Defense responses of Arabidopsis thaliana inoculated with Pseudomonas syringae pv. tabaci wild type and defective mutants for flagellin (ΔfliC) and flagellin-glycosylation (Δorf1)

2005 ◽  
Vol 71 (4) ◽  
pp. 302-307 ◽  
Author(s):  
Yasuhiro Ishiga ◽  
Kasumi Takeuchi ◽  
Fumiko Taguchi ◽  
Yoshishige Inagaki ◽  
Kazuhiro Toyoda ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Wild Type ◽  
Flagellin Glycosylation

scholarly journals Bacillus cereus AR156 Activates Defense Responses to Pseudomonas syringae pv. tomato in Arabidopsis thaliana Similarly to flg22

2018 ◽  
Vol 31 (3) ◽  
pp. 311-322 ◽  
Author(s):  
Shune Wang ◽  
Ying Zheng ◽  
Chun Gu ◽  
Chan He ◽  
Mengying Yang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Cereus ◽  
Pseudomonas Syringae ◽  
Transcriptional Profiling ◽  
Quantitative Polymerase Chain Reaction ◽  
Polymerase Chain Reaction Analysis ◽  
Defense Responses ◽  
Systemic Resistance ◽  
Callose Deposition ◽  
Plant Growth Promoting

Bacillus cereus AR156 (AR156) is a plant growth–promoting rhizobacterium capable of inducing systemic resistance to Pseudomonas syringae pv. tomato in Arabidopsis thaliana. Here, we show that, when applied to Arabidopsis leaves, AR156 acted similarly to flg22, a typical pathogen-associated molecular pattern (PAMP), in initiating PAMP-triggered immunity (PTI). AR156-elicited PTI responses included phosphorylation of MPK3 and MPK6, induction of the expression of defense-related genes PR1, FRK1, WRKY22, and WRKY29, production of reactive oxygen species, and callose deposition. Pretreatment with AR156 still significantly reduced P. syringae pv. tomato multiplication and disease severity in NahG transgenic plants and mutants sid2-2, jar1, etr1, ein2, npr1, and fls2. This suggests that AR156-induced PTI responses require neither salicylic acid, jasmonic acid, and ethylene signaling nor flagella receptor kinase FLS2, the receptor of flg22. On the other hand, AR156 and flg22 acted in concert to differentially regulate a number of AGO1-bound microRNAs that function to mediate PTI. A full-genome transcriptional profiling analysis indicated that AR156 and flg22 activated similar transcriptional programs, coregulating the expression of 117 genes; their concerted regulation of 16 genes was confirmed by real-time quantitative polymerase chain reaction analysis. These results suggest that AR156 activates basal defense responses to P. syringae pv. tomato in Arabidopsis, similarly to flg22.

scholarly journals Induced Systemic Resistance in Arabidopsis thaliana Against Pseudomonas syringae pv. tomato by 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens

2012 ◽  
Vol 102 (4) ◽  
pp. 403-412 ◽  
Author(s):  
David M. Weller ◽  
Dmitri V. Mavrodi ◽  
Johan A. van Pelt ◽  
Corné M. J. Pieterse ◽  
Leendert C. van Loon ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Fluorescens ◽  
Induced Resistance ◽  
Pseudomonas Syringae ◽  
Induced Systemic Resistance ◽  
Signal Transduction Pathway ◽  
Systemic Resistance ◽  
Wild Type ◽  
Challenge Inoculation ◽  
Dependent Signal

Pseudomonas fluorescens strains that produce the polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are among the most effective rhizobacteria that suppress root and crown rots, wilts, and damping-off diseases of a variety of crops, and they play a key role in the natural suppressiveness of some soils to certain soilborne pathogens. Root colonization by 2,4-DAPG-producing P. fluorescens strains Pf-5 (genotype A), Q2-87 (genotype B), Q8r1-96 (genotype D), and HT5-1 (genotype N) produced induced systemic resistance (ISR) in Arabidopsis thaliana accession Col-0 against bacterial speck caused by P. syringae pv. tomato. The ISR-eliciting activity of the four bacterial genotypes was similar, and all genotypes were equivalent in activity to the well-characterized strain P. fluorescens WCS417r. The 2,4-DAPG biosynthetic locus consists of the genes phlHGF and phlACBDE. phlD or phlBC mutants of Q2-87 (2,4-DAPG minus) were significantly reduced in ISR activity, and genetic complementation of the mutants restored ISR activity back to wild-type levels. A phlF regulatory mutant (overproducer of 2,4-DAPG) had ISR activity equivalent to the wild-type Q2-87. Introduction of DAPG into soil at concentrations of 10 to 250 μM 4 days before challenge inoculation induced resistance equivalent to or better than the bacteria. Strain Q2-87 induced resistance on transgenic NahG plants but not on npr1-1, jar1, and etr1 Arabidopsis mutants. These results indicate that the antibiotic 2,4-DAPG is a major determinant of ISR in 2,4-DAPG-producing P. fluorescens, that the genotype of the strain does not affect its ISR activity, and that the activity induced by these bacteria operates through the ethylene- and jasmonic acid-dependent signal transduction pathway.

scholarly journals Convergent Evolution of Effector Protease Recognition by Arabidopsis and Barley

2019 ◽  
Vol 32 (5) ◽  
pp. 550-565 ◽  
Author(s):  
Morgan E. Carter ◽  
Matthew Helm ◽  
Antony V. E. Chapman ◽  
Emily Wan ◽  
Ana Maria Restrepo Sierra ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Protease Activity ◽  
Phylogenetic Analyses ◽  
Defense Responses ◽  
Host Protein ◽  
Wheat Cultivars ◽  
Wild Type ◽  
Barley Cultivars ◽  
Resistance Protein ◽  
Effector Recognition

The Pseudomonas syringae cysteine protease AvrPphB activates the Arabidopsis resistance protein RPS5 by cleaving a second host protein, PBS1. AvrPphB induces defense responses in other plant species, but the genes and mechanisms mediating AvrPphB recognition in those species have not been defined. Here, we show that AvrPphB induces defense responses in diverse barley cultivars. We also show that barley contains two PBS1 orthologs, that their products are cleaved by AvrPphB, and that the barley AvrPphB response maps to a single locus containing a nucleotide-binding leucine-rich repeat (NLR) gene, which we termed AvrPphB Response 1 (Pbr1). Transient coexpression of PBR1 with wild-type AvrPphB but not with a protease inactive mutant triggered defense responses, indicating that PBR1 detects AvrPphB protease activity. Additionally, PBR1 coimmunoprecipitated with barley and Nicotiana benthamiana PBS1 proteins, suggesting mechanistic similarity to detection by RPS5. Lastly, we determined that wheat cultivars also recognize AvrPphB protease activity and contain two putative Pbr1 orthologs. Phylogenetic analyses showed, however, that Pbr1 is not orthologous to RPS5. Our results indicate that the ability to recognize AvrPphB evolved convergently and imply that selection to guard PBS1-like proteins occurs across species. Also, these results suggest that PBS1-based decoys may be used to engineer protease effector recognition–based resistance in barley and wheat.

scholarly journals Involvement of the Small GTPase Rac in the Defense Responses of Tobacco to Pathogens

2005 ◽  
Vol 18 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Wolfgang Moeder ◽  
Keiko Yoshioka ◽  
Daniel F. Klessig
Keyword(s):  
Nadph Oxidase ◽  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Defense Responses ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Helicase Domain ◽  
Wild Type ◽  
Antioxidant Genes

During the hypersensitive response (HR), plants accumulate reactive oxygen species (ROS) that are likely generated at least in part by an NADPH oxidase similar to that found in mammalian neutrophils. An essential regulator of mammalian NADPH oxidase is the small GTP-binding protein Rac. To investigate whether Rac also regulates the pathogen-induced oxidative burst in plants, a dominant negative form of the rice OsRac1 gene was overexpressed in tobacco carrying the N resistance gene. Following infection with Tobacco mosaic virus (TMV), DN-OsRac1 plants developed smaller lesions than wild-type plants, accumulated lower levels of lipid peroxidation products, and failed to activate expression of antioxidant genes. These results, combined with the demonstration that superoxide and hydrogen peroxide levels were reduced in DN-OsRac1 tobacco developing a synchronous HR triggered by transient expression of the TMV p50 helicase domain or the Pto and AvrPto proteins, suggest that ROS production is impaired. The dominant negative effect of DN-OsRac1 could be rescued by transiently overexpressing the wild-type OsRac1 protein. TMV-induced salicylic acid accumulation also was compromised in DN-OsRac1 tobacco. Interestingly, while systemic acquired resistance to TMV was not impaired, nonhost resistance to Pseudomonas syringae pv. maculicola ES4326 was suppressed. Thus, the effect DN-OsRac1 expression exerts on the resistance signaling pathway appears to vary depending on the identity of the inoculated 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 HopZ Family of Pseudomonas syringae Type III Effectors Require Myristoylation for Virulence and Avirulence Functions in Arabidopsis thaliana

2008 ◽  
Vol 190 (8) ◽  
pp. 2880-2891 ◽  
Author(s):  
Jennifer D. Lewis ◽  
Wasan Abada ◽  
Wenbo Ma ◽  
David S. Guttman ◽  
Darrell Desveaux
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Hypersensitive Response ◽  
Pathogenic Bacteria ◽  
Functional Characterization ◽  
Defense Responses ◽  
Effector Proteins ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Virulence Protein

ABSTRACT Pseudomonas syringae utilizes the type III secretion system to translocate effector proteins into plant cells, where they can contribute to the pathogen's ability to infect and cause disease. Recognition of these effectors by resistance proteins induces defense responses that typically include a programmed cell death reaction called the hypersensitive response. The YopJ/HopZ family of type III effector proteins is a common family of effector proteins found in animal- and plant-pathogenic bacteria. The HopZ family in P. syringae includes HopZ1aPsyA2, HopZ1bPgyUnB647, HopZ1cPmaE54326, HopZ2Ppi895A and HopZ3PsyB728a. HopZ1a is predicted to be most similar to the ancestral hopZ allele and causes a hypersensitive response in multiple plant species, including Arabidopsis thaliana. Therefore, it has been proposed that host defense responses have driven the diversification of this effector family. In this study, we further characterized the hypersensitive response induced by HopZ1a and demonstrated that it is not dependent on known resistance genes. Further, we identified a novel virulence function for HopZ2 that requires the catalytic cysteine demonstrated to be required for protease activity. Sequence analysis of the HopZ family revealed the presence of a predicted myristoylation sequence in all members except HopZ3. We demonstrated that the myristoylation site is required for membrane localization of this effector family and contributes to the virulence and avirulence activities of HopZ2 and HopZ1a, respectively. This paper provides insight into the selective pressures driving virulence protein evolution by describing a detailed functional characterization of the diverse HopZ family of type III effectors with the model plant Arabidopsis.

scholarly journals Contrasting functions of Arabidopsis SUMO1/2 isoforms with SUMO3 intersect to modulate innate immunity and global SUMOylome responses

2020 ◽  
Author(s):  
Kishor Dnyaneshwar Ingole ◽  
Mritunjay Kasera ◽  
Harrold A. van den Burg ◽  
Saikat Bhattacharjee
Keyword(s):  
Arabidopsis Thaliana ◽  
Steady State ◽  
Heat Shock ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Defense Responses ◽  
Vital Role ◽  
Covalent Attachment ◽  
Developmental Defects ◽  
Small Proteins

AbstractReversible covalent attachment of SMALL UBIQUITIN-LIKE MODIFIERS (SUMOs) on target proteins regulate diverse cellular process across all eukaryotes. In Arabidopsis thaliana, most mutants with perturbed global SUMOylome display severe impairments in growth and adaptations to physiological stresses. Since SUMOs self-regulate activities of SUMOylation-associated proteins, existence of multiple isoforms introduces possibilities of their functional intersections which remain unexplored especially in plant systems. Using well-established defense responses elicited against virulent and avirulent Pseudomonas syringae pv. tomato strains, we investigated crosstalks in individual and combinatorial Arabidopsis sum mutants. Here we report that while SUM1 and SUM2 additively, but not equivalently suppress basal and TNL-specific immunity via down-regulation of salicylic acid (SA)-dependent responses, SUM3 promotes these defenses genetically downstream of SA. Remarkably, the expression of SUM3 is transcriptionally suppressed by SUMO1 or SUMO2. The loss of SUM3 not only lowers basal or post-bacterial challenge responsive enhancements of SUMO1/2-congugates but also reduces upregulation dynamics of defensive proteins and SUMOylation-associated transcripts. Combining a sum3 mutation partially attenuates heightened immunity of sum1 or sum2 mutants suggesting intricate functional impingements among these isoforms in optimizing immune amplitudes. Similar SUM1-SUM3 intersections also affect global SUMOylome responses to heat-shock affecting most notably the induction of selective heat-shock transcription factors. Overall, our investigations reveal novel insights into auto-regulatory mechanisms among SUMO isoforms in host SUMOylome maintenance and adjustments to environmental challenges.Author SummaryIn plants, similar to animals, protein functions are regulated at multiple levels. One prevalent mode is to allow covalent linkage of small proteins to specific amino acids on targets thereby affecting its fate and function. One such kind of modification named as SUMOylation involves attachment of SUMO proteins. A plant maintains strict control over its pool of SUMOylated proteins (termed SUMOylome) which upon biotic or abiotic stresses are altered to facilitate appropriate responses, returning back to steady-state when the threat subsides. In mutants of the model plant Arabidopsis thaliana having disturbed steady-state SUMOylome, growth and developmental defects ensue. These mutants are auto-immune showing more resistance to infection by the bacterial pathogen Pseudomonas syringae. However, Arabidopsis SUMO-family are comprised of multiple members raising the question about their specificity or functional crosstalks. We discovered that two SUMO members function in coordination to suppress immunity including the repression of a third member which supports defenses. The expression of this third member during pathogen attack or heat-shock influences the responsive changes in the host SUMOylome likely suggesting SUMOs themselves play vital role in these adaptations. Overall, our work highlights novel intersections of SUMO members in mounting stress-specific responses.

scholarly journals Molecular defense responses of apple genotypes in compatible and incompatible interactions with Erwinia amylovora

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. S139-S140
Author(s):  
M.N. Brisset ◽  
J.S. Venisse ◽  
J.P. Paulin
Keyword(s):  
Pseudomonas Syringae ◽  
Type Strain ◽  
Fire Blight ◽  
Molecular Mechanisms ◽  
Erwinia Amylovora ◽  
Wild Type Strain ◽  
Defense Responses ◽  
Bacterial Disease ◽  
Wild Type ◽  
Susceptible Host

Erwinia amylovora is the causal agent of fire blight, a bacterial disease of apple and pear. Pathogenicity determinants of the bacteria are identified (hrp-dsp cluster, capsule, siderophore) but molecular mechanisms leading to susceptibility or resistance of the plant are not yet understood. To address this question, we challenged two genotypes of apple, known for their contrasting susceptibility to fire blight, with a wild-type strain of E. amylovora (Ea wt), an avirulent hrp mutant of this bacteria (Ea hrp) or a wild-type strain of the incompatible pathogen Pseudomonas syringae pv. tabaci (Pst wt). Mechanisms usually related to resistance responses were investigated i.e. oxidative stress, accumulation of PR-proteins and induction of genes encoding various enzymes of the phenylpropanoid pathway. Results showed two kinds of responses (i) some mechanisms were elicited in both susceptible and resistant genotypes by Ea wt and Pst wt with similar kinetics and not induced by Ea hrp, (ii) others were specifically repressed by Ea wt in its susceptible host, when induced by Pst wt and Ea hrp. These results suggest several hypothesis about the cross-talk between E. amylovora and its host plants.

scholarly journals Identification of MAMP-Responsive Plasma Membrane-Associated Proteins in Arabidopsis thaliana Following Challenge with Different LPS Chemotypes from Xanthomonas campestris

Pathogens ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 787
Author(s):  
Raeesa H. Hussan ◽  
Ian A. Dubery ◽  
Lizelle A. Piater
Keyword(s):  
Arabidopsis Thaliana ◽  
Plasma Membrane ◽  
Xanthomonas Campestris ◽  
Induced Defense ◽  
Defense Responses ◽  
Structural Features ◽  
Wild Type ◽  
Core Oligosaccharide ◽  
Associated Proteins ◽  
Induced Defense Responses

Lipopolysaccharides (LPS) are recognized as microbe-associated molecular patterns (MAMPs) responsible for eliciting defense-related responses and while the effects have been well-documented in mammals, there is a lack of knowledge regarding the mechanism of perception in plant systems and recognized structural moieties within the macromolecular lipoglycan structure. Thus, identification of the LPS plasma membrane (PM) receptor(s)/receptor complex in Arabidopsis thaliana through proteomics will contribute to a deeper understanding of induced defense responses. As such, structurally characterized LPS chemotypes from Xanthomonas campestris pv. campestris (Xcc) wild-type 8004 (prototypical smooth-type LPS) and mutant 8530 (truncated core with no O–chain) strains were utilized to pre-treat A. thaliana plants. The associated proteomic response/changes within the PM were compared over a 24 h period using mass spectrometry-based methodologies following three variants of LPS-immobilized affinity chromatography. This resulted in the identification of proteins from several functional categories, but importantly, those involved in perception and defense. The distinct structural features between wild-type and mutant LPS are likely responsible for the differential changes to the proteome profiles, and many of the significant proteins were identified in response to the wild-type Xcc LPS where it is suggested that the core oligosaccharide and O-chain participate in recognition by receptor-like kinases (RLKs) in a multiprotein complex and, notably, varied from that of the mutant chemotype.

scholarly journals Serendipita indica changes host sugar and defense status in Arabidopsis thaliana: cooperation or exploitation?

Planta ◽  
2021 ◽  
Vol 253 (3) ◽  
Author(s):  
Michael W. Opitz ◽  
Roshanak Daneshkhah ◽  
Cindy Lorenz ◽  
Roland Ludwig ◽  
Siegrid Steinkellner ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Endophytic Fungus ◽  
Abiotic Stresses ◽  
Root Colonization ◽  
Growth Promotion ◽  
Sugar Metabolism ◽  
Defense Responses ◽  
Marker Genes ◽  
Wild Type ◽  
Biotic And Abiotic Stresses

Abstract Main conclusion Manipulation of sugar metabolism upon S. indica root colonization triggers changes in sugar pools and defense responses in A. thaliana. Abstract Serendipita indica is an endophytic fungus that establishes mutualistic relationships with many different plants including important crops as well as the model plant A. thaliana. Successful root colonization typically results in growth promotion and enhanced tolerance against various biotic and abiotic stresses. The fungus delivers phosphorus to the host and receives in exchange carbohydrates. There are hints that S. indica prefers hexoses, glucose, and fructose, products of saccharose cleavage driven by invertases (INVs) and sucrose synthases (SUSs). Carbohydrate metabolism in this interaction, however, remains still widely unexplored. Therefore, in this work, the sugar pools as well as the expression of SUSs and cytosolic INVs in plants colonized by S. indica were analyzed. Using sus1/2/3/4 and cinv1/2 mutants the importance of these genes for the induction of growth promotion and proper root colonization was demonstrated. Furthermore, the expression of several defense-related marker genes in both multiple mutants in comparison to the wild-type plants was determined. Our results show that in colonized A. thaliana plants S. indica manipulates the sugar metabolism by altering the expression of host’s INV and SUS and modulates both the sugar pools and plant defense in its favor. We conclude that the interaction A. thaliana–S. indica is a balancing act between cooperation and exploitation, in which sugar metabolism plays a crucial role. Small changes in this mechanism can lead to severe disruption resulting in the lack of growth promotion or altered colonization rate.

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