Construction and physiological analysis of a Xanthomonas mutant to examine the role of the oxyR gene in oxidant-induced protection against peroxide killing.
We constructed and characterized a Xanthomonas campestris pv. phaseoli oxyR mutant. The mutant was hypersensitive to H2O2 and menadione killing and had reduced aerobic plating efficiency. The oxidants' induction of the catalase and ahpC genes was also abolished in the mutant. Analysis of the adaptive responses showed that hydrogen peroxide-induced protection against hydrogen peroxide was lost, while menadione-induced protection against hydrogen peroxide was retained in the oxyR mutant. These results show that X. campestris pv. phaseoli oxyR is essential to peroxide adaptation and revealed the existence of a novel superoxide-inducible peroxide protection system that is independent of OxyR.
Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand.
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S
Mongkolsuk
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R
Sukchawalit
S
S
Loprasert
W
W
Praituan
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A
Upaichit
D000332:Aerobiosis; D001426:Bacterial Proteins / Q000235:genetics; D002374:Catalase / Q000096:biosynthesis; D004268:DNA-Binding Proteins; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007700:Kinetics; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000096:biosynthesis; D010544:Peroxidases; D054464:Peroxiredoxins; D010957:Plasmids; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D014812:Vitamin K / Q000494:pharmacology*; D016959:Xanthomonas campestris / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D016877:Oxidants; D012097:Repressor Proteins; D014157:Transcription Factors; D014812:Vitamin K; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D010544:Peroxidases; D054464:Peroxiredoxins; D002374:Catalase; D013482:Superoxide Dismutase