Figure 3.

Expression profiles of the hrpG promoter in wild type R. solanacearum or virulence regulatory mutants in co-culture with Arabidopsis cells. The wt or the prhA, solR, xpsR, phcA, vsrA, vsrC, and pehR disruption mutants carrying the PhrpG::LuxCDABE fusion were grown in Gamborg medium in the presence of plant cells and luminescence measured at different time points (A). Zoom-in of hrpG expression during the first 3 h of co-culture with Arabidopsis cells to better appreciate that all mutants show comparable expression profiles as the wild type in the first induction peak during growth in the presence of plant cells (B). A representative result using three biological replicates is shown. Promoter output is presented as relative luminescence units (R.L.U) produced by the lux reporter corrected by cell density estimated by OD₆₀₀. Error bars indicate standard deviations.