Antiviral Activity of TiO₂ NPs against Tobacco Mosaic Virus in Chili Pepper (Capsicum annuum L.)

Tobacco mosaic virus is the etiological agent of one of the most critical diseases limiting chili pepper production. Various practices have been used to manage the disease, e.g., the use of resistant varieties and interference with the vector through chemical control. However, these practices are not helpful once the virus has been established in the plant. There is still no effective method for the sustainable management of the disease; therefore, exploring new options is required. Currently, some studies have reported the activity of TiO2 NPs against viruses in plants, although not against TMV in chili pepper. The present work aims to determine a possible direct action of TiO2 NPs against TMV and if there is a relationship between the amount of virus and symptoms. The application of TiO2 NPs at 150 μg/mL in infected pepper plants reduced symptoms and viral load and improved the morphological characteristics compared to the control. Incubation of 150 µg/mL TiO2 NPs with the virus for 6 and 8 h before infection decreased viral concentration significantly after infection compared to the control. In this work, it is reported, for the first time, that the use of TiO2 NPs is a novel practice for the control of TMV in chili pepper.