Pseudomonas syringae evades phagocytosis in animal cells through type III effector-mediated inhibition of the LIM kinase-cofilin system

ABSTRACTCertain animal and plant pathogenic bacteria have developed virulence factors (including effector proteins) that enable them to overcome host immunity. A plant pathogen, Pseudomonas syringae pv. tomato (Pto), secretes a large repertoire of effectors into plant cells via a type III secretory apparatus, thereby suppressing plant immunity. Here, we show that exposure to Pto caused sepsis in mice. Surprisingly, the effector HopQ1 disrupted phagocytosis by inhibiting actin rearrangement via a direct interaction with the LIM domain of the animal target protein LIM kinase, a key regulator of actin polymerization. The results provide new insights into cross-kingdom pathogenicity of bacteria. The current studies demonstrate that certain plant pathogenic bacteria such as Pto can be fatal in animals due to cross-kingdom host immune suppression.

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Identification of Novel Type III Secretion Effectors in Xanthomonas oryzae pv. oryzae

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-22-1-0096 ◽

2009 ◽

Vol 22 (1) ◽

pp. 96-106 ◽

Cited By ~ 71

Author(s):

Ayako Furutani ◽

Minako Takaoka ◽

Harumi Sanada ◽

Yukari Noguchi ◽

Takashi Oku ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Type Iii Secretion ◽

Pathogenic Bacteria ◽

Regulatory Protein ◽

Effector Proteins ◽

Xanthomonas Oryzae ◽

Dependent Manner ◽

Plant Pathogenic Bacteria ◽

Type Iii ◽

Genes Encoding

Many gram-negative bacteria secrete so-called effector proteins via a type III secretion (T3S) system. Through genome screening for genes encoding potential T3S effectors, 60 candidates were selected from rice pathogen Xanthomonas oryzae pv. oryzae MAFF311018 using these criteria: i) homologs of known T3S effectors in plant-pathogenic bacteria, ii) genes with expression regulated by hrp regulatory protein HrpX, or iii) proteins with N-terminal amino acid patterns associated with T3S substrates of Pseudomonas syringae. Of effector candidates tested with the Bordetella pertussis calmodulin-dependent adenylate cyclase reporter for translocation into plant cells, 16 proteins were translocated in a T3S system-dependent manner. Of these 16 proteins, nine were homologs of known effectors in other plant-pathogenic bacteria and seven were not. Most of the effectors were widely conserved in Xanthomonas spp.; however, some were specific to X. oryzae. Interestingly, all these effectors were expressed in an HrpX-dependent manner, suggesting coregulation of effectors and the T3S system. In X. campestris pv. vesicatoria, HpaB and HpaC (HpaP in X. oryzae pv. oryzae) have a central role in recruiting T3S substrates to the secretion apparatus. Secretion of all but one effector was reduced in both HpaB– and HpaP– mutant strains, indicating that HpaB and HpaP are widely involved in efficient secretion of the effectors.

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XopC and XopJ, Two Novel Type III Effector Proteinsfrom Xanthomonas campestris pv.vesicatoria

Journal of Bacteriology ◽

10.1128/jb.185.24.7092-7102.2003 ◽

2003 ◽

Vol 185 (24) ◽

pp. 7092-7102 ◽

Cited By ~ 65

Author(s):

Laurent Noël ◽

Frank Thieme ◽

Jana Gäbler ◽

Daniela Büttner ◽

Ulla Bonas

Keyword(s):

Pseudomonas Syringae ◽

Plant Cell ◽

Type Iii Secretion ◽

Xanthomonas Campestris ◽

Pathogenic Bacteria ◽

Effector Proteins ◽

Type Iii ◽

Genome Wide ◽

A Genome ◽

Xanthomonas Campestris Pv.Vesicatoria

ABSTRACT Pathogenicity of the gram-negative plant pathogen Xanthomonas campestris pv. vesicatoria depends on a type III secretion (TTS) system which translocates bacterial effector proteins into the plant cell. Previous transcriptome analysis identified a genome-wide regulon of putative virulence genes that are coexpressed with the TTS system. In this study, we characterized two of these genes, xopC and xopJ. Both genes encode Xanthomonas outer proteins (Xops) that were shown to be secreted by the TTS system. In addition, type III-dependent translocation of both proteins into the plant cell was demonstrated using the AvrBs3 effector domain as a reporter. XopJ belongs to the AvrRxv/YopJ family of effector proteins from plant and animal pathogenic bacteria. By contrast, XopC does not share significant homology to proteins in the database. Sequence analysis revealed that the xopC locus contains several features that are reminiscent of pathogenicity islands. Interestingly, the xopC region is flanked by 62-bp inverted repeats that are also associated with members of the Xanthomonas avrBs3 effector family. Besides xopC, a second gene of the locus, designated hpaJ, was shown to be coexpressed with the TTS system. hpaJ encodes a protein with similarity to transglycosylases and to the Pseudomonas syringae pv. maculicola protein HopPmaG. HpaJ secretion and translocation by the X. campestris pv. vesicatoria TTS system was not detectable, which is consistent with its predicted Sec signal and a putative function as transglycosylase in the bacterial periplasm.

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The type III effector HopF2Pto targets Arabidopsis RIN4 protein to promote Pseudomonas syringae virulence

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0904739107 ◽

2010 ◽

Vol 107 (5) ◽

pp. 2349-2354 ◽

Cited By ~ 92

Author(s):

Mike Wilton ◽

Rajagopal Subramaniam ◽

James Elmore ◽

Corinna Felsensteiner ◽

Gitta Coaker ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Plant Immunity ◽

Effector Proteins ◽

Type Iii ◽

Pathogen Effector ◽

Effector Triggered Immunity ◽

Type Iii Secretion Effector ◽

Virulence Target

Plant immunity can be induced by two major classes of pathogen-associated molecules. Pathogen- or microbe-associated molecular patterns (PAMPs or MAMPs) are conserved molecular components of microbes that serve as “non-self” features to induce PAMP-triggered immunity (PTI). Pathogen effector proteins used to promote virulence can also be recognized as “non-self” features or induce a “modified-self” state that can induce effector-triggered immunity (ETI). The Arabidopsis protein RIN4 plays an important role in both branches of plant immunity. Three unrelated type III secretion effector (TTSE) proteins from the phytopathogen Pseudomonas syringae, AvrRpm1, AvrRpt2, and AvrB, target RIN4, resulting in ETI that effectively restricts pathogen growth. However, no pathogenic advantage has been demonstrated for RIN4 manipulation by these TTSEs. Here, we show that the TTSE HopF2Pto also targets Arabidopsis RIN4. Transgenic plants conditionally expressing HopF2Pto were compromised for AvrRpt2-induced RIN4 modification and associated ETI. HopF2Pto interfered with AvrRpt2-induced RIN4 modification in vitro but not with AvrRpt2 activation, suggestive of RIN4 targeting by HopF2Pto. In support of this hypothesis, HopF2Pto interacted with RIN4 in vitro and in vivo. Unlike AvrRpm1, AvrRpt2, and AvrB, HopF2Pto did not induce ETI and instead promoted P. syringae growth in Arabidopsis. This virulence activity was not observed in plants genetically lacking RIN4. These data provide evidence that RIN4 is a major virulence target of HopF2Pto and that a pathogenic advantage can be conveyed by TTSEs that target RIN4.

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The HopZ Family of Pseudomonas syringae Type III Effectors Require Myristoylation for Virulence and Avirulence Functions in Arabidopsis thaliana

Journal of Bacteriology ◽

10.1128/jb.01702-07 ◽

2008 ◽

Vol 190 (8) ◽

pp. 2880-2891 ◽

Cited By ~ 68

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.

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The proteasome acts as a hub for local and systemic plant immunity in Arabidopsis thaliana and constitutes a virulence target of Pseudomonas syringae type-III effector proteins

10.1101/053504 ◽

2016 ◽

Author(s):

Suayib Üstün ◽

Arsheed Sheikh ◽

Selena Gimenez-Ibanez ◽

Alexandra Jones ◽

Vardis Ntoukakis ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Bacterial Growth ◽

Plant Immunity ◽

Effector Proteins ◽

Proteasome Activity ◽

General Strategy ◽

Dependent Manner ◽

Type Iii Effector ◽

Type Iii ◽

Proteasome Subunits

AbstractRecent evidence suggests that the ubiquitin-proteasome system (UPS) is involved in several aspects of plant immunity and a range of plant pathogens subvert the UPS to enhance their virulence. Here, we show that proteasome activity is strongly induced during basal defense in Arabidopsis and mutant lines defective in proteasome subunits RPT2a and RPN12a support increased bacterial growth of virulent Pseudomonas syringae DC3000 (Pst), strains in local leaves. Both proteasome subunits are required for PTI events such as production of reactive oxygen species and mitogen-activated protein kinases signaling as well as for defense gene expression. Furthermore, analysis of bacterial growth after a secondary infection of systemic leaves revealed that the establishment of systemic-acquired resistance (SAR) is impaired in proteasome mutants, suggesting that the proteasome plays an important role in defense priming and SAR. In addition, we show that Pst inhibits proteasome activity in a type-III secretion dependent manner. A systematic screen for type-III effector proteins from Pst for their ability to interfere with proteasome activity revealed HopM1, HopAO1, HopA1 and HopG1 as candidates. Identification of proteins interacting with HopM1 by mass-spectrometry indicate that HopM1 resides in a complex together with several E3 ubiquitin ligases and proteasome subunits, supporting the hypothesis that HopM1 associates with the proteasome leading to its inhibition. We conclude that the proteasome is an essential component of the plant immune system and that some pathogens have developed a general strategy to overcome proteasome-mediated defense.One sentence summaryThe proteasome is required for local and systemic immune responses and is targeted by Pseudomonas type-III effectors

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THE ACTIVITY OF ESSENTIAL OILS OBTAINED FROM SPECIES AND INTERSPECIES HYBRIDS OF THE Mentha GENUS AGAINST SELECTED PLANT PATHOGENIC BACTERIA

Acta Scientiarum Polonorum Hortorum Cultus ◽

10.24326/asphc.2018.6.17 ◽

2018 ◽

Vol 17 (6) ◽

pp. 167-174 ◽

Cited By ~ 1

Author(s):

Małgorzata Schollenberger ◽

Tomasz M. Staniek ◽

Elżbieta Paduch-Cichal ◽

Beata Dasiewicz ◽

Agnieszka Gadomska-Gajadhur ◽

...

Keyword(s):

Essential Oils ◽

Pseudomonas Syringae ◽

Pathogenic Bacteria ◽

Antimicrobial Effect ◽

Mentha Piperita ◽

Mentha Spicata ◽

Plant Essential Oils ◽

Plant Pathogenic Bacteria ◽

Interspecies Hybrids

Plant essential oils of six aromatic herb species and interspecies hybrids of the family Lamiaceae – chocolate mint (Mentha piperita × ‘Chocolate’), pineapple mint (Mentha suaveolens ‘Variegata’), apple mint (Mentha × rotundifolia), spearmint (Mentha spicata), orange mint (Mentha × piperita ‘Granada’) and strawberry mint (Mentha × villosa ‘Strawberry’) – were investigated for antimicrobial effects against plant pathogenic bacteria: Agrobacterium tumefaciens, Pseudomonas syringae pv. syringae and Xanthomonas arboricola pv. corylina. The screening was carried out in vitro on agar plates filled with the target organism. All essential oils screened exhibited a higher level of antibacterial activity against A. tumefaciens and X. arboricola pv. corylina than streptomycin used as a standard in all tests. The antimicrobial effect of streptomycin and five mint oils was at the same level for P. syringae pv. syringae. There were no significant differences in the influence of the chocolate mint oil on the growth inhibition of all bacteria tested. Plant essential oils from pineapple mint, apple mint, spearmint and strawberry mint showed the weakest antimicrobial activity against P. syringae pv. syringae and the strongest towards A. tumefaciens and X. arboricola pv. corylina. The essential oils from strawberry mint, pineapple mint, spearmint and apple mint had the strongest effect on A. tumefaciens, and the lowest inhibitory activity was exhibited by the chocolate mint and orange mint essential oils. X. arboricola pv. corylina was the most sensitive to the strawberry mint, pineapple mint and spearmint oils. The chocolate mint oil showed the greatest activity against P. syringae pv. syringae.

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BAK1 Is Not a Target of the Pseudomonas syringae Effector AvrPto

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-04-10-0096 ◽

2011 ◽

Vol 24 (1) ◽

pp. 100-107 ◽

Cited By ~ 49

Author(s):

Tingting Xiang ◽

Na Zong ◽

Jie Zhang ◽

Jinfeng Chen ◽

Mingsheng Chen ◽

...

Keyword(s):

Cell Surface ◽

Immune Responses ◽

Pseudomonas Syringae ◽

Plant Cell ◽

Crucial Role ◽

Pathogenic Bacteria ◽

Effector Proteins ◽

Receptor Like Kinase ◽

Receptor Kinases ◽

New Evidence

Plant cell surface-localized receptor kinases such as FLS2, EFR, and CERK1 play a crucial role in detecting invading pathogenic bacteria. Upon stimulation by bacterium-derived ligands, FLS2 and EFR interact with BAK1, a receptor-like kinase, to activate immune responses. A number of Pseudomonas syringae effector proteins are known to block immune responses mediated by these receptors. Previous reports suggested that both FLS2 and BAK1 could be targeted by the P. syringae effector AvrPto to inhibit plant defenses. Here, we provide new evidence further supporting that FLS2 but not BAK1 is targeted by AvrPto in plants. The AvrPto-FLS2 interaction prevented the phosphorylation of BIK1, a downstream component of the FLS2 pathway.

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What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins

Microorganisms ◽

10.3390/microorganisms9051029 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1029

Author(s):

Karl J. Schreiber ◽

Ilea J. Chau-Ly ◽

Jennifer D. Lewis

Keyword(s):

Pseudomonas Syringae ◽

Structural Data ◽

Enzymatic Activities ◽

Effector Proteins ◽

Host Recognition ◽

Plant Host ◽

Type Iii ◽

Xanthomonas Species ◽

Pathogen Fitness ◽

Enzymatic Mechanisms

Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.

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Pseudomonas syringae Strains Naturally Lacking the Classical P. syringae hrp/hrc Locus Are Common Leaf Colonizers Equipped with an Atypical Type III Secretion System

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-2-0198 ◽

2010 ◽

Vol 23 (2) ◽

pp. 198-210 ◽

Cited By ~ 69

Author(s):

Christopher R. Clarke ◽

Rongman Cai ◽

David J. Studholme ◽

David S. Guttman ◽

Boris A. Vinatzer

Keyword(s):

Pseudomonas Syringae ◽

Type Iii Secretion ◽

Plant Cells ◽

Type Iii Secretion System ◽

Ice Nucleation ◽

Secretion System ◽

Effector Proteins ◽

Population Densities ◽

Type Iii ◽

Effector Genes

Pseudomonas syringae is best known as a plant pathogen that causes disease by translocating immune-suppressing effector proteins into plant cells through a type III secretion system (T3SS). However, P. syringae strains belonging to a newly described phylogenetic subgroup (group 2c) are missing the canonical P. syringae hrp/hrc cluster coding for a T3SS, flanking effector loci, and any close orthologue of known P. syringae effectors. Nonetheless, P. syringae group 2c strains are common leaf colonizers and grow on some tested plant species to population densities higher than those obtained by other P. syringae strains on nonhost species. Moreover, group 2c strains have genes necessary for the production of phytotoxins, have an ice nucleation gene, and, most interestingly, contain a novel hrp/hrc cluster, which is only distantly related to the canonical P. syringae hrp/hrc cluster. This hrp/hrc cluster appears to encode a functional T3SS although the genes hrpK and hrpS, present in the classical P. syringae hrp/hrc cluster, are missing. The genome sequence of a representative group 2c strain also revealed distant orthologues of the P. syringae effector genes avrE1 and hopM1 and the P. aeruginosa effector genes exoU and exoY. A putative life cycle for group 2c P. syringae is discussed.

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