Fig 1. HopZ3 promotes the growth of PsyB728a on PTO-containing tomato plants (PtoR) and suppresses defenses triggered by AvrPto1_Psy.

Plants were spray inoculated with PsyB728a-derived strains at an OD₆₀₀ = 0.01 and total (epiphytic + endophytic) or epiphytic bacterial populations were quantified in 8 leaf discs or leaf disc washes, respectively. (A) Total bacterial populations of PsyB728a and PsyΔHopZ3 were different in PtoR but were not statistically different in pto11 and prf-3 plants after 4 days (n = 8, t-test *P<0.05). (B) HopZ3 (Z3), but not the catalytic mutant (Z3_C300A) complements the low growth phenotype of PsyΔHopZ3 in PtoR tomato. (C-D) Deletion of AvrPto1_Psy (ΔA1) from PsyΔHopZ3 (ΔZ3) restores total (C) and epiphytic (D) bacterial growth to WT (PsyB728a or PsyB728a/vector) levels in PtoR tomato. (E) Deletion of AvrPto1_Psy from WT PsyB728a does not affect bacterial growth in PtoR tomato. (F) AvrPto1_Psy does not confer resistance in pto11 plants, regardless of the presence of HopZ3. For (B,D,E) epiphytic bacteria were collected by leaf disc washes five (B) or four (D-E) days after inoculation. Different letters indicate significant differences in growth as assessed by ANOVA with Tukey’s test (P<0.0002) or Fisher’s test P<0.0001, n = 8). For C and F, total bacteria were quantified 3 days after spray inoculation. Different letters indicate significant differences in growth (n = 8, ANOVA with Tukey’s test, P<0.05). All experiments were repeated at least twice with similar results. Bars indicate standard errors.