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Identification of a novel beta-lactamase produced by Xanthomonas campestris, a phytopathogenic bacterium.

ABSTRACT: The Xanthomonas campestris pv. campestris 11 chromosome encodes a periplasmic beta-lactamase of 30 kDa. Gene replacement and complementation confirmed the presence of this enzyme. Its deduced amino acid sequence shows identity and conserved domains between it and Stenotrophomonas maltophilia L2 and other Ambler class A/Bush group 2 beta-lactamases. Southern hybridization detected a single homologous fragment in each of 12 other Xanthomonas strains, indicating that the presence of a beta-lactamase gene is common among xanthomonads.

SUBMITTER: Weng SF

PROVIDER: S-EPMC89368 | biostudies-literature | 1999 Jul

REPOSITORIES: biostudies-literature

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Identification of a novel beta-lactamase produced by Xanthomonas campestris, a phytopathogenic bacterium.

Weng S F SF Chen C Y CY Lee Y S YS Lin J W JW Tseng Y H YH

Antimicrobial agents and chemotherapy 19990701 7

The Xanthomonas campestris pv. campestris 11 chromosome encodes a periplasmic beta-lactamase of 30 kDa. Gene replacement and complementation confirmed the presence of this enzyme. Its deduced amino acid sequence shows identity and conserved domains between it and Stenotrophomonas maltophilia L2 and other Ambler class A/Bush group 2 beta-lactamases. Southern hybridization detected a single homologous fragment in each of 12 other Xanthomonas strains, indicating that the presence of a beta-lactamas ...[more]

PMID: 10390247

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Fatty acid DSF binds and allosterically activates histidine kinase RpfC of phytopathogenic bacterium Xanthomonas campestris pv. campestris to regulate quorum-sensing and virulence.

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| S-EPMC5391125 | biostudies-literature

Identification of four novel small non-coding RNAs from Xanthomonas campestris pathovar campestris.

Project description:BackgroundIn bacteria, small non-coding RNAs (sRNAs) have been recognized as important regulators of various cellular processes. Approximately 200 bacterial sRNAs in total have been reported. However, very few sRNAs have been identified from phytopathogenic bacteria.ResultsXanthomons campestris pathovar campestris (Xcc) is the causal agent of black rot disease of cruciferous crops. In this study, a cDNA library was constructed from the low-molecular weight RNA isolated from the Xcc strain 8004 grown to exponential phase in the minimal medium XVM2. Seven sRNA candidates were obtained by sequencing screen of 2,500 clones from the library and four of them were confirmed to be sRNAs by Northern hybridization, which were named sRNA-Xcc1, sRNA-Xcc2, sRNA-Xcc3, and sRNA-Xcc4. The transcription start and stop sites of these sRNAs were further determined. BLAST analysis revealed that the four sRNAs are novel. Bioinformatics prediction showed that a large number of genes with various known or unknown functions in Xcc 8004 are potential targets of sRNA-Xcc1, sRNA-Xcc3 and sRNA-Xcc4. In contrast, only a few genes were predicted to be potential targets of sRNA-Xcc2.ConclusionWe have identified four novel sRNAs from Xcc by a large-scale screen. Bioinformatics analysis suggests that they may perform various functions. This work provides the first step toward understanding the role of sRNAs in the molecular mechanisms of Xanthomonas campestris pathogenesis.

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Real time live imaging of phytopathogenic bacteria Xanthomonas campestris pv. campestris MAFF106712 in 'plant sweet home'.

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Identification and regulation of the N-acetylglucosamine utilization pathway of the plant pathogenic bacterium Xanthomonas campestris pv. campestris.

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| S-EPMC2832512 | biostudies-literature

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| S-EPMC310161 | biostudies-literature

Identification of a novel type III secretion-associated outer membrane-bound protein from Xanthomonas campestris pv. campestris.

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| S-EPMC5309889 | biostudies-literature

Analysis of outer membrane vesicle associated proteins isolated from the plant pathogenic bacterium Xanthomonas campestris pv. campestris.

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| S-EPMC2438364 | biostudies-literature

Contribution of Phe-7 to Tat-dependent export of ?-lactamase in Xanthomonas campestris.

Project description:Strains of Xanthomonas campestris pv. campestris isolated in Taiwan are commonly resistant to ampicillin owing to the constitutive expression of a chromosomally encoded ?-lactamase that is secreted into the periplasm. In this study, we found that levels of ?-lactamase vary among X. campestris pv. campestris strains, a difference that can be attributed to amino acid substitutions at least at positions 7 and 206, with the former having the major impact. Bioinformatic and PCR analyses indicated that X. campestris pv. campestris possesses tatABC genes and that the signal peptide of X. campestris pv. campestris pre-Bla contains the typical twin-arginine motif (N-R-R-Q-F-L at amino acid residues 3 to 8 in strain X. campestris pv. campestris strain 11), suggesting that Bla is secreted via the Tat pathway. To assess the importance of Phe(7) in the efficient export of X. campestris pv. campestris Bla, we prepared mutant constructs containing amino acid substitutions and monitored their expression by measuring enzyme activity and detecting Bla protein by Western blotting. The results indicate that replacement of Phe(7) with Leu severely inhibited Bla export whereas replacement with Pro almost abolished it. Although a change to Arg caused moderate inhibition of export, replacement with Tyr had no effect. These results suggest that for efficient export of Bla by X. campestris pv. campestris, the aromatic-aromatic interactions and stability of protein structure around the twin-arginine motif are important, since only proteins that can attain a folded state in the cytoplasm are competent for export via the Tat pathway.

| S-EPMC3393447 | biostudies-literature

Structure determination of a sugar-binding protein from the phytopathogenic bacterium Xanthomonas citri.

Project description:The uptake of maltose and related sugars in Gram-negative bacteria is mediated by an ABC transporter encompassing a periplasmic component (the maltose-binding protein or MalE), a pore-forming membrane protein (MalF and MalG) and a membrane-associated ATPase (MalK). In the present study, the structure determination of the apo form of the putative maltose/trehalose-binding protein (Xac-MalE) from the citrus pathogen Xanthomonas citri in space group P6522 is described. The crystals contained two protein molecules in the asymmetric unit and diffracted to 2.8 Å resolution. Xac-MalE conserves the structural and functional features of sugar-binding proteins and a ligand-binding pocket with similar characteristics to eight different orthologues, including the residues for maltose and trehalose interaction. This is the first structure of a sugar-binding protein from a phytopathogenic bacterium, which is highly conserved in all species from the Xanthomonas genus.

| S-EPMC4014320 | biostudies-literature

An oxidoreductase is involved in cercosporin degradation by the bacterium Xanthomonas campestris pv. zinniae.

Project description:The polyketide toxin cercosporin plays a key role in pathogenesis by fungal species of the genus Cercospora. The bacterium Xanthomonas campestris pv. zinniae is able to rapidly degrade this toxin. Growth of X. campestris pv. zinniae strains in cercosporin-containing medium leads to the breakdown of cercosporin and to the formation of xanosporic acid, a nontoxic breakdown product. Five non-cercosporin-degrading mutants of a strain that rapidly degrades cercosporin (XCZ-3) were generated by ethyl methanesulfonate mutagenesis and were then transformed with a genomic library from the wild-type strain. All five mutants were complemented with the same genomic clone, which encoded a putative transcriptional regulator and an oxidoreductase. Simultaneous expression of these two genes was necessary to complement the mutant phenotype. Sequence analysis of the mutants showed that all five mutants had point mutations in the oxidoreductase gene and no mutations in the regulator. Quantitative reverse transcription-PCR (RT-PCR) showed that the expression of both of these genes in the wild-type strain is upregulated after exposure to cercosporin. Both the oxidoreductase and transcriptional regulator genes were transformed into three non-cercosporin-degrading bacteria to determine if they are sufficient for cercosporin degradation. Quantitative RT-PCR analysis confirmed that the oxidoreductase was expressed in all transconjugants. However, none of the transconjugants were able to degrade cercosporin, suggesting that additional factors are required for cercosporin degradation. Further study of cercosporin degradation in X. campestris pv. zinniae may allow for the engineering of Cercospora-resistant plants by using a suite of genes.

| S-EPMC1563685 | biostudies-literature

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