Pseudomonas syringae pv. tomato DC3000 Improves Escherichia coli O157:H7 Survival in Tomato Plants

In this study, we have analyzed the expression of the Pseudomonas syringae pv. tomato DC3000 mexAB-oprM efflux pump operon and of the regulatory gene pmeR, and we have investigated the role of the PmeR protein on transcription from both promoters. We demonstrate that mexAB-oprM and pmeR are expressed in vivo at a relatively high and moderate basal level, respectively, which, in both cases, increases in the presence of different flavonoids and other compounds, such as butyl and methylparaben. We show that PmeR is the local repressor of the mexAB-oprM promoter and is able to regulate its own expression. The mechanism for this regulation includes binding to a pseudopalindromic operator site which overlaps both mexAB-oprM and pmeR promoters. We have also proven that flavonoids are able to interact with PmeR and induce a conformational change that interferes with the DNA binding ability of PmeR, thereby modulating mexAB-oprM and pmeR expression. Finally, we demonstrate by in vivo experiments that the PmeR/MexAB-OprM system contributes to the colonization of tomato plants. These results provide new insight into a transcriptional regulator and a transport system that play essential roles in the ability of P. syringae pv. tomato DC3000 to resist the action of flavonoids produced by the host.

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CorR Regulates Multiple Components of Virulence in Pseudomonas syringae pv. tomato DC3000

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-19-0768 ◽

2006 ◽

Vol 19 (7) ◽

pp. 768-779 ◽

Cited By ~ 51

Author(s):

Aswathy Sreedharan ◽

Alejandro Penaloza-Vazquez ◽

Barbara N. Kunkel ◽

Carol L. Bender

Keyword(s):

Pseudomonas Syringae ◽

Biosynthetic Pathway ◽

Response Regulator ◽

Tomato Dc3000 ◽

Tomato Plants ◽

Coronafacic Acid ◽

Multiple Components ◽

Expression Of Genes ◽

Genes Encoding ◽

Polymerase Chain

The phytotoxin coronatine (COR) is produced by various pathovars of Pseudomonas syringae, including P. syringae pv. tomato DC3000, which is pathogenic on crucifers and tomato, and P. syringae pv. glycinea PG4180, a soybean pathogen. The COR molecule contains two distinct components, coronafacic acid (CFA) and coronamic acid (CMA), which are intermediates in the COR biosynthetic pathway. In P. syringae pv. tomato DC3000, it is not clear whether corR, which encodes a response regulator, positively regulates CFA and CMA synthesis as it does in P. syringae pv. glycinea PG4180. In this study, a corR mutant of P. syringae pv. tomato DC3000 was constructed and was shown to be defective in the production of COR, CFA, and CMA. Furthermore, disease severity was greatly reduced in tomato plants inoculated with the corR mutant compared with wild-type P. syringae pv. tomato DC3000. We also showed that a mutation in hrpL, which encodes an alternate RNA polymerase sigma factor (σL) required for the expression of genes encoding components of the type III secretion system, abrogated production of COR in P. syringae pv. tomato DC3000. The presence of a potential hrp box, the recognition site for σL, upstream of corR suggested that corR might be regulated by hrpL. This was confirmed in reverse-transcription polymerase chain reaction experiments showing that the upstream effector gene holPtoAA, which was associated with the hrp box, was cotranscribed with corR. Furthermore, studies also were conducted to investigate whether mutations in corR had effects on the expression of hrpL. The corR mutant of P. syringae pv. tomato DC3000 showed both a reduction and delay in the expression of hrpL and was impaired in its ability to elicit a hypersensitive response on Nicotiana benthamiana. A putative CorR-binding site was identified upstream of hrpL, and gel shift studies confirmed the binding of CorR to this region. These results indicate that corR directly impacts the expression of the hrp regulon in P. syringae.

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A Pseudomonas syringae pv. tomato DC3000 Hrp (Type III Secretion) Deletion Mutant Expressing the Hrp System of Bean Pathogen P. syringae pv. syringae 61 Retains Normal Host Specificity for Tomato

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.1.43 ◽

2003 ◽

Vol 16 (1) ◽

pp. 43-52 ◽

Cited By ~ 29

Author(s):

Derrick E. Fouts ◽

Jorge L. Badel ◽

Adela R. Ramos ◽

Ryan A. Rapp ◽

Alan Collmer

Keyword(s):

Host Range ◽

Resistance Gene ◽

Host Specificity ◽

Pseudomonas Syringae ◽

Type Iii Secretion ◽

Secretion System ◽

Effector Proteins ◽

Tomato Dc3000 ◽

Tomato Plants ◽

Type Iii

The plant pathogenic species Pseudomonas syringae is divided into numerous pathovars based on host specificity. For example, P. syringae pv. tomato DC3000 is pathogenic on tomato and Arabidopsis, whereas P. syringae pv. syringae 61 is pathogenic on bean. The ability of P. syringae strains to elicit the hypersensitive response (HR) in non-hosts or be pathogenic (or parasitic) in hosts is dependent on the Hrp (type III secretion) system and effector proteins this system is thought to inject into plant cells. To test the role of the Hrp system in determining host range, the hrp/hrc gene cluster (hrpK through hrpR) was deleted from DC3000 and complemented in trans with the orthologous cluster from strain 61. Mutant CUCPB5114 expressing the bean pathogen Hrp system on plasmid pCPP2071 retained the ability of wild-type DC3000 to elicit the HR in bean, to grow and cause bacterial speck in tomato, and to elicit a cultivar-specific (gene-for-gene) HR in tomato plants carrying the Pto resistance gene. However, the symptoms produced in compatible tomato plants involved markedly reduced chlorosis, and CUCPB5114(pCPP2071) did not grow or produce symptoms in Arabidopsis Col-0 although it was weakly virulent in NahG Arabidopsis. A hypersensitive-like collapse was produced by CUCPB5114(pCPP2071) in Arabidopsis Col-0 at 1 × 107 CFU/ml, but only if the bacteria also expressed AvrB, which is recognized by the RPM1 resistance gene in Col-0 and confers incompatibility. These observations support the concept that the P. syringae effector proteins, rather than secretion system components, are the primary determinants of host range at both the species and cultivar levels of host specificity.

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Recombineering Using RecTE from Pseudomonas syringae

Applied and Environmental Microbiology ◽

10.1128/aem.00911-10 ◽

2010 ◽

Vol 76 (15) ◽

pp. 4960-4968 ◽

Cited By ~ 64

Author(s):

Bryan Swingle ◽

Zhongmeng Bao ◽

Eric Markel ◽

Alan Chambers ◽

Samuel Cartinhour

Keyword(s):

Escherichia Coli ◽

Pseudomonas Syringae ◽

Recombination Frequency ◽

Quantitative Assay ◽

Tomato Dc3000 ◽

Linear Dna ◽

Dna Oligonucleotides ◽

Double Stranded Dna ◽

Genes Encoding ◽

Genomic Recombination

ABSTRACT In this report, we describe the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecET proteins encoded by the lambda and Rac bacteriophages of Escherichia coli. The ability of the pseudomonad-encoded proteins to promote recombination was tested in P. syringae pv. tomato DC3000 using a quantitative assay based on recombination frequency. The results show that the Pseudomonas RecT homolog is sufficient to promote recombination of single-stranded DNA oligonucleotides and that efficient recombination of double-stranded DNA requires the expression of both the RecT and RecE homologs. Additionally, we illustrate the utility of this recombineering system to make targeted gene disruptions in the P. syringae chromosome.

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The Phytotoxin Coronatine Contributes to Pathogen Fitness and Is Required for Suppression of Salicylic Acid Accumulation in Tomato Inoculated with Pseudomonas syringae pv. tomato DC3000

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-8-0955 ◽

2007 ◽

Vol 20 (8) ◽

pp. 955-965 ◽

Cited By ~ 149

Author(s):

Srinivasa Rao Uppalapati ◽

Yasuhiro Ishiga ◽

Tamding Wangdi ◽

Barbara N. Kunkel ◽

Ajith Anand ◽

...

Keyword(s):

Salicylic Acid ◽

Pseudomonas Syringae ◽

Defense Responses ◽

Tomato Dc3000 ◽

Defense Proteins ◽

Tomato Plants ◽

Expression Of Genes ◽

Genes Encoding ◽

Salicylic Acid Accumulation ◽

Pathogen Fitness

The roles of the phytotoxin coronatine (COR) and salicylic acid (SA)-mediated defenses in the interaction of Pseudomonas syringae pv. tomato DC3000 and tomato (Solanum lycopersicum) were investigated. Unlike findings reported for Arabidopsis thaliana, DC3000 mutants impaired for production of COR or one of its components, coronafacic acid (CFA) or coronamic acid (CMA), induced distinctly different disease lesion phenotypes in tomato. Tomato plants inoculated with the CFA- CMA- mutant DB29 showed elevated transcript levels of SlICS, which encodes isochorismate synthase, an enzyme involved in SA biosynthesis in S. lycopersicum. Furthermore, expression of genes encoding SA-mediated defense proteins were elevated in DB29-inoculated plants compared with plants inoculated with DC3000, suggesting that COR suppresses SlICS-mediated SA responses. Sequence analysis of SlICS revealed that it encodes a protein that is 55 and 59.6% identical to the A. thaliana ICS-encoded proteins AtICS1 and AtICS2, respectively. Tomato plants silenced for SlICS were hypersusceptible to DC3000 and accumulated lower levels of SA after infection with DC3000 compared with inoculated wild-type tomato plants. Unlike what has been shown for A. thaliana, the COR- mutant DB29 was impaired for persistence in SlICS-silenced tomato plants; thus, COR has additional roles in virulence that are SA independent and important in the latter stages of disease development. In summary, the infection assays, metabolic profiling, and gene expression results described in this study indicate that the intact COR molecule is required for both suppression of SA-mediated defense responses and full disease symptom development in tomato.

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Functions of pipecolic acid on induced resistance against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000 in tomato plants

Journal of Phytopathology ◽

10.1111/jph.12938 ◽

2020 ◽

Vol 168 (10) ◽

pp. 591-600

Author(s):

Huijuan Zhang ◽

Yating Qiu ◽

Miao Li ◽

Fengming Song ◽

Ming Jiang

Keyword(s):

Botrytis Cinerea ◽

Induced Resistance ◽

Pseudomonas Syringae ◽

Pipecolic Acid ◽

Tomato Dc3000 ◽

Tomato Plants

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Biological Control of Postharvest Decays of Apple Can Prevent Growth of Escherichia coli O157:H7 in Apple Wounds

Journal of Food Protection ◽

10.4315/0362-028x-62.12.1372 ◽

1999 ◽

Vol 62 (12) ◽

pp. 1372-1375 ◽

Cited By ~ 74

Author(s):

W. J. JANISIEWICZ ◽

W. S. CONWAY ◽

B. LEVERENTZ

Keyword(s):

Escherichia Coli ◽

Pseudomonas Syringae ◽

Foodborne Pathogens ◽

Additional Benefit ◽

Escherichia Coli O157 ◽

Water Control ◽

Commercial Formulation ◽

E Coli ◽

Golden Delicious ◽

Fresh Cut

Fresh cells of the antagonist Pseudomonas syringae at 2.4 × 108 CFU/ml inoculated into wounds of ‘Golden Delicious’ apple prevented Escherichia coli O157:H7 (concentrations ranging from 2.4 × 105 to 2.4 × 107 CFU/ml) from growing in the wounds. This occurred when the two microorganisms were co-inoculated or inoculation with E. coli O157:H7 was conducted 1 or 2 days after inoculation with the antagonist. In similar tests, application of the commercial formulation of this antagonist prevented the growth of E. coli O157:H7 in wounds when inoculated 1 or 2 days after application of the antagonist. Populations of E. coli O157:H7 in wounds treated with water (control) before inoculation with this pathogen increased approximately 2 log units during the first 48 h after inoculation. These results indicate that biocontrol agents developed for controlling storage decays of fruits may have the additional benefit of preventing the growth of foodborne pathogens in freshly wounded tissue of intact and fresh-cut fruits.

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