Investigation of Mechanisms that Control the Transition to Flowering in Higher Plants

一个多世纪以来，植物生物学家一直在慢慢破译植物是如何控制开花时间的。直到最近，导致植物开花的信号的性质仍然是一个完全的谜。早期的研究人员发现，一种诱导开花的物质是在叶片中合成的，然后长距离地运输到植物的中心芽，再到真正的花起源的干细胞区域。我的研究使用了分子生物学、遗传学、生物化学和基因组学的工具，以更好地了解开花过程的本质。我们的研究围绕着对玉米ID1基因的研究，该基因对开花至关重要。具有该基因功能版本的玉米植株在适当的时间开花，而具有ID1基因缺陷的玉米植株开花很晚，并产生异常的花。我们使用分子技术分离和鉴定了ID1基因，发现它编码一种锌指转录因子蛋白，该蛋白在叶片中作为其他基因的主要调节因子。这表明ID1通过开启或关闭控制远距离叶片信号的基因而导致玉米开花。这项提议有三个主要目标：1)识别由ID1基因控制的基因；2)表征植物中组成叶片信号的分子、生化和生理成分，这些信号指定开花时间；3)找出ID1用来使基因活跃或不活跃的基本分子机制。最近，我们发现了ID1可能通过表观遗传机制控制基因的证据。表观遗传学代表了我们对基因如何控制的理解的一个令人兴奋的新范式。最终，我们的目标是破译支持ID1功能的表观遗传机制，导致影响开花过程的生化成分和代谢变化。发现开花时间是如何工作的对农业来说至关重要。全球气候变化，加上人口不断增加，将对世界粮食供应产生严重影响。更好地了解玉米以及小麦、水稻、高粱和甘蔗等农业上重要亲缘关系的开花情况，可能有助于稳定粮食生产。控制开花时间的能力对农业至关重要，因为植物协调开花，以获得最佳的种子和果实生产。因此，了解开花将有助于提高重要作物的生产力。

Plant biologists have been slowly deciphering how plants control flowering time for over a century. Until recently the nature of the signals that cause plants to flower remained a complete mystery. Early researchers discovered that a flower-inducing substance is synthesized in leaves and then transported a long distance to the central shoot of the plant to a region of stem cells from which the actual flowers originate. My research uses the tools of molecular biology, genetics, biochemistry and genomics to better understand the nature of the flowering process. Our research revolves around the study of the maize INDETERMINATE1 gene, or ID1, which is critically important for flowering. Maize plants with a functional version of this gene flower at the proper time, whereas maize plants with a defective ID1 gene flower very late and produce aberrant flowers. We used molecular techniques to isolate and characterize the ID1 gene and found that it encodes a zinc finger transcription factor protein that acts in leaves as a master regulator of other genes. This suggests that ID1 causes flowering in maize by turning 'on' or 'off' the genes that control the long distance leaf signal. There are three main goals of this proposal: 1) identify genes that are controlled by the ID1 gene, 2) characterize the molecular, biochemical and physiological components in plants that make up the leaf signals that specify time to flower; and 3) work out the basic molecular mechanism used by ID1 to make genes active or inactive. Recently we found evidence that one way that ID1 may control genes is by epigenetic mechanisms. Epigenetics represents an exciting new paradigm in our understanding of how genes are controlled. Ultimately we aim to decipher the epigenetic mechanisms that underpin ID1 function leading to the biochemical components and metabolic changes that affect the flowering process. Discovering how flowering time works is vitally important to agriculture. Global climate change, coupled with an expanding population, will have a severe impact on the world food supply. A better understanding of flowering in maize and agriculturally important relatives such as wheat, rice, sorghum and sugarcane could help stabilize food production. The ability to control time to flowering is of fundamental importance to agriculture because plants coordinate flowering for optimal seed and fruit production. Therefore understanding flowering will help to improve the productivity of vital crop plants.