Li Pai, Kelley Brittni, Li Zizhang, Proctor Bruce, Corrion Alex, Xie Xuan, Sheick Ryan, Lu Yi-Ju, Nomoto Mika, Wei Cheng-I, Tada Yasuomi, He Sheng-Yang, Xiao Shunyuan, Day Brad
bioRxiv. 2025 Aug 23:2025.04.29.651294. doi: 10.1101/2025.04.29.651294.
Remodeling of the actin cytoskeleton is a critical process for plant immunity, essential for the transport, activation, and stabilization of immune-regulatory molecules and organelles. In this process, actin depolymerization factors (ADFs) function as key players through severing and depolymerizing actin microfilaments. However, recent evidence suggests that ADFs may possess non-canonical immune functions inside the nucleus, in addition to the canonic cytosolic role, a phenomenon not adequately explained by the traditional mechanistic model of ADF-actin dynamics. In this study, we demonstrate that Arabidopsis ADFs exhibit a moonlighting function in the nucleus, where they interact with transcriptional machinery to regulate the transcriptome during both the resting state and the immune responses. We show that ADF2/3/4 have redundant functions in defense against virulent and avirulent . Notably, it is nuclear - rather than cytosolic - ADFs that contribute to defense against and mediate pro-immune transcription. Mechanistically, we demonstrate that nuclear ADFs interact with transcription factors, histone complexes, and other components of the transcriptional machinery. Specifically, ADF2/3/4 can form a complex with WRKY transcription factors, such as WRKY22/29/48, thereby directly regulating WRKY activity to shape the pro-immune transcriptome. In summary, our study reveals that ADFs moonlight as direct regulators of transcription factors, mediating a broad range of nuclear-cytoplasmic regulation in plant immunity and potentially other biological processes.
肌动蛋白细胞骨架的重塑是植物免疫的关键过程,对于免疫调节分子和细胞器的运输、激活及稳定至关重要。在这一过程中,肌动蛋白解聚因子(ADFs)通过切断和解聚肌动蛋白微丝发挥关键作用。然而,最近的证据表明,ADFs除了在传统的胞质作用外,可能在细胞核内具有非经典免疫功能,这一现象无法用ADF-肌动蛋白动力学的传统机制模型充分解释。在本研究中,我们证明拟南芥ADFs在细胞核中展现出兼职功能,在静息状态和免疫反应期间,它们与转录机制相互作用以调节转录组。我们发现ADF2/3/4在抵御毒性和无毒病原体方面具有冗余功能。值得注意的是,是细胞核而非胞质中的ADFs有助于抵御病原体并介导促免疫转录。从机制上讲,我们证明细胞核ADFs与转录因子、组蛋白复合物及转录机制的其他成分相互作用。具体而言,ADF2/3/4可与WRKY转录因子(如WRKY22/29/48)形成复合物,从而直接调节WRKY活性以塑造促免疫转录组。总之,我们的研究揭示ADFs作为转录因子的直接调节因子发挥兼职功能,介导植物免疫及潜在其他生物过程中的广泛核质调节。