Figure 7. Trehalose or ammonium nitrate does not suppress the Arabidopsis flg22-mediated defense response and does not make Arabidopsis more susceptible to non-pathogenic P. syringae strains.

(A) Growth of P. syringae pv. tomato strain DC3000 three days post infiltration of Col-0 plants pretreated for 24 hours with 1 µM flg22, 1 mM trehalose, 1 mM ammonium nitrate individually or with a mixture of flg22 with trehalose or ammonium nitrate. (B) P. syringae pv. tomato strain DC3000 hrcC or (C) P. syringae pv. phaseolicola strain 3121 were co-inoculated with 1 mM trehalose or 1 mM ammonium nitrate and bacterial counts determined 3 days post infiltration. Glucose or glucose plus ammonium nitrate were included as controls. Data represent the mean of bacterial titers ± SE of six leaf disks excised from 6 leaves of 3 plants. Letters above bars denote statistically significant differences (P<0.05, Fisher's PLSD test). Absence of letters indicates no statistically significant differences. The experiments were repeated at least two times.