Summary Cover crop integration into grain crop rotations is a promising strategy for mitigating nematode‐induced diseases in agriculture. However, the precise mechanisms underlying this phenomenon remain elusive. Here, we first assessed the impact of five commonly used cover crops on the suppression of rice root‐knot nematodes (RKNs). We then chose ryegrass as a model to explore the mechanistic basis of the suppression effect. Contrary to expectations, while ryegrass rotation significantly enhances soil fertility, this increased fertility has minimal impact on RKN suppression. Furthermore, neither integrated ryegrass residues nor root exudates exhibit direct toxicity towards RKNs. We demonstrated that ryegrass rotation primarily suppresses RKNs by enriching beneficial soil microbiota. By complementing with isolated bacteria strains, we further demonstrated that ryegrass‐enriched bacteria not only directly reduce RKN infectivity and preference, but also activate plant immunity via the OsLRR‐RLK‐MAPK‐WRKY‐JA cascade, thereby diminishing RKN infection. Our study highlights the crucial role of soil microbiota in plant–nematode interactions, challenging conventional views on the direct effects of cover crops in nematode suppression. It offers a mechanistic understanding of the regulation potential and action modes of cover crops in mitigating nematode diseases, providing valuable insights for sustainable agriculture.

中文翻译：

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覆盖作物轮作通过塑造土壤微生物群来抑制根结线虫感染


总结 将覆盖作物纳入粮食作物轮作是减轻农业中线虫诱发疾病的一种有前途的策略。然而，这种现象背后的确切机制仍然难以捉摸。在这里，我们首先评估了五种常用覆盖作物对抑制水稻根结线虫 （RKN） 的影响。然后，我们选择黑麦草作为模型来探索抑制效应的机理基础。与预期相反，虽然黑麦草轮作显著提高了土壤肥力，但这种肥力的增加对 RKN 抑制的影响很小。此外，整合的黑麦草残留物和根系分泌物均不对 RKN 表现出直接毒性。我们证明，黑麦草轮作主要通过丰富有益的土壤微生物群来抑制 RKN。通过与分离的细菌菌株互补，我们进一步证明富含黑麦草的细菌不仅直接降低 RKN 的感染性和偏好性，而且还通过 OsLRR-RLK-MAPK-WRKY-JA 级联反应激活植物免疫，从而减少 RKN 感染。我们的研究强调了土壤微生物群在植物-线虫相互作用中的关键作用，挑战了关于覆盖作物对线虫抑制的直接影响的传统观点。它提供了对覆盖作物在减轻线虫病害方面的调节潜力和作用模式的机制理解，为可持续农业提供了有价值的见解。