Diversity and evolution of Pseudomonas syringae type III effectors (RO1GM066025)

描述（由申请人提供）：致病菌使用各种毒力机制感染宿主，包括人类。基于多种致病菌株基因组测序的比较研究表明，细菌物种具有比任何单一细菌基因组大得多的泛基因组。本文主要研究丁香假单胞菌与植物的相互作用。丁香假单胞菌利用进化保守的III型分泌系统将III型效应蛋白毒力因子传递到寄主植物细胞中。从基因组组织水平和水平基因流水平，到病原体毒力蛋白与其宿主靶点之间的相互作用水平，该致病菌属为分析宿主和病原体的共同进化提供了一套极好的基因组和遗传工具。利用III型分泌系统的动物病原体包括沙门氏菌、耶尔森氏菌、志贺氏菌和致病性大肠杆菌。因此，这项研究的结果将为这些细菌及其动物宿主（包括人类）的进化和机制研究提供信息。第一期经费用于快速鉴定丁香假单胞菌III型效应基因及其产物的方法。主要目标已经完成，并促进了针对特定III型效应（毒力）因子家族的其他生物学研究。在这一竞争更新中，建议继续使用功能基因组学和高通量下一代基因组测序来剖析丁香假单胞菌的毒力机制和进化。此外，这一建议提供了可信的证据，比较基因组学和分子进化方法可用于鉴定新的候选毒力基因。

DESCRIPTION (provided by applicant): Pathogenic bacteria use various virulence mechanisms to infect hosts, including humans. Comparative studies based on genome sequencing of multiple pathogenic strains have suggested that bacterial species possess a pan-genome that is much larger than the genome of any single bacterium. This research focuses on the interaction between Pseudomonas syringae and plants. P. syringae delivers virulence factors called type III effector proteins into host plant cells using an evolutionarily conserved type III secretion system. This genus of pathogenic bacteria provides an excellent set of genomic and genetic tools to analyze co-evolution of host and pathogen, from the level of genome organization and horizontal gene flow down to the level of the interaction between pathogen virulence proteins and their host targets. Animal pathogens that utilize the type III secretion system include Salmonella spp., Yersinia spp., Shigella spp. and pathogenic E. coli. Thus, the results from this research will inform evolutionary and mechanistic studies of these bacteria and their animal hosts, including humans. The first grant period was devoted to methods for rapidly identifying P. syringae type III effector genes and their products. The main goals were completed and additional biological studies focused on particular type III effector (virulence) factor families was facilitated. In this competitive renewal, it is proposed to continue to use functional genomics and high throughput next generation genome sequencing to dissect both the mechanisms and evolution of virulence in P. syringae. In addition, this proposal presents plausible evidence that comparative genomics and molecular evolutionary methods can be used to identify novel candidate virulence genes. Our ultimate goal is to identify the pan genome of P. syringae and characterize both type III effectors and novel virulence factors across this pan-genome. This goal will provide both methods and data that will inform similar studies of human bacterial pathogens that continue to kill and sicken millions each year around the world. Project Narrative: Pathogenic bacteria use various virulence mechanisms to infect hosts, including humans. Bacterial pathogens cause a variety of human diseases and kill millions of people each year around the world. Bacterial disease of plants is also important, and they lead to loss of crops with values of several billion dollars worldwide each year. Crop loss further therefore directly adds to threats to human health, particularly in developing countries where the disease pressure from both bacterial pathogens of humans and of plants converge. Loss of crops is also tied to human health because those lost crops used precious water before they were infected and rendered useless as food or fodder. Thus, crop loss impacts human health by impacting water use efficiency in human populations. Plant pathogens like the one that is the focus of this proposal and animal pathogens including Salmonella spp., Yersinia spp., Shigella spp. and pathogenic E. coli all use a similar mechanism to infect their hosts. Thus, the results from this research will inform evolutionary and mechanistic studies of these bacteria and their animal hosts, including humans.