Fig 4. Defense and ROS related gene expression in PPA-pretreated leaves infected with bacteria.

Nineteen-day-old leaves pretreated with 40 μM PPA (A and B) for 2 days and 100 μM BTH (B) for 3 days, then infiltrated with 10 mM MgSO₄, 0.3% acetone (solvent of BTH) and DG3 (OD₆₀₀ = 0.005) for 12 h. Total RNA was extracted for qRT-PCR. ACT2 (At3g18780) was used as an internal control. Gene expression values are presented relative to average MgSO₄ treated leaf levels (set as 1). Error bars represent the means ±SE from triplicate reactions in each experiment. Data sets marked with different letters indicate significant differences (P<0.05, PLSD-test). This experiment was repeated three times with similar results. The primers used for this analysis are provided in S3 Table.