Pollination in Lilium longiflorum and Arabidopsis thaliana: The Role of Adhesion Molecules in Pollen Tube Cell Movement in the Style

长花百合和拟南芥授粉：粘附分子在花柱花粉管细胞运动中的作用

• 批准号: 0077886
• 负责人: Elizabeth Lord
• 金额: $ 42万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0077886&HistoricalAwards=false
• 关键词: Pollination; Lilium; longiflorum; Arabidopsis; thaliana

0077886LordThe goals of this study of plant reproduction are to describe the interaction between the pollen tube, which carries sperm cells, and the style, which must be traversed by the pollen tube before the sperm can be released in the ovule to the egg cell. Two adhesion molecules have been identified from the style in lily that are responsible for pollen tube cell adhesion and guidance. These are the first adhesion molecules to be described in plants. In lily, the transmitting tract is a secreting epidermis that lines the stylar canal which empties into the ovary. Pollen tubes germinate on the secretory epidermis of the top of this canal, the stigma, and enter the style tracking the epidermal surface. These secretions can be isolated from dissected styles and used to make an in vitro stylar matrix which serves as an adhesion assay. When pollen tubes are added to this assay system, they adhere to each other and to the artificial stylar matrix. This assay was used to isolate two fractions from the stigma/stylar transmitting tract that are necessary for adhesion; one is a small cysteine rich 9kD protein and the other a large pectic polysaccharide (sugar). Neither of these molecules alone is adhesive; the combination of the two is necessary to induce pollen tube adhesion to other pollen tubes and to the stylar matrix.The hypothesis is that the adhesive molecules are involved both in guiding the tube cell to the ovule and in the mechanism of tube cell movement that accompanies this guidance. A multifaceted approach incorporating the tools of developmental, cell and molecular biology is being used to: 1) decipher the mechanism by which the 9kD protein in lily acts with a pectin to induce adhesion of the pollen tube to the stylar matrix. 2) develop an in vivo test for the 9kD protein's role in adhesion using both lily and Arabidopsis. 3) understand the role of the cytoskeleton in tube cell movement and adhesion. 4) study tip growth in both lily and Arabidopsis pollen tubes. The proposed work on adhesion molecules in the lily and Arabidopsis pollination systems addresses two major questions: 1) What is the mechanism of adhesion of the pollen tube cell to the stylar extracellular matrix? 2) How is adhesion related to tube cell movement and what is the role of tip growth? Adhesion molecules, other than the two we have described for pollination, have yet to be described in plants though adhesion is critical for plant development. There are few cases in plants where

0077886Lord 这项植物繁殖研究的目标是描述携带精子细胞的花粉管与花柱之间的相互作用，花粉管必须穿过花粉管，然后精子才能在胚珠中释放到卵细胞。从百合的花柱中鉴定出两种粘附分子，它们负责花粉管细胞的粘附和引导。 这些是植物中第一个被描述的粘附分子。 在百合中，传输道是分泌表皮，排列在花柱管内，流入子房。 花粉管在该管顶部的分泌表皮（柱头）上发芽，并沿着表皮表面进入花柱。 这些分泌物可以从解剖的花柱中分离出来，并用于制备体外花柱基质，用作粘附测定。 当花粉管被添加到该测定系统中时，它们彼此粘附并粘附到人工花柱基质上。 该测定用于从柱头/花柱传输道中分离出粘附所必需的两个部分；一种是富含半胱氨酸的 9kD 蛋白质，另一种是大果胶多糖（糖）。 这些分子本身都没有粘合性；两者的结合对于诱导花粉管粘附到其他花粉管和花柱基质上是必要的。假设认为粘附分子既参与引导管细胞到胚珠，又参与伴随这种引导的管细胞运动机制。结合发育、细胞和分子生物学工具的多方面方法被用于：1）破译百合中的 9kD 蛋白与果胶作用以诱导花粉管粘附到花柱基质的机制。 2) 使用百合和拟南芥对 9kD 蛋白在粘附中的作用进行体内测试。 3）了解细胞骨架在管细胞运动和粘附中的作用。 4) 研究百合和拟南芥花粉管的尖端生长。拟议的百合和拟南芥授粉系统中粘附分子的工作解决了两个主要问题：1）花粉管细胞与花柱细胞外基质的粘附机制是什么？ 2）粘附与管细胞运动有何关系？尖端生长的作用是什么？尽管粘附对于植物发育至关重要，但除了我们描述的用于授粉的两种粘附分子外，植物中的粘附分子尚未得到描述。 植物中很少有这样的情况