Investigating mechanisms of specificity in a bioluminescent vertebrate-bacteria symbiosis

项目摘要 脊椎动物-细菌共生的特异性机制研究 尽管人们越来越认识到微生物组对人类健康和疾病的重要性， 关于共生细菌稳定地定殖于肠道所采用的分子机制知之甚少， 它们很难单独分开并进行实验研究。有几个既定的模式 用于探索支持共生关系的特定途径和过程的系统，然而， 没有一个代表脊椎动物宿主和单一细菌之间自然进化的二元共生关系 物种这项研究的一个主要的长期目标是建立生物发光共生 在珊瑚礁鱼（管形管鼻鱼）和弧菌科发光细菌之间， （发光杆菌mandapamensis）作为一种模式协会，以确定参与的机制， 调节肠道相关共生中的特异性和定殖。该项目的成果将 为脊椎动物宿主和有益细菌之间稳定相互作用的进化提供了新的见解 并且可以在模式宿主之间进行比较，以进一步定义动物-微生物基础的普遍原则 协会. 这个项目的总体目标是研究脊椎动物-细菌协会的特异性是如何 通过解决以下研究，从广泛的进化规模到分子水平， 目的：1）确定Siphamia-Photobacterium共生的特异性程度，2）表征 宿主光器官内的感染动力学和共生体竞争，以及3）确定关键 参与共生关系的建立和持续的机制。为此， 共生关系将首先在宿主鱼类属的所有23个物种中广泛定义，然后在广泛的 地理分布单一的寄主种，S tubifer。S.曼达巴木 然后将在文化中进行测试，以确定它是否受当地环境和 生态因素或在分子水平上保守。接下来，物种内共生体多样性将是 通过实验测试，以更好地了解宿主内的菌株竞争和感染动力学。最后， 调节共生关系的遗传机制将通过比较宿主和 在整个感染过程中共生体基因的表达。总的来说，这项研究将揭示的过程， 调节脊椎动物宿主和有益动物之间特定联系的建立和维持 细菌跨越多个时间尺度，并在这样做，将提供更大的研究社区与一个新的 二进制脊椎动物-细菌模型系统，以加深我们对这些重要的相互作用的理解。

Project Summary Investigating mechanisms of specificity in a vertebrate-bacteria symbiosis Despite an increased awareness of the importance of the microbiome to human health and disease, relatively little is known about the molecular mechanisms employed by symbiotic bacteria to stably colonize the gut, as they are difficult to disentangle and experimentally study in isolation. There are several established model systems used to explore specific pathways and processes underpinning symbiotic associations, however, none represent a naturally evolved, binary symbiosis between a vertebrate host and a single bacterial species. A major, long-term objective of this study is to establish the bioluminescent symbiosis between a coral reef fish (Siphamia tubifer) and a luminous bacterium in the Vibrio family, (Photobacterium mandapamensis) as a model association to define the mechanisms involved in regulating specificity and colonization in a gut-associated symbiosis. The results of this project will provide new insights on the evolution of stable interactions between vertebrate hosts and beneficial bacteria and can be compared across model hosts to further define the universal principals underlying animal-microbe associations. The overall objective of this project is to investigate how the specificity of vertebrate-bacteria associations is maintained from a broad evolutionary scale down to the molecular level by addressing the following research aims: 1) Define the degree of specificity of the Siphamia–Photobacterium symbiosis, 2) Characterize the infection dynamics and symbiont competition within a host light organ, and 3) Identify key mechanisms involved in the establishment and persistence of the symbiosis. To do so, the specificity of the symbiosis will first be broadly defined across all 23 species in the host fish genus, then across the broad geographic distribution of a single host species, S tubifer. The specificity of the S. tubifer-P. mandapamensis association will then be tested in culture to determine whether it is regulated by local environmental and ecological factors or conserved at a more molecular level. Next, the intra-species symbiont diversity will be experimentally tested to better understand strain competition and infection dynamics within a host. Finally, the genetic mechanisms involved in regulating the symbiosis will be determined by comparing both host and symbiont gene expression throughout the infection process. Overall this study will reveal the processes that regulate the establishment and maintenance of specific associations between vertebrate hosts and beneficial bacteria across multiple timescales, and in doing so, will provide the greater research community with a novel binary vertebrate-bacteria model system with which to deepen our understanding of these vital interactions.