Novel Roles of SoxR, a Transcriptional Regulator from Xanthomonas campestris, in Sensing Redox-Cycling Drugs and Regulating a Protective Gene That Have Overall Implications for Bacterial Stress Physiology and Virulence on a Host Plant

摘要

In Xanthomonas campestris pv. campestris, SoxR likely functions as a sensor of redox-cycling drugs and as a transcriptional regulator. Oxidized SoxR binds directly to its target site and activates the expression of xcc0300, a gene that has protective roles against the toxicity of redox-cycling compounds. In addition, SoxR acts as a noninducible repressor of its own expression. X. campestris pv. campestris requires SoxR both for protection against redox-cycling drugs and for full virulence on a host plant. The X. campestris model of the gene regulation and physiological roles of SoxR represents a novel variant of existing bacterial SoxR models.