Genetic organization of a cluster of genes involved in the production of phaseolotoxin, a toxin produced by Pseudomonas syringae pv. phaseolicola

Zhang, Yuanxin; Rowley, Karla B.; Patil, Suresh S.

doi:10.1128/jb.175.20.6451-6458.1993

Cited by 37 publications

(27 citation statements)

References 34 publications

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“…Indeed, it lacks the genes for coronatine biosynthesis found in Pst DC3000. However, homologs of all six genes from one of the eight phaseolotoxin biosynthesis loci, phtE (43,44), were found in Pss B728a (Psyr2549-2555). Orthologs of these six genes are absent from Pst DC3000.…”

Section: Figmentioning

confidence: 99%

Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

Feil

Chain

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

405

340

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The complete genomic sequence of Pseudomonas syringae pv. syringae B728a (Pss B728a) has been determined and is compared with that of P. syringae pv. tomato DC3000 (Pst DC3000). The two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with Pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and Pst DC3000 having a more pronounced apoplastic growth habitat. The Pss B728a genome (6.1 Mb) contains a circular chromosome and no plasmid, whereas the Pst DC3000 genome is 6.5 mbp in size, composed of a circular chromosome and two plasmids. Although a high degree of similarity exists between the two sequenced Pseudomonads, 976 protein-encoding genes are unique to Pss B728a when compared with Pst DC3000, including large genomic islands likely to contribute to virulence and host specificity. Over 375 repetitive extragenic palindromic sequences unique to Pss B728a when compared with Pst DC3000 are widely distributed throughout the chromosome except in 14 genomic islands, which generally had lower GC content than the genome as a whole. Content of the genomic islands varies, with one containing a prophage and another the plasmid pKLC102 of Pseudomonas aeruginosa PAO1. Among the 976 genes of Pss B728a with no counterpart in Pst DC3000 are those encoding for syringopeptin, syringomycin, indole acetic acid biosynthesis, arginine degradation, and production of ice nuclei. The genomic comparison suggests that several unique genes for Pss B728a such as ectoine synthase, DNA repair, and antibiotic production may contribute to the epiphytic fitness and stress tolerance of this organism.virulence genes ͉ epiphyte ͉ plant pathogen

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Section: Figmentioning

confidence: 99%

Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

Feil

Chain

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

405

340

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“…This clone, pHK120, was shown to contain eight transcriptional units that were designated phtA through phtH. Both clones pRCP17 and pHK120 were shown to be partially overlapping; however, pHK120 lacked argK but contained sequences missing in pRCP17 (43). A gene coding an amidinotransferase, amtA, and shown to be involved in the synthesis of the homoarginine residue of the tripeptide moiety of phaseolotoxin was also found to be linked to argK (12).…”

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confidence: 99%

Functional Characterization of the Gene Cluster from Pseudomonas syringae pv. phaseolicola NPS3121 Involved in Synthesis of Phaseolotoxin

Aguilera¹,

López‐López

Nieto³

et al. 2007

J Bacteriol

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Pseudomonas syringae pv. phaseolicola is the causal agent of halo blight disease of beans (Phaseolus vulgaris L.), which is characterized by water-soaked lesions surrounded by a chlorotic halo resulting from the action of a non-host-specific toxin known as phaseolotoxin. This phytotoxin inhibits the enzyme ornithine carbamoyltransferase involved in arginine biosynthesis. Different evidence suggested that genes involved in phaseolotoxin production were clustered. Two genes had been previously identified in our laboratory within this cluster: argK, which is involved in the immunity of the bacterium to its own toxin, and amtA, which is involved in the synthesis of homoarginine. We sequenced the region around argK and amtA in P. syringae pv. phaseolicola NPS3121 to determine the limits of the putative phaseolotoxin gene cluster and to determine the transcriptional pattern of the genes comprising it. We report that the phaseolotoxin cluster (Pht cluster) is composed of 23 genes and is flanked by insertion sequences and transposases. The mutation of 14 of the genes within the cluster lead to a Tox ؊ phenotype for 11 of them, while three mutants exhibited low levels of toxin production. The analysis of fusions of selected DNA fragments to uidA, Northern probing, and reverse transcription-PCR indicate the presence of five transcriptional units, two monocistronic and three polycistronic; one is internal to a larger operon. The site for transcription initiation has been determined for each promoter, and the putative promoter regions were identified. Preliminary results also indicate that the gene product of phtL is involved in the regulation of the synthesis of phaseolotoxin.Pseudomonas syringae pv. phaseolicola is the causal agent of halo blight disease of beans (Phaseolus vulgaris L.), which is characterized by water-soaked lesions surrounded by a chlorotic halo (23). This halo results from the action of a non-hostspecific toxin known as phaseolotoxin [N ␦

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“…High levels of the isolated pDHO subunit were expressed when the truncated plasmid was transformed into BL21(DE3) cells. 2 This species was completely soluble but, as expected, had no catalytic activity.…”

Section: Expression and Purification Of P Aeruginosa Atcase-ini-mentioning

confidence: 98%

“…Thus, although dissociated and denatured ATCase can be reconstituted into a complex resembling the native enzyme in size and subunit composition, it has not been possible to restore catalytic activity. 2 N. Sahay, unpublished data. a The extracts were prepared from 10 liters and 100 ml of culture for pA10 and pJV34 clones, respectively.…”

Section: Expression and Purification Of P Aeruginosa Atcase-ini-mentioning

confidence: 99%

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Pseudomonas aeruginosa Aspartate Transcarbamoylase

Vickrey¹,

Hervé²,

Evans³

2002

Journal of Biological Chemistry

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Aspartate transcarbamoylase from Pseudomonadaceae is a class A enzyme consisting of six copies of a 36-kDa catalytic chain and six copies of a 45-kDa polypeptide of unknown function. The 45-kDa polypeptide is homologous to dihydroorotase but lacks catalytic activity. Pseudomonas aeruginosa aspartate transcarbamoylase was overexpressed in Escherichia coli. The homogeneous His-tagged protein isolated in high yield, 30 mg/liter of culture, by affinity chromatography and crystallized. Attempts to dissociate the catalytic and pseudo-dihydroorotase (pDHO) subunits or to express catalytic subunits only were unsuccessful suggesting that the pDHO subunits are required for the proper folding and assembly of the complex. As reported previously, the enzyme was inhibited by micromolar concentrations of all nucleotide triphosphates. In the absence of effectors, the aspartate saturation curves were hyperbolic but became strongly sigmoidal in the presence of low concentrations of nucleotide triphosphates. The inhibition was unusual in that only free ATP, not MgATP, inhibits the enzyme. Moreover, kinetic and binding studies with a fluorescent ATP analog suggested that ATP induces a conformational change that interferes with the binding of carbamoyl phosphate but has little effect once carbamoyl phosphate is bound. The peculiar allosteric properties suggest that the enzyme may be a potential target for novel chemotherapeutic agents designed to combat Pseudomonas infection.Pseudomonadaceae is a family of eubacteria with a wide ecological distribution that is pathogenic in animals (1, 2). Pseudomonas aeruginosa, the principle cause of morbidity and mortality in immunocompromised patients and burn victims (3-5), is an obligate pathogen. In cystic fibrosis, P. aeruginosa infection is the usual cause of death. In the design of therapeutic strategies, comparatively little attention has focused on the physiology of the organism itself, despite the unusual metabolism exhibited by Pseudomonadaceae such as uracil catabolism (6), the lack of gene repression (7,8), and the ability to use arginine as the sole source of carbon, nitrogen, and energy (9, 10).In other organisms, studies of de novo pyrimidine biosynthesis and salvage are actively pursued because of the relationship of these pathways to growth, development, and chemotherapy. Aspartate transcarbamoylase (ATCase, 1 EC 2.1.3.2) catalyzes the formation of carbamoyl aspartate from carbamoyl phosphate and aspartate (11) in the de novo biosynthetic pathway. The structure and function of the enzyme from Escherichia coli has been extensively studied and has become the prototype of allosteric enzymes. However, ATCases are highly polymorphic differing both in structure and mode of regulation. Jones and co-workers (12) identified three distinct classes of bacterial aspartate transcarbamoylase.E. coli ATCase, designated a class B enzyme, consists of six copies of two types of polypeptide chains, catalytic and regulatory. The 34-kDa catalytic chains associate to form catalytically active but unr...

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Genetic organization of a cluster of genes involved in the production of phaseolotoxin, a toxin produced by Pseudomonas syringae pv. phaseolicola

Cited by 37 publications

References 34 publications

Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

Functional Characterization of the Gene Cluster from Pseudomonas syringae pv. phaseolicola NPS3121 Involved in Synthesis of Phaseolotoxin

Pseudomonas aeruginosa Aspartate Transcarbamoylase

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