scholarly journals Interaction of the Xanthomonas effectors XopQ and XopX results in induction of rice immune responses

2020 ◽  
Author(s):  
Sohini Deb ◽  
Palash Ghosh ◽  
Hitendra K. Patel ◽  
Ramesh V. Sonti
Keyword(s):  
Immune Responses ◽  
Type Iii Secretion ◽  
Cell Wall Degrading Enzymes ◽  
Type Iii Effector ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Effector Triggered Immunity ◽  
Two Hybrid ◽  
Do So

SummaryXanthomonas oryzae pv. oryzae uses several type III secretion system (T3SS) effectors, namely XopN, XopQ, XopX, and XopZ, to suppress rice immune responses that are induced following treatment with cell wall degrading enzymes. Here we show that the T3SS secreted effector XopX interacts with two of the eight rice 14-3-3 proteins. Mutants of XopX that are defective in 14-3-3 binding are also defective in suppression of immune responses, suggesting that interaction with 14-3-3 proteins is required for suppression of host innate immunity. However, Agrobacterium mediated delivery of both XopX and XopQ into rice cells results in induction of rice immune responses. These immune responses are not observed when either protein is individually delivered into rice cells. XopQ-XopX induced rice immune responses are not observed in a XopX mutant that is defective in 14-3-3 binding. Yeast two-hybrid and BiFC assays indicate that XopQ and XopX interact with each other. In a screen for Xanthomonas effectors which can suppress XopQ-XopX induced rice immune responses, five effectors were identified, namely XopU, XopV, XopP, XopG and AvrBs2, which were able to do so. These results suggest a complex interplay of Xanthomonas T3SS effectors in suppression of pathogen triggered immunity and effector triggered immunity to promote virulence on rice.Significance statementThis work studies the role of the type III effector XopX in the suppression and induction of rice immune responses, by differential interaction with the 14-3-3 proteins, or with the type III effector XopQ respectively. We have also identified a subset of type III effectors which can suppress this form of immune responses.

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 The 33 carboxyl-terminal residues of Spa40 orchestrate the multi-step assembly process of the type III secretion needle complex in Shigella flexneri

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2807-2817 ◽  
Author(s):  
Anne Botteaux ◽  
Christian A. Kayath ◽  
Anne-Laure Page ◽  
Nouredine Jouihri ◽  
Musa Sani ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Shigella Flexneri ◽  
Gram Negative Bacteria ◽  
Assembly Process ◽  
Gram Negative ◽  
Type Iii ◽  
Carboxyl Terminal ◽  
Functional Analyses ◽  
Two Hybrid

The type III secretion apparatus (T3SA) is a central virulence factor of many Gram-negative bacteria. Its overall morphology consists of a cytoplasmic region, inner- and outer-membrane sections and an extracellular needle. In Shigella, the length of the needle is regulated by Spa32. To understand better the role of Spa32 we searched for its interacting partners using a two-hybrid screen in yeast. We found that Spa32 interacts with the 33 C-terminal residues (CC*) of Spa40, a member of the conserved FlhB/YscU family. Using a GST pull-down assay we confirmed this interaction and identified additional interactions between Spa40 and the type III secretion components Spa33, Spa47, MxiK, MxiN and MxiA. Inactivation of spa40 abolished protein secretion and led to needleless structures. Genetic and functional analyses were used to investigate the roles of residues L310 and V320, located within the CC* domain of Spa40, in the assembly of the T3SA. Spa40 cleavage, at the conserved NPTH motif, is required for assembly of the T3SA and for its interaction with Spa32, Spa33 and Spa47. In contrast, unprocessed forms of Spa40 interacted only with MxiA, MxiK and MxiN. Our data suggest that the conformation of the cytoplasmic domain of Spa40 defines the multi-step assembly process of the T3SA.

Effect of plant systemic resistance and role of type III secretion system in colonization of basil and lettuce by Salmonella enterica

2015 ◽  
Author(s):  
Shulamit Manulis ◽  
Maria Brandl ◽  
Isaac Barash ◽  
Laura Chalupowicz ◽  
Michael McClelland ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Salmonella Enterica ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Systemic Resistance ◽  
Type Iii

scholarly journals Use of the Galleria mellonella Caterpillar as a Model Host To Study the Role of the Type III Secretion System in Pseudomonas aeruginosa Pathogenesis

2003 ◽  
Vol 71 (5) ◽  
pp. 2404-2413 ◽  
Author(s):  
Sachiko Miyata ◽  
Monika Casey ◽  
Dara W. Frank ◽  
Frederick M. Ausubel ◽  
Eliana Drenkard
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Galleria Mellonella ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Triple Mutant ◽  
Type Iii ◽  
Wax Moth

ABSTRACT Nonvertebrate model hosts represent valuable tools for the study of host-pathogen interactions because they facilitate the identification of bacterial virulence factors and allow the discovery of novel components involved in host innate immune responses. In this report, we determined that the greater wax moth caterpillar Galleria mellonella is a convenient nonmammalian model host for study of the role of the type III secretion system (TTSS) in Pseudomonas aeruginosa pathogenesis. Based on the observation that a mutation in the TTSS pscD gene of P. aeruginosa strain PA14 resulted in a highly attenuated virulence phenotype in G. mellonella, we examined the roles of the four known effector proteins of P. aeruginosa (ExoS, ExoT, ExoU, and ExoY) in wax moth killing. We determined that in P. aeruginosa strain PA14, only ExoT and ExoU play a significant role in G. mellonella killing. Strain PA14 lacks the coding sequence for the ExoS effector protein and does not seem to express ExoY. Moreover, using ΔexoU ΔexoY, ΔexoT ΔexoY, and ΔexoT ΔexoU double mutants, we determined that individual translocation of either ExoT or ExoU is sufficient to obtain nearly wild-type levels of G. mellonella killing. On the other hand, data obtained with a ΔexoT ΔexoU ΔexoY triple mutant and a ΔpscD mutant suggested that additional, as-yet-unidentified P. aeruginosa components of type III secretion are involved in virulence in G. mellonella. A high level of correlation between the results obtained in the G. mellonella model and the results of cytopathology assays performed with a mammalian tissue culture system validated the use of G. mellonella for the study of the P. aeruginosa TTSS.

scholarly journals Characterization, Phylogeny, and Genome Analyses of Nonpathogenic Xanthomonas campestris Strains Isolated from Brassica Seeds

2020 ◽  
Vol 110 (5) ◽  
pp. 981-988 ◽  
Author(s):  
Yung-An Lee ◽  
Pei-Yu Yang ◽  
Shau-Chang Huang
Keyword(s):  
Type Iii Secretion ◽  
Xanthomonas Campestris ◽  
Pathogenicity Island ◽  
Whole Genome Sequence ◽  
Effector Protein ◽  
Type Iii Effector ◽  
Type Iii ◽  
Effector Genes ◽  
Genome Analyses ◽  
Xanthomonas Campestris Pv Campestris

Xanthomonads were detected by using the Xan-D(CCF) medium from the brassica seeds, and their pathogenicity was determined by plant inoculation tests. It was found that some seed lots were infested with Xanthomonas campestris pv. campestris, some with X. campestris pv. raphani, and some with nonpathogenic xanthomonads. The nonpathogenic xanthomonad strains were identified as X. campestris, and the multilocus sequence analysis showed that the nonpathogenic X. campestris strains were grouped together with pathogenic X. campestris, but not with nonpathogenic strains of X. arboricola. In addition, all isolated X. campestris pv. campestris and X. campestris pv. raphani strains were positive in the hrpF-PCR, but the nonpathogenic strains were negative. It was further found that nonpathogenic X. campestris strain nE1 does not contain the entire pathogenicity island (hrp gene cluster; type III secretion system) and all type III effector protein genes based on the whole genome sequence analyses. The nonpathogenic X. campestris strain nE1 could acquire the entire pathogenicity island from the endemic X. campestris pv. campestris and X. campestris pv. raphani strains by conjugation, but type III effector genes were not cotransferred. The studies showed that the nonpathogenic X. campestris strains indeed exist on the brassica seeds, but it could be differentiated by the PCR assays on the hrp and type III effector genes. Nevertheless, the nonpathogenic X. campestris strains cannot be ignored because they may be potential gene resources to increase genetic diversity in the endemic pathogenic X. campestris pv. campestris and X. campestris pv. raphani strains.

scholarly journals A revised model for the role of GacS/GacA in regulating type III secretion by Pseudomonas syringae pv. tomato DC3000

2019 ◽  
Vol 21 (1) ◽  
pp. 139-144 ◽  
Author(s):  
Megan R. O’Malley ◽  
Ching‐Fang Chien ◽  
Scott C. Peck ◽  
Nai‐Chun Lin ◽  
Jeffrey C. Anderson
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Tomato Dc3000 ◽  
Type Iii

Distribution of espI among clinical enterohaemorrhagic and enteropathogenic Escherichia coli isolates

2004 ◽  
Vol 53 (11) ◽  
pp. 1145-1149 ◽  
Author(s):  
Rosanna Mundy ◽  
Claire Jenkins ◽  
Jun Yu ◽  
Henry Smith ◽  
Gad Frankel
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Severe Disease ◽  
Pathogenicity Island ◽  
Effector Proteins ◽  
Effector Protein ◽  
Enteropathogenic Escherichia Coli ◽  
Type Iii Effector ◽  
Type Iii

Enterohaemorrhagic (EHEC) and enteropathogenic (EPEC) Escherichia coli are important diarrhoeagenic pathogens; infection is dependent on translocation of a number of type III effector proteins. Until recently all the known effectors were encoded on the LEE pathogenicity island, which also encodes the adhesin intimin and the type III secretion apparatus. Recently, a novel non-LEE effector protein, EspI/NleA, which is required for full virulence in vivo and is encoded on a prophage, was identified. The aim of this study was to determine the distribution of espI among clinical EHEC and EPEC isolates. espI was detected in 86 % and 53 % of LEE+ EHEC and EPEC strains, respectively. Moreover, the espI gene was more commonly found in patients suffering from a more severe disease.

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