Application of fatty acids as antiviral agents against tobacco mosaic virus.

Numerous studies reported fatty acids (FAs) affecting basal resistance to bacterial and fungal pathogens in plants, but limited reports focused on antiviral agents. In this study, oleic acid was separated from cottonseed oil sludge by antiviral bioassay-guided methods. Antiviral activity of FAs was compared with that of Ningnanmycin. Subsequently, effects of FAs on defense-related enzymes (PAL, POD) and defense-related genes (PR-1a, PR-5) were studied. FAs presented moderate antiviral activity, which is close to that of Ningnanmycin, and activities of PAL and POD were higher in oleic-acid-treated tobacco leaves than those inoculated with tobacco mosaic virus (TMV) and water-treated tobacco. In oleic-acid-treated tobacco, expression levels of PR-1a and PR-5 genes rapidly increased from days 1-3. All results showed that FAs can increase resistance against TMV, and related mechanism can be attributed to activated expressions of a number of defense-related genes, suggesting that FAs can potentially act as pesticides for integrated control of plant viruses in the future.