Figure 6.

Cell death and hypersensitive response (HR) observation in non‐host plant tobacco and host plant cabbage leaves. Purified proline iminopeptidase (PIP) protein (A) and PIP^S106A protein (B) were injected into non‐host leaves and led to cell death symptoms after 2 days. Left halves: phosphate‐buffered saline (PBS) treatment as the negative control; right halves: different concentrations of PIP protein (A) or PIP^S106A protein (B) treatment for cell death observation. From left to right: 1 mg/mL, 5 mg/mL and 10 mg/mL of protein. PIP protein (C) and PIP^S106A protein (D) could not induce cell death in cabbage leaves, and the protein inocula were the same as in (A) and (B). (E) HR assay of different bacterial strains with a bacterial titre of 10⁹ colony‐forming units (CFU)/mL in tobacco leaves. Mock: 10 mm MgCl₂ buffer. Scale bar, 1 cm.