State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.
New Phytol. 2024 Aug;243(3):1154-1171. doi: 10.1111/nph.19867. Epub 2024 Jun 1.
Cross-kingdom RNA interference (RNAi) is a crucial mechanism in host-pathogen interactions, with RNA-dependent RNA polymerase (RdRP) playing a vital role in signal amplification during RNAi. However, the role of pathogenic fungal RdRP in siRNAs generation and the regulation of plant-pathogen interactions remains elusive. Using deep sequencing, molecular, genetic, and biochemical approaches, this study revealed that VmRDR2 of Valsa mali regulates VmR2-siR1 to suppress the disease resistance-related gene MdLRP14 in apple. Both VmRDR1 and VmRDR2 are essential for the pathogenicity of V. mali in apple, with VmRDR2 mediating the generation of endogenous siRNAs, including an infection-related siRNA, VmR2-siR1. This siRNA specifically degrades the apple intracellular LRR-RI protein gene MdLRP14 in a sequence-specific manner, and overexpression of MdLRP14 enhances apple resistance against V. mali, which can be suppressed by VmR2-siR1. Conversely, MdLRP14 knockdown reduces resistance. In summary, this study demonstrates that VmRDR2 contributes to the generation of VmR2-siR1, which silences the host's intracellular LRR protein gene, thereby inhibiting host resistance. These findings offer novel insights into the fungi-mediated pathogenicity mechanism through RNAi.
跨物种 RNA 干扰 (RNAi) 是宿主-病原体相互作用中的一个关键机制，RNA 依赖性 RNA 聚合酶 (RdRP) 在 RNAi 过程中的信号放大中起着至关重要的作用。然而，病原真菌 RdRP 在 siRNA 的产生和植物-病原体相互作用的调控中的作用仍不清楚。本研究采用深度测序、分子、遗传和生化方法，揭示了苹果腐烂病菌 VmRDR2 调控 VmR2-siR1 抑制苹果抗病相关基因 MdLRP14 的表达。VmRDR1 和 VmRDR2 均对苹果腐烂病菌在苹果上的致病性至关重要，其中 VmRDR2 介导内源性 siRNA 的产生，包括一个与感染相关的 siRNA，VmR2-siR1。该 siRNA 以序列特异性方式特异性降解苹果细胞内 LRR-RI 蛋白基因 MdLRP14，过表达 MdLRP14 增强了苹果对腐烂病菌的抗性，而 VmR2-siR1 可以抑制这种抗性。相反，MdLRP14 的敲低则降低了抗性。总之，本研究表明 VmRDR2 有助于 VmR2-siR1 的产生，该 siRNA 沉默了宿主细胞内的 LRR 蛋白基因，从而抑制了宿主的抗性。这些发现为通过 RNAi 介导的真菌致病性机制提供了新的见解。
