Feng Hui, Liu Tianli, Wan Chuanxu, Zhang Zhichao, Wang Yuanchao, Zheng Xiaobo, Wang Jie, Ye Wenwu
Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China.
Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China.
PLoS Pathog. 2025 Jul 31;21(7):e1013379. doi: 10.1371/journal.ppat.1013379. eCollection 2025 Jul.
Ribosome biogenesis is an essential and tightly regulated process linked to cell proliferation and growth. However, its regulatory mechanisms in oomycetes, a group of organisms with significant agricultural and ecological importance, remain unclear. In this study, we identify Puf4, a non-classical PUF (Pumilio and FBF) family RNA-binding protein that plays a conserved and crucial role in pre-rRNA processing in oomycetes. Knockout of PuPuf4 in Pythium ultimum or its ortholog PsPuf4 in Phytophthora sojae results in defective vegetative growth, impaired development, and reduced pathogenicity. Specifically, PuPuf4 binds to the H68 component of 25S rRNA, and its knockout leads to overaccumulation of rRNA processing intermediates, including 5'ETS, ITS1, and ITS2 precursors. Additionally, the AG-rich motif identified as the first binding motif of L-shaped PUF proteins, including PuPuf4, APUM24, and ScPuf6, may contribute to their specific RNA-binding affinity due to its unique structural features. Given the conserved role of Puf4 in oomycete pathogenicity, we developed the first nano-material-free dsRNA delivery system via zoospore-specific uptake, effectively attenuating virulence in Pythium aphanidermatum and Ph. sojae through RNAi targeting Puf4. This study presents novel findings on structural and functional conservation of Puf4 and offers a promising RNAi-based strategy for controlling oomycete plant diseases.
核糖体生物合成是一个与细胞增殖和生长相关的基本且受到严格调控的过程。然而，在卵菌纲（一类具有重要农业和生态意义的生物）中其调控机制仍不清楚。在本研究中，我们鉴定出Puf4，一种非经典的PUF（Pumilio和FBF）家族RNA结合蛋白，它在卵菌纲的前体rRNA加工中发挥着保守且关键的作用。在终极腐霉中敲除Puf4或在大豆疫霉中敲除其直系同源物PsPuf4会导致营养生长缺陷、发育受损和致病性降低。具体而言，PuPuf4与25S rRNA的H68组分结合，其敲除会导致rRNA加工中间体的过度积累，包括5'ETS、ITS1和ITS2前体。此外，被鉴定为L形PUF蛋白（包括PuPuf4、APUM24和ScPuf6）首个结合基序的富含AG的基序，由于其独特的结构特征，可能有助于它们的特异性RNA结合亲和力。鉴于Puf4在卵菌纲致病性中的保守作用，我们通过游动孢子特异性摄取开发了首个无纳米材料的dsRNA递送系统，通过靶向Puf4的RNA干扰有效地减弱了瓜果腐霉和大豆疫霉的毒力。本研究提出了关于Puf4结构和功能保守性的新发现，并为控制卵菌纲植物病害提供了一种有前景的基于RNA干扰的策略。
