Microbial evolution along the parasitism-mutualism continuum

动物和植物拥有多种微生物群落，包括有害（寄生）和有益（共生）的物种。然而，这些作用不是固定的，可能取决于存在哪些其他物种。微生物存在于寄生和共生之间，但我们还不知道是什么驱使一些微生物寄生而另一些微生物共生。至关重要的是，我们不知道宿主内的微生物相互作用如何与宿主之间的传播结合起来，从而推动寄生-共生连续体的选择。我的研究项目的首要长期目标是发展和测试新的理论，以理解微生物是如何以及为什么进化成寄生或共生的。在接下来的五年里，我的团队将解决三个短期目标：(1)从理论上确定宿主内部和宿主之间的过程如何驱动微生物中寄生和互惠性状的进化；(2)对微生物共同进化如何改变群落和群落层面的寄生和共生关系进行理论预测；(3)预测宿主体内特定微生物群落的进化，并与实验室科学家合作，利用已建立的进化实验对这些预测进行测试。我们将开发数学模型，以捕获跨尺度（宿主内部和宿主之间）的微生物相互作用，并分析微生物特征（如毒力、传播性和宿主保护（共同））如何进化。这种方法将使我们能够描述宿主内和宿主间尺度对寄生和互惠性状选择的影响。然后，我们将通过与实验室科学家合作，通过实验进化微小蠕虫中的细菌来测试我们的模型预测。我们的研究是理解宿主-微生物进化生态学的关键，为进化生物学家提供了新的理论框架和可测试的预测。了解微生物沿着寄生-共生连续体的进化也对未来治疗传染病具有重要意义。例如，已知健康人类供体的微生物群落移植是治疗某些抗微生物药物耐药性感染的有效方法。随着对微生物（co）群落进化的基本过程的重要见解，我们将更好地安全地、有目的地操纵我们体内的这些群落，为各种传染病创造新的治疗选择。

Animals and plants host diverse microbial communities consisting of both harmful (parasitic) and beneficial (mutualistic) species. However, these roles are not fixed and may depend on which other species are present. Microbes exist along a continuum between parasitism and mutualism, but we do not yet know what drives some to be parasitic and others to be mutualistic. Crucially, we do not know how microbial interactions within a host combine with transmission between hosts to drive selection along the parasitism-mutualism continuum. The overarching long-term goal of my research program is to develop and test novel theory to understand how and why microbes evolve to be parasitic or mutualistic. Over the next five years, my team will address three short-term objectives: (1) theoretically determine how within- and between-host processes drive the evolution of parasitic and mutualistic traits in a microbe; (2) develop theoretical predictions for how microbial coevolution shifts constituent- and community-level parasitism and mutualism; and (3) predict evolution in specific microbial communities inside a host and test these predictions in collaboration with lab scientists using established evolution experiments. We will develop mathematical models that capture microbial interactions across scales (within- and between-host) and analyse how microbial traits such as virulence, transmissibility, and host protection (co-)evolve. This approach will allow us to delineate the impact of the within- and between-host scales on selection for parasitic and mutualistic traits. Then, we will test our modelling predictions by working with lab scientists to experimentally evolve bacteria in microscopic worms. Our research is key to understanding host-microbe evolutionary ecology, providing evolutionary biologists with novel theoretical frameworks and testable predictions. Understanding microbial evolution along the parasitism-mutualism continuum also has important implications for future therapeutics to treat infectious diseases. For example, transplantation of microbial communities from healthy human donors is known to be an effective treatment for certain antimicrobial resistant infections. With crucial insights into the fundamental processes of how microbes (co)evolve in communities, we will be better placed to manipulate these communities inside our bodies safely and purposefully to create new therapeutic options for a variety of infectious diseases.