Actin Depolymerization Factors (ADFs) Moonlighting: Nuclear Immune Regulation by Interacting with WRKY Transcription Factors and Shaping the Transcriptome

Li, P.; Kelley, B.; Li, Z.; Procter, B.; Corrion, A.; Xie, X.; Sheick, R.; Lu, Y.-j.; Nomoto, M.; Wei, C.-i.; Tada, Y.; He, S.-Y.; Xiao, S.; Day, B.

doi:10.1101/2025.04.29.651294

bioRxiv · 10.1101/2025.04.29.651294

Actin Depolymerization Factors (ADFs) Moonlighting: Nuclear Immune Regulation by Interacting with WRKY Transcription Factors and Shaping the Transcriptome

Li, P.·Kelley, B.·Li, Z.·Procter, B.·Corrion, A.·Xie, X.·Sheick, R.·Lu, Y.-j.·Nomoto, M.·Wei, C.-i.·Tada, Y.·He, S.-Y.·Xiao, S.·Day, B.

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Abstract

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 Pseudomonas syringae. Notably, it is nuclear - rather than cytosolic - ADFs that contribute to defense against P. syringae 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.

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Li, P., Kelley, B., Li, Z., Procter, B., Corrion, A., Xie, X., Sheick, R., Lu, Y.-j., Nomoto, M., Wei, C.-i., Tada, Y., He, S.-Y., Xiao, S., Day, B.. 2025-04-30. Actin Depolymerization Factors (ADFs) Moonlighting: Nuclear Immune Regulation by Interacting with WRKY Transcription Factors and Shaping the Transcriptome. https://doi.org/10.1101/2025.04.29.651294

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