scholarly journals Components of the Pseudomonas syringae Type III Secretion System Can Suppress and May Elicit Plant Innate Immunity

2010 ◽  
Vol 23 (6) ◽  
pp. 727-739 ◽  
Author(s):  
Hye-Sook Oh ◽  
Duck Hwan Park ◽  
Alan Collmer
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Leaf Tissue ◽  
Secretion System ◽  
Colony Development ◽  
Plant Responses ◽  
In Planta ◽  
Callose Deposition ◽  
Type Iii

The type III secretion system (T3SS) of Pseudomonas syringae translocates into plant cells multiple effectors that suppress pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). P. syringae pv. tomato DC3000 no longer delivers the T3SS translocation reporter AvrPto-Cya in Nicotiana benthamiana leaf tissue in which PTI was induced by prior inoculation with P. fluorescens(pLN18). Cosmid pLN18 expresses the T3SS system of P. syringae pv. syringae 61 but lacks the hopA1Psy61 effector gene. P. fluorescens(pLN18) expressing HrpHPtoDC3000 or HopP1PtoDC3000, two T3SS-associated putative lytic transglycosylases, suppresses PTI, based on multiple assays involving DC3000 challenge inoculum (AvrPto-Cya translocation, hypersensitive response elicitation, and colony development in planta) or on plant responses (vascular dye uptake or callose deposition). Analysis of additional mutations in pHIR11 derivatives revealed that the pLN18-encoded T3SS elicits a higher level of reactive oxygen species (ROS) than does P. fluorescens without a T3SS, that enhanced ROS production is dependent on the HrpK1 translocator, and that HopA1Psy61 suppresses ROS elicitation attributable to both the P. fluorescens PAMPs and the presence of a functional T3SS.

scholarly journals Naturally Occurring Nonpathogenic Isolates of the Plant Pathogen Pseudomonas syringae Lack a Type III Secretion System and Effector Gene Orthologues

2008 ◽  
Vol 190 (8) ◽  
pp. 2858-2870 ◽  
Author(s):  
Toni J. Mohr ◽  
Haijie Liu ◽  
Shuangchun Yan ◽  
Cindy E. Morris ◽  
José A. Castillo ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Plant Cells ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Plant Diseases ◽  
In Planta ◽  
Type Iii ◽  
Effector Gene

ABSTRACT Pseudomonas syringae causes plant diseases, and the main virulence mechanism is a type III secretion system (T3SS) that translocates dozens of effector proteins into plant cells. Here we report the existence of a subgroup of P. syringae isolates that do not cause disease on any plant species tested. This group is monophyletic and most likely evolved from a pathogenic P. syringae ancestor through loss of the T3SS. In the nonpathogenic isolate P. syringae 508 the genomic region that in pathogenic P. syringae strains contains the hrp-hrc cluster coding for the T3SS and flanking effector genes is absent. P. syringae 508 was also surveyed for the presence of effector orthologues from the closely related pathogenic strain P. syringae pv. syringae B728a, but none were detected. The absence of the hrp-hrc cluster and effector orthologues was confirmed for other nonpathogenic isolates. Using the AvrRpt2 effector as reporter revealed the inability of P. syringae 508 to translocate effectors into plant cells. Adding a plasmid-encoded T3SS and the P. syringae pv. syringae 61 effector gene hopA1 increased in planta growth almost 10-fold. This suggests that P. syringae 508 supplemented with a T3SS could be used to determine functions of individual effectors in the context of a plant infection, avoiding the confounding effect of other effectors with similar functions present in effector mutants of pathogenic isolates.

scholarly journals Transcriptional Regulation of Components of the Type III Secretion System and Effectors in Pseudomonas syringae pv. phaseolicola

2004 ◽  
Vol 17 (11) ◽  
pp. 1250-1258 ◽  
Author(s):  
R. Thwaites ◽  
P. D. Spanu ◽  
N. J. Panopoulos ◽  
C. Stevens ◽  
J. W. Mansfield
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Plant Cell Wall ◽  
Type Iii Secretion System ◽  
Regulatory Elements ◽  
Secretion System ◽  
Mrna Levels ◽  
In Planta ◽  
Type Iii ◽  
Effector Genes

Quantitative real-time polymerase chain reaction was used with specific TaqMan probes to examine transcription of selected hrp and effector genes in Pseudomonas syringae pv. phaseolicola strains 1448A (race 6) and 1449B (race 7). Transcripts examined were from genes encoding the regulators hrpR and hrpL, core structural components of the type III secretion system (TTSS) hrcC, hrcJ, hrcN, hrcU, and hrpA; the first open-reading frame of each hrp operon, including hrpF, hrpJ, hrpP, and hrpY; and also secreted effectors hrpZ, avrPphE, avrPphF, and virPphA. All genes were induced by incubation in a minimal medium and showed patterns of expression indicating regulation by HrpRS and HrpL. Basal mRNA levels and the timing of accumulation of transcripts after induction differed significantly, suggesting the operation of additional regulatory elements. However, no clear transcriptional hierarchy emerged to explain the ordered construction of the TTSS. Quantitative analysis confirmed that the rates and levels of transcript accumulation within the first 2 h after inoculation were considerably higher in planta than in vitro, and indicated that plant cell wall contact may enhance transcription of TTSS and effector genes in P. syringae pv. phaseolicola. The low-abundance hrcU mRNA had a half-life of 16.5 min, whereas other transcripts had half-lives between 3 and 8 min.

scholarly journals Translocation and Functional Analysis of Pseudomonas savastanoi pv. savastanoi NCPPB 3335 Type III Secretion System Effectors Reveals Two Novel Effector Families of the Pseudomonas syringae Complex

2014 ◽  
Vol 27 (5) ◽  
pp. 424-436 ◽  
Author(s):  
Isabel M. Matas ◽  
M. Pilar Castañeda-Ojeda ◽  
Isabel M. Aragón ◽  
María Antúnez-Lamas ◽  
Jesús Murillo ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Dna Sequences ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Callose Deposition ◽  
Type Iii ◽  
T3ss Effector ◽  
Olive Knot Disease ◽  
Relevant Role

Pseudomonas savastanoi pv. savastanoi NCPPB 3335 causes olive knot disease and is a model pathogen for exploring bacterial infection of woody hosts. The type III secretion system (T3SS) effector repertoire of this strain includes 31 effector candidates plus two novel candidates identified in this study which have not been reported to translocate into plant cells. In this work, we demonstrate the delivery of seven NCPPB 3335 effectors into Nicotiana tabacum leaves, including three proteins from two novel families of the P. syringae complex effector super-repertoire (HopBK and HopBL), one of which comprises two proteins (HopBL1 and HopBL2) that harbor a SUMO protease domain. When delivered by P. fluorescens heterologously expressing a P. syringae T3SS, all seven effectors were found to suppress the production of defense-associated reactive oxygen species. Moreover, six of these effectors, including the truncated versions of HopAA1 and HopAZ1 encoded by NCPPB 3335, suppressed callose deposition. The expression of HopAZ1 and HopBL1 by functionally effectorless P. syringae pv. tomato DC3000D28E inhibited the hypersensitive response in tobacco and, additionally, expression of HopBL2 by this strain significantly increased its competitiveness in N. benthamiana. DNA sequences encoding HopBL1 and HopBL2 were uniquely detected in a collection of 31 P. savastanoi pv. savastanoi strains and other P. syringae strains isolated from woody hosts, suggesting a relevant role of these two effectors in bacterial interactions with olive and other woody plants.

scholarly journals Decreased abundance of type III secretion system-inducing signals in Arabidopsis mkp1 enhances resistance against Pseudomonas syringae

2014 ◽  
Vol 111 (18) ◽  
pp. 6846-6851 ◽  
Author(s):  
J. C. Anderson ◽  
Y. Wan ◽  
Y.-M. Kim ◽  
L. Pasa-Tolic ◽  
T. O. Metz ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Iii

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

2010 ◽  
Vol 23 (2) ◽  
pp. 198-210 ◽  
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.

Inhibition of the type III secretion system of Pseudomonas syringae pv. tomato DC3000 by resveratrol oligomers identified in Vitis vinifera L

2020 ◽  
Vol 76 (7) ◽  
pp. 2294-2303 ◽  
Author(s):  
Ji Eun Kang ◽  
Byeong Jun Jeon ◽  
Min Young Park ◽  
Hye Ji Yang ◽  
Jaeyoung Kwon ◽  
...  
Keyword(s):  
Vitis Vinifera ◽  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Vitis Vinifera L ◽  
Tomato Dc3000 ◽  
Type Iii

scholarly journals Molecular mechanisms of two-component system RhpRS regulating type III secretion system in Pseudomonas syringae

2014 ◽  
Vol 42 (18) ◽  
pp. 11472-11486 ◽  
Author(s):  
Xin Deng ◽  
Haihua Liang ◽  
Kai Chen ◽  
Chuan He ◽  
Lefu Lan ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Molecular Mechanisms ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Two Component System ◽  
Component System ◽  
Type Iii ◽  
Two Component

scholarly journals Identification of Pseudomonas syringae pv. syringae 61 Type III Secretion System Hrp Proteins That Can Travel the Type III Pathway and Contribute to the Translocation of Effector Proteins into Plant Cells

2007 ◽  
Vol 189 (15) ◽  
pp. 5773-5778 ◽  
Author(s):  
Adela R. Ramos ◽  
Joanne E. Morello ◽  
Sandeep Ravindran ◽  
Wen-Ling Deng ◽  
Hsiou-Chen Huang ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Hypersensitive Response ◽  
Type Iii Secretion ◽  
Plant Cells ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Type Iii

ABSTRACT Pseudomonas syringae translocates effector proteins into plant cells via an Hrp1 type III secretion system (T3SS). T3SS components HrpB, HrpD, HrpF, and HrpP were shown to be pathway substrates and to contribute to elicitation of the plant hypersensitive response and to translocation and secretion of the model effector AvrPto1.

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