Advances in next-generation sequencing have enabled the widespread measurement of microbiome composition across systems and over the course of microbiome assembly. Despite substantial progress in understanding the deterministic drivers of community composition, the role of historical contingency remains poorly understood. The establishment of new species in a community can depend on the order and/or timing of their arrival, a phenomenon known as a priority effect. Here, we review the mechanisms of priority effects and evidence for their importance in microbial communities inhabiting a range of environments, including the mammalian gut, the plant phyllosphere and rhizosphere, soil, freshwaters and oceans. We describe approaches for the direct testing and prediction of priority effects in complex microbial communities and illustrate these with re-analysis of publicly available plant and animal microbiome datasets. Finally, we discuss the shared principles that emerge across study systems, focusing on eco-evolutionary dynamics and the importance of scale. Overall, we argue that predicting when and how current community state impacts the success of newly arriving microbial taxa is crucial for the management of microbiomes to sustain ecological function and host health. We conclude by discussing outstanding conceptual and practical challenges that are faced when measuring priority effects in microbiomes.

新一代测序技术的进步使得能够在整个系统和微生物组组装过程中广泛测量微生物组的组成。尽管在理解社区组成的确定性驱动因素方面取得了实质性进展，但对历史偶然性的作用仍然知之甚少。社区中新物种的建立可能取决于它们到达的顺序和/或时间，这种现象称为优先效应。在这里，我们回顾了优先效应的机制以及它们在栖息在哺乳动物肠道、植物叶际和根际、土壤、淡水和海洋等一系列环境中的微生物群落中的重要性的证据。我们描述了在复杂微生物群落中直接测试和预测优先效应的方法，并通过对公开可用的植物和动物微生物组数据集的重新分析来说明这些方法。最后，我们讨论了跨研究系统出现的共同原则，重点关注生态进化动力学和规模的重要性。总体而言，我们认为预测当前的社区状态何时以及如何影响新到达的微生物类群的成功对于微生物组管理以维持生态功能和宿主健康至关重要。最后，我们讨论了在测量微生物组中的优先效应时面临的突出的概念和实践挑战。关注生态进化动态和规模的重要性。总体而言，我们认为预测当前的社区状态何时以及如何影响新到达的微生物类群的成功对于微生物组管理以维持生态功能和宿主健康至关重要。最后，我们讨论了在测量微生物组中的优先效应时面临的突出的概念和实践挑战。关注生态进化动态和规模的重要性。总体而言，我们认为预测当前的社区状态何时以及如何影响新到达的微生物类群的成功对于微生物组管理以维持生态功能和宿主健康至关重要。最后，我们讨论了在测量微生物组中的优先效应时面临的突出的概念和实践挑战。