scholarly journals Multiple CsrA Proteins Control Key Virulence Traits in Pseudomonas syringae pv. tomato DC3000

2018 ◽  
Vol 31 (5) ◽  
pp. 525-536 ◽  
Author(s):  
María-Dolores Ferreiro ◽  
Joaquina Nogales ◽  
Gabriela A. Farias ◽  
Adela Olmedilla ◽  
Juan Sanjuán ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Environmental Cues ◽  
Symptom Development ◽  
Regulatory Pathway ◽  
In Planta ◽  
Tomato Dc3000 ◽  
Phytopathogenic Bacterium ◽  
Virulence Traits ◽  
Expression Of Genes ◽  
Physiological Outcomes

The phytopathogenic bacterium Pseudomonas syringae pv. tomato DC3000 has a complex Gac-rsm global regulatory pathway that controls virulence, motility, production of secondary metabolites, carbon metabolism, and quorum sensing. However, despite the fact that components of this pathway are known, their physiological roles have not yet been established. Regarding the CsrA/RsmA type proteins, five paralogs, three of which are well conserved within the Pseudomonas genus (csrA1, csrA2, and csrA3), have been found in the DC3000 genome. To decipher their function, mutants lacking the three most conserved CsrA proteins have been constructed and their physiological outcomes examined. We show that they exert nonredundant functions and demonstrate that CsrA3 and, to a lesser extent, CsrA2 but not CsrA1 alter the expression of genes involved in a variety of pathways and systems important for motility, exopolysaccharide synthesis, growth, and virulence. Particularly, alginate synthesis, syringafactin production, and virulence are considerably de-repressed in a csrA3 mutant, whereas growth in planta is impaired. We propose that the linkage of growth and symptom development is under the control of CsrA3, which functions as a pivotal regulator of the DC3000 life cycle, repressing virulence traits and promoting cell division in response to environmental cues.

scholarly journals The algT Gene of Pseudomonas syringae pv. glycinea andNew Insights into the Transcriptional Organization of thealgT-muc Gene Cluster

2006 ◽  
Vol 188 (23) ◽  
pp. 8013-8021 ◽  
Author(s):  
Alexander Schenk ◽  
Michael Berger ◽  
Lisa M. Keith ◽  
Carol L. Bender ◽  
Georgi Muskhelishvili ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Pseudomonas Syringae ◽  
Azotobacter Vinelandii ◽  
Regulatory Gene ◽  
In Planta ◽  
Phytopathogenic Bacterium ◽  
Reverse Transcription Pcr ◽  
Alginate Production ◽  
Alginate Biosynthesis

ABSTRACT The phytopathogenic bacterium Pseudomonas syringae pv. glycinea infects soybean plants and causes bacterial blight. In addition to P. syringae, the human pathogen Pseudomonas aeruginosa and the soil bacterium Azotobacter vinelandii produce the exopolysaccharide alginate, a copolymer of d-mannuronic and l-guluronic acids. Alginate production in P. syringae has been associated with increased fitness and virulence in planta. Alginate biosynthesis is tightly controlled by proteins encoded by the algT-muc regulatory gene cluster in P. aeruginosa and A. vinelandii. These genes encode the alternative sigma factor AlgT (σ22), its anti-sigma factors MucA and MucB, MucC, a protein with a controversial function that is absent in P. syringae, and MucD, a periplasmic serine protease and homolog of HtrA in Escherichia coli. We compared an alginate-deficient algT mutant of P. syringae pv. glycinea with an alginate-producing derivative in which algT is intact. The alginate-producing derivative grew significantly slower in vitro growth but showed increased epiphytic fitness and better symptom development in planta. Evaluation of expression levels for algT, mucA, mucB, mucD, and algD, which encodes an alginate biosynthesis gene, showed that mucD transcription is not dependent on AlgT in P. syringae in vitro. Promoter mapping using primer extension experiments confirmed this finding. Results of reverse transcription-PCR demonstrated that algT, mucA, and mucB are cotranscribed as an operon in P. syringae. Northern blot analysis revealed that mucD was expressed as a 1.75-kb monocistronic mRNA in P. syringae.

scholarly journals Chitosan Oligosaccharide Induces Resistance to Pseudomonas syringae pv. tomato DC3000 in Arabidopsis thaliana by Activating Both Salicylic Acid– and Jasmonic Acid–Mediated Pathways

2018 ◽  
Vol 31 (12) ◽  
pp. 1271-1279 ◽  
Author(s):  
Xiaochen Jia ◽  
Haihong Zeng ◽  
Wenxia Wang ◽  
Fuyun Zhang ◽  
Heng Yin
Keyword(s):  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Induced Resistance ◽  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Chitosan Oligosaccharide ◽  
Induction Effect ◽  
Tomato Dc3000 ◽  
Expression Of Genes ◽  
Underlying Mechanisms

Chitosan oligosaccharide (COS) is an effective plant immunity elicitor; however, its induction mechanism in plants is complex and needs further investigation. In this study, the Arabidopsis–Pseudomonas syringae pv. tomato DC3000 (hereafter called DC3000) interaction was used to investigate the induction effect and the underlying mechanisms of COS. COS is effective in inducing resistance to DC3000 in Arabidopsis, and our results demonstrate that treatment with COS 3 days before DC3000 inoculation provided the most effective resistance. Disease severity in jar1 (jasmonic acid [JA]-deficient mutant), NahG, and sid2 (salicylic acid [SA]-deficient mutants) suggest both the SA and JA pathways are required for the Arabidopsis response to DC3000. COS pretreatment induced resistance in wild type (WT), jar1, and also, although to a lesser degree, in NahG and sid2 plants, implying that the SA and JA pathways play redundant roles in COS-induced resistance to DC3000. In COS-pretreated plants, expression of genes related to the SA pathway (PR1, PR2, and PR5) and SA content increased in both WT and jar1. Moreover, expression of genes related to the JA pathway (PDF1.2 and VSP2) and JA content both increased in WT and NahG. In conclusion, COS induces resistance to DC3000 in Arabidopsis by activating both SA- and JA-mediated pathways, although SA and JA pathways play redundant roles in this COS-induced resistance.

scholarly journals The Majority of the Type III Effector Inventory of Pseudomonas syringae pv. tomato DC3000 Can Suppress Plant Immunity

2009 ◽  
Vol 22 (9) ◽  
pp. 1069-1080 ◽  
Author(s):  
Ming Guo ◽  
Fang Tian ◽  
Yashitola Wamboldt ◽  
James R. Alfano
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
In Planta ◽  
Tomato Dc3000 ◽  
Type Iii Effector ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Molecular Pattern ◽  
Effector Triggered Immunity ◽  
Type Iii Protein Secretion

The Pseudomonas syringae type III protein secretion system (T3SS) and the type III effectors it injects into plant cells are required for plant pathogenicity and the ability to elicit a hypersensitive response (HR). The HR is a programmed cell death that is associated with effector-triggered immunity (ETI). A primary function of P. syringae type III effectors appears to be the suppression of ETI and pathogen-associated molecular pattern–triggered immunity (PTI), which is induced by conserved molecules on microorganisms. We reported that seven type III effectors from P. syringae pv. tomato DC3000 were capable of suppressing an HR induced by P. fluorescens(pHIR11) and have now tested 35 DC3000 type III effectors in this assay, finding that the majority of them can suppress the HR induced by HopA1. One newly identified type III effector with particularly strong HR suppression activity was HopS2. We used the pHIR11 derivative pLN1965, which lacks hopA1, in related assays and found that a subset of the type III effectors that suppressed HopA1-induced ETI also suppressed an ETI response induced by AvrRpm1 in Arabidopsis thaliana. A. thaliana plants expressing either HopAO1 or HopF2, two type III effectors that suppressed the HopA1-induced HR, were reduced in the flagellin-induced PTI response as well as PTI induced by other PAMPs and allowed enhanced in planta growth of P. syringae. Collectively, our results suggest that the majority of DC3000 type III effectors can suppress plant immunity. Additionally, the construct pLN1965 will likely be a useful tool in determining whether other type III effectors or effectors from other types of pathogens can suppress either ETI, PTI, or both.

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

2006 ◽  
Vol 19 (7) ◽  
pp. 768-779 ◽  
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.

scholarly journals Regulation of Biosynthesis of Syringolin A, a Pseudomonas syringae Virulence Factor Targeting the Host Proteasome

2012 ◽  
Vol 25 (9) ◽  
pp. 1198-1208 ◽  
Author(s):  
Christina Ramel ◽  
Nando Baechler ◽  
Michel Hildbrand ◽  
Martin Meyer ◽  
David Schädeli ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Pseudomonas Syringae ◽  
Virulence Factor ◽  
Homoserine Lactone ◽  
Defined Medium ◽  
Lacz Gene ◽  
In Planta ◽  
Phytopathogenic Bacterium ◽  
Promoter Sequences

Many strains of the phytopathogenic bacterium Pseudomonas syringae pv. syringae synthesize the virulence factor syringolin A, which irreversibly inactivates the eukaryotic proteasome. Syringolin A, a peptide derivative, is synthesized by a mixed nonribosomal peptide/polyketide synthetase encoded by five clustered genes, sylA to sylE. Biosynthesis of syringolin A, previously shown to be dependent on the GacS/GacA two-component system, occurs in planta and in vitro but only under still culture conditions in a defined medium. Here, we show that the sylC, sylD, and sylE genes of P. syringae pv. syringae B301D-R form an operon transcribed by promoter sequences located between the sylCDE operon and the sylB gene residing on opposite strands. Assays of overlapping sylB and sylCDE promoter deletions translationally fused to the lacZ gene defined promoter sequences required for gene activity both in vitro and in planta. Activation of both promoters depended on the sylA gene encoding a helix-turn-helix (HTH) LuxR-type transcription factor which was shown to directly bind to the promoters. Activity of the sylA gene, in turn, required a functional salA gene, which also encodes an HTH LuxR-type transcription factor. Furthermore, evidence is presented that acyl-homoserine lactone-mediated quorum-sensing regulation is not involved in syringolin A biosynthesis but that oxygen concentration appears to play a role.

scholarly journals 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

2007 ◽  
Vol 20 (8) ◽  
pp. 955-965 ◽  
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.

scholarly journals The Arabidopsis thaliana JASMONATE INSENSITIVE 1 Gene Is Required for Suppression of Salicylic Acid-Dependent Defenses During Infection by Pseudomonas syringae

2006 ◽  
Vol 19 (7) ◽  
pp. 789-800 ◽  
Author(s):  
Neva Laurie-Berry ◽  
Vinita Joardar ◽  
Ian H. Street ◽  
Barbara N. Kunkel
Keyword(s):  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Plant Pathogens ◽  
Symptom Development ◽  
Tomato Dc3000 ◽  
Jasmonate Signaling ◽  
Pathogenesis Related ◽  
Elevated Expression

Many plant pathogens suppress antimicrobial defenses using virulence factors that modulate endogenous host defenses. The Pseudomonas syringae phytotoxin coronatine (COR) is believed to promote virulence by acting as a jasmonate analog, because COR-insensitive 1 (coi1) Arabidopsis thaliana and tomato mutants are impaired in jasmonate signaling and exhibit reduced susceptibility to P. syringae. To further investigate the role of jasmonate signaling in disease development, we analyzed several jasmonate-insensitive A. thaliana mutants for susceptibility to P. syringae pv. tomato strain DC3000 and sensitivity to COR. Jasmonate-insensitive1 (jin1) mutants exhibit both reduced susceptibility to P. syringae pv. tomato DC3000 and reduced sensitivity to COR, whereas jasmonate-resistant 1 (jar1) plants exhibit wild-type responses to both COR and P. syringae pv. tomato DC3000. A jin1 jar1 double mutant does not exhibit enhanced jasmonate insensitivity, suggesting that JIN1 functions downstream of jasmonic acid-amino acid conjugates synthesized by JAR1. Reduced disease susceptibility in jin1 mutants is correlated with elevated expression of pathogenesis-related 1(PR-1) and is dependent on accumulation of salicylic acid (SA). We also show that JIN1 is required for normal P. syringae pv. tomato DC3000 symptom development through an SA-independent mechanism. Thus,P. syringae pv. tomatoDC3000 appears to utilize COR to manipulate JIN1-dependent jasmonate signaling both to suppress SA-mediated defenses and to promote symptom development.

scholarly journals Identification of Tomato Leaf Factors that Activate Toxin Gene Expression in Pseudomonas syringae pv. tomato DC3000

1998 ◽  
Vol 88 (10) ◽  
pp. 1094-1100 ◽  
Author(s):  
Xiu-Zhen Li ◽  
Alvin N. Starratt ◽  
Diane A. Cuppels
Keyword(s):  
Gene Expression ◽  
Pseudomonas Syringae ◽  
High Performance ◽  
Shikimic Acid ◽  
Ice Nucleation ◽  
Tomato Leaf ◽  
Toxin Gene ◽  
In Planta ◽  
Active Components ◽  
Tomato Dc3000

Coronatine is a non-host-specific chlorosis-inducing phytotoxin produced by the tomato and crucifer pathogen Pseudomonas syringae pv. tomato DC3000. How the chromosomal gene cluster controlling toxin synthesis in this strain is regulated in planta is unknown. Ice nucleation-active cor:inaZ marker-exchange derivatives of strain DC3000 were used to determine coronatine gene expression in various host and nonhost plants and in a minimal medium supplemented with selected tomato plant constituents. Ice nucleation activity, which was first detected 4 h after inoculation, was highest in cabbage, tomato, and soybean and lowest in melon and cucumber. No correlation existed between bacterial population size and expression level on the various plants. Crude tomato leaf extract and intercellular fluid were strong inducers of toxin synthesis. Based on high-performance liquid chromatography analyses and bioassays, we concluded that the active components of both preparations were malic and citric acids, with minor contributions coming from shikimic and quinic acid. Although several compounds including glucose and inositol activated the toxin genes when tested at high concentrations (3 to 5 mM), shikimic and quinic acids were the only ones with activity at concentrations below 0.1 mM. Neither acid could be used as a sole carbon source by strain DC3000. The signal activity of shikimic acid was enhanced 10-fold by the addition of glucose. None of the plant phenolics that we screened affected coronatine gene expression.

scholarly journals In planta transcriptomics reveals conflicts between pattern-triggered immunity and the AlgU sigma factor regulon

2022 ◽  
Author(s):  
Haibi Wang ◽  
Amelia Lovelace ◽  
Amy Smith ◽  
Brian H Kvitko
Keyword(s):  
Pseudomonas Syringae ◽  
Sigma Factor ◽  
Expression Patterns ◽  
Flagellar Motility ◽  
In Planta ◽  
Tomato Dc3000 ◽  
Transcriptomic Data ◽  
Almost All ◽  
Extracytoplasmic Function Sigma Factor

In previous work, we determined the transcriptomic impacts of flg22 pre-induced Pattern Triggered Immunity (PTI) in Arabidopsis thaliana on the pathogen Pseudomonas syringae pv. tomato DC3000 (Pto). During PTI exposure we observed expression patterns in Pto reminiscent of those previously observed in a Pto algU mutant. AlgU is a conserved extracytoplasmic function sigma factor which has been observed to regulate over 950 genes in Pto in vitro. We sought to identify the AlgU regulon in planta.and which PTI-regulated genes overlapped with AlgU-regulated genes. In this study, we analyzed transcriptomic data from RNA-sequencing to identify the AlgU in planta regulon and its relationship with PTI. Our results showed that approximately 224 genes are induced by AlgU, while another 154 genes are downregulated by AlgU in Arabidopsis during early infection. Both stress response and virulence-associated genes were induced by AlgU, while the flagellar motility genes are downregulated by AlgU. Under the pre-induced PTI condition, more than half of these AlgU-regulated genes have lost induction/suppression in contrast to naive plants, and almost all function groups regulated by AlgU were affected by PTI.

scholarly journals Identification of a Twin-Arginine Translocation System in Pseudomonas syringae pv. tomato DC3000 and Its Contribution to Pathogenicity and Fitness

2005 ◽  
Vol 187 (24) ◽  
pp. 8450-8461 ◽  
Author(s):  
Philip A. Bronstein ◽  
Matthew Marrichi ◽  
Sam Cartinhour ◽  
David J. Schneider ◽  
Matthew P. DeLisa
Keyword(s):  
Pseudomonas Syringae ◽  
Virulence Factors ◽  
Fluorescent Protein ◽  
Effector Proteins ◽  
Broad Host Range ◽  
Tomato Dc3000 ◽  
Phytopathogenic Bacterium ◽  
Type Iii ◽  
Twin Arginine Translocation ◽  
Tat System

ABSTRACT The bacterial plant pathogen Pseudomonas syringae pv. tomato DC3000 (DC3000) causes disease in Arabidopsis thaliana and tomato plants, and it elicits the hypersensitive response in nonhost plants such as Nicotiana tabacum and Nicotiana benthamiana. While these events chiefly depend upon the type III protein secretion system and the effector proteins that this system translocates into plant cells, additional factors have been shown to contribute to DC3000 virulence and still many others are likely to exist. Therefore, we explored the contribution of the twin-arginine translocation (Tat) system to the physiology of DC3000. We found that a tatC mutant strain of DC3000 displayed a number of phenotypes, including loss of motility on soft agar plates, deficiency in siderophore synthesis and iron acquisition, sensitivity to copper, loss of extracellular phospholipase activity, and attenuated virulence in host plant leaves. In the latter case, we provide evidence that decreased virulence of tatC mutants likely arises from a synergistic combination of (i) compromised fitness of bacteria in planta; (ii) decreased efficiency of type III translocation; and (iii) cytoplasmically retained virulence factors. Finally, we demonstrate a novel broad-host-range genetic reporter based on the green fluorescent protein for the identification of Tat-targeted secreted virulence factors that should be generally applicable to any gram-negative bacterium. Collectively, our evidence supports the notion that virulence of DC3000 is a multifactorial process and that the Tat system is an important virulence determinant of this phytopathogenic bacterium.

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