4.5. Pseudomonas Syringae Infection Assay

The infection assay was conducted according to [43], using the strain P. syringae pv tomato DC3000. Arabidopsis plants were grown on half strength MS medium with 0.3% phytagel in a growth chamber at 24 °C with a 12 h light/12 h dark photoperiod for 2 weeks. P. syringae was cultured on King’s B medium, and for inoculation, the cells were suspended in 10 mM MgCl₂ at a concentration of 5 × 10⁵ CFU/mL. Arabidopsis seedlings were inoculated by flooding the plate with the P. syringae suspension until the seedlings were completely submerged in the inoculum. The P. syringae suspension was removed from the plates and the plates with the inoculated seedlings were put back into the growth chamber. One hour after the inoculation and at 3 dpi, 4 seedlings (only aerial parts) of each line were removed and surface sterilized with 5% H₂O₂ for 3 min and washed three times with sterile distilled water. The pooled sample of 4 seedlings was homogenized in 10 mL sterile distilled water using a mortar and pestle. Diluted samples were plated onto King’s B medium containing rifampicin (50 μg/mL) and colonies were counted after 24 h using proper diluted samples. Data were normalized as CFU/mg using the total weight of inoculated seedlings. Bacterial numbers were evaluated in three independent experiments.