Fungal pathogens are seriously threatening food security and natural ecosystems; efficient and environmentally friendly control methods are essential to help safeguard such resources for increasing human populations on a global scale. Here, we find that Sclerotinia sclerotiorum, a widespread pathogen of dicotyledons, can grow endophytically in wheat, rice, barley, maize, and oat, providing protection against Fusarium head blight, stripe rust, and rice blast. Protection is also provided by disabled S. sclerotiorum strains harboring a hypovirulence virus. The disabled strain DT-8 promoted wheat yields by 4–18% in the field and consistently reduced Fusarium disease by 40–60% across multiple field trials. We term the host-dependent trophism of S. sclerotiorum, destructively pathogenic or mutualistically endophytic, as schizotrophism. As a biotroph, S. sclerotiorum modified the expression of wheat genes involved in disease resistance and photosynthesis and increased the level of IAA. Our study shows that a broad-spectrum pathogen of one group of plants may be employed as a biocontrol agent in a different group of plants where they can be utilized as beneficial microorganisms while avoiding the risk of in-field release of pathogens. Our study also raises provocative questions about the potential role of schizotrophic endophytes in natural ecosystems.

真菌病原体严重威胁粮食安全和自然生态系统；高效和环境友好的控制方法对于帮助保护此类资源以应对全球范围内不断增加的人口至关重要。在这里，我们发现核盘菌（Sclerotinia sclerotiorum ）是双子叶植物中广泛分布的病原体，可以在小麦、水稻、大麦、玉米和燕麦中内生生长，从而提供针对镰刀菌赤霉病、条锈病和稻瘟病的保护。携带低毒力病毒的失效的核盘菌菌株也能提供保护。在多项田间试验中，失效菌株 DT-8 使小麦田间产量提高了 4-18%，并持续将镰刀菌病害减少了 40-60%。我们将核盘菌的宿主依赖性营养性、破坏性致病性或互利内生性称为分裂营养性。作为一种活体营养生物，核盘菌改变了小麦抗病和光合作用基因的表达，并提高了 IAA 的水平。我们的研究表明，一组植物的广谱病原体可以用作另一组植物的生物防治剂，它们可以用作有益微生物，同时避免病原体在田间释放的风险。我们的研究还提出了关于分裂营养型内生菌在自然生态系统中的潜在作用的挑衅性问题。