A Natural Coniferylaldehyde-Derived Inhibitor of Phytoviral Intercellular Traffic via Targeting Capsid Protein Residue THR155

Phytoviruses depend on intercellular movement to implement systemic infection, which is controlled by several biological macromolecules from pathogens and hosts. Strategically interrupting this process holds promise for plant protection, while few traffic inhibitors are being discovered. In this study, natural coniferylaldehyde is implemented to lead optimization involving dithioacetal modification for virucide discovery. Derivative <b>L2</b> is screened to show excellent inactivating properties against Potato virus Y (PVY) with a half-maximal effective concentration (EC₅₀) of 128.10 μg/mL lower than those of ribavirin (223.08 μg/mL) and vanisulfane (286.13 μg/mL). Combining molecular docking, molecular dynamics simulation, and biolayer interferometry techniques allows <i>in vitro</i> verification of residue threonine 155 (T¹⁵⁵) on PVY coat protein (CP) as the potential targeting site for <b>L2</b> binding. <i>In vivo</i>, <b>L2</b> treatment and T155A-mutation significantly decrease viral pathogenicity in <i>Nicotiana benthamiana</i>. Confocal observation reveals the potential function of T¹⁵⁵ is engaged in viral movement between host cells. The study contributes a brand-new lead structure and targeting site for discovering traffic inhibitors.