The ToBRFV Movement Protein Promotes Infection by Targeting Host Catalases to Disrupt ROS Homeostasis and Serves as an Effective Target for RNAi-Based Nanocarrier Control

Tomato brown rugose fruit virus (ToBRFV) is an emerging pathogen that overcomes tomato resistance genes, threatening global production. How ToBRFV achieves such high virulence and how hosts defend themselves remain unclear. Here, we report that the ToBRFV movement protein (MP) acts as a master virulence effector, directly binding host catalase SiCAT2 via specific molecular interfaces (MP: ASP194/GLU95; SiCAT2: GLN96/PRO98) to inhibit its activity and disrupt redox homeostasis, thereby promoting infection. We further discover that the host counteracts this by deploying the apoplastic subtilisin protease SiSBT5, which degrades MP in a serine protease-dependent manner, revealing an extracellular layer of antiviral immunity. Notably, MP is delivered to this battleground via extracellular vesicles, illustrating a novel pathogen transmission and host defense route. Furthermore, ToBRFV-induced ROS attracts whiteflies, potentially facilitating viral spread. Translating these insights, we develop a biodegradable nanoparticle spray (CQAS-dsMP) that silences MP, effectively controlling ToBRFV. Our work elucidates a multi-layered molecular arms race and provides a sustainable solution against this devastating virus.