The CompletehrpGene Cluster ofPseudomonas syringaepv.syringae61 Includes Two Blocks of Genes Required for HarpinPssSecretion that Are Arranged Colinearly withYersinia yscHomologs

Huang, Hsiou-Chen; Lin, Rong‐Hwa; Chang, Chung‐Cheng; Collmer, Alan; Deng, Wen-Ling

doi:10.1094/mpmi-8-0733

Cited by 99 publications

(75 citation statements)

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“…AF 268940) with the hrpZ operon described for other pathovars of P. syringae (15) revealed Psph genes homologous to hrpA, hrpZ, hrpB, hrcJ, hrpD, and hrpE. In contrast to other pathovars of P. syringae (15,34), Northern blot analysis of RNA prepared from Psph grown in minimal medium revealed separate hrpA and hrpZ ϩ hrpB-specific transcripts (not shown). The deletion of basepairs 46-356 of hrpZ abolished accumulation of the gene product in bacteria grown under hrp-inducing conditions, but no alteration in pathogenicity on bean was associated with the hrpZ mutation (not shown).…”

Section: Resultsmentioning

confidence: 85%

HrpZPsph from the plant pathogen Pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore invitro

Lee

Klüsener²,

Tsiamis³

et al. 2000

Proceedings of the National Academy of Sciences

120

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The hrp gene clusters of plant pathogenic bacteria control pathogenicity on their host plants and ability to elicit the hypersensitive reaction in resistant plants. Some hrp gene products constitute elements of the type III secretion system, by which effector proteins are exported and delivered into plant cells. Here, we show that the hrpZ gene product from the bean halo-blight pathogen, Pseudomonas syringae pv. phaseolicola (HrpZPsph), is secreted in an hrp-dependent manner in P. syringae pv. phaseolicola and exported by the type III secretion system in the mammalian pathogen Yersinia enterocolitica. HrpZPsph was found to associate stably with liposomes and synthetic bilayer membranes. Under symmetric ionic conditions, addition of 2 nM of purified recombinant HrpZ Psph to the cis compartment of planar lipid bilayers provoked an ion current with a large unitary conductivity of 207 pS. HrpZPsphrelated proteins from P. syringae pv. tomato or syringae triggered ion currents similar to those stimulated by HrpZPsph. The HrpZPsphmediated ion-conducting pore was permeable for cations but did not mediate fluxes of Cl ؊ . Such pore-forming activity may allow nutrient release and͞or delivery of virulence factors during bacterial colonization of host plants.

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Section: Resultsmentioning

confidence: 85%

HrpZPsph from the plant pathogen Pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore invitro

Lee

Klüsener²,

Tsiamis³

et al. 2000

Proceedings of the National Academy of Sciences

120

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“…In the hrp/hrc gene cluster, hrpZ and hrpW encode harpin proteins, defined as glycine-rich, cysteine-lacking proteins that are secreted by the TTSS and that possess heatstable HR elicitor activity (Wei et al 1992;Huang et al 1995;Charkowski et al 1998). HrpZ in P. viridiflava shares these features of amino acid sequences, containing no cystein-coding codons and 42-46 out of 314-337 glycine-coding codons.…”

Section: Resultsmentioning

confidence: 99%

Molecular Evolution of Pathogenicity-Island Genes in Pseudomonas viridiflava

et al. 2007

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The bacterial pathogen Pseudomonas viridiflava possesses two pathogenicity islands (PAIs) that share many gene homologs, but are structurally and phenotypically differentiated (T-PAI and S-PAI). These PAIs are paralogous, but only one is present in each isolate. While this dual presence/absence polymorphism has been shown to be maintained by balancing selection, little is known about the molecular evolution of individual genes on the PAIs. Here we investigate genetic variation of 12 PAI gene loci (7 on T-PAI and 5 on S-PAI) in 96 worldwide isolates of P. viridiflava. These genes include avirulence genes (hopPsyA and avrE ), their putative chaperones (shcA and avrF ), and genes encoding the type III outer proteins (hrpA, hrpZ, and hrpW ). Average nucleotide diversities in these genes (p ¼ 0.004-0.020) were close to those in the genetic background. Large numbers of recombination events were found within PAIs and a sign of positive selection was detected in avrE. These results suggest that the PAI genes are evolving relatively freely from each other on the PAIs, rather than as a single unit under balancing selection. Evolutionarily stable PAIs may be preferable in this species because preexisting genetic variation enables P. viridiflava to respond rapidly to natural selection.

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“…Sixteen of the 25 genes in this completely sequenced hrp͞hrmA gene cluster are either predicted or shown to be required for secretion of harpin Pss , a proteinaceous elicitor of the HR encoded by hrpZ (9,10). Nine of these hrp genes, recently renamed hrc genes (11), are broadly conserved among P. syringae pathovars, Erwinia, Xanthomonas, and Ralstonia (9,(12)(13)(14)(15). hrc genes, including hrcC (formerly hrpH; ref.…”

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confidence: 99%

Hrp pilus: An hrp -dependent bacterial surface appendage produced by Pseudomonas syringae pv. tomato DC3000

Roine

Wei

Yuan

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

323

279

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Hypersensitive response and pathogenicity (hrp) genes control the ability of major groups of plant pathogenic bacteria to elicit the hypersensitive response (HR) in resistant plants and to cause disease in susceptible plants. A number of Hrp proteins share significant similarities with components of the type III secretion apparatus and f lagellar assembly apparatus in animal pathogenic bacteria. Here we report that Pseudomonas syringae pv. tomato strain DC3000 (race 0) produces a filamentous surface appendage (Hrp pilus) of 6-8 nm in diameter in a solid minimal medium that induces hrp genes. Formation of the Hrp pilus is dependent on at least two hrp genes, hrpS and hrpH (recently renamed hrcC), which are involved in gene regulation and protein secretion, respectively. Our finding of the Hrp pilus, together with recent reports of Salmonella typhimurium surface appendages that are involved in bacterial invasion into the animal cell and of the Agrobacterium tumefaciens virB-dependent pilus that is involved in the transfer of T-DNA into plant cells, suggests that surface appendage formation is a common feature of animal and plant pathogenic bacteria in the infection of eukaryotic cells. Furthermore, we have identified HrpA as a major structural protein of the Hrp pilus. Finally, we show that a nonpolar hrpA mutant of P. syringae pv. tomato DC3000 is unable to form the Hrp pilus or to cause either an HR or disease in plants.Major groups of Gram-negative plant pathogenic bacteria belonging to genera Erwinia, Pseudomonas, Ralstonia, and Xanthomonas contain hypersensitive reaction and pathogenicity (hrp) genes. These genes control the ability of these bacteria to initiate interactions with plants, including elicitation of the hypersensitive reaction (HR), characterized by rapid localized death of plant cells at the pathogen infection site in resistant plants and causation of disease in susceptible plants (1, 2).hrp genes of Pseudomonas syringae are expressed in planta as a result of a regulatory cascade involving the gene products of hrpS and hrpR, positive transcriptional regulators, and of hrpL, an alternative sigma factor (3, 4). HrpL recognizes a consensus sequence motif (''harp box'') that has been identified in the upstream regions of many hrp and avr genes (4). The expression of hrp genes of many P. syringae pathovars can also be induced in vitro when bacteria are grown in defined minimal medium with low pH and containing certain sugars or sugar alcohols as carbon sources (5-7).The 25-kb hrp͞hrmA gene cluster of Pseudomonas syringae pv. syringae strain 61 is sufficient to enable nonpathogenic strains of Pseudomonas fluorescens and Escherichia coli to elicit the HR in nonhost plants (8). Sixteen of the 25 genes in this completely sequenced hrp͞hrmA gene cluster are either predicted or shown to be required for secretion of harpin Pss , a proteinaceous elicitor of the HR encoded by hrpZ (9, 10). Nine of these hrp genes, recently renamed hrc genes (11), are broadly conserved among P. syringae pathovars, Erwi...

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The CompletehrpGene Cluster ofPseudomonas syringaepv.syringae61 Includes Two Blocks of Genes Required for Harpin_PssSecretion that Are Arranged Colinearly withYersinia yscHomologs

Cited by 99 publications

References 0 publications

HrpZPsph from the plant pathogen Pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore invitro

HrpZPsph from the plant pathogen Pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore invitro

Molecular Evolution of Pathogenicity-Island Genes in Pseudomonas viridiflava

Hrp pilus: An hrp -dependent bacterial surface appendage produced by Pseudomonas syringae pv. tomato DC3000

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