Fig 3.

Expression analysis of soxR. (A) soxR transcript levels in the X. campestris pv. campestris wild-type strain were determined under uninducing (UN) conditions or following induction with 100 μM H₂O₂, CHP, PQ, or MD using endpoint RT-PCR. (B) soxR transcript levels in X. campestris pv. campestris wild-type, soxR mutant, and soxR/pSoxR strains cultivated under UN conditions or following MD induction were determined by using endpoint RT-PCR. (C) A gel retardation assay was conducted by using purified SoxR protein and a ³²P-labeled 285-bp soxR promoter fragment. CP and UD represent the cold probe and unrelated DNA, respectively. F and B indicate the free and bound probes, respectively.