FIG 2.
T408A RNA editing modulates bacterial responses to iron concentrations. (a) Growth curve of X. oryzae pv. oryzicola T408A, T408silent, and WT in NB medium. Strains were grown in quadruplicate to mid-exponential phase, diluted to an OD600 of 0.1, transferred to fresh NB, and monitored for growth in a Bioscreen C apparatus at 28°C. Growth in NB supplemented with 50 μM (b), 100 μM (c), and 150 μM (d) DP. Error intervals (shaded regions bordering each line) indicate mean ± SE of four replicates. The F test was used to compare growth of the T408A and WT strains with T408silent; asterisks (* and **) indicate significance at P < 0.05 and 0.01, respectively. (e) Iron content in X. oryzae pv. oryzicola T408A, T408silent, and WT strains. Bacterial cells were cultured in NB, NB + 50 μM DP, or NB + 100 μM FeCl3. The iron content in X. oryzae pv. oryzicola was measured with inductively coupled plasma spectroscopy (ICP-OES). (f) Survival rates of X. oryzae pv. oryzicola T408A, T408silent, and WT strains exposed to streptonigrin. Strains were grown to mid-log phase (OD600 = 0.5) in NB or NB + DP and treated with 1 μg/ml streptonigrin for 24 h. Survival was assessed by colony counts from 10-fold serial dilutions. Error bars in panels e and f represent standard deviations (n = 3). Asterisks (* and **) indicate significant differences between the T408A or WT strains with T408silent (control) at P < 0.05 and 0.01, respectively (Student's t test).