Functional characterization of a cytochrome P450 involved in gravitropic signal transdution

重力对植物的生长发育起着基础性的作用。为了应对重力矢量的变化，植物通过不同的生长进行重新定向。为了简单起见，反应途径被分成三个连续的步骤：重力感知、信号转导和反应组织的不对称生长。大量的研究已经帮助确定了感知事件、植物生长调节剂生长素的作用以及导致反应的机制。信号转导的事件，即那些将感知的生物物理行为与导致生长素重新分配的生化信号联系起来的事件，仍然是一个黑匣子。重力持续信号(GPS)突变体为植物重力信号转导中的基因发现提供了一个很好的工具。GPS突变体已经为重力信号转导途径提供了新的见解。对GPS基因的克隆已经确定了与这些事件有关的三种新蛋白质：编码细胞色素P450的GPS1，参与囊泡运输的突触短肽GPS2，以及转录因子GPS3。这项研究的重点是GPS1编码的蛋白质的功能特性，即研究细胞色素P450的底物结合，并确定P450活性在信号转导事件中是器官特异性的还是结构性的。这些实验应该为GPS1蛋白的活性及其在重力信号转导途径中的作用提供可靠的信息。阐明控制植物对重力的反应的因素对于控制人类使用的植物生长和发育以及理解其他信号转导事件，特别是那些由生物物理刺激引发的信号转导事件具有潜在的深远意义。更广泛的影响：除了为补充现有的植物向重力性模型提供新的基本信息外，这项研究的结果还可以促进技术的开发，导致在运输或储存期间经常被重力刺激导致畸形和不值钱的茎的商业重要花卉作物的收获后处理方面的创新，以及园艺或农业作物的创新，以提高收获能力或导致更适合人类需求的新品种。此外，PI和研究生致力于教育和推广，并将他们的研究作为这些互动的起点。国际和平协会积极参与合作研究和教学，不仅为科学期刊发表论文，还为教育和宣传材料发表文章，并向K-12学生/教师和社区团体举办了多次讲座。俄亥俄大学25%的本科生来自周边的阿巴拉契亚地区俄亥俄州和西弗吉尼亚州。该大学的学生通过课堂和研究实验室的个人工作接触到研究实验室可用的技术。PI坚信为本科生开展研究活动，并为他们提供旅行介绍工作的机会，目前有6名本科生在实验室工作，3名来自阿巴拉契亚地区，4名第一代大学。目前的项目将为几名本科生提供研究和培训机会，此外还需要一个职位。它还将提供资源，通过将材料纳入实验室和讲座课程，为研究生和本科生提供更多的培训机会。

Gravity plays a fundamental role in plant growth and development. In response to changes in the gravity vector, plants reorient by differential growth. For simplicity, the response pathway has been separated into three sequential steps: gravity perception, signal transduction, and asymmetric growth of the responding tissue. A significant body of research has helped define the events of perception, the role of the plant growth regulator auxin, and the mechanisms resulting in the response. The events of signal transduction, those that link the biophysical action of perception to a biochemical signal that results in auxin redistribution remains a black box. The gravity persistent signal (gps) mutants provide a wonderful tool for gene discovery in plant gravitropic signal transduction. The gps mutants have already provided new insights into the gravity signal transduction pathway. Cloning of the GPS genes have identified three new proteins involved in those events: GPS1 encodes a cytochrome P450, GPS2, a synaptobrevin involved in vesicle trafficking, and GPS3, a transcription factor. The research proposed focuses on the functional characterization of the protein encoded by GPS1, i.e. investigating the substrate binding of the cytochrome P450 and determining whether the P450 activity is organ specific or constitutive in the signal transduction events. The experiments should provide solid information on the activity of the GPS1 protein and its role in the gravity signal transduction pathway. Elucidating factors governing plant responses to gravitational forces has potentially far-reaching implications for manipulating plant growth and development for human use and for understanding other signal transduction events, especially those initiated by biophysical stimuli. Broader impact: Besides providing new, fundamental information to supplement existing models of plant gravitropism, results of this research could enable the development of technologies leading to innovations in post-harvest handling of commercially important floricultural crops that are often gravistimulated during shipment or storage resulting in misshapen and worthless stems, to innovations in horticulture or agriculture crops that improve harvesting capability or that lead to new varieties that better suit human needs. In addition, the PI and graduate students are dedicated to education and outreach and use their research as a launching point for those interactions. The PI is active in collaborative research and teaching, has published not only papers for scientific journals but materials for education and outreach, and has presented numerous talks to K-12 students/ teachers and to community groups. Ohio University draws 25% of its undergraduate population from the surrounding Appalachian region of Ohio and West Virginia. Students at the university are exposed to the technologies available in the research laboratories through both the classroom and working individually in research laboratories. The PI believes strongly in research activities for undergraduates and in providing opportunities for them to travel to present their work and currently has six undergraduates working in the laboratory, three from the Appalachian area and four first generation college. The current project will provide research and training opportunities for several undergraduates in addition to the one position requested. It will also provide resources to provide additional training opportunities for graduate and undergraduate students through incorporation of materials into laboratory and lecture courses.