Plant-Derived Anti-TMV Metabolites: Mechanisms, Limitations and Future Perspectives

Tobacco mosaic virus (TMV) poses a serious threat to global agricultural production. It is an exceptionally stable virus with a broad host range and is widespread across diverse agroecosystems. Concerning TMV management, plant-derived metabolites have emerged as promising and eco-friendly antiviral agents. To date, numerous plant-derived metabolites with potent anti-TMV activity and their underlying mechanisms of action have been identified. However, a comprehensive understanding of their mechanisms of action is still lacking. This review summarizes the diversity of anti-TMV mechanisms triggered by natural and plant-sourced semisynthetic compounds. These metabolites mainly include alkaloids, flavonoids, terpenoids, phenylpropanoids, and glycosides, which act either directly targeting virus particles or indirectly by eliciting host immunity. Together, these mechanisms form an integrated defence network that restricts viral replication and movement within the host. This mechanistic understanding will be essential for the rational development of sustainable and effective plant-derived antiviral agents.