(A) β-glucuronidase (GUS) activity in plants PR1p:GUS and rdr6 PR1p:GUS plants reporting PR1 transcriptional activity in WT and rdr6-15 mutant, respectively. (B) The transcript level of PR1 and ICS1 were detected by RT-qPCR. Error bars indicate standard deviation from technical repeats. Expression levels are normalized to the same internal controls At2g36060, At4g29130, and At5g13440. (C) Bacterial growth in five- to six-week-old plants from WT, single rdr6-15 and sid2-2 mutants or double rdr6-sid2 mutant infiltrated with Pto DC3000 (2×105 CFU mL−1). (D) Bacterial growth in five- to six-week-old plants from WT, simple rdr6-15 and npr1-1 mutants or double rdr6-npr1 mutant infiltrated with Pto DC3000 (2×105 CFU mL−1). (E) Bacterial growth in five- to six-week-old plants from WT, single (rdr6-15, rar1-21) or double mutant (rdr6-rar1) infiltrated with Pto DC3000 (2×105 CFU mL1). F) Bacterial growth in five- to six-week-old plants from WT, single (rdr6-15, rar1-21) or double mutant (rdr6-rar1) infiltrated with Pto DC3000 (AvrPphB) (2 105 CFU mL1). For C, D, E and F values are average ± se of four leaf discs (n = 8). Wilcoxon test was performed to determine the significant differences between rdr6 and double mutant plants. Asterisks “**” and “*” indicate statistically significant differences at a P value<0.01 and <0.05 respectively. Experiments were performed in two independent biological replicates with similar results.