Studies on ETR1 Ethylene Receptor Structure, Function and Output

植物激素乙烯调节植物的许多关键过程，包括生长、果实成熟、衰老以及叶片和花瓣的脱落。这个信号通路的第一步是乙烯与受体的结合。植物含有多种乙烯受体同种异构体。最早被分离和研究最多的是模式植物拟南芥中的ETR1受体。尽管经过十多年的研究，ETR1受体的工作机制仍然未知。本研究项目的重点是跟进Binder实验室最近观察到的ETR1受体具有多种独特的功能。ETR1受体同种异构体的丢失，而不是其他同种异构体，导致乙烯刺激的章动（振荡弯曲）的丢失，但导致对乙烯的其他性状更敏感的反应，如生长抑制。这些明显矛盾的结果首次描述了乙烯受体的非重叠作用。因此，PI将在新的背景下研究ETR1受体的作用，以揭示有关乙烯受体功能和输出的更多细节。为了做到这一点，将描述导致章动与其他性状的ETR1受体的输出。这个项目有三个总体目标。首先是确定ETR1下游是否存在多条信号通路。第二个目标是确定ETR1上的哪些域或位点是周旋和其他特征所必需的。这两个目标都将通过对突变体的生理分析来解决。第三个目的是确定ETR1的矛盾作用是否是由ETR1在生长植物中的分布变化引起的。这些研究将提供乙烯受体如何调节多种性状的细节。这个多方面的项目将改变我们对分子水平与器官水平事件之间联系的理解，从而更广泛地了解植物是如何生长和发育的。项目的广泛影响：该项目将通过扩大本科生和研究生在宾德实验室从事研究的机会来加强研究和教育基础设施。宾德博士还鼓励高中生参与实验室研究。他参加了田纳西大学大学预科研究学者项目，该项目是田纳西大学和诺克斯维尔法拉格特高中科学院合作的项目。目前，一名学生通过这个项目在实验室工作，另一名学生是独立从另一所高中招募的。该项目将加强田纳西大学和该地区高中之间的合作。这是培养未来科学家的一个重要因素。学生培训将在宾德博士的指导下进行。此外，宾德博士将继续访问当地的教室，讨论生物研究，并将指导种植科学（plantingscience.org），这是一个为K-16学生和教师提供植物科学学习和研究资源的在线项目。所有这些活动都将提高人们对科学研究的认识，并确保有兴趣的学生成为我们未来的科学家。从该项目中获得的对乙烯信号的进一步了解将对各种作物相关实践产生深远影响，尤其是收获后储存实践。这项研究将提供更多的关注，以便在不影响植物生存和活力的情况下操纵对乙烯的特定反应。

The plant hormone ethylene regulates many critical processes in plants including growth, fruit ripening, senescence, and shedding of leaves and petals. The first step in this signaling pathway is the binding of ethylene to receptors. Plants contain multiple ethylene receptor isoforms. The first to be isolated and the most studied is the ETR1 receptor from the model plant, Arabidopsis thaliana. Despite over a decade of study, the mechanisms for how the ETR1 receptor works are still unknown. The focus of this research project is to follow up on the recent observation from the Binder laboratory that the ETR1 receptor has multiple and unique functions. Loss of the ETR1 receptor isoform, but not other isoforms, causes loss of ethylene-stimulated nutations (oscillatory bending) yet results in more sensitive responses to ethylene for other traits such as inhibition of growth. These apparently contradictory results represent the first description of a non-overlapping role for an ethylene receptor. Therefore the PI will study the role of the ETR1 receptor in a new context to uncover more details about ethylene receptor function and output. To do this, the output of the ETR1 receptor that leads to nutations versus other traits will be delineated. There are three general aims to this project. The first is to determine whether or not there are multiple signaling pathways downstream of ETR1. The second aim is to ascertain which domains or sites on ETR1 are required for nutations versus other characteristics. Both of these objectives will be addressed using physiological analysis of mutants. The third aim is to determine whether or not the paradoxical role of ETR1 is caused by changes in the distribution of ETR1 within the growing plant. These studies will provide details about how ethylene receptors function to regulate multiple traits. This multifaceted project will transform our understanding about links between events at the molecular level with those at the organ level to give a broader understanding of how plants grow and develop.Broader Impacts of the Project: This project will enhance research and educational infrastructure by broadening opportunities for undergraduate and graduate students to engage in research in the Binder lab. Dr. Binder also encourages high school students to engage in lab research. He participates in the University of Tennessee Pre-Collegiate Research Scholars Program that is a collaboration between The University of Tennessee and the Science Academy at Farragut High School in Knoxville. Currently one student is in the lab through this program and another was recruited from another high school independently. This project will enhance collaborations between the University of Tennessee and high schools in the area. This is an important element in educating future scientists. Student training will occur under the mentorship of Dr. Binder. In addition, Dr. Binder will continue to visit local classrooms to talk about biology research and will mentor for Planting Science (plantingscience.org), an on-line program that provides a learning and research resource in the plant sciences for K-16 students and teachers. All these activities will increase awareness about scientific research and ensure interested students become our future scientists. The increased understanding about ethylene signaling gained from this project will have profound impacts on a variety of crop related practices, most notably on post-harvest storage practices. This research will provide more focus so that specific responses to ethylene can be manipulated without compromising plant survival and vigor.