Well-conserved mitogen-activated protein kinase (MAPK) cascades are essential for orchestrating of a wide range of cellular processes in plants, including defense responses against pathogen attack. NAC transcription factors play important roles in plant immunity, but their targets and how they are regulated remain largely unknown. Here, we identified the transcription factor OsNAC29 as a key component of a MAPK signaling pathway involved in rice (Oryza sativa) disease resistance. OsNAC29 binds directly to CACGTG motifs in the promoters of OsTPS28 and OsCYP71Z2, which are crucial for the biosynthesis of the phytoalexin 5,10-diketo-casbene and consequently rice blast resistance. OsNAC29 positively regulates rice blast resistance by promoting the expression of of OsTPS28 and OsCYP71Z2, and the function of OsNAC29 is genetically dependent on OsCYP71Z2 and OsTPS28. Furthermore, OsNAC29 interacts with OsRACK1A and OsMAPK3/6 to form an immune complex; OsMAPK3 phosphorylates OsNAC29 at Thr304 to prevent its proteasome-mediated degradation and promote its function against rice blast fungus. Phosphorylation of OsNAC29 at Thr304 is induced upon Magnaporthe oryzae infection and chitin treatment. Our data demonstrate the positive role of the OsMAPK3–OsNAC29–OsTPS28/OsCYP71Z2 module in rice blast resistance, providing insights into the molecular regulatory network and fine-tuning of NAC transcription factors in rice immunity.

中文翻译：

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OsMAPK3 磷酸化转录因子 OsNAC29 激活二萜类基因以促进水稻免疫


保守的丝裂原活化蛋白激酶 （MAPK） 级联反应对于协调植物中的各种细胞过程至关重要，包括对病原体攻击的防御反应。NAC 转录因子在植物免疫中起着重要作用，但其靶标及其调节方式在很大程度上仍是未知数。在这里，我们确定转录因子 OsNAC29 是参与水稻 （Oryza sativa） 病害抗性的 MAPK 信号通路的关键组分。OsNAC29 直接与 OsTPS28 和 OsCYP71Z2 启动子中的 CACGTG 基序结合，这对植物抗毒素 5,10-二酮基-卡斯本的生物合成至关重要，因此对稻瘟病抗性至关重要。OsNAC29 通过促进 OsTPS28 和 OsCYP71Z2 的表达正向调节稻瘟病抗性，OsNAC29 的功能在遗传上依赖于 OsCYP71Z2 和 OsTPS28。此外，OsNAC29 与 OsRACK1A 和 OsMAPK3/6 相互作用形成免疫复合物;OsMAPK3 在 Thr304 位点磷酸化 OsNAC29 以防止其蛋白酶体介导的降解并促进其对抗稻瘟病菌的功能。在米病菌感染和几丁质处理后诱导 OsNAC29 在 Thr304 位点的磷酸化。我们的数据证明了 OsMAPK3–OsNAC29–OsTPS28/OsCYP71Z2 模块在稻瘟病抗性中的积极作用，为水稻免疫中 NAC 转录因子的分子调控网络和微调提供了见解。