FIG 2 .

(A) Quantification of root colonization by B. subtilis and various mutants 4 h postinoculation. One-week-old A. thaliana seedlings were coincubated with either WT or mutant B. subtilis strains in MSNg. After 4 h of incubation, the roots were collected, measured, washed in PBS, and sonicated to disperse the bacteria. CFU were evaluated after overnight culture on LB agar. For each strain, the bar represents the mean and standard deviation of four biological replicates. (B) Protection of A. thaliana against P. syringae pv. tomato DC3000 conferred by WT B. subtilis or a chemotaxis mutant. Three-week-old A. thaliana Col-0 plants were rhizo-inoculated with a mock control, WT NCIB3610 B. subtilis, or a cheA mutant and infiltrated with strain DC3000. After 72 h of infection, strain DC3000 growth in leaves was quantified by CFU counts. For each strain, the bar represents the mean and standard deviation of at least nine biological replicates. Bars marked with an asterisk indicate a significant difference from the WT result.