Using a multi-host bacterial pathogen to understand host-specific adaptation and virulence

了解细菌病原体的宿主范围和毒力对我们预测和控制新出现和再出现的传染病的能力至关重要。对于已经进化出利用植物和动物的能力的多宿主病原体，了解其宿主范围和疾病策略对于评估其进化势头和出现潜力至关重要。这项工作将包括对Pantoea agglomerans的临床和植物致病分离株进行系统发育分析，以确定这些分离株是否密切相关或形成不同的进化群体。检测其在植物和动物宿主中的致病性将揭示其真正的宿主范围，以及植物分离株是否具有感染动物的能力。这将辅以遗传筛选，以确定动物特异性毒力因子，然后可用于确定特定菌株是否有可能成为动物致病性。多个聚团假单胞菌分离株的全基因组比较以及对所有分离株的毒力基因分布的分析将允许重建逐步进化事件，这些事件使这种细菌物种能够利用植物和动物宿主。作为一种具有遗传多样性的多宿主病原菌，团聚单胞菌不仅为研究宿主特异性毒力决定因素提供了独特的机会，而且还为研究宿主范围的扩大和缩小提供了进化动力。这项研究有可能从根本上改变我们对控制宿主特异性毒力和疾病的进化过程以及新感染因子出现的理解。

Understanding the host range and virulence of bacterial pathogens is central to our ability to predict and control emerging and reemerging infectious diseases. For multi-host pathogens, which have evolved the ability to exploit both plants and animals, knowledge of their host range and disease strategies is critical to assessing their evolutionary momentum and potential for emergence. This work will involve a phylogenetic analysis of clinical and plant pathogenic isolates of Pantoea agglomerans to determine whether these isolates are closely related or form distinct evolutionary groups. Testing their pathogenicity in both plant and animal hosts will reveal their true host range, and whether plant isolates have the capacity to infect animals. This will be complemented by genetic screening to identify animal-specific virulence factors, which can then be used to identify whether a specific strain has the potential to become animal-pathogenic. Whole-genome comparisons of multiple P. agglomerans isolates along with an analysis of virulence gene distribution across all isolates will permit the reconstruction of the stepwise evolutionary events that have allowed this bacterial species to exploit both plant and animal hosts. As a genetically diverse multi-host pathogen, P. agglomerans not only provides the unique opportunity to study host-specific virulence determinants, but also the evolutionary forces contributing to the expansion and retraction of host range. This research has the potential to fundamentally alter our understanding of the evolutionary processes that govern host-specific virulence and disease, and the emergence of new infectious agents.