FIGURE 6.

Induction of systemic resistance by B. pumulis INR7 and benzothiadiazol and population change by BTH treatment in tobacco under field conditions. (A) Induction of plant resistance against a compatible P. syringae pv. tabaci. Disease severity was measured 21 days after infilteration of P. syringae pv. tabaci at 10⁶ cfu/ml in plants pretreated with bacterial suspension of strain INR7 (INR7), 0.5 mM BTH (BTH), and the combination (INR7 + BTH). Bars represent the mean ± SE (sample size, N = 40 replications per treatment). Different letters indicate significant differences between treatments (P = 0.05 according to least significant difference). (B) Endophytic population dynamics of B. pumilus INR7 with and without 0.5 mM BTH treatment. Bacterial populations of spontaneous rifampicin resistant B. pumilus INR7 were quantified at the day of application on pepper roots and 0, 7, 21, and 42 days after the application. Bars represent mean ± SEM.