Molecular genetic analysis of LORELEI function in inducing the arrest of pollen tube growth in the Arabidopsis female gametophyte

LORELEI 诱导拟南芥雌配子体花粉管生长停滞的分子遗传学分析

• 批准号: 1146090
• 负责人: Ravishankar Palanivelu
• 金额: $ 56.4万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1146090&HistoricalAwards=false
• 关键词: Molecular; genetic; analysis; LORELEI; function

The seeds we depend on for our food are products of double fertilization. This essential process in plant reproduction requires delivery of sperm cells by the pollen tube to the egg and central cells of the embryo sac (female gametophyte). Although double fertilization was discovered more than a century ago, the controlling molecular mechanisms and genes remain poorly understood. We identified the Arabidopsis LORELEI (LRE) gene as critically important for an early step in reproduction. In lre mutants, pollen tubes do not arrest growth in the female gametophyte prior to releasing the sperm cells and consequently fail to complete double fertilization. We found that LRE encodes a putative membrane-anchored glycosylphosphatidylinositol (GPI)-anchored protein and is, therefore, an excellent candidate for mediating some aspects of signaling between the pollen tube and the female gametophyte. In this current project, molecular, genetic, and cell biological experiments will be conducted to elucidate the role of LORELEI protein in inducing pollen tube growth arrest in Arabidopsis female gametophytes. Specifically, we will determine the subcellular localization of LORELEI protein in the synergid cell and whether the LORELEI GPI anchor in is essential for its function in the synergid cell. The mechanism of LORELEI function in inducing the arrest of pollen tube growth will also be examined, and additional genes that function with LORELEI in this important signaling event will be identified.A comprehensive molecular understanding of seed formation may help generate tools to manipulate plant reproduction and increase seed yield. Consequently, this project could have a major impact since seeds are a source of staple food, fiber, nutrition, industrial products and biofuels. Additionally, this project will also have a major human resource impact. Undergraduate students will carry out some experiments and two post doctoral fellows and a research technician will be trained in experimental procedures, data analysis, and scientific data presentation.

我们赖以为生的种子是双受精的产物。这是植物繁殖的基本过程，需要通过花粉管将精细胞输送到卵和胚囊（雌配子体）的中央细胞。尽管双受精现象早在世纪就已被发现，但其控制分子机制和基因仍知之甚少。我们确定了拟南芥LORELEI（LRE）基因作为繁殖的早期步骤至关重要。在lre突变体中，在释放精细胞之前，花粉管不会阻止雌配子体的生长，因此不能完成双受精。我们发现，LRE编码一个假定的膜锚定的糖基磷脂酰肌醇（GPI）锚定蛋白，因此，是一个很好的候选人，用于介导花粉管和雌配子体之间的信号转导的某些方面。本研究将通过分子生物学、遗传学和细胞生物学实验来研究LORELEI蛋白在诱导拟南芥雌配子体花粉管生长停滞中的作用。具体地，我们将确定LORELEI蛋白在助细胞中的亚细胞定位以及LORELEI GPI锚是否对其在助细胞中的功能是必需的。LORELEI在诱导花粉管生长停滞中的作用机制也将被研究，并且在这一重要的信号事件中与LORELEI一起起作用的其他基因也将被鉴定。对种子形成的全面分子理解可能有助于产生操纵植物繁殖和提高种子产量的工具。因此，该项目可能产生重大影响，因为种子是主食、纤维、营养、工业产品和生物燃料的来源。此外，该项目还将对人力资源产生重大影响。本科生将进行一些实验，两名博士后研究员和一名研究技术人员将接受实验程序，数据分析和科学数据演示方面的培训。