Causes and Consequences of an Age Dependent Breakdown in Self-Incompatibility in Campanula rapunculoides

斯蒂芬森9527739 植物的受精作用是花粉粒与花的雌性部分（雌蕊）之间一系列相互作用的结果。今天世界上的每一种开花植物都在这里，因为它的每一个父系祖先的花粉都成功地繁殖了一个产生种子的卵。对花粉管生长以及生长中的花粉管与雌蕊的相互作用的理解是植物科学的基础，就像操纵花粉生长的能力对应用植物科学和生物技术具有深远的影响一样。自交不亲和性是花粉-雌蕊相互作用中最有趣和最有潜力的一种。SI是一种允许植物识别和排斥自花花粉而允许杂交花粉生长的遗传系统。这种机制使植物能够避免近亲繁殖的有害影响。最近，我们发现风铃草属植物的花在刚开放时是自交不亲和的，但是随着花的成熟，它们允许生长和通过自花花粉受精。 该奖项资助的研究将确定SI随时间推移而崩溃的遗传原因;它将检查SI崩溃的分子基础;它将确定SI崩溃如何在不同环境条件下导致不同水平的近亲繁殖;它将使用DNA序列信息开始研究SI的进化。 结果将允许在三个活跃的和高度争议的基础植物生物学领域的竞争假说的测试：花粉性能的群体生物学，混合交配系统（部分自交）的进化和维护，以及SI的进化。 研究结果应有助于开发节省成本和节省时间的方法，用于生产商业植物育种计划所需的自交系。

9527739 STEPHENSON Fertilization in plants is the culmination of a series of interactions between the pollen grain and the female part of a flower (the pistil). Each flowering plant in the world today is here because the pollen of each of its paternal ancesters succeeded in fertilizing an egg that produced a seed. An understanding of pollen tube growth and the interactions of growing pollen tubes with the pistil are fundamental to the plant sciences, just as the ability to manipulate the growth of pollen has profound implications for the applied plant science and biotechnology. One of the most interesting and potentially useful pollen-pistil interactions is self-incompatibility (SI). SI is a genetic system that allows a plant to recognize and reject self pollen while permitting the growth of cross pollen. This mechanism allows plants to avoid the deleterious effects of inbreeding. Recently, we have found that the flowers of Campanula plants are self-incompatible when they first open but, as the flowers become older, they permit growth and fertilization by self pollen. The research funded in this award will identify the genetic causes of this breakdown in SI over time; it will examine the molecular basis for the breakdown in SI; it will determine how the breakdown in SI leads to different levels of inbreeding under different environmental circumstances; and it will use DNA sequence information to begin to look at the evolution of SI. Results will allow tests of competing hypotheses in three active and highly debated areas of basic plant biology: the population biology of pollen performance, the evolution and maintenance of mixed mating systems (partial selfing), and the evolution of SI. Findings should assist in the development of cost-saving and time-saving methodology for the production of inbred lines needed by commercial plant breeding programs.