Biochemical Mechanism of Regulation of Phytochrome Interacting Factor 1 by Light

光是调节植物生长发育的关键因素。例如，红光和远红光调节种子萌发和绿化等重要过程。光敏色素家族的光感受器监测红(R)/远红(FR)光，并启动这些反应。这个项目将阐明鲜为人知的光敏色素作用的生化机制。关键调节蛋白(转录因子)在黑暗和光照下的降解已被证明在光形态发生中起着核心作用。一般来说，有两类光信号因子受到降解的调节：光形态建成的正调控因子如HY5、LAF1和HFR1在黑暗中降解，负调控因子光敏色素相互作用因子(PIF)在光响应下降解。虽然黑暗诱导的正性调节剂的降解已经被彻底研究，但光诱导的PIF的降解还不是很清楚。该项目将使用生化、分子和遗传学方法来阐明在蓝光、红光和远红光条件下光诱导降解PIF1的早期事件。光诱导的PIF1降解解除了PIF1促进种子萌发和绿化、抑制下胚轴生长的负调控作用。该项目的更广泛影响包括根本性进展、人力资源开发和培训。由于PIF1是主要的光敏色素信号伙伴，其稳定性受光敏色素调节，该项目将提供有关这些重要过程的基本信息。此外，由于转录因子是所有发育过程的关键调节因子，了解PIF1调节机制将有助于农业生物技术和生物质生产。项目成果和开发的研究工具将通过出版物、会议报告和网站张贴以及直接从实验室分发。该项目将为现代功能基因组学和分子遗传学方面的本科生、研究生和博士后学生提供必要的培训。最后，该项目的各个方面将积极融入本科生和研究生课堂教学。

Light is a critical factor regulating plant growth and development. For example, red and far-red light regulate important processes like seed germination and greening. The phytochrome family of photoreceptors monitors the red (R)/far-red (FR) light and initiate these responses. This project will elucidate poorly understood biochemical mechanisms of phytochrome action. Degradation of critical regulatory proteins (transcription factors) both in the dark and light has been shown to play a central role in photomorphogenesis. In general, two classes of light signaling factors are regulated by degradation: Positive regulators of photomorphogenesis such as HY5, LAF1 and HFR1 are degraded in the dark and negative regulators called Phytochrome Interacting Factors (PIFs) are degraded in response to light. Although dark-induced degradation of positive regulators has been thoroughly investigated, light-induced degradation of PIFs is less well understood. This project will use biochemical, molecular and genetic approaches to elucidate early events in the light-induced degradation PIF1 under blue, red and far-red light conditions. Light-induced degradation of PIF1 relieves the negative regulation by PIF1 to promote seed germination and greening, and inhibit hypocotyl growth. The broader impacts of the project include fundamental advances, human resource development, and training. Since PIF1 is a primary phytochrome-signaling partner whose stability is regulated by phytochromes, the project will provide fundamental information on these important processes. Moreover, as transcription factors are critical regulators of all developmental processes, understanding the mechanism of PIF1 regulation will be enabling for agricultural biotechnology and biomass production. Project results and the research tools developed will be distributed through publications, conference presentations, and website postings as well as directly from the laboratory. This project will provide needed training for undergraduate, graduate and postdoctoral students in modern functional genomics and molecular genetics. Finally, aspects of the project will be actively integrated into undergraduate and graduate classroom teaching.