The association between plants and arbuscular mycorrhizal fungi (AMF) affects plant performance and ecosystem functioning. Recent studies have identified AMF-associated bacteria as cooperative partners that participate in AMF–plant symbiosis: specific endobacteria live inside AMF, and hyphospheric bacteria colonize the soil that surrounds the extraradical hyphae. In this Review, we describe the concept of a plant–AMF–bacterium continuum, summarize current advances and provide perspectives on soil microbiology. First, we review the top-down carbon flow and the bottom-up mineral flow (especially phosphorus and nitrogen) in this continuum, as well as how AMF–bacteria interactions influence the biogeochemical cycling of nutrients (for example, carbon, phosphorus and nitrogen). Second, we discuss how AMF interact with hyphospheric bacteria or endobacteria to regulate nutrient exchange between plants and AMF, and the possible molecular mechanisms that underpin this continuum. Finally, we explore future prospects for studies on the hyphosphere to facilitate the utilization of AMF and hyphospheric bacteria in sustainable agriculture.

植物与丛枝菌根真菌 （AMF） 之间的关联会影响植物的性能和生态系统功能。最近的研究已经确定 AMF 相关细菌是参与 AMF-植物共生的合作伙伴：特定的内细菌生活在 AMF 内部，菌丝球细菌定植在根外菌丝周围的土壤中。在这篇综述中，我们描述了植物-AMF-细菌连续体的概念，总结了当前的进展并提供了土壤微生物学的观点。首先，我们回顾了这个连续体中自上而下的碳流和自下而上的矿物流（尤其是磷和氮），以及 AMF-细菌相互作用如何影响营养物质（例如碳、磷和氮）的生物地球化学循环。其次，我们讨论了 AMF 如何与菌圈细菌或内生菌相互作用以调节植物与 AMF 之间的营养交换，以及支撑这一连续体的可能分子机制。最后，我们探讨了 Hyphosphere 研究的未来前景，以促进 AMF 和Hyphospheric Bacteria在可持续农业中的利用。