Plant health is strongly impacted by beneficial and pathogenic plant microbes, which are themselves structured by resource inputs. Organic fertilizer inputs may thus offer a means of steering soil-borne microbes, thereby affecting plant health. Concurrently, soil microbes are subject to top-down control by predators, particularly protists. However, little is known regarding the impact of microbiome predators on plant health-influencing microbes and the interactive links to plant health. Here, we aimed to decipher the importance of predator-prey interactions in influencing plant health. To achieve this goal, we investigated soil and root-associated microbiomes (bacteria, fungi and protists) over nine years of banana planting under conventional and organic fertilization regimes differing in Fusarium wilt disease incidence. We found that the reduced disease incidence and improved yield associated with organic fertilization could be best explained by higher abundances of protists and pathogen-suppressive bacteria (e.g. Bacillus spp.). The pathogen-suppressive actions of predatory protists and Bacillus spp. were mainly determined by their interactions that increased the relative abundance of secondary metabolite Q genes (e.g. nonribosomal peptide synthetase gene) within the microbiome. In a subsequent microcosm assay, we tested the interactions between predatory protists and pathogen-suppressive Bacillus spp. that showed strong improvements in plant defense. Our study shows how protistan predators stimulate disease-suppressive bacteria in the plant microbiome, ultimately enhancing plant health and yield. Thus, we suggest a new biological model useful for improving sustainable agricultural practices that is based on complex interactions between different domains of life.

植物健康受到有益和致病植物微生物的强烈影响，这些微生物本身是由资源投入构成的。因此，有机肥料投入可能提供一种控制土传微生物的方法，从而影响植物健康。同时，土壤微生物受到捕食者，特别是原生生物自上而下的控制。然而，关于微生物组捕食者对影响植物健康的微生物的影响以及与植物健康的交互联系知之甚少。在这里，我们的目的是破译捕食者与猎物相互作用对影响植物健康的重要性。为了实现这一目标，我们在九年的香蕉种植过程中，在不同镰刀菌枯萎病发病率的传统和有机施肥制度下，调查了土壤和根部相关微生物组（细菌、真菌和原生生物）。我们发现，与有机施肥相关的疾病发病率降低和产量提高可以最好地用原生生物和病原体抑制细菌（例如芽孢杆菌属）丰度来解释。捕食性原生生物和芽孢杆菌属的病原体抑制作用。主要是由它们的相互作用决定的，这些相互作用增加了微生物组内次级代谢物Q基因（例如非核糖体肽合成酶基因）的相对丰度。在随后的微观实验中，我们测试了捕食性原生生物和抑制病原体的芽孢杆菌之间的相互作用。这表明植物防御能力得到了显着改善。我们的研究表明原生生物捕食者如何刺激植物微生物组中的抑制疾病的细菌，最终提高植物的健康和产量。因此，我们提出了一种新的生物模型，可用于改善可持续农业实践，该模型基于不同生活领域之间的复杂相互作用。