Elucidating Molecular Mechanisms Underlying Cooperation in Animal-Bacterial Symbioses

项目摘要 大多数动物，如果不是全部，与细菌形成有益的共生关系，并与这些细菌接触 微生物的大部分时间。了解动物 与它们的共生体联系对人类健康很重要，因为我们维持着 有益的细菌在多个身体部位，如肠道和皮肤。虽然双方最终 从互惠互动中受益，宿主和共生体都需要维持机制， 他们可以确保他们的合作伙伴的合作，也称为“制裁”。在制裁 共生体是一种普遍的现象，由于数量庞大， 和多样性的微生物物种存在于许多相互作用和共生的可及性 主机内的接口。 拟议的工作将确定在两个不同的制裁分子的决定因素 模式系统：夏威夷短尾乌贼Euprymna sputteropes及其共生体弧菌 fischeri和蝾螈Taricha granulosa的皮肤微生物组。这两个协会都是 防御性互惠，其中共生体向宿主提供产品， 来逃避捕食我们还将利用这些系统的易处理性和可访问性 作为我们已经开发的技术，来回答有关 制裁。首先，我们将确定主机如何检测共生货币， 通过候选基因和无偏见的方法进行制裁。二是 通过确定哪些细胞来定义宿主制裁共生体的机制， 分子导致制裁以及它们如何影响细菌共生体。 总的来说，这项工作将确定允许动物宿主确保 通过它们的共生体生产有价值的共生货币，填补了我们 了解动物一生中如何维持互惠关系。

PROJECT SUMMARY Most, if not all, animals form beneficial symbioses with bacteria and live in contact with these microbes for the majority of their lives. Understanding the mechanisms by which animals associate with their symbionts is important to human health as we maintain consortia of benefical bacteria at multiple body sites such as the gut and skin. While both partners ultimately benefit from mutualistic interactions, hosts and symbionts both need to maintain mechanisms by which they can ensure cooperation by their partner, also called “sanctioning”. While sanctioning of symbionts is a widespread phenomenon, it can be difficult to study due to the large number and diversity of microbial species present in many interactions and the accessibility of symbiotic interfaces within the host. The proposed work will determine the molecular determinants of sanctioning in two different model systems: The Hawaiian Bobtail Squid Euprymna scolopes and its symbiont Vibrio fischeri, and the skin microbiome of the newt Taricha granulosa. Both of these associations are defensive mutualisms where the symbiont provides a product to the host that enables the host to escape predation. We will leverage the tractability and accessibility of these systems, as well as techniques that we have already developed, to answer crucial questions pertaining to sanctioning. First, we will determine how the host detects symbiotic currency, the first step in some sanctioning efforts, through candidate gene and unbiased approaches. Second, we will define the mechanisms by which hosts sanction symbionts by determining which cells and molecules lead to sanctioning and how they influence bacterial symbionts. Overall, this work will determine the molecular mechanisms that allow animal hosts to ensure the production of valuable symbiotic currency by their symbionts, filling a major gap in our understanding of how mutualistic associations are maintained over the life of an animal.