FIG 6.

The HR of the T3SS mutants of MS2 and strain JZL7 on Nicotiana tabacum K326 (A, C, and E) and N. benthamiana (B and D) after 12 and 24 hpi. Bacterial cultures (OD₆₀₀ of 1.0 in LS5 medium) were dipped by a puncher (5 mm), pressed on the back of tobacco leaves, and incubated at 28°C. The area of HR lesions was measured using Image J 1.52a after 12 and 24 h. **, P < 0.001; ***, P < 0.0001; ****, P < 0.0001; ns, not significant (Student’s t test, n = 3 independent experiments). (E) Quantitative determination of the T3SS functions in hypersensitive response indicated that the threshold of 10⁶ CFU of MS2 elicits HR at 12 h.