Kith and kin in amoeba-bacteria cooperation

了解微生物之间的合作至关重要。病原微生物有时会以对我们有害的方式合作。组成我们肠道微生物群的细菌可以以有益于我们的方式进行合作。微生物既可以与自己物种的成员合作，也可以与其他物种合作。这个项目将展示物种内部和物种之间的合作实际上是如何密切相关的。首先，这两个过程经常协同工作。微生物种群之间的合作是它们与更大的宿主有机体合作所必需的。这项研究将使用一个简单、可理解的模型系统来检验恩惠亲戚如何影响与主人的合作。许多伯克霍尔德氏菌寄生在阿米巴宿主体内，既有有益的影响，也有有害的影响。这项研究将展示细菌的合作能力，特别是亲属之间的合作能力，如何影响宿主的生存和繁殖。物种内合作和物种间合作的理论有相似之处。研究人员将为一个更统一的理论构建数学模型，这将允许对一种类型的合作的见解应用于另一种类型。最后，这项研究将在实验室中将微生物伙伴放在一起，通过实验进化来观察随着时间的推移发生了什么变化，从而检验这些理论。这项工作的结果将解释远远超出细菌-阿米巴系统的微生物相互作用，对医学和农业具有潜在的见解。研究人员将开发主动学习模块，允许学生操纵微生物相互作用的模型并看到结果。他们还将制作将广泛使用的教育短片。合作发生在物种内部和物种之间，但这两个领域是完全分开研究的。这项研究将通过三种方式将这些研究传统联系起来，通过研究阿米巴-细菌互惠关系中亲缘选择的重要性，通过开发在形式上类似于亲缘选择模型的互惠关系的亲缘选择模型，以及通过将这些模型应用于阿米巴-细菌互惠关系。首先，研究人员将研究种内亲缘选择在种间共生--阿米巴-细菌原始养殖系统中的重要性。他们将调查细菌的亲缘关系，它们的亲缘识别，以及这些因素对宿主适应性的影响。其次，他们将模拟未被研究的物种选择方面，在这些方面，合作者支付直接的适应度成本，但可以通过从其他物种获得的间接收益来补偿，通过形式上类似于遗传关联的回归系数来建模。最后，研究人员将在阿米巴-细菌互惠关系中进化出不同相互作用环境下的参与者，以应用和测试模型。他们将确定直接选择、合作伙伴的间接选择及其相互作用的相对作用。这一理论将有助于统一不同的思想流派，经验方法将被移植到许多其他系统。此外，调查人员将开发关于他们研究主题的教育模块，将涉及本科生和K12学生，并向公众展示。他们还将促进教授的多样化，提供关于学术成功战略的信息文章。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding cooperation among microbes is vital. Pathogenic microbes sometimes cooperate in ways that harm us. The bacteria comprising our gut microbiome can cooperate in ways that benefit us. Microbes can cooperate both with members of their own species and with other species. This project will show how within- and between species cooperation are actually closely related. First, the two processes often work together. Cooperation among microbial populations is required for them to cooperate with a larger host organism. This study will examine how favoring relatives affects cooperation with their host by using a simple, understandable model system. Many Burkholderia bacteria inhabit an amoeba host, conferring both helpful and harmful effects. The study will show how the ability of bacteria to cooperate, especially among relatives, affects host survival and reproduction. There are similarities between the theories of within- and between-species cooperation. The investigators will construct mathematical models for a more unified theory that will allow insights about one type of cooperation to be applied to the other type. Finally, this study will test these theories by putting the microbial partners together in the lab to see what changes occur over time using experimental evolution. The results of this work will explain microbial interactions far beyond this bacteria-amoeba system, with potential insights for medicine and agriculture. The investigators will develop active learning modules that allow students to manipulate models of microbial interactions and see the consequences. They will also produce short educational videos that will be widely available.Cooperation occurs both within and between species, but these two realms have been studied rather separately. This study will bridge these research traditions in three ways, by studying the importance of kin selection in an amoeba-bacteria mutualism, by developing kith selection models of mutualism that are formally similar to kin selection models, and by applying those models to an amoeba-bacteria mutualism. First, the investigators will study the importance of within-species kin selection in a between-species symbiosis, the amoeba-bacteria proto-farming system. They will investigate relatedness of the bacteria, their kin recognition, and the effects of these on host fitness. Second, they will model understudied aspects of kith selection in which cooperators pay a direct fitness cost but can be compensated by an indirect benefit from the other species, modeled by a regression coefficient that is formally similar to genetic relatedness. Finally, the investigators will evolve the participants under different interaction circumstances in the amoeba-bacteria mutualism to apply and test the models. They will determine the relative roles of direct selection, indirect selection due to partners, and their interaction. The theory will help unify disparate schools of thought and the empirical methods will be transferable to many other systems. Furthermore, the investigators will develop educational modules on the topic of their research, will involve undergraduates, and K12 students, and make presentations to the public. They also will facilitate diversification of the professoriate with informative pieces on academic success strategies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.