RUI: Collaborative Research: Understanding the role of a modified phosphotransferase system and a unique two component signal transduction system in regulating gene expression.

细菌有能力直接感知环境，并根据环境改变自己的行为。虽然细菌的行为变化可以直观地看到，但导致某些变化的复杂遗传过程尚未完全了解。本项目将以梅利洛中华根瘤菌为模型，研究细菌进行这些过程的一些方式。Sinorhizobium meliloti是根瘤菌（rhizobia）中的一员，在农业领域具有重要的环境和经济意义。根瘤菌侵染豆科植物并提供氮肥以提高作物产量。根瘤菌感染的高效和高产减少了对化肥的需求。扩大我们对控制这种细菌行为的遗传系统的了解，有可能允许操纵来优化根瘤菌与植物的相互作用。该项目将培养从高中到研究生的不同教育水平的学生在这一领域进行科学工作并进行适当的交流。本研究的总体目标是研究和理解一个杂交磷酸转移酶系统（PTS）和一个独特的双组分信号转导系统在细菌固氮革兰氏阴性共生菌Sinorhizobium meliloti中调控基因表达的作用。该项目将研究最近确定的两个系统之间的新相互作用，这两个系统调节了几个细胞过程。此外，系统本身是有趣的，但没有充分表征：磷酸转移酶系统是一个简短的氮糖杂交，而双组分系统有一个有趣的多传感域HWE激酶（Sma0113）和一个没有效应域的非典型反应调节器（Sma0114）。双重调控下的一个过程是分解代谢抑制。这是一个复杂的过程，细菌细胞通过这个过程来适应获取能量和原料，并且在相关细菌中，控制与它们与宿主相互作用能力相关的基因的表达。三种方法将用于阐明如何将系统集成到蜂窝网络中。转录组分析将允许鉴定两个系统的联合调控。遗传、生化和蛋白质组学方法将揭示它们的下游伙伴。遗传学工具将用于表征允许双重调控的启动子结构。该结果将有助于更好地了解这两个系统的特点，以及它们在调节S. meliloti和类似革兰氏阴性菌基因表达中的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Bacteria have the ability to directly sense their environment and change their behavior according to their surroundings. While the behavioral changes in the bacteria can be seen visually, the intricate genetic processes that lead to some of the changes are not fully understood. This project will investigate some of the ways in which bacteria carry out these processes using Sinorhizobium meliloti as a model. Sinorhizobium meliloti is a member of a larger group of bacteria called rhizobia, and is environmentally and economically vital in the field of agriculture. Sinorhizobium beneficially infects legumes and provides useable nitrogen to increase crop yield. An efficient and productive rhizobium infection reduces the need for chemical fertilizers. Expanding our knowledge of the genetic systems that control the behavior of this bacterium has the potential to allow manipulation to optimize the rhizobium-plant interaction. The project will train students from the across educational levels, from high school to graduate students to do scientific work in this field and to communicate it properly. The overarching goal of this proposal is to investigate and understand the role of a hybrid phosphotransferase system (PTS) and a unique two component signal transduction system in regulating gene expression in the bacterial nitrogen-fixing gram-negative symbiont Sinorhizobium meliloti. The project will study a recently identified and novel interaction between the two systems that regulates several cellular processes. Additionally, the systems themselves are interesting and insufficiently characterized: the phosphotransferase system is an abbreviated nitrogen-sugar hybrid while the two-component system has an intriguing multiple-sensing domain HWE kinase (Sma0113) and an atypical response regulator with no effector domain (Sma0114). One of the processes under dual regulation is catabolite repression. This is a complex process through which bacterial cells adapt to obtain energy and raw materials, and, in related bacteria, controls the expression of genes associated to their ability to interact with their hosts. Three approaches will be used to elucidate how the systems are integrated into the cellular network. Transcriptome analysis will allow identification of the combined regulon of the two systems. Genetic, biochemical, and proteomic methods will reveal their downstream partners. Genetic tools will be used to characterize the promoter structure that allows dual regulation. The results will bring better understanding of the characteristics of the two systems and the role each plays in regulating gene expression in S. meliloti and similar gram negative bacteria.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.