EAGER: Salicylic acid signaling in plant pathogen interactions

EAGER：植物病原体相互作用中的水杨酸信号传导

• 批准号: 1464527
• 负责人: Zhengqing Fu
• 金额: $ 14.8万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1464527&HistoricalAwards=false
• 关键词: EAGER; Salicylic; acid; signaling; plant

During their lifetime plants face many kinds of abiotic and biotic stresses. Major threats include fungal, oomycete, viral, bacterial and nematode pathogens. It is estimated that diseases caused by these plant pathogens reduce plant yield by 10-20% every year. Over millions of years of molecular interactions and co-evolution of host plants and their pathogens, plants developed a sophisticated immune system that senses an impending infection and organizes appropriate defense responses. A key and essential player in this process is the hormone salicylic acid (SA). Although receiving considerable attention from the research community, essential aspects of its role in immunity remain unknown. This project seeks to resolve fundamental new mechanisms through which this major immune regulator achieves its effects. These may provide new strategies for developing disease resistant crop plants. As a master regulator of plant defense, the protein NPR1 is required for SA-mediated systemic acquired resistance (SAR) and basal defense. In the absence of pathogens or SA treatment, most NPR1 exists in the cytosol as oligomers. After pathogen challenge or SA treatment, NPR1 oligomers are reduced to monomers which enter the nucleus where they function as transcriptional coactivators, binding TGA transcription factors to activate the expression of plant defense genes. Recent publications demonstrated that NPR1 and its paralogs NPR3 and NPR4 bind SA with different affinities and function as SA receptors. In addition, the PI has identified HEN3, a nuclear kinase which is required for NPR1 monomer formation, plant defense gene expression and SAR. Significantly, SA promotes interactions between NPR1 and TGA1/4 transcription factors in a yeast two-hybrid assay, thus supporting the hypothesis that SA and NPR1 activate plant defense through increased protein-protein interactions between NPR1 and TGA1/4. This project seeks to resolve molecular mechanisms that underlie and regulate the function of this key immune signaling hub. Mechanisms to be explored include the role of the HEN3 kinase in regulating NPR1 function, and the effect of SA on interactions between NPR1/3/4 and TGA1/4. The broader impacts of the project include the participation of a postdoc, a graduate student and four undergraduates, including two from groups underrepresented in the sciences.

植物在其一生中面临着多种非生物和生物胁迫。主要威胁包括真菌、卵菌、病毒、细菌和线虫病原体。据估计，由这些植物病原体引起的疾病每年使植物产量减少10-20%。经过数百万年的分子相互作用和宿主植物及其病原体的共同进化，植物发展了一种复杂的免疫系统，可以感知即将发生的感染并组织适当的防御反应。在这个过程中的一个关键和重要的球员是激素水杨酸（SA）。虽然受到研究界的相当大的关注，但其在免疫中的作用的基本方面仍然未知。该项目旨在解决这种主要免疫调节剂实现其效果的基本新机制。这可能为培育抗病作物提供新的策略。作为植物防御的主要调节因子，NPR 1蛋白是SA介导的系统获得抗性（SAR）和基础防御所必需的。在没有病原体或SA处理的情况下，大多数NPR 1作为寡聚体存在于胞质溶胶中。在病原体攻击或SA处理后，NPR 1寡聚体被还原成单体，这些单体进入细胞核，在那里它们作为转录共激活因子发挥作用，结合TGA转录因子以激活植物防御基因的表达。最近的出版物表明，NPR 1及其旁系同源物NPR 3和NPR 4以不同的亲和力结合SA，并作为SA受体发挥功能。此外，PI还鉴定了HEN 3，一种NPR 1单体形成、植物防御基因表达和SAR所需的核激酶。值得注意的是，SA促进NPR 1和TGA 1/4转录因子之间的相互作用，在酵母双杂交试验，从而支持的假设，SA和NPR 1激活植物防御通过增加NPR 1和TGA 1/4之间的蛋白质-蛋白质相互作用。该项目旨在解决这个关键免疫信号枢纽的基础和调节功能的分子机制。有待探索的机制包括HEN 3激酶在调节NPR 1功能中的作用，以及SA对NPR 1/3/4和TGA 1/4之间相互作用的影响。该项目更广泛的影响包括一名博士后、一名研究生和四名本科生的参与，其中两名来自科学领域代表性不足的群体。