Figure 7. Volatiles produced by B. amyloliquefacians FZB42 and B. artrophaeus LSSC22 reduced the virulence of Ralstonia solanacearumand and induced systemic resistance.

%Wilted plants was calculated after 21 days of inoculation according to the Winstead formula. Five tobacco plants were inoculated at the three to four leaf stage by puncturing the stem at the third fully expanded leaf from the apex with the help of an inoculum-dipped needle. Then, 100 μl of the VOC-treated Rsc suspension was injected into each plant stem. In the control, plants were inoculated with sterile water, and in the non-treated group, plants were inoculated with a suspension of Rsc cells that were not exposed to VOCs. For the Petri plate experiment (B2), 5-6-day-old emerging tobacco seedlings inoculated with Rsc were transplanted into one compartment, bacterial strains were cultured in other compartment of I-plate. In the non-inoculated control, the roots were dipped in sterile water. Wilt symptoms were observed after 7 days of inoculation, and the data were recorded as described earlier. In B3, plastic pots, fixed on glass jars, having a Petri dish inoculated with FZB42, LSSC22 or sterilized water were used. All three pots were inoculated with a suspension of Rsc by the root dip method, except the non-inoculated control, and were kept in a growth chamber at 28/22 °C day/night temperature for a 16-h light/8-h dark photoperiod at 85% relative humidity. Error bars indicate standard deviations of the means. Different letters above error bars represent significant differences according to Duncan’s multiple-range test (P = 0.05) using SPSS software (SPSS, Chicago, IL).