Novel Two Component Regulation of Quorum Sensing & Secondary Metabolite Production in Bacteria

摘要标题：细菌群体感应和次生代谢物产生的新型双组分调控-宿主相关细菌，无论是致病的还是有益的，都在由宿主及其相关微生物群落决定的环境中生存。宿主相关细菌利用感觉网络来调节建立和维持宿主关联所需的次级代谢物的表达。非那嗪是金黄色假单胞菌控制植物病害和人类病原体铜绿假单胞菌毒力的重要次生代谢物。在这两种细菌中，非那嗪在一定程度上受双组分群体感应（QS）系统的调节（例如，非那嗪只有在细菌种群达到足够的密度或群体数量后才会表达）。在这两种细菌中发现了一种新的双组分调控系统（RpeA/RpeB），当突变时，该系统消除了对QS的需求，并导致吩那嗪的过量生产。这一发现特别有趣，因为（RpeA/RpeB）系统的突变绕过QS控制，可能严重限制旨在通过干扰QS调节来降低细菌毒力和感染的新抗生素疗法的有效性。本文概述了一种系统的方法来表征新的负双组分调控系统（RpeA/RpeB）及其与营养感知和QS的联系。这两种感觉系统之间的联系将在金黄色葡萄球菌和铜绿假单胞菌中使用全局基因表达分析来确定。当细菌与宿主结合时，这种双组分系统的丧失对细菌生态适应性的影响也将被确定。了解这种双组分系统的损失如何绕过QS调控，将为提高次生代谢物的产生提供洞见，这些次生代谢物是成功控制植物疾病所必需的，或者是阻断人类疾病建立所需的次生代谢物的产生。拟议研究的多学科性质将i)为本科生和研究生提供培训机会，并将信息和技术整合到讲座、实验室练习和现有的本科生和研究生研究机会中，ii)通过美国植物病理学学会教育中心进行推广。

ABSTRACTLELAND S. PIERSON IIIPROPOSAL # NSF 0545804TITLE: Novel Two-Component Regulation of Quorum Sensing and Secondary Metabolite Production in BacteriaHost-associated bacteria, whether pathogenic or beneficial, survive in an environment determined by the host and its associated microbial community. Host-associated bacteria use sensory networks to regulate the expression of secondary metabolites needed to establish and maintain host associations. Phenazines are secondary metabolites important in plant disease control by Pseudomonas aureofaciens and also in virulence by the human pathogen P. aeruginosa. In both bacteria, phenazines are regulated, in part, by a two-component quorum sensing (QS) system (e.g. phenazines are expressed only after bacterial populations reach a sufficient density or quorum). A novel two-component regulatory system (RpeA/RpeB) was identified in both bacteria that, when mutated, removed the requirement for QS and resulted in overproduction of phenazines. This finding is particularly interesting because mutations in the (RpeA/RpeB) system, which bypasses QS control, could severely limit the effectiveness of new antibiotic therapies aimed at reducing bacterial virulence and infection by interfering with QS regulation. This proposal outlines a systematic approach to characterize the novel negative two component regulatory system (RpeA/RpeB) and its linkage to nutritional sensing and QS. The linkage between these two sensory systems will be determined in both P. aureofaciens and P. aeruginosa using global gene expression analysis. The effect of loss of this two-component system on the ecological fitness of the bacteria when associated with hosts also will be determined. Understanding how loss of this two-component system bypasses QS regulation will provide insights into strategies for enhancing secondary metabolite production essential for successful plant disease control or for blocking secondary metabolite production required for human disease establishment. The multidisciplinary nature of the proposed research will i) provide training opportunities for undergraduate and graduate students and integration of information and technologies into lectures, laboratory exercises and existing undergraduate and graduate research opportunities, ii) outreach via the American Phytopathological Society Education Center.