A series of novel trans-ferulic acid derivatives containing a chalcone moiety were designed and synthesized to induce plant resistance. Antiviral activities of the compounds were evaluated. Bioassay results demonstrated that compounds F3, F6, F17, and F27 showed remarkable curative, protective, and inactivating activities against tobacco mosaic virus (TMV). With a 50% effective concentration (EC50) value of 98.78 μg mL-1, compound F27 exhibited the best protective activity compared with trans-ferulic acid (328.6 μg mL-1), dufulin (385.6 μg mL-1), and ningnanmycin (241.3 μg mL-1). This protective ability was associated with potentiation of defense-related enzyme activity and activation of photosynthesis of tobacco at an early stage. This notion was confirmed by up-regulated expression of stress responses and photosynthesis regulating proteins. This work revealed that F27 can induce resistance and enhance plant tolerance to TMV infection. Hence, F27 can be considered as a novel activator for inducing plant resistance.
Keywords: antiviral activity; chalcone; plant resistance; tobacco mosaic virus; trans-ferulic acid.