Summary Rice false smut disease, caused by the fungal pathogen Ustilaginoidea virens, significantly restricts both the production and quality of rice grains. However, the molecular mechanism underlying rice resistance against U. virens remain largely elusive. Transcriptome analysis of rice panicles infected with U. virens revealing the crucial role of genes involved in sakuranetin biosynthesis in conferring resistance to the pathogen. In vitro assays demonstrated that sakuranetin was most effective at inhibiting mycelial growth, spore germination, and host infection by U. virens. The expression of OsNOMT, the key enzyme in sakuranetin biosynthesis, is directly regulated by the transcription factor OsWRKY67. Furthermore, OsMPK6, a mitogen‐activated protein kinase, interacts with and phosphorylates OsWRKY67, thereby modulating sakuranetin biosynthesis and resistance to U. virens. Moreover, the exogenous application of synthetic sakuranetin significantly reduces U. virens infection. Our findings reveal that the OsMPK6‐OsWRKY67‐OsNOMT signaling cascade plays a pivotal role in rice resistance to U. virens by regulating sakuranetin biosynthesis.

中文翻译：

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OsMPK6‐OsWRKY67‐OsNOMT 级联调控的樱花素的生物合成增强了对假黑穗病的抵抗力


摘要 由真菌病原体 Ustilaginoidea virens 引起的水稻假黑穗病严重限制了稻米粒的生产和质量。然而，水稻对 U. virens 抗性的分子机制在很大程度上仍然难以捉摸。感染 U. virens 的水稻穗的转录组分析揭示了参与樱花素生物合成的基因在赋予对病原体的抗性方面的关键作用。体外试验表明，樱花素在抑制菌丝生长、孢子萌发和蚜虫宿主感染方面最有效。樱花素生物合成中的关键酶 OsNOMT 的表达受转录因子 OsWRKY67 的直接调控。此外，OsMPK6 是一种丝裂原活化蛋白激酶，与 OsWRKY67 相互作用并磷酸化 OsWRKY67，从而调节樱花素的生物合成和对 U. virens 的抗性。此外，合成樱花素的外源应用显着减少了 U. virens 感染。我们的研究结果表明，OsMPK6-OsWRKY67-OsNOMT 信号级联反应通过调节樱花素的生物合成在水稻对 U. virens 的抗性中起关键作用。