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. 2017 Feb 15;7:42724. doi: 10.1038/srep42724

Figure 7. HpaM homologues in Xoo and Xoc are critical for virulence and HR induction.

Figure 7

Bacterial cells were cultured in NB medium and resuspended in sterile distilled water to a concentration of OD600 of 0.3 (for virulence assay) or 0.5 (for HR assay). For virulence test, the bacterial resuspensions were inoculated onto 6-week-old leaves of rice plant (Oryza sativa L. ssp. Japonica cultivar Nipponbare) by the leaf-clipping method (for Xoo) or by infiltrating with needleless syringe (for Xoc). For HR induction, the bacterial resuspensions were infiltrated into tobacco (Nicotina benthamiana) leaf mesophyll tissue. (A) Xoo strains; (B) Xoc strains. (a) Disease symptoms 14 days after inoculation; (b) lesion lengths scored 14 days after inoculation. Values represent means and standard deviation from twenty inoculated leaves in one experiment. The experiment was repeated three times with similar results. (c) HR symptoms photographed at 24, 36 and 48 h after infiltration. The hrcC deletion mutant strains ΔhrcCXoo (derivative of Xoo) and ΔhrcCXoc (derivative of Xoc) were used as negative controls. Three replications were done in each experiment and the experiment was repeated three times. The results presented are from a representative experiment, and similar results were obtained in all other independent experiments. (d) Electrolyte leakage from tobacco leaves inoculated with Xoo or Xoc strains. For each sample, four 0.4 cm2 leaf disks were collected from the bacteria-inoculated area and incubated in 5 ml distilled water. Conductivity was measured with a DDS-307A conductometer. Three samples were taken for each measurement in each experiment. Results presented are from a representative experiment, and similar results were obtained in two other independent experiments.