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

9527739植物中的斯蒂芬森受精是花粉粒和花的雌性部分(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之所以在这里，是因为它的每一位父系祖先的花粉都成功地使一个产生种子的卵受精。了解花粉管的生长和花粉管与雌蕊的相互作用是植物科学的基础，就像控制花粉生长的能力对应用植物科学和生物技术具有深远的意义一样。自交不亲和性(SI)是花粉-雌蕊相互作用中最有趣和最有潜力的作用之一。SI是一种遗传系统，它允许植物识别和拒绝自体花粉，同时允许异花花粉的生长。这种机制使植物可以避免近亲繁殖的有害影响。最近，我们发现风铃属植物的花在第一次开放时是自交不亲和的，但随着花的老化，它们可以通过自体花粉生长和受精。该奖项资助的研究将确定SI随着时间的推移而崩溃的遗传原因；它将研究SI崩溃的分子基础；它将确定SI的崩溃如何在不同的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。这些结果将允许在基础植物生物学的三个活跃和高度争论的领域检验相互竞争的假说：花粉表现的种群生物学，混合交配系统的进化和维持(部分自交)，以及SI的进化。这些发现将有助于开发生产商业植物育种计划所需的自交系的成本和时间节约的方法。

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.