Figure 1. Agroinfiltration of N. tabacum leaves prior to P. syringae infection reduces macroscopic symptoms and P. syringae growth.

A. N. tabacum leaves were infiltrated with 10 mM MgCl₂(AS) (MgCl₂) or A. tumefaciens GV3101 (AtGV3101) at 10⁷ cfu/ml. P. syringae pv. tabaci 11528 (Pta) and P. s. pv. tomato DC3000 (Pto) were infiltrated 48 hours later at 10⁷ cfu/ml. Images show infiltrated areas from representative leaves photographed 24 hours after inoculation with Pta and Pto at 10⁷ cfu/ml, (top panels) or 6 days after inoculation with Pta at 10⁵ cfu/ml (bottom panels). B. N. tabacum leaves were inoculated with 10 mM MgCl₂(AS) or AtGV3101 as described in A, followed 48 hours later by inoculation with P. syringae at 10⁵ cfu/ml. Population densities of P. syringae were estimated at 0, 3, 5 and 11 days after inoculation by dilution plating of homogenised leaf extracts onto selective media. CFU, colony forming units; MgCl₂-Pta, Pta population density after MgCl₂(AS) treatment; MgCl₂-Pto, Pto population density after MgCl₂(AS) treatment; At-Pta, Pta population density after AtGV3101 treatment; At-Pto, Pto population density after AtGV3101 treatment. Data shown is the average of three replicates. Error bars show standard deviation. General Linear Model (GLM) analysis revealed statistical differences between treatments (F = 56.4244; p<0.0001; df = 15). Means with the same letter were not significantly different at the 5% confidence level based on Tukey's Honestly Significant Mean Differences (HSD) Test. The experiment was performed twice with similar results.