scholarly journals Characterization of a Novel, Defense-Related Arabidopsis Mutant, cir1, Isolated By Luciferase Imaging

2002 ◽  
Vol 15 (6) ◽  
pp. 557-566 ◽  
Author(s):  
Shane L. Murray ◽  
Catherine Thomson ◽  
Andrea Chini ◽  
Nick D. Read ◽  
Gary J. Loake
Keyword(s):  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Constitutive Expression ◽  
Bacterial Pathogen ◽  
Negative Regulator ◽  
Reactive Oxygen Intermediate ◽  
Peronospora Parasitica ◽  
Tomato Dc3000 ◽  
Pathogen Invasion ◽  
Arabidopsis Mutant

In order to identify components of the defense signaling network engaged following attempted pathogen invasion, we generated a novel PR-1∷luciferase (LUC) transgenic line that was deployed in an imaging-based screen to uncover defense-related mutants. The recessive mutant designated cir1 exhibited constitutive expression of salicylic acid (SA), jasmonic acid (JA)/ethylene, and reactive oxygen intermediate-dependent genes. Moreover, this mutation conferred resistance against the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 and a virulent oomycete pathogen Peronospora parasitica Noco2. Epistasis analyses were undertaken between cir1 and mutants that disrupt the SA (npr1, nahG), JA (jar1), and ethylene (ET) (ein2) signaling pathways. While resistance against both P. syringae pv. tomato DC3000 and Peronospora parasitica Noco2 was partially reduced by npr1, resistance against both of these pathogens was lost in an nahG genetic background. Hence, cir1-mediated resistance is established via NPR1-dependent and -independent signaling pathways and SA accumulation is essential for the function of both pathways. While jar1 and ein2 reduced resistance against P. syringae pv. tomato DC3000, these mutations appeared not to impact cir1-mediated resistance against Peronospora parasitica Noco2. Thus, JA and ET sensitivity are required for cir1-mediated resistance against P. syringae pv. tomato DC3000 but not Peronospora parasitica Noco2. Therefore, the cir1 mutation may define a negative regulator of disease resistance that operates upstream of SA, JA, and ET accumulation.

scholarly journals Molecular characterization of differences between the tomato immune receptors Fls3 and Fls2

2020 ◽  
Author(s):  
Robyn Roberts ◽  
Alexander E. Liu ◽  
Lingwei Wan ◽  
Annie M. Geiger ◽  
Sarah R. Hind ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Molecular Mechanisms ◽  
Bacterial Pathogen ◽  
Transcript Abundance ◽  
Defense Responses ◽  
Structural Features ◽  
Host Responses ◽  
Pathogen Invasion

AbstractPlants mount defense responses by recognizing indications of pathogen invasion, including microbe-associated molecular patterns (MAMPs). Flagellin from the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) contains two MAMPs, flg22 and flgII-28, that are recognized by tomato receptors Flagellin sensing 2 (Fls2) and Flagellin sensing 3 (Fls3), respectively. It is unknown to what degree each receptor contributes to immunity and if they promote immune responses using the same molecular mechanisms. Characterization of CRISPR/Cas9-generated Fls2 and Fls3 tomato mutants revealed that the two receptors contribute equally to disease resistance both on the leaf surface and in the apoplast. However, striking differences were observed in certain host responses mediated by the two receptors. Compared to Fls2, Fls3 mediated a more sustained production of reactive oxygen species (ROS) and an increase in transcript abundance of 44 tomato genes, with two genes serving as reporters for Fls3. Fls3 had greater in vitro kinase activity and interacted differently with the Pst effector AvrPtoB as compared to Fls2. Using chimeric Fls2/Fls3 proteins, we found that no receptor domain was solely responsible for the Fls3 sustained ROS, suggesting involvement of multiple structural features. This work reveals differences in the immunity outputs between Fls2 and Fls3, suggesting they use distinct molecular mechanisms to activate pattern-triggered immunity in response to flagellin-derived MAMPs.

scholarly journals Induction and Suppression of PEN3 Focal Accumulation During Pseudomonas syringae pv. tomato DC3000 Infection of Arabidopsis

2013 ◽  
Vol 26 (8) ◽  
pp. 861-867 ◽  
Author(s):  
Xiu-Fang Xin ◽  
Kinya Nomura ◽  
William Underwood ◽  
Sheng Yang He
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Cellular Response ◽  
Fluorescent Protein ◽  
Bacterial Pathogen ◽  
Tomato Dc3000 ◽  
Positive Role ◽  
Powdery Mildew Fungi ◽  
Combined Action ◽  
Green Fluorescent

The pleiotropic drug resistance (PDR) proteins belong to the super-family of ATP-binding cassette (ABC) transporters. AtPDR8, also called PEN3, is required for penetration resistance of Arabidopsis to nonadapted powdery mildew fungi. During fungal infection, plasma-membrane-localized PEN3 is concentrated at fungal entry sites, as part of the plant's focal immune response. Here, we show that the pen3 mutant is compromised in resistance to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. P. syringae pv. tomato DC3000 infection or treatment with a flagellin-derived peptide, flg22, induced strong focal accumulation of PEN3-green fluorescent protein. Interestingly, after an initial induction of PEN3 accumulation, P. syringae pv. tomato DC3000 but not the type-III-secretion-deficient mutant hrcC could suppress PEN3 accumulation. Moreover, transgenic overexpression of the P. syringae pv. tomato DC3000 effector AvrPto was sufficient to suppress PEN3 focal accumulation in response to flg22. Analyses of P. syringae pv. tomato DC3000 effector deletion mutants showed that individual effectors, including AvrPto, appear to be insufficient to suppress PEN3 accumulation when delivered by bacteria, suggesting a requirement for a combined action of multiple effectors. Collectively, our results indicate that PEN3 plays a positive role in plant resistance to a bacterial pathogen and show that focal accumulation of PEN3 protein may be a useful cellular response marker for the Arabidopsis–P. syringae interaction.

scholarly journals Complete Genome Sequence of the Endophytic Bacterium Chryseobacterium indologenes PgBE177, Isolated from Panax quinquefolius

2018 ◽  
Vol 7 (14) ◽  
Author(s):  
Chi Eun Hong ◽  
Jang Uk Kim ◽  
Jung Woo Lee ◽  
Kyong Hwan Bang ◽  
Ick-Hyun Jo
Keyword(s):  
Pseudomonas Syringae ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Bacterial Pathogen ◽  
Endophytic Bacterium ◽  
Antagonistic Activity ◽  
Panax Quinquefolius ◽  
Tomato Dc3000 ◽  
Content Type ◽  
Chryseobacterium Indologenes

Chryseobacterium indologenes PgBE177, isolated from the root tissue of a 4-year-old Panax quinquefolius plant, showed antagonistic activity against Pseudomonas syringae pv. tomato DC3000, a bacterial pathogen.

scholarly journals Analysis of Resistance Gene-Mediated Defense Responses in Arabidopsis thaliana Plants Carrying a Mutation in CPR5

1998 ◽  
Vol 11 (12) ◽  
pp. 1196-1206 ◽  
Author(s):  
Jens Boch ◽  
Michelle L. Verbsky ◽  
Tara L. Robertson ◽  
John C. Larkin ◽  
Barbara N. Kunkel
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Resistance Gene ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Defense Responses ◽  
Negative Regulator ◽  
Suppressor Mutations ◽  
Defense Related Gene ◽  
Rapid Activation

In resistant plants, pathogen attack often leads to rapid activation of defense responses that limit multiplication and spread of the pathogen. To investigate the signaling mechanisms underlying this process, we carried out a screen for mutants in the signaling pathway governing resistance in Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae. This involved screening for suppressor mutations that restored resistance to a susceptible line carrying a mutation in the RPS2 resistance gene. A mutant that conferred resistance by activating defense responses in the absence of pathogens was isolated. This mutant, which carries a mutation at the CPR5 locus and was thus designated cpr5-2, exhibited resistance to P. syringae, spontaneous development of necrotic lesions, elevated PR gene expression in the absence of pathogens, and abnormal trichomes. Resistance gene-mediated defenses, including the hypersensitive response, restriction of pathogen growth, and induction of defense-related gene expression, were functional in cpr5-2 mutant plants. Additionally, in cpr5-2 plants RPS2-mediated induction of PR-1 expression was enhanced, whereas RPM1-mediated induction of ELI3 was not. These findings suggest that CPR5 encodes a negative regulator of the RPS2 signal transduc-tion pathway.

scholarly journals The BIR2/BIR3-interacting Phospholipase D gamma 1 negatively regulates immunity in Arabidopsis

2019 ◽  
Author(s):  
Maria A. Schlöffel ◽  
Andrea Salzer ◽  
Wei-Lin Wan ◽  
Ringo van Wijk ◽  
Maja Šemanjski ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Pseudomonas Syringae ◽  
Phospholipase D ◽  
Plant Immunity ◽  
Negative Regulator ◽  
Regulatory Function ◽  
Membrane Phospholipids ◽  
Effective Strategies ◽  
Pathogen Invasion ◽  
Molecular Patterns

ABSTRACTPlants have evolved effective strategies to defend themselves against pathogen invasion. Starting from the plasma membrane with the recognition of microbe-associated molecular patterns (MAMPs) via pattern recognition receptors, internal cellular signaling pathways are induced to ultimately fend off the attack. Phospholipase D (PLD) hydrolyzes membrane phospholipids to produce phosphatidic acid (PA), which has been proposed to play a second messenger role in immunity. The Arabidopsis PLD family consists of 12 members and for some a specific function in resistance towards a subset of pathogens has been shown. We demonstrate here that Arabidopsis PLDγ1, but not its close homologs PLDγ2 and PLDγ3, is specifically involved in plant immunity. Genetic inactivation of PLDγ1 resulted in increased resistance towards the virulent bacterium Pseudomonas syringae pv. tomato DC3000 and the necrotrophic fungus Botrytis cinerea. As pldγ1 mutant plants responded with elevated levels of reactive oxygen species to MAMP-treatment, a negative regulatory function for this PLD isoform is proposed. Importantly, PA levels in pldγ1 mutants were not affected compared to stressed wild-type plants, suggesting that alterations in PA levels are unlikely the cause for the enhanced immunity in the pldγ1 line. Instead, the plasma-membrane-attached PLDγ1 protein colocalized and associated with the receptor-like kinases BIR2 and BIR3, which are known negative regulators of pattern-triggered immunity. Moreover, complex formation of PLDγ1 and BIR2 was further promoted upon MAMP-treatment. Hence, we propose that PLDγ1 acts as a negative regulator of plant immune responses in complex with immunity-related proteins BIR2 and BIR3.One-sentence summaryA phospholipase D is a novel negative regulator of plant immunity and forms complexes with regulatory receptor-like kinases.

scholarly journals XAP5 CIRCADIAN TIMEKEEPER Affects Both DNA Damage Responses and Immune Signaling in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Roderick W. Kumimoto ◽  
Cory T. Ellison ◽  
Tania Y. Toruño ◽  
Aurélie Bak ◽  
Hongtao Zhang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Pseudomonas Syringae ◽  
Dna Damage Response ◽  
Elevated Temperatures ◽  
Bacterial Pathogen ◽  
Negative Regulator ◽  
Positive Role ◽  
Damage Repair ◽  
Damage Response ◽  
Effector Triggered Immunity

Numerous links have been reported between immune response and DNA damage repair pathways in both plants and animals but the precise nature of the relationship between these fundamental processes is not entirely clear. Here, we report that XAP5 CIRCADIAN TIMEKEEPER (XCT), a protein highly conserved across eukaryotes, acts as a negative regulator of immunity in Arabidopsis thaliana and plays a positive role in responses to DNA damaging radiation. We find xct mutants have enhanced resistance to infection by a virulent bacterial pathogen, Pseudomonas syringae pv. tomato DC3000, and are hyper-responsive to the defense-activating hormone salicylic acid (SA) when compared to wild-type. Unlike most mutants with constitutive effector-triggered immunity (ETI), xct plants do not have increased levels of SA and retain enhanced immunity at elevated temperatures. Genetic analysis indicates XCT acts independently of NONEXPRESSOR OF PATHOGENESIS RELATED GENES1 (NPR1), which encodes a known SA receptor. Since DNA damage has been reported to potentiate immune responses, we next investigated the DNA damage response in our mutants. We found xct seedlings to be hypersensitive to UV-C and γ radiation and deficient in phosphorylation of the histone variant H2A.X, one of the earliest known responses to DNA damage. These data demonstrate that loss of XCT causes a defect in an early step of the DNA damage response pathway. Together, our data suggest that alterations in DNA damage response pathways may underlie the enhanced immunity seen in xct mutants.

scholarly journals The Cuticle Mutant eca2 Modifies Plant Defense Responses to Biotrophic and Necrotrophic Pathogens and Herbivory Insects

2018 ◽  
Vol 31 (3) ◽  
pp. 344-355 ◽  
Author(s):  
Catherine Blanc ◽  
Fania Coluccia ◽  
Floriane L’Haridon ◽  
Martha Torres ◽  
Marlene Ortiz-Berrocal ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Mechanism ◽  
Induced Defense ◽  
Constitutive Expression ◽  
Bacterial Pathogen ◽  
Transcriptional Response ◽  
Chemical Characterization ◽  
Biotic Interactions ◽  
Defense Responses ◽  
Herbivorous Insect

We isolated previously several Arabidopsis thaliana mutants with constitutive expression of the early microbe-associated molecular pattern–induced gene ATL2, named eca (expresión constitutiva de ATL2). Here, we further explored the interaction of eca mutants with pest and pathogens. Of all eca mutants, eca2 was more resistant to a fungal pathogen (Botrytis cinerea) and a bacterial pathogen (Pseudomonas syringae) as well as to a generalist herbivorous insect (Spodoptera littoralis). Permeability of the cuticle is increased in eca2; chemical characterization shows that eca2 has a significant reduction of both cuticular wax and cutin. Additionally, we determined that eca2 did not display a similar compensatory transcriptional response, compared with a previously characterized cuticular mutant, and that resistance to B. cinerea is mediated by the priming of the early and late induced defense responses, including salicylic acid– and jasmonic acid–induced genes. These results suggest that ECA2-dependent responses are involved in the nonhost defense mechanism against biotrophic and necrotrophic pathogens and against a generalist insect by modulation and priming of innate immunity and late defense responses. Making eca2 an interesting model to characterize the molecular basis for plant defenses against different biotic interactions and to study the initial events that take place in the cuticle surface of the aerial organs.

scholarly journals Constitutive Activation of Jasmonate Signaling in an Arabidopsis Mutant Correlates with Enhanced Resistance to Erysiphe cichoracearum, Pseudomonas syringae, and Myzus persicae

2002 ◽  
Vol 15 (10) ◽  
pp. 1025-1030 ◽  
Author(s):  
Christine Ellis ◽  
Ioannis Karafyllidis ◽  
John G. Turner
Keyword(s):  
Pseudomonas Syringae ◽  
Myzus Persicae ◽  
Green Peach Aphid ◽  
Bacterial Pathogen ◽  
Wild Type ◽  
Defense Genes ◽  
Erysiphe Cichoracearum ◽  
Enhanced Resistance ◽  
Arabidopsis Mutant ◽  
Ja Signaling

In Arabidopsis spp., the jasmonate (JA) response pathway generally is required for defenses against necrotrophic pathogens and chewing insects, while the salicylic acid (SA) response pathway is generally required for specific, resistance (R) gene-mediated defenses against both biotrophic and necrotrophic pathogens. For example, SA-dependent defenses are required for resistance to the biotrophic fungal pathogen Erysiphe cichoracearum UCSC1 and the bacterial pathogen Pseudomonas syringae pv. maculicola, and also are expressed during response to the green peach aphid Myzus persicae. However, recent evidence indicates that the expression of JA-dependent defenses also may confer resistance to E. cichoracearum. To confirm and to extend this observation, we have compared the disease and pest resistance of wild-type Arabidopsis plants with that of the mutants coi1, which is insensitive to JA, and cev1, which has constitutive JA signaling. Measurements of the colonization of these plants by E. cichoracearum, P. syringae pv. maculicola, and M. persicae indicated that activation of the JA signal pathway enhanced resistance, and was associated with the activation of JA-dependent defense genes and the suppression of SA-dependent defense genes. We conclude that JA and SA induce alternative defense pathways that can confer resistance to the same pathogens and pests.

scholarly journals Regulated Disorder: Posttranslational Modifications Control the RIN4 Plant Immune Signaling Hub

2019 ◽  
Vol 32 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Tania Y. Toruño ◽  
Mingzhe Shen ◽  
Gitta Coaker ◽  
David Mackey
Keyword(s):  
Pseudomonas Syringae ◽  
Posttranslational Modifications ◽  
Protein Complex ◽  
Bacterial Pathogen ◽  
Intrinsically Disordered Protein ◽  
Negative Regulator ◽  
Regulatory Function ◽  
Immune Signaling ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions

RIN4 is an intensively studied immune regulator in Arabidopsis and is involved in perception of microbial features outside and bacterial effectors inside plant cells. Furthermore, RIN4 is conserved in land plants and is targeted for posttranslational modifications by several virulence proteins from the bacterial pathogen Pseudomonas syringae. Despite the important roles of RIN4 in plant immune responses, its molecular function is not known. RIN4 is an intrinsically disordered protein (IDP), except at regions where pathogen-induced posttranslational modifications take place. IDP act as hubs for protein complex formation due to their ability to bind to multiple client proteins and, thus, are important players in signal transduction pathways. RIN4 is known to associate with multiple proteins involved in immunity, likely acting as an immune-signaling hub for the formation of distinct protein complexes. Genetically, RIN4 is a negative regulator of immunity, but diverse posttranslational modifications can either enhance its negative regulatory function or, on the contrary, render it a potent immune activator. In this review, we describe the structural domains of RIN4 proteins, their intrinsically disordered regions, posttranslational modifications, and highlight the implications that these features have on RIN4 function. In addition, we will discuss the potential role of plasma membrane subdomains in mediating RIN4 protein complex formations.

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.

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