Collaborative Research: Chemotactic signaling in Sinorhizobium meliloti symbiotic plant host interaction

合作研究：苜蓿中华根瘤菌共生植物宿主相互作用中的趋化信号传导

• 批准号: 2128233
• 负责人: Ann Stock
• 金额: $ 39.46万
• 依托单位: Rutgers, The State University of New Jersey-RBHS-Robert Wood
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2128233&HistoricalAwards=false
• 关键词: Collaborative; Research; Chemotactic; signaling; Sinorhizobium

Chemotaxis enables motile bacteria to move away from harmful and towards beneficial chemicals. One unique group of motile soil bacteria are rhizobia, which can engage in specific symbiotic relationships with leguminous plants such as peas, soy beans, and alfalfa. This symbiosis supplies the host plant with nitrogen, which is the most limiting nutrient for plant growth. The process of chemotaxis allows rhizobia to recognize and move towards its host, which improves the symbiotic relationship, and consequently, enhances plant growth. Multiple chemoreceptor proteins are being used by rhizobia to sense a wide spectrum of chemical compounds secreted by the host plants. However, little is known about the specific processes involved in the regulation of sensitivity and adaptation, which are essential features for an effective chemotactic response. The overarching goal of this project is to decode the pathway that controls stimuli adaptation. Outcomes will transform our current concepts of the biology of bacterial chemotaxis and their interaction with their eukaryotic hosts. The results of this research can directly benefit future agricultural and environmental issues by potentially reducing the use of artificial fertilizers, resulting in less expensive and less polluting agriculture. Broader Impacts activities include the intrinsic merit of the research as nitrogen fixation is one of the most important processes in the biosphere. In addition, the project will involve the interdisciplinary training of graduate students. The team is committed to mentoring graduate and undergraduate students, especially underrepresented populations and women. Public outreach activities include hands-on demonstrations for elementary and high school students, both on- and off-campus, and involvement of undergraduate and high school students in research.The chemotaxis system of the model plant symbiont Sinorhizobium meliloti evolved a greater complexity than that of enteric bacteria. Although several unique components and features controlling chemotaxis have been recently uncovered, regulation of pathway sensitivity and stimuli adaptation are unknown. The aim of this research project is to elucidate the receptor modification system, which plays a pivotal role in this process. Specifically, the function of a novel chemotaxis protein, CheT, which unprecedentedly interacts with a conserved element of the adaptation pathway, will be deciphered. First, the investigators will characterize the chemotactic pathway controlling adaptation. Two chemoreceptors with a central role in host-plant sensing, namely amino acid sensor McpU and betaine sensors McpX, will serve as models because they are expected to exhibit different modes of interaction with the adaptation pathway. Behavioral, microscopic, and mutational analyses, as well as mass spectrometry will be used to uncover the molecular basis for stimuli adaptation. Second, the role of CheT in chemotactic signaling will be elucidated through genetic, behavioral, phosphorylation, and structural analyses. The proposed research will advance knowledge of complex sensory systems.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.

趋化性使运动细菌能够从有害和有益的化学物质转移到有益的化学物质上。根瘤菌是一组独特的运动土壤细菌，它们可以与豆类，大豆和苜蓿等豆科植物建立特定的共生关系。这种共生为宿主植物提供氮，这是植物生长的最有限的营养。趋化性过程允许根茎识别并朝向其宿主，从而改善了共生关系，从而增强了植物的生长。根茎正在使用多种化学感受器蛋白来感知宿主植物分泌的各种化合物。但是，对于调节灵敏度和适应性的特定过程知之甚少，这是有效的趋化反应的重要特征。该项目的总体目标是解码控制刺激适应的途径。结果将改变我们当前的细菌趋化性生物学概念及其与真核宿主的相互作用。这项研究的结果可以通过减少人工肥料的使用来直接使未来的农业和环境问题受益，从而导致更便宜，污染的农业较少。更广泛的影响活动包括研究的内在优点，因为氮固定是生物圈中最重要的过程之一。 此外，该项目将涉及研究生的跨学科培训。该团队致力于指导毕业生和本科生，尤其是代表人数不足的人群和女性。公共外展活动包括在校外和校外的小学和高中生的动手演示，以及本科生和高中生从事研究的参与。模型植物植物Symbiont Sinorhizobium Meliloti的趋化性系统进化出来的复杂性比企业细菌的复杂性更大。尽管最近已经发现了几种独特的组件和控制趋化性的特征，但途径敏感性和刺激适应性的调节尚不清楚。该研究项目的目的是阐明受体修饰系统，该系统在此过程中起着关键作用。具体而言，新型趋化蛋白CHET的功能将被解密，该功能与适应途径的保守元素相互作用。首先，研究人员将表征控制适应的趋化途径。两个在宿主植物传感中具有核心作用的化学感受器，即氨基酸传感器MCPU和BETAINE传感器MCPX，将作为模型，因为它们有望与适应途径表现出不同的相互作用模式。行为，显微镜和突变分析以及质谱法将用于揭示刺激适应的分子基础。其次，CHET在趋化信号传导中的作用将通过遗传，行为，磷酸化和结构分析来阐明。拟议的研究将促进对复杂的感官系统的了解。该奖项反映了NSF的法定使命，并被认为是值得通过基金会的知识分子优点和更广泛影响的评论标准来评估值得支持的。