Figure 6. DSF and OMV production are not affected by PrtA.

(a) Xylella fastidiosa biosensor strain showing significant increases (rpfC⁻ control) and decreases (rpfF⁻ control) in DSF relative to wild type Temecula1, but no significant changes in the prtA mutant. Response to DSF is measured via alkaline phosphatase activity of the hxfA’::phoA reporter gene fusion. All independent measurements were plotted (n = 7) and averages plus standard deviations are indicated. Groups significantly different to the wild type are indicated (*p-value < 0.05, **p-value < 0.01, ANOVA). (b) Quantification of number and size of outer membrane vesicles by nanoparticle tracking analysis isolated from wild type X. fastidiosa and mutant prtA, rpfC, and rpfF strains after five days growth in PD3 broth cultures. Plotted values are averages of 5 replicates after combining 5 independent cultures for each strain. This was repeated three times independently.