Abstract: To test whether application of jasmonic acid (JA) to seeds influence the resistance of tobacco (Var.Yunyan87) to insects, the herbivore performance of Spodoptera litura, as well as the contents of JA and JA-Ile of the Yunyan87 plants were measured.The caterpillars feeding on the Yunyan 87 plants from JA-treated seeds gained 15% less weight than those grown on the control plants.After simulated S.litura larval feeding, JA and JA-Ile (a bioactive signal which can induce defenses to arthropod herbivores) accumulation was 41% and 42% higher in tobacco plants from JA-treated seeds, respectively.Meanwhile, several JA-Ile-dependent defensive metabolites including caffeoylputrescine, dicaffeoylspermidine, nicotine, diterpene glycosides, and the activities of trypsin proteinase inhibitors increased 60%, 79%, 19%, 29%, and 80%, respectively, in tobacco grown from JA-treated seeds.Importantly, the JA treatment to seeds did not influence the growth of plants:the dry weight of 6-week-old plants grown from the JA-treated seeds was not reduced.We conclude that application of JA to seeds increases tobacco resistance to S.litura, without reducing the yield.