Role of Type III Effector Secretion during Bacterial Pathogenesis in Another Kingdom

Bretz, James R.; Hutcheson, Steven W.

doi:10.1128/iai.72.7.3697-3705.2004

Cited by 15 publications

(14 citation statements)

References 87 publications

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“…Although the P. syringae species as a whole causes plant diseases on a multitude of agriculturally important plant species, individual P. syringae strains typically have a more limited host range (3,25,35). In the past decade, significant progress in unveiling the mechanisms of pathogenesis of P. syringae and other plant pathogens has been made (3,9,36,51). With either complete or draft sequences of three P. syringae pathovars currently available, this organism is an attractive model for molecular studies of plant-pathogen interactions (9,10).…”

mentioning

confidence: 99%

“…tomato DC3000 (10,16,24,50,72). To date, more than 150 effector genes have been identified in P. syringae, and it has been suggested that variations in host specificity may be due to differences in the effector complements of individual P. syringae strains (3,9,29,30). TTSS effectors are encoded by genes that are either linked with the hrp PAI, dispersed throughout the chromosome, or harbored on indigenous plasmids (2,4,10,37,38,52,64).…”

mentioning

confidence: 99%

“…In the past decade, significant progress in unveiling the mechanisms of pathogenesis of P. syringae and other plant pathogens has been made (3,9,36,51). With either complete or draft sequences of three P. syringae pathovars currently available, this organism is an attractive model for molecular studies of plant-pathogen interactions (9,10). A functional hypersensitive response and pathogenicity (hrp pathogenicity island [PAI]) type III secretion system (TTSS) that directs the delivery of effector proteins into host cells has been shown to be the key pathogenicity factor required for P. syringae to colonize and parasitize host plants (3,9,40,46,51).…”

mentioning

confidence: 99%

“…With either complete or draft sequences of three P. syringae pathovars currently available, this organism is an attractive model for molecular studies of plant-pathogen interactions (9, 10). A functional hypersensitive response and pathogenicity (hrp pathogenicity island [PAI]) type III secretion system (TTSS) that directs the delivery of effector proteins into host cells has been shown to be the key pathogenicity factor required for P. syringae to colonize and parasitize host plants (3,9,40,46,51). While the complete repertoire of effectors of any one P. syringae strain is still unknown, several recent studies have revealed that this number can be as large as 58 in P. syringae pv.…”

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confidence: 99%

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Comparative Genomic Analysis of the pPT23A Plasmid Family of Pseudomonas syringae

Zhao¹,

Ma²,

Sundin

2005

J Bacteriol

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Members of the pPT23A plasmid family of Pseudomonas syringae play an important role in the interaction of this bacterial pathogen with host plants. Complete sequence analysis of several pPT23A family plasmids (PFPs) has provided a glimpse of the gene content and virulence function of these plasmids. We constructed a macroarray containing 161 genes to estimate and compare the gene contents of 23 newly analyzed and eight known PFPs from 12 pathovars of P. syringae, which belong to four genomospecies. Hybridization results revealed that PFPs could be distinguished by the type IV secretion system (T4SS) encoded and separated into four groups. Twelve PFPs along with pPSR1 from P. syringae pv. syringae, pPh1448B from P. syringae pv. phaseolicola, and pPMA4326A from P. syringae pv. maculicola encoded a type IVA T4SS (VirB-VirD4 conjugative system), whereas 10 PFPs along with pDC3000A and pDC3000B from P. syringae pv. tomato encoded a type IVB T4SS (tra system). Two plasmids encoded both T4SSs, whereas six other plasmids carried none or only a few genes of either the type IVA or type IVB secretion system. Most PFPs hybridized to more than one putative type III secretion system effector gene and to a variety of additional genes encoding known P. syringae virulence factors. The overall gene contents of individual PFPs were more similar among plasmids within each of the four groups based on T4SS genes; however, a number of genes, encoding plasmid-specific functions or hypothetical proteins, were shared among plasmids from different T4SS groups. The only gene shared by all PFPs in this study was the repA gene, which encoded sequences with 87 to 99% amino acid identity among 25 sequences examined. We proposed a model to illustrate the evolution and gene acquisition of the pPT23A plasmid family. To our knowledge, this is the first such attempt to conduct a global genetic analysis of this important plasmid family.The species Pseudomonas syringae comprises a group of plant-associated bacteria that act either as epiphytes or as plant pathogens causing important diseases with significant economic consequences (35). Although the P. syringae species as a whole causes plant diseases on a multitude of agriculturally important plant species, individual P. syringae strains typically have a more limited host range (3,25,35). In the past decade, significant progress in unveiling the mechanisms of pathogenesis of P. syringae and other plant pathogens has been made (3,9,36,51). With either complete or draft sequences of three P. syringae pathovars currently available, this organism is an attractive model for molecular studies of plant-pathogen interactions (9, 10). A functional hypersensitive response and pathogenicity (hrp pathogenicity island [PAI]) type III secretion system (TTSS) that directs the delivery of effector proteins into host cells has been shown to be the key pathogenicity factor required for P. syringae to colonize and parasitize host plants (3,9,40,46,51). While the complete repertoire of effectors of any one P. syringae s...

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confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Comparative Genomic Analysis of the pPT23A Plasmid Family of Pseudomonas syringae

Zhao¹,

Ma²,

Sundin

2005

J Bacteriol

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“…Previous studies have demonstrated that the inactivation of T3SEs from P. syringae and other plant pathogens in agricultural or contrived conditions can profoundly influence pathogen-host interactions [11,[23][24][25][26]. Most of this work has implicated horizontal gene transfer and the resulting acquisition and loss of T3SE as an important arms race strategy [27,28].…”

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confidence: 99%

Diversification of a Type III Effector Family via both Pathoadaptation and Horizontal Transfer in Response to a Coevolutionary Arms Race

Ma¹,

Dong²,

Stavrinides³

et al. 2005

PLoS Genet

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The concept of the coevolutionary arms race holds a central position in our understanding of pathogen-host interactions. Here we identify the molecular mechanisms and follow the stepwise progression of an arms race in a natural system. We show how the evolution and function of the HopZ family of type III secreted effector proteins carried by the plant pathogen Pseudomonas syringae are influenced by a coevolutionary arms race between pathogen and host. We surveyed 96 isolates of P. syringae and identified three homologs (HopZ1, HopZ2, and HopZ3) distributed among ;45% of the strains. All alleles were sequenced and their expression was confirmed. Evolutionary analyses determined that the diverse HopZ1 homologs are ancestral to P. syringae, and have diverged via pathoadaptive mutational changes into three functional and two degenerate forms, while HopZ2 and HopZ3 have been brought into P. syringae via horizontal transfer from other ecologically similar bacteria. A PAML selection analysis revealed that the C terminus of HopZ1 is under strong positive selection. Despite the extensive genetic variation observed in this family, all three homologs have cysteine-protease activity, although their substrate specificity may vary. The introduction of the ancestral hopZ1 allele into strains harboring alternate alleles results in a resistance protein-mediated defense response in their respective hosts, which is not observed with the endogenous allele. These data indicate that the P. syringae HopZ family has undergone allelic diversification via both pathoadaptive mutational changes and horizontal transfer in response to selection imposed by the host defense system. This genetic diversity permits the pathogen to avoid host defenses while still maintaining a virulence-associated protease, thereby allowing it to thrive on its current host, while simultaneously impacting its host range.Citation: Ma W, Dong FFT, Stavrinides J, Guttman DS (2006) Type III effector diversification via both pathoadaptation and horizontal transfer in response to a coevolutionary arms race. PLoS Genet 2(12): e209.

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Phosphatidylcholine synthesis is essential for HrpZ harpin secretion in plant pathogenic Pseudomonas syringae and non-pathogenic Pseudomonas sp. 593

Xiong

Long²,

He³

et al. 2014

Microbiological Research

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Pseudomonas syringae pv. syringae van Hall is important phytopathogenic bacterium of stone fruit trees, and able to elicit hypersensitive response (HR) in nonhost plants. The HrpZ, secreted via type III secretion system (T3SS) to the extracellular space of the plant, is a T3SS-dependent protein and a sole T3SS effector able to induce the host defense response outside host cells. We deleted the phosphatidylcholine synthase gene (pcs) of P. syringae pv. syringae van Hall CFCC 1336, and found that the 1336 pcs(-) mutant was unable to synthesize phosphatidylcholine and elicit a typical HR in soybean. Further studies showed that the 1336 pcs(-) mutant was unable to secrete HrpZ harpin but could express HrpZ protein in cytoplasm as effectively as the wild type. To confirm if phosphatidylcholine affects HrpZ harpin secretion, we introduced the hrpZ gene into the soil-dwelling bacterium Pseudomonas sp. 593 and the 593 pcs(-) mutant, which were unable to express HrpZ harpin and elicit HR in tobacco or soybean. Western blotting and HR assay showed that the 593H not only secreted HrpZ harpin but also caused a strong HR in tobacco and soybean. In contrast, the 593 pcs(-)H only expressed HrpZ protein in its cytoplasm at the wild type level, but did not secrete HrpZ harpin or elicit HR reaction. Our results demonstrate that phosphatidylcholine is essential for the secretion of HrpZ harpin in P. syringae pv. syringae van Hall and other Pseudomonas strains.

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Role of Type III Effector Secretion during Bacterial Pathogenesis in Another Kingdom

Cited by 15 publications

References 87 publications

Comparative Genomic Analysis of the pPT23A Plasmid Family of Pseudomonas syringae

Comparative Genomic Analysis of the pPT23A Plasmid Family of Pseudomonas syringae

Diversification of a Type III Effector Family via both Pathoadaptation and Horizontal Transfer in Response to a Coevolutionary Arms Race

Phosphatidylcholine synthesis is essential for HrpZ harpin secretion in plant pathogenic Pseudomonas syringae and non-pathogenic Pseudomonas sp. 593

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