Editor: Wolfgang Schumann
Challenging Xanthomonas campestris with low levels of arsenic mediates cross-protection against oxidant killing
Article first published online: 18 JUL 2006
FEMS Microbiology Letters
Volume 262, Issue 1, pages 121–127, September 2006
How to Cite
Hrimpeng, K., Prapagdee, B., Banjerdkij, P., Vattanaviboon, P., Dubbs, J. M. and Mongkolsuk, S. (2006), Challenging Xanthomonas campestris with low levels of arsenic mediates cross-protection against oxidant killing. FEMS Microbiology Letters, 262: 121–127. doi: 10.1111/j.1574-6968.2006.00383.x
- Issue published online: 18 JUL 2006
- Article first published online: 18 JUL 2006
- Received 2 April 2006; revised 26 June 2006; accepted 27 June 2006.First published online 18 July 2006.
- organic hydroperoxide;
Xanthomonas encounters highly toxic reactive oxygen species (ROS) from many sources, such as those generated by plants against invading bacteria, other soil bacteria and from aerobic respiration. Thus, conditions that alter intracellular ROS levels such as exposure to toxic metalloids would have profound effects on bacterial physiology. Here, we report that exposure of Xanthomonas campestris pv. phaseoli (Xp) to low levels of arsenic induces physiological cross-protection against killing by H2O2 and organic hydroperoxide but not a superoxide generator. Cross-protection against H2O2 and organic hydroperoxide toxicity was due to increased expression of genes encoding major peroxide-metabolizing enzymes such as alkyl hydroperoxide reductase (AhpC), catalase (KatA) and organic hydroperoxide resistance protein (Ohr). Arsenic-induced protection against H2O2 and organic hydroperoxide requires the peroxide stress response regulators, OxyR and OhrR, respectively. Moreover, analyses of double mutants of the major H2O2 and organic hyproperoxide-scavenging enzymes, Xp ahpC katA and Xp ahpC ohr, respectively, suggested the existence of unidentified OxyR- and OhrR-regulated genes that are involved in arsenic-induced resistance to H2O2 and organic hyproperoxide killing in Xp. These arsenic-induced physiological alterations could play an important role in bacterial survival both in the soil environment and during plant–pathogen interactions.