Biochemical Mechanism of Regulation of Phytochrome Interacting Factor 1 by Light

光调控光敏色素相互作用因子1的生化机制

• 批准号: 0822811
• 负责人: Enamul Huq
• 金额: $ 43.5万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0822811&HistoricalAwards=false
• 关键词: Biochemical; Mechanism; Regulation; Phytochrome; Interacting

PI: Enamul HuqProposal # 0822811Title: Biochemical Mechanism of Regulation of Phytochrome Interacting Factor 1 by LightGrowth and development are highly regulated by environmental light signals at all phases of a plant's life cycle. Plants have evolved several light receptors including the phytochrome (phy) family of photoreceptors to monitor the red and far-red light, the cryptochromes, the phototropins and the ZTL/FKF1 family of F-box proteins to monitor the UV-A and blue light, and an unidentified receptor to monitor the UV-B light. Although much has been learned on these photoreceptors, the primary biochemical mechanism by which they regulate plant growth and development is still unknown. In recent years, degradation of transcription factors both in the dark and light has been shown to play central roles in the light signaling pathways. In general, one class of light signaling factors are degraded in the dark. They include HY5, LAF1 and HFR1, most of which are positive regulators of photomorphogenesis. The second class factors are degraded in light. This class includes Phytochrome Interacting Factors(PIFs), most of which negatively regulate photomorphogenesis. Although, the mechanisms of dark-induced degradation are well investigated, the light-induced degradation of PIFs is less well understood. This project is focused on investigating the early events in the light-induced degradation of the bHLH transcription factor, PIF1, using biochemical, molecular and genetic approaches. PIF1 is rapidly degraded under both red and far-red light conditions. Light-induced proteolytic removal of PIF1 relieves the negative regulation by PIF1 and promote seed germination, chlorophyll biosynthesis and hypocotyl growth inhibition. Since PIF1 is a primary phytochrome-signaling partner, whose stability is regulated by phytochromes through direct physical interaction, the results from this project will provide fundamental information on the mechanism of phytochrome regulated developmental pathways. This study will have broad implications in several ways. First, understanding the biochemical mechanism of regulation of PIF1 in plants will provide fundamental knowledge and molecular tools applicable in agricultural biotechnology for enhanced crop and biomass production. Second, the results and the research tools will be distributed to the community through publications, conference presentations, and website postings directly from our laboratories. Third, this project will contribute to training the next generation scientists in modern functional genomics and molecular genetics, including undergraduate, graduate and postdoctoral students. This training will provide them with the unique opportunity to make significant contributions to the field of plant biology and biotechnology and will prepare them for future careers as independent researchers.

植物的生长发育在生命周期的各个阶段都受到环境光信号的高度调控。植物已经进化出多种光受体，包括光敏色素（phy）家族光受体，用于监测红光和远红光；隐色素、光促素和F-box蛋白的ZTL/FKF1家族光受体，用于监测UV-A和蓝光；以及一种未知的受体，用于监测UV-B光。尽管人们对这些光感受器了解甚多，但它们调控植物生长发育的主要生化机制仍不清楚。近年来，转录因子在黑暗和光中的降解已被证明在光信号通路中发挥核心作用。一般来说，一类光信号因子在黑暗中被降解。它们包括HY5、LAF1和HFR1，其中大部分是光形态发生的正调控因子。第二类因子在光照下降解。这一类包括光敏色素相互作用因子（pif），其中大部分负调控光形态发生。虽然，暗诱导降解的机制已经得到了很好的研究，但光诱导pif降解的机制还不太清楚。该项目的重点是研究光诱导bHLH转录因子PIF1降解的早期事件，使用生化，分子和遗传方法。PIF1在红光和远红光条件下都能迅速降解。光诱导蛋白水解去除PIF1可缓解PIF1的负调控，促进种子萌发、叶绿素生物合成和下胚轴生长抑制。由于PIF1是光敏色素的主要信号伙伴，其稳定性通过直接的物理相互作用受到光敏色素的调节，本项目的结果将为光敏色素调节发育途径的机制提供基础信息。这项研究将在几个方面产生广泛的影响。首先，了解植物中PIF1调控的生化机制将为农业生物技术提供基础知识和分子工具，以提高作物和生物质产量。其次，结果和研究工具将通过出版物、会议报告和网站直接从我们的实验室发布到社区。三是培养现代功能基因组学和分子遗传学的下一代科学家，包括本科生、研究生和博士后。这项培训将为他们提供独特的机会，为植物生物学和生物技术领域做出重大贡献，并为他们未来作为独立研究人员的职业生涯做好准备。