Induction of terpenoids in cotton with and without Trichoderma virens seed treatment and inoculation with and without Verticillium dahliae.
Time is the incubation period between inoculation and tissue extraction.
Each number is the average from eight samples with standard deviation. Terpenoids were induced in both cultivars at all times tested after inoculation with V. dahliae . As expected, the levels of terpenoids were higher in the moderately resistant cultivar, Deltapine 50, than in the susceptible cultivar, Rowden, at all times tested. These results suggest that the reduction in Verticillium wilt found in plants treated with T. virens was caused by a mechanism other than an earlier induction of defense responses, at least as far as terpenoid phytoalexins are concerned. Further work is needed to determine whether other resistance pathways are induced.