposal#：0723421拟南芥中花粉管排斥的特征细胞与细胞之间的相互作用在所有真核生物的发育过程中都是重要的。一个特别独特的例子涉及迁移细胞与其路径上的细胞之间的相互作用。避免不适当的交互对于导航单元格到达其预期目标至关重要。在人类中，这一过程的中断会导致多精细胞和神经元缺陷。在植物中，当花粉管避开已经受精的有卵的胚珠结构时，在繁殖过程中避免细胞是特别重要的。然而，由于花粉管排斥发生在不透明的花结构中，这些相互作用的动态性质和调节它们的信号仍然没有得到很好的描述。最近，人们发展了一种简单的生物学方法来直接观察花粉管与胚珠的相互作用。这项分析表明，在花粉管进入胚珠后不久，胚珠就会发出短程排斥信号。利用这一发现，提出了各种细胞生物学、分子、遗传、生化和计算方法，以彻底表征模式植物拟南芥的花粉管排斥。在避免虚假受精事件方面获得的见解最终可能有助于开发无法与本地物种授粉的转基因花粉，这是育种者在开发转基因作物品种时必须克服的障碍。这项研究将产生新的图像分析算法，将造福于其他迁移细胞模型，如神经元和网柄柄细胞，以及一个可供教育工作者、学生和公众免费使用的开放访问的植物繁殖教育网站。来自皮马社区学院的生物学教师，一个非授予博士学位的机构，以及本科生，特别是那些来自代表性不足的美洲原住民、非裔美国人和西班牙裔社区的本科生，将实施这一项目的部分内容。接触生物学和研究方面的实践培训将激励他们选择科学职业。

Dr. Ravishankar PalaniveluProposal #: 0723421Characterization of pollen tube repulsion in Arabidopsis thalianaCell-cell interactions are important during development of all eukaryotic organisms. One particularly unique example involves interactions between a migrating cell and those that are in its path. Avoiding inappropriate interactions is essential for a navigating cell to reach its intended target. In humans, disruption in this process results in polyspermy and neuronal defects. In plants, cell avoidance is exceptionally important during reproduction when pollen tubes avoid egg-bearing ovule structures that have already been fertilized. However, since pollen tube repulsion occurs within opaque floral structures, the dynamic nature of these interactions and the signals that mediate them remain poorly characterized. Recently, a simple biological assay was developed to directly observe pollen tube-ovule interactions. This assay revealed that a short-range repulsion signaling is initiated from an ovule soon after a pollen tube enters it. Capitalizing on this finding, a variety of cell biological, molecular, genetic, biochemical and computational approaches are proposed to conduct a thorough characterization of pollen tube repulsion in the model plant, Arabidopsis thaliana. Insights gained on avoidance of spurious fertilization events could ultimately help in developing genetically modified pollen that cannot fertilize native species, which is an impediment breeders must overcome while developing transgenic crop varieties. This study will generate novel image analysis algorithms that will benefit other migratory cell models such as neurons and dictyostelium, and an open-access educational website on plant reproduction that can be freely used by educators, students, and the public. Biology faculty from Pima Community College, a non-Ph.D. granting institution, and undergraduates, especially those from under represented Native American, African-American and Hispanic communities, will carry out parts of this project. Exposure to biology and hands-on training in research will motivate them to choose a career in science.