EAGER: A novel mechanism for the regulation of cytokinin signaling in plants

EAGER：调节植物细胞分裂素信号传导的新机制

• 批准号: 1833135
• 负责人: George Schaller
• 金额: $ 29.52万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1833135&HistoricalAwards=false
• 关键词: EAGER; novel; mechanism; regulation; cytokinin

Cytokinins are plant hormones that regulate many agronomically important traits, including plant architecture, biomass, senescence, disease resistance, drought resistance, and grain yield. A better understanding of cytokinin signaling will enable optimization of crops to improve their performance in various agricultural settings. The goal of this project is to uncover how the cytokinin hormone signal regulates gene expression in plants, and thereby controls plant growth and development. State-of-the art mass spectrometry approaches will be used to identify regulatory modifications on proteins and how these modifications change during the cytokinin response. The proposed research will provide excellent training opportunities for graduate students and postdoctoral fellows. In addition, through a local partnership, the project will establish a summer program aimed at developing education and science awareness through participatory activities that integrate science with art.The current paradigm for cytokinin signaling involves a two-component His-Asp phosphorelay similar to that found in prokaryotes. In this model, phosphorylation of the type-B response regulators (RRs) on a conserved Asp residue regulates their transcriptional activity, thereby controlling the transcriptional response to cytokinin. The goal of this project is to test the hypothesis that Ser/Thr phosphorylation of the type-B RRs also serves to regulate their activity. The prediction is that rapid cytokinin-dependent changes in Ser/Thr phosphorylation will occur, and that these will activate the type-B response regulators independently of Asp phosphorylation. Phosphoproteomic approaches will be employed to identify in vivo phosphorylation sites of the type-B response regulators and to characterize their phosphorylation dynamics in response to cytokinin. The regulatory significance of Ser/Thr phosphorylation sites will be tested by mutating the residues to phosphomimic (Glu) and non-phosphorylatable (Ala) versions of the residues, and their activity examined in a reporter system. Uncovering a Ser/Thr regulatory mechanism for the type-B RRs will fundamentally alter our model as to how cytokinin signal transduction occurs in plants, and also yield novel information on how the evolutionarily ancient two-component signaling pathway has been adapted to the needs of a eukaryote.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

细胞分裂素是调节许多农艺学上重要的性状的植物激素，包括植物结构、生物量、衰老、抗病性、抗旱性和谷物产量。更好地理解细胞分裂素信号将使作物优化，以提高其在各种农业环境中的表现。该项目的目标是揭示细胞分裂素激素信号如何调节植物基因表达，从而控制植物生长和发育。国家的最先进的质谱方法将被用来确定蛋白质的调节修饰，以及这些修饰如何在细胞分裂素反应的变化。拟议的研究将为研究生和博士后研究员提供极好的培训机会。此外，通过当地的合作伙伴关系，该项目将建立一个夏季计划，旨在发展教育和科学意识，通过参与性活动，将科学与艺术相结合。目前的细胞分裂素信号传导的范例涉及一个双组分组氨酸-天冬氨酸磷酸化类似于原核生物中发现的。在该模型中，保守的Asp残基上的B型反应调节因子（RR）的磷酸化调节其转录活性，从而控制对细胞分裂素的转录反应。该项目的目标是测试B型RRs的Ser/Thr磷酸化也用于调节其活性的假设。预测是，快速细胞分裂素依赖性的变化，丝氨酸/苏氨酸磷酸化将发生，这些将激活B型反应调节独立的天冬氨酸磷酸化。磷酸化蛋白质组学的方法将被用来确定在体内的磷酸化位点的B型反应调节剂，并表征其磷酸化动力学响应细胞分裂素。通过将残基突变为残基的拟磷酸化（Glu）和不可磷酸化（Ala）形式，并在报告系统中检查其活性，来检测Ser/Thr磷酸化位点的调节意义。揭示B型受体的Ser/Thr调节机制将从根本上改变我们关于细胞分裂素信号转导在植物中如何发生的模型，同时也提供了关于进化上古老的两个-该奖项反映了NSF的法定使命，并被认为值得通过利用基金会的知识价值和更广泛的影响进行评估来支持审查标准。