Figure 4.

Root exudates from Arabidopsis mutants with distinct flavonoids exudation pattern affected P. xenovorans LB400 early colonization and were diversely exploited by the bacterium for growth. (A) Early colonization was measured via re-isolation of strain LB400 from Arabidopsis roots after 1 h of incubation. The graph reported the average and standard deviation values of three independent replicates for all the assayed Arabidopsis genotypes. Statistical analysis was performed using Dunn’s post-hoc test, and letters indicate statistically different groups (p ≤ 0.05). (B) Strain LB400 growth on root exudates collected from WT Arabidopsis and flavonoid metabolic mutant lines at day 7 of treatment under control conditions (plants exposed to acetone, the solvent used to dissolve PCB-18) or PCB stress induced by the treatment with 70 µM PCB-18. NC indicates 1/2 MS medium containing only acetone or 70 µM PCB-18, without plants, and was used as axenic control. Strain LB400 was inoculated at a concentration of 5 × 10⁴ cells/mL and grown for 3 days before re-isolation. The bars represent the average and standard deviation values of three independent experiments. Statistical analysis was performed using Dunn’s post-hoc test and letters indicate statistically different groups (p ≤ 0.05).