ABSTRACT Common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans, is one of the most important diseases of common bean (Phaseolus vulgaris) in East Africa and other bean-growing regions. Xanthomonad-like bacteria associated with CBB in Malawi and Tanzania, East Africa, and in Wisconsin, U.S., were characterized based on brown pigm...

From Xanthomonas campestris pv. phaseoli, we have isolated by two independent methods genes involved in peroxide detoxification (ahpC and ahpF), a gene involved in peroxide sensing and transcription regulation (oxyR), and a gene of unknown function (orfX). Amino acid sequence analysis of AhpC, AhpF, and OxyR showed high identity with bacterial homologs. OrfX was a small cysteine-rich protein wi...

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, ...

An antibacterial metabolite extracted from Paenibacillus polymyxa HKA-15 showed strong inhibition against Xanthomonas campestris pv. phaseoli strains CP-1-1 and M-5. Minimum inhibitory concentration (MIC) of crude extract against strains CP-1-1 and M-5 was found to be 1.7 mg/ml and 1.52 mg/ml, respectively. In UV-Vis range, the absorption peak of crude extract was maximum at 240 nm. The compoun...

During plant-microbe interactions and in the environment, Xanthomonas campestris pv. phaseoli is likely to be exposed to high concentrations of multiple oxidants. Here, we show that simultaneous exposures of the bacteria to multiple oxidants affects cell survival in a complex manner. A superoxide generator (menadione) enhanced the lethal effect of an organic peroxide (tert-butyl hydroperoxide) ...

A methionine sulfoxide reductase gene (msrA) from Xanthomonas campestris pv. phaseoli has unique expression patterns and physiological function. msrA expression is growth dependent and is highly induced by exposure to oxidants and N-ethylmaleimide in an OxyR- and OhrR-independent manner. An msrA mutant showed increased sensitivity to oxidants but only during stationary phase.

Various organic and aqueous extracts of aerial part of Boenninghausenia albiflora (Rutaceae) obtained by infusion and maceration were screened for their antimicrobial activity against eight animal and plant pathogenic bacteria (Bacillus subtilis, Staphylococcus aureus, Erwinia chrysanthemi, Escherichia coli, Proteus vulgaris, Xanthomonas phaseoli, Agrobacterium tumefaciens and Xanthomonas campe...

Lipid hydroperoxides are highly toxic to biological systems. Here, the Xanthomonas campestris pv. phaseoli sensing and protective systems against linoleic hydroperoxide (LOOH) were investigated by examining the phenotypes, biochemical and regulatory characteristics of various Xanthomonas mutants in known peroxide resistance pathways. Analysis of LOOH resistance levels indicates that both alkyl ...

The ability of XANTHOMONAS: campestris pv. phaseoli to protect itself against lethal concentrations of man-made (N:-ethylmaleimide, NEM) and endogenously produced (methylglyoxal, MG) electrophiles was investigated. Pretreatment of X. c. pv. phaseoli with a low concentration of NEM induced protection against lethal concentrations of NEM and MG. MG pretreatment weakly induced protection against N...

We have analyzed the transcription organization of ahpC, ahpF, oxyR, and orfX from Xanthomonas campestris pv. phaseoli. ahpC was transcribed as a monocistronic 0.6-kb mRNA, while ahpF-oxyR-orfX were transcribed as a polycistronic approximately 3.0-kb-long mRNA. The novel transcription organization of these genes has not observed in other bacteria. Western analysis showed that oxidants (peroxide...