Figure 5.

Protective effect of Xcc OMVs against bacterial infection. A, OMVs protect Arabidopsis seedlings from Xcc infection. OMVs from Xcc 8004 were extracted as indicated above. Arabidopsis Col-0, rem1.2 1.3c, Ler, and fk-X224 seedlings were incubated with 10 µg·mL⁻¹ Xcc OMVs or PBS (control) for 24 h prior to flooding inoculation with 20 mL of 10⁷ CFU·mL⁻¹ Xcc 8004 bacterial suspension. Seedlings were sampled at 3 DPI and the bacterial population was quantified by serial dilution plating on NYG plates (three plants were pooled as a single technical replicate, N ≥ 9 replicates/treatment). Statistical differences between treatments were determined by one-way ANOVA using GraphPad Prism 8.0 (ns, not significant, *P ≤ 0.05; **P ≤ 0.01, ***P ≤ 0.001). OMV-induced protection of cell damage from pathogen infection is dependent on Remorin and sterol balance (bars, 1 cm). B, Arabidopsis leaf discs of WT ecotypes (Col-0, Ler), remorin double mutant (rem1.2 1.3c), sterol biosynthesis mutant (fk-X224 – Ler background) were incubated with Xcc OMV (30 µg·mL⁻¹) for 24 h, then infiltrated with Xcc 8004. Xcc hrcC⁻ was infiltrated into Col-0 leaf discs as the negative control. AUC of conductivity increase was calculated by GraphPad Prism 8.0 and statistical differences between treatments were determined by one-way ANOVA (ns, not significant, *P ≤ 0.05; **P ≤ 0.01, ***P ≤ 0.001, ****P ≤ 0.0001). C, Ion leakage measurement from Arabidopsis Col-0 leaf discs incubated with OMVs (30 µg·mL⁻¹), MβCD (2 mM), or a combination of both (MβCD +OMV) prior to vacuum infiltration with Xcc 8004 (WT). The Xcc hrcC^- mutant was used as the negative control. Statistical differences between treatments were determined by one-way ANOVA (ns, not significant, *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ****P < 0.0001).