Fig 5. QS responders restrict the fitness of QS mutants in Xcc during late stage of infection.
In planta competition assay indicating a significantly compromised survival fitness of QS mutants (QS-) in presence of QS responders (QS+) of Xcc at late stage of infection, where (A) Representative CLSM pictures for (i) Single infection (with the panels of merged images of green and red fluorescence), and (ii) Mixed infections (i.e. co-inoculation; with the panels of gfp, mCherry and gfp-mCherry merged images from left to right respectively); indicating the cell densities of QS + and QS- cells of Xcc 8004/gfp, Xcc ΔrpfF/mCherry and Xcc ΔrpfC/mCherry bioreporter strains spanning transverse sections of leaf vascular regions on dpi 1, 6 and 12 (from top to bottom). Images were prepared using FIJI (image J) software. Scale bars on each panel, 5 μm. (B) Quantification of QS + and QS- bacterial populations for single and mixed infections per cm2 proximal regions of inoculated leaves on dpi 1, 6 and 12. (C) Quantification of percentage survival of QS + and QS- bacterial populations for mixed infection per cm2 proximal region of inoculated leaves on dpi 1, 6 and 12. WT; wild-type Xcc 8004, ΔF; Xcc ΔrpfF, and ΔC; Xcc ΔrpfC. The bacterial population size observed was normalized; values are expressed per cm2 leaf region. Bacterial fluorescence and quantification were analysed from CLSM images using FIJI (image J) software. The characteristics of the total region of the leaf observed on each sampling day were slightly different. Data analysis was done by taking six different sites from three infected leaves as samples for each combination at a time with the experimental repeat of at least thrice and represented with Mean ± SD. P-values for significant difference level were determined by performing student’s T-test (two tailed, paired). ***; p < 0.001.