The Ubiquitin-Proteasome System Plays Dual Roles in Plant Antiviral Defense and Viral Pathogenicity.

The ubiquitin-proteasome system (UPS) constitutes a highly conserved regulatory hub governing protein turnover and signal transduction in eukaryotes, which precisely determines the fate of substrate proteins via dynamic and reversible ubiquitination. During long-term coevolution between plants and viruses, the UPS has evolved into a critical battlefield for host-virus arms races. Plants exploit the substrate recognition specificity and proteolytic activity of the UPS to selectively eliminate essential viral proteins required for infection, thereby establishing multilayered antiviral immune barriers. In contrast, viruses have evolved diverse effector proteins to antagonize or hijack this pathway to facilitate their replication and spread. Competitive exploitation of this shared regulatory machinery underlies the fundamental logic of bidirectional regulation in plant-virus interactions. This review systematically summarizes the molecular basis of UPS-mediated plant antiviral immunity, as well as convergent pathogenic strategies adopted by diverse viruses to perturb ubiquitin signaling, suppress host immune responses, and reprogram the intracellular environment. The work aims to provide theoretical insights for deciphering viral pathogenesis and breeding crops with durable virus resistance.