Figure 3.

Additive effect of PthAs on bacterial growth in planta. Leaves of sweet orange and lemon plants were infiltrated with bacterial suspensions (10⁶ cells/mL) and the growth of wild‐type Xanthomonas citri (WT) and respective pthA‐deletion mutants (Δ) was monitored at 2 and 14 days after bacterial inoculation. The double (Δ1‐4 and Δ3‐4) and triple (Δ1‐3‐4) pthA‐deletion mutants grew significantly less well than the respective single mutants and the WT bacteria in all the citrus hosts tested, suggesting an additive effect of PthAs on bacterial growth in planta. Bacterial growth, expressed in colony‐forming units (CFU)/cm² of leaf, is the mean of three biological replicates. The error bars denote standard deviations, whereas the asterisks above the bars indicate statistically significant differences between X. citri and mutant‐inoculated plants (P < 0.05).