A perillaldehyde‐derived virucide targets phytoviral coat protein at Ser207 to impede intercellular spread

BACKGROUND Plant viruses rely on long‐distance transport to establish systemic infection within hosts, and cell‐to‐cell movement is often a prerequisite for vascular entry and subsequent systemic spread. Therefore, interference with virus movement represents an attractive antiviral strategy. Here, we report a series of perillaldehyde‐derived compounds bearing an α ‐aminophosphonate moiety, evaluate their anti‐phytoviral activities, and elucidate the mechanism of a representative lead. RESULTS A total of 38 target derivatives were designed and synthesized by introducing an aminophosphonate pharmacophore onto the perillaldehyde scaffold. Using the half‐leaf lesion assay, compound Y14 was identified as a potent inhibitor against Potato virus Y (PVY), exhibiting an inactivation half‐maximal effective concentration (EC 50 ) of 122.40 ± 9.34 μg mL −1 , outperforming the commercial antiviral dufulin (140.40 ± 6.75 μg mL −1 ) and ribavirin (238.90 ± 10.58 μg mL −1 ). Activity‐based protein profiling, molecular docking, microscale thermophoresis, together with immunoblotting and real‐time quantitative polymerase chain reaction (RT‐qPCR) analyses, collectively suggested that Ser207 in the PVY coat protein (CP) is a key residue for compound Y14 engagement. Notably, the CP S207A mutation markedly reduced the binding affinity of compound Y14 and attenuated PVY systemic infection in planta. Confocal imaging showed that the CP S207A recombinant PVY produced predominantly single‐cell fluorescence, indicating impaired cell‐to‐cell movement. The co‐immunoprecipitation results further suggested that this inhibition may arise from disrupted interaction with the host factor NtCPIP. CONCLUSION This study identifies compound Y14 as an antiviral lead that targets PVY CP and functionally compromises viral intercellular spread, thereby suppressing systemic infection. These findings provide a mechanistically distinctive chemical for PVY management.