EAGER: Development of a Novel Genetic Screen for Plant Mutants in Medicago-Sinorhizobium Signaling

氮是所有生命赖以生存的重要元素。然而，只有某些微生物物种能够将元素氮转化（“固定”）为生物可用的形式;多细胞生物只能利用已经固定的氮。豆科植物能够通过与称为根瘤菌的固氮细菌形成密切的共生关系来获得氮。由于这种独特的共生获取氮的能力，豆科植物在农业和自然环境中起着至关重要的作用。豆科植物和根瘤菌之间的相互作用是迄今为止研究共生关系的最佳模型。它也是一个高度复杂的系统：细菌进入宿主，在宿主细胞内分化，固定氮，并将还原的氮交换为宿主提供的光合产物。寄主提供了一个专门的寄主根器官，根瘤，其中的生理条件得到精确的控制。神经元的形成、发育和功能依赖于一系列细胞程序，这些程序由两个伴侣之间高度特异性的分子对话触发。近年来，我们对豆科植物和根瘤菌之间的初始识别的理解取得了重大进展。另一方面，更下游的遗传组分和生化机制仍有待阐明。 EaGER项目将满足这一需求，并开发一种新的遗传筛选，以确定共生固氮中期和后期宿主细菌信号传导所需的豆类基因。 如果成功，该项目可能为所有豆科植物共生系统的研究提供技术途径。为促进宿主-微生物相互作用领域的工作，将出版这一信息，并向科学界感兴趣的团体提供材料。该项目将为博士后研究人员和本科生提供研究培训。此外，该项目将为本科生和当地高中生提供研究机会。

Nitrogen is a critical element on which all life depends. However, only certain microbial species are capable of converting ("fixing") elemental nitrogen into a biologically useable form; multicellular organisms can only utilize nitrogen that is already fixed. Legumes are able to obtain nitrogen by forming an intimate symbiotic relationship with nitrogen-fixing bacteria called rhizobia. Because of this unique ability to acquire nitrogen symbiotically, legumes play a critical role in agriculture and in natural environments.The interaction between legumes and rhizobia is by far the best characterized model for studying symbiosis. It is also a highly complex system: the bacteria enter the host, differentiate inside the host cell, fix nitrogen, and exchange the reduced nitrogen for photosynthate provided by the host. The host provides a specialized host root organ, the nodule, in which physiological conditions are accurately controlled. Nodule formation, development, and function depend on a suite of cellular programs which are triggered by highly specific molecular dialogs between the two partners. Recent years have seen major advances in our understanding of the initial recognition between legumes and rhizobia. On the other hand, the genetic components and biochemical mechanisms further downstream remains to be elucidated. This EaGER project will address this need and develop a novel genetic screen to identify legume genes required for host-bacterial signaling during the intermediate and late stages of symbiotic nitrogen fixation. If successful, this project may provide technical approaches for researchers in all legume symbiosis systems. Contributing to the field of host-microbe interactions, this body of information will be published and materials will be made available to interested groups from the scientific community. The project will provide research training for postdoctoral researchers and undergraduate students. In addition, the project will provide research opportunities to undergraduates and local high school students.