FEMS Microbiology Letters (2006) 262, 121-127

Karnjana Hrimpeng, Benjaphorn Prapagdee, Peerakan Banjerdkij, Paiboon Vattanaviboon, James M. Dubbs and Skorn Mongkolsuk (2006)
Challenging Xanthomonas campestris with low levels of arsenic mediates cross-protection against oxidant killing
FEMS Microbiology Letters 262 (1), 121-127
Abstract: 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.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Xanthomonas phaseoli