Figure 4. HopZ1a has a virulence function in zar1-1 Arabidopsis plants.

Pci0788-9 expressing the indicated construct was syringe infiltrated at 1×10⁵ cfu/mL into Arabidopsis Col-0 or zar1-1 leaves and bacterial counts were determined one hour post-infection (Day 0) and 3 days post-infection (Day 3). C/A indicates the C216A mutation of HopZ1a in the predicted catalytic triad and the mutant protein is expressed at a similar level to HopZ1a [39]. Two-tailed homoschedastic t-tests were performed to test for significant differences. Within a plant genotype, treatments were compared to empty vector and significant differences are indicated by an asterisk (* P<0.01). To compare between plant genotypes, growth of Pci0788-9 carrying HopZ1a, or HopZ1a^C216A (HopZ1a^C/A) was normalized to the average growth of Pci0788-9(Ev). Significant differences between zar1-1 and Col-0 are indicated by a triangle (▴ P<0.01). Error bars indicate the standard deviation from the mean of 10 samples. Growth assays were performed at least 3 times.