Tomatoes are one of the most important vegetables thanks to their taste attributes and nutritional value. Their
cultivation is threatened by various pathogens including viruses. The application of resistance inducers (RI), such as benzo(1,2,3)-
thiadiazole-7-carbothioic acid S-methyl ester (BTH) may be used to enhance plant performance against viruses. Here we aimed to
compare the impact of BTH and its choline derivative (Chol-BTH) on resistance induction and antioxidant properties of healthy
plants and tomato mosaic virus (ToMV)-infected ones. The response of tomato plants to treatment with BTH or Chol-BTH was
manifested by increased expression of not only pathogenesis-related (PR) genes but also WRKY and Jasmonate Zim-domain protein
(JAZ) genes and increased jasmonic acid (JA) levels. The effect of BTH as a resistance inducer was observed early after application,
while with Chol-BTH the plant defense system reacted more strongly after 8 days. The antioxidant properties of RI-treated tomatoes
are related to both glutathione content and peroxidase activity. In the case of BTH, an increase in these activities occurred early after
application, while in the case of Chol-BTH, the glutathione level was particularly high in the plant early after treatment, and high
peroxidase activity was observed 8 days post-treatment. Overall, the collected results indicate that Chol-BTH, due to its
physicochemical parameters (e.g., good solubility) and biological activity (increased expression of lignification-related genes,
supported by increases in peroxidase activity and total phenolic compounds levels), can also be a very useful agent inducing tomato
resistance against viral pathogens.