scholarly journals Hcp2, a Secreted Protein of the Phytopathogen Pseudomonas syringae pv. Tomato DC3000, Is Required for Fitness for Competition against Bacteria and Yeasts

2012 ◽  
Vol 194 (18) ◽  
pp. 4810-4822 ◽  
Author(s):  
Minna Haapalainen ◽  
Hanna Mosorin ◽  
Federico Dorati ◽  
Ru-Fen Wu ◽  
Elina Roine ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Expression Patterns ◽  
Stationary Growth Phase ◽  
Plant Colonization ◽  
In Planta ◽  
Type Vi Secretion System ◽  
Tomato Dc3000 ◽  
Content Type ◽  
Covalently Linked

ABSTRACTWhen analyzing the secretome of the plant pathogenPseudomonas syringaepv. tomato DC3000, we identified hemolysin-coregulated protein (Hcp) as one of the secreted proteins. Hcp is assumed to be an extracellular component of the type VI secretion system (T6SS). Two copies ofhcpgenes are present in theP. syringaepv. tomato DC3000 genome,hcp1(PSPTO_2539) andhcp2(PSPTO_5435). We studied the expression patterns of thehcpgenes and tested the fitness ofhcpknockout mutants in host plant colonization and in intermicrobial competition. We found that thehcp2gene is expressed most actively at the stationary growth phase and that the Hcp2 protein is secreted via the T6SS and appears in the culture medium as covalently linked dimers. Expression ofhcp2is not inducedin plantaand does not contribute to virulence in or colonization of tomato orArabidopsisplants. Instead,hcp2is required for survival in competition with enterobacteria and yeasts, and its function is associated with the suppression of the growth of these competitors. This is the first report on bacterial T6SS-associated genes functioning in competition with yeast. Our results suggest that the T6SS ofP. syringaemay play an important role in bacterial fitness, allowing this plant pathogen to survive under conditions where it has to compete with other microorganisms for resources.

scholarly journals Transcriptional Analysis of the Global Regulatory Networks Active in Pseudomonas syringae during Leaf Colonization

mBio ◽  
2014 ◽  
Vol 5 (5) ◽  
Author(s):  
Xilan Yu ◽  
Steven P. Lund ◽  
Jessica W. Greenwald ◽  
Angela H. Records ◽  
Russell A. Scott ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Secondary Metabolite ◽  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Regulatory Network ◽  
Sigma Factors ◽  
In Planta ◽  
Content Type ◽  
Environmental Signals

ABSTRACTThe plant pathogenPseudomonas syringaepv. syringae B728a grows and survives on leaf surfaces and in the leaf apoplast of its host, bean (Phaseolus vulgaris). To understand the contribution of distinct regulators to B728a fitness and pathogenicity, we performed a transcriptome analysis of strain B728a and nine regulatory mutants recovered from the surfaces and interior of leaves and exposed to environmental stresses in culture. The quorum-sensing regulators AhlR and AefR influenced few genesin plantaorin vitro. In contrast, GacS and a downstream regulator, SalA, formed a large regulatory network that included a branch that regulated diverse traits and was independent of plant-specific environmental signals and a plant signal-dependent branch that positively regulated secondary metabolite genes and negatively regulated the type III secretion system. SalA functioned as a central regulator of iron status based on its reciprocal regulation of pyoverdine and achromobactin genes and also sulfur uptake, suggesting a role in the iron-sulfur balance. RetS functioned almost exclusively to repress secondary metabolite genes when the cells were not on leaves. Among the sigma factors examined, AlgU influenced many more genes than RpoS, and most AlgU-regulated genes depended on RpoN. RpoN differentially impacted many AlgU- and GacS-activated genes in cells recovered from apoplastic versus epiphytic sites, suggesting differences in environmental signals or bacterial stress status in these two habitats. Collectively, our findings illustrate a central role for GacS, SalA, RpoN, and AlgU in global regulation in B728ain plantaand a high level of plasticity in these regulators’ responses to distinct environmental signals.IMPORTANCELeaves harbor abundant microorganisms, all of which must withstand challenges such as active plant defenses and a highly dynamic environment. Some of these microbes can influence plant health. Despite knowledge of individual regulators that affect the fitness or pathogenicity of foliar pathogens, our understanding of the relative importance of various global regulators to leaf colonization is limited.Pseudomonas syringaestrain B728a is a plant pathogen and a good colonist of both the surfaces and interior of leaves. This study used global transcript profiles of strain B728a to investigate the complex regulatory network of putative quorum-sensing regulators, two-component regulators, and sigma factors in cells colonizing the leaf surface and leaf interior under stressfulin vitroconditions. The results highlighted the value of evaluating these networksin plantadue to the impact of leaf-specific environmental signals and suggested signal differences that may enable cells to differentiate surface versus interior leaf habitats.

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 Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

2012 ◽  
Vol 194 (18) ◽  
pp. 5054-5064 ◽  
Author(s):  
Ming Guo ◽  
Anna Block ◽  
Crystal D. Bryan ◽  
Donald F. Becker ◽  
James R. Alfano
Keyword(s):  
Hydrogen Peroxide ◽  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
In Planta ◽  
Tomato Dc3000 ◽  
Triple Mutant ◽  
Content Type ◽  
Catalase Peroxidase ◽  
Plant Pathogenesis

ABSTRACTThe bacterial pathogenPseudomonas syringaepv. tomato DC3000 must detoxify plant-produced hydrogen peroxide (H2O2) in order to survive in its host plant. Candidate enzymes for this detoxification include the monofunctional catalases KatB and KatE and the bifunctional catalase-peroxidase KatG of DC3000. This study shows that KatG is the major housekeeping catalase of DC3000 and provides protection against menadione-generated endogenous H2O2. In contrast, KatB rapidly and substantially accumulates in response to exogenous H2O2. Furthermore, KatB and KatG have nonredundant roles in detoxifying exogenous H2O2and are required for full virulence of DC3000 inArabidopsis thaliana. Therefore, the nonredundant ability of KatB and KatG to detoxify plant-produced H2O2is essential for the bacteria to survive in plants. Indeed, a DC3000 catalase triple mutant is severely compromised in its ability to growin planta, and its growth can be partially rescued by the expression ofkatB,katE, orkatG. Interestingly, our data demonstrate that although KatB and KatG are the major catalases involved in the virulence of DC3000, KatE can also provide some protectionin planta. Thus, our results indicate that these catalases are virulence factors for DC3000 and are collectively required for pathogenesis.

scholarly journals Tomato Stress-Associated Protein 4 Contributes Positively to Immunity Against Necrotrophic Fungus Botrytis cinerea

2019 ◽  
Vol 32 (5) ◽  
pp. 566-582 ◽  
Author(s):  
Shixia Liu ◽  
Xi Yuan ◽  
Yuyan Wang ◽  
Hui Wang ◽  
Jiali Wang ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Pseudomonas Syringae ◽  
Expression Patterns ◽  
Plant Stress ◽  
Oxygen Species ◽  
Virus Induced Gene Silencing ◽  
Tomato Dc3000 ◽  
Enhanced Resistance ◽  
Stress Associated Protein ◽  
Associated Proteins

Stress-associated proteins (SAPs) are A20 and AN1 domain–containing proteins, some of which play important roles in plant stress signaling. Here, we report the involvement of tomato SlSAP family in immunity. SlSAPs responded with different expression patterns to Botrytis cinerea and defense signaling hormones. Virus-induced gene silencing of each of the SlSAP genes and disease assays revealed that SlSAP4 and SlSAP10 play roles in immunity against B. cinerea. Silencing of SlSAP4 resulted in attenuated immunity to B. cinerea, accompanying increased accumulation of reactive oxygen species and downregulated expression of jasmonate and ethylene (JA/ET) signaling-responsive defense genes. Transient expression of SlSAP4 in Nicotiana benthamiana led to enhanced resistance to B. cinerea. Exogenous application of methyl jasmonate partially restored the resistance of the SlSAP4-silenced plants against B. cinerea. SlSAP4 interacted with three of four SlRAD23 proteins. The A20 domain in SlSAP4 and the Ub-associated domains in SlRAD23d are critical for SlSAP4-SlRAD23d interaction. Silencing of SlRAD23d led to decreased resistance to B. cinerea, but silencing of each of other SlRAD23s did not affect immunity against B. cinerea. Furthermore, silencing of SlSAP4 and each of the SlRAD23s did not affect immunity to Pseudomonas syringae pv. tomato DC3000. These data suggest that SlSAP4 contributes positively to tomato immunity against B. cinereal through affecting JA/ET signaling and may be involved in the substrate ubiquitination process via interacting with SlRAD23d.

scholarly journals Pseudomonas syringae AlgU Downregulates Flagellin Gene Expression, Helping Evade Plant Immunity

2019 ◽  
Vol 202 (4) ◽  
Author(s):  
Zhongmeng Bao ◽  
Hai-Lei Wei ◽  
Xing Ma ◽  
Bryan Swingle
Keyword(s):  
Gene Expression ◽  
Pseudomonas Syringae ◽  
Plant Pathogens ◽  
Control Point ◽  
Plant Colonization ◽  
Compensatory Mechanisms ◽  
Flagellin Gene ◽  
Content Type ◽  
Immune Systems ◽  
Plant Infection

ABSTRACT Flagella power bacterial movement through liquids and over surfaces to access or avoid certain environmental conditions, ultimately increasing a cell’s probability of survival and reproduction. In some cases, flagella and chemotaxis are key virulence factors enabling pathogens to gain entry and attach to suitable host tissues. However, flagella are not always beneficial; both plant and animal immune systems have evolved receptors to sense the proteins that make up flagellar filaments as signatures of bacterial infection. Microbes poorly adapted to avoid or counteract these immune functions are unlikely to be successful in host environments, and this selective pressure has driven the evolution of diverse and often redundant pathogen compensatory mechanisms. We tested the role of AlgU, the Pseudomonas extracytoplasmic function sigma factor σE/σ22 ortholog, in regulating flagellar expression in the context of Pseudomonas syringae-plant interactions. We found that AlgU is necessary for downregulating bacterial flagellin expression in planta and that this results in a corresponding reduction in plant immune elicitation. This AlgU-dependent regulation of flagellin gene expression is beneficial to bacterial growth in the course of plant infection, and eliminating the plant’s ability to detect flagellin makes this AlgU-dependent function irrelevant for bacteria growing in the apoplast. Together, these results add support to an emerging model in which P. syringae AlgU functions at a key control point that serves to optimize the expression of bacterial functions during host interactions, including minimizing the expression of immune elicitors and concomitantly upregulating beneficial virulence functions. IMPORTANCE Foliar plant pathogens, like Pseudomonas syringae, adjust their physiology and behavior to facilitate host colonization and disease, but the full extent of these adaptations is not known. Plant immune systems are triggered by bacterial molecules, such as the proteins that make up flagellar filaments. In this study, we found that during plant infection, AlgU, a gene expression regulator that is responsive to external stimuli, downregulates expression of fliC, which encodes the flagellin protein, a strong elicitor of plant immune systems. This change in gene expression and resultant change in behavior correlate with reduced plant immune activation and improved P. syringae plant colonization. The results of this study demonstrate the proximate and ultimate causes of flagellar regulation in a plant-pathogen interaction.

Bacteriophytochromes from Pseudomonas syringae pv. tomato DC3000 modulate the early stages of plant colonization during bacterial speck disease

2020 ◽  
Vol 156 (3) ◽  
pp. 695-712 ◽  
Author(s):  
Laura Moyano ◽  
Analía Carrau ◽  
Silvana Petrocelli ◽  
Ivana Kraiselburd ◽  
Wolfgang Gärtner ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Colonization ◽  
Tomato Dc3000 ◽  
Bacterial Speck ◽  
Early Stages ◽  
Bacterial Speck Disease

scholarly journals Pseudomonas syringae pv. tomato DC3000 CmaL (PSPTO4723), a DUF1330 Family Member, Is Needed To Produce l-allo-Isoleucine, a Precursor for the Phytotoxin Coronatine

2012 ◽  
Vol 195 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Jay N. Worley ◽  
Alistair B. Russell ◽  
Aaron G. Wexler ◽  
Philip A. Bronstein ◽  
Brian H. Kvitko ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Genomic Region ◽  
Tomato Dc3000 ◽  
Content Type ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Coronafacic Acid ◽  
Feeding Experiments ◽  
Leaf Chlorosis

ABSTRACTPseudomonas syringaepv. tomato DC3000 produces the phytotoxin coronatine, a major determinant of the leaf chlorosis associated with DC3000 pathogenesis. The DC3000 PSPTO4723 (cmaL) gene is located in a genomic region encoding type III effectors; however, it promotes chlorosis in the model plantNicotiana benthamianain a manner independent of type III secretion. Coronatine is produced by the ligation of two moieties, coronafacic acid (CFA) and coronamic acid (CMA), which are produced by biosynthetic pathways encoded in separate operons. Cross-feeding experiments, performed inN. benthamianawithcfa,cma, andcmaLmutants, implicate CmaL in CMA production. Furthermore, analysis of bacterial supernatants under coronatine-inducing conditions revealed that mutants lacking either thecmaoperon orcmaLaccumulate CFA rather than coronatine, supporting a role for CmaL in the regulation or biosynthesis of CMA. CmaL does not appear to regulate CMA production, since the expression of proteins with known roles in CMA production is unaltered incmaLmutants. Rather, CmaL is needed for the first step in CMA synthesis, as evidenced by the fact that wild-type levels of coronatine production are restored to a ΔcmaLmutant when it is supplemented with 50 μg/mll-allo-isoleucine, the starting unit for CMA production.cmaLis found in all other sequencedP. syringaestrains with coronatine biosynthesis genes. This characterization of CmaL identifies a critical missing factor in coronatine production and provides a foundation for further investigation of a member of the widespread DUF1330 protein family.

The Use of Bioluminescence for Monitoring in planta Growth Dynamics of a Pseudomonas syringae Plant Pathogen

2006 ◽  
Vol 115 (3) ◽  
pp. 363-366 ◽  
Author(s):  
Christopher D. Paynter ◽  
Vyvyan C. Salisbury ◽  
Dawn L. Arnold ◽  
Robert W. Jackson
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Growth Dynamics ◽  
In Planta

scholarly journals Draft Genome Sequence of Pseudomonas syringae RAYR-BL, a Strain Isolated from Natural Accessions of Arabidopsis thaliana Plants

2022 ◽  
Author(s):  
Isabel Fuenzalida-Valdivia ◽  
Maria Victoria Gangas ◽  
Diego Zavala ◽  
Ariel Herrera-Vásquez ◽  
Fabrice Roux ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Genome Sequence ◽  
Plant Pathogen ◽  
Environmental Conditions ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Content Type ◽  
Molecular Features ◽  
Plant Pathogen Interaction

Here, we report the genome sequence of the P. syringae strain RAYR-BL, isolated from natural accessions of Arabidopsis plants. The draft genome sequence consists of 5.85 Mbp assembled in 110 contigs. The study of P. syringae RAYR-BL is a valuable tool to investigate molecular features of plant-pathogen interaction under environmental conditions.

scholarly journals Differential Gene Expression Patterns ofYersinia pestisandYersinia pseudotuberculosisduring Infection and Biofilm Formation in the Flea Digestive Tract

mSystems ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Iman Chouikha ◽  
Daniel E. Sturdevant ◽  
Clayton Jarrett ◽  
Yi-Cheng Sun ◽  
B. Joseph Hinnebusch
Keyword(s):  
Digestive Tract ◽  
Biofilm Formation ◽  
Yersinia Pseudotuberculosis ◽  
Expression Patterns ◽  
Type Vi Secretion System ◽  
Genetic Changes ◽  
Content Type ◽  
Biofilm Development

ABSTRACTYersinia pestis, the etiologic agent of plague, emerged as a fleaborne pathogen only within the last 6,000 years. Just five simple genetic changes in theYersinia pseudotuberculosisprogenitor, which served to eliminate toxicity to fleas and to enhance survival and biofilm formation in the flea digestive tract, were key to the transition to the arthropodborne transmission route. To gain a deeper understanding of the genetic basis for the development of a transmissible biofilm infection in the flea foregut, we evaluated additional gene differences and performedin vivotranscriptional profiling ofY. pestis, aY. pseudotuberculosiswild-type strain (unable to form biofilm in the flea foregut), and aY. pseudotuberculosismutant strain (able to produce foregut-blocking biofilm in fleas) recovered from fleas 1 day and 14 days after an infectious blood meal. Surprisingly, theY. pseudotuberculosismutations that increased c-di-GMP levels and enabled biofilm development in the flea did not change the expression levels of thehmsgenes responsible for the synthesis and export of the extracellular polysaccharide matrix required for mature biofilm formation. TheY. pseudotuberculosismutant uniquely expressed much higher levels ofYersiniatype VI secretion system 4 (T6SS-4) in the flea, and this locus was required for flea blockage byY. pseudotuberculosisbut not for blockage byY. pestis. Significant differences between the two species in expression of several metabolism genes, the Psa fimbrial genes, quorum sensing-related genes, transcription regulation genes, and stress response genes were evident during flea infection.IMPORTANCEY. pestisemerged as a highly virulent, arthropod-transmitted pathogen on the basis of relatively few and discrete genetic changes fromY. pseudotuberculosis. Parallel comparisons of thein vitroandin vivotranscriptomes ofY. pestisand twoY. pseudotuberculosisvariants that produce a nontransmissible infection and a transmissible infection of the flea vector, respectively, provided insights into howY. pestishas adapted to life in its flea vector and point to evolutionary changes in the regulation of metabolic and biofilm development pathways in these two closely related species.

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