Fig. 5. CPK3 is required for immunity to Pst DC3000-AvrPphB. a CPK3 kinase function is required for disease resistance to Pst DC3000 and Pst DC3000-AvrPphB.

Four-week-old plants were dip-inoculated with Pst DC3000 strains [3 × 10⁷ CFU mL⁻¹]. Images were taken at 4 dpi. Three representative leaves are shown from n ≥ 30. All experiments were performed three times, with similar results. b In planta bacterial growth was enumerated at 4 days post-inoculation (dpi). Error bars represent means ± SD from three technical replicates of three independent biological repeats (n = 9, one-way ANOVA; p < 0.05; ns, not significant). c The CPK3 mutant, cpk3-2, is specifically compromised in the activation of the Pst DC3000-AvrPphB-induced hypersensitive response (HR). Leaves from 4-week-old plants were infiltrated with Pst DC3000-AvrPphB [10⁷ colony-forming units (CFU mL⁻¹)] using a 1-mL needleless syringe. Images were taken at 24 h post-inoculation (hpi). CPK6 and CPK28 mutants show WT levels of HR induction following Pst DC3000-AvrPphB inoculation. d CPK3 kinase function is required for HR to Pst DC3000-AvrPphB. Four-week-old plants were infiltrated with Pst DC3000 strains [10⁷ CFU mL⁻¹] using a 1-mL needleless syringe.