Figure 1.

YtrA is crucial for Xanthomonas citri ssp. citri (Xac) virulence and for induction of the hypersensitive response (HR). (A) Bacterial pathogenicity on citrus plant. Xac wild‐type, ytrA mutant (ΔytrA), complementation strain (ΔytrA/pTF53‐YtrA) and ytrA mutant expressing the empty vector (ΔytrA/pTF53) were infiltrated into citrus leaves at 10⁸ colony‐forming units (cfu)/mL. The leaves were photographed at 4 days post‐inoculation (dpi). (B) Bacterial population in the plant. Xac cells were recovered from the inoculated leaves at 0, 4 and 8 dpi, and the values are the means of three repeats. Means ± standard deviations are plotted. (C) HR induction on Nicotiana benthamiana. Xac strains were inoculated in tobacco [optical density at 600 nm (OD₆₀₀) = 0.8]. WT, wild‐type 306 with empty vector pUFR053; M, ytrA mutant with pUFR053; MC, ytrA mutant with complementary vector p53‐YtrA; MC‐X, ytrA mutant with p53‐HrpX; MC‐G, ytrA mutant with p53‐HrpG. (D) Detection of protein expression from strain containing pTF53‐YtrA in nutrient broth (NB) medium and in planta.