Bacterial populations of nonhost pathogens Pseudomonas syringae pv. tabaci ( Psta ), Pseudomonas syringae pv. glycinea ( Psg ), Pseudomonas syringae pv. tomato T1 ( Pst T1) and Xanthomonas campestris pv. vesicatoria ( Xcv ) in Arabidopsis wild-type (Col-0), fls2 and sid2 mutants. Bacterial populations of Psta.(A), Psg (B), Pst T1 (C) and Xcv (D) were quantified at 0, 2 and 4 dpi. Vertical bars indicate the standard errors for three independent experiments. Asterisks indicate a significant difference from wild-type Col-0 in a t-test (* = p < 0.05, ** = p < 0.01).