Organization and Expression of the hrp Gene Cluster in Pseudomonas Syringae Pv. Phaseolicola

Rahme, Laurence G.; Mindrinos, Michael; Grimm, Charlotte; Frederick, Reid D.; Lindgren, P. B.; Panopoulos, Nickolas J.

doi:10.1007/978-3-642-73166-2_22

Cited by 2 publications

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“…However, as further discussed below and elaborated in more detail elsewhere (22,40), the inaZ reporter also has certain peculiarities that we took into consideration in designing our approach to the transcriptional studies. For As reported elsewhere (10,11,30,36), the hrpS gene is a positive regulator of hrpAB, hrpC, and hrpD expression. Regulatory functions have also been proposed for genes located at the termini of the hrp cluster of P. syringae pv.…”

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confidence: 73%

“…(27) are located on large plasmids, we also investigated whether the hrp cluster of P. syringae pv. phaseolicola might be located on extrachromosomal elements.(Preliminary results of these studies have been presented elsewhere [30,36]. )…”

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confidence: 99%

“…phaseolicola, possesses a group of genes, designated hrp ("harp"), that are essential for the development of disease symptoms and for the elicitation of the hypersensitive reaction on resistant plants. The majority of known hrp genes in this bacterium are clustered in a large genomic region that has been designated the hrp cluster, whereas one locus (hrpM) is located elsewhere in the genome (24,29,31,36). Besides P. syringae pv.…”

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confidence: 99%

“…phaseolicola and other phytopathogenic bacteria has been carried out (2,16,24,30,31,36), none of these regions has been fully characterized in respect to its overall genetic organization, such as the number of complementation groups and the transcriptional orientation of the various genes.…”

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“…(Preliminary results of these studies have been presented elsewhere [30,36].) NPS3121 NPS4000 NPS4002 NPS4004 NPS4007 NPS4001 NPS4003 NPS4006 LRB1011 LRB1013 LRB210 LRD410 LRE613 LRE813 LR72 LR323 LR42 LR71 LR348 LR70 LR413 LR2 LR328 LR38 LR62 LR50 LR12 LR57 LR6 LR65 LRB42 LR7 LR5 LR33 LR66 LRA11 LRE44 LR64 LRD71 LRB63 LRA102 LR8 LR4 LRG94 LRB14 LRH122 LRC124 LRB24 LRA32 LRB104 Plasmids pLAFR3 pLAFR6 pLAFR6-inaZ pPL6, pPL3, pNN56 pPL1 F-hsdS20 (hsdR hsdM) recAJ3 thi leu arg-14 proA2 lacYl galK2 rpsL xyl-S mtl-l supE44 A- (26).…”

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Genetic and transcriptional organization of the hrp cluster of Pseudomonas syringae pv. phaseolicola

1991

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The hrp cluster of Pseudomonas syringae pv. phaseolicola encodes functions that are essential for pathogenicity on bean plants and for the elicitation of the hypersensitive response on resistant plants. The cluster was saturated with insertions of transposon Tn3-spice that served both as a mutagen and as a sensitive reporter of the expression of the target regions. The mutations covered a 17.5-kb segment in strain NPS3121, in which seven hrp::Tn5 insertions had been previously mapped, and regions outside this segment. The cluster is organized into seven distinct complementation groups (hrpL, hrpAB, hrpC, hrpD, hrpE, hrpF, and hrpSR) on the basis of the analysis of over 100 Tn3-spice insertions in plasmids and 43 similar insertions in the chromosome; it spans nearly 22 kb and is chromosomally located. The transcriptional orientation of all genes in the cluster was established by measuring the level of ice nucleation activity of complemented merodiploids carrying chromosomal hrp::inaZ fusions after inoculation in Red Kidney bean leaves. Although all seven loci were actively expressed in Red Kidney bean leaves, none of them was substantially expressed when the bacteria were grown in King B broth medium. Mutations in all loci, except those in hrpC, greatly reduced the ability of the bacteria to multiply in bean leaves. Mutations in the hrpC locus, although preventing the bacteria from eliciting a hypersensitive reaction on tobacco, allowed the bacteria to produce delayed and attenuated symptoms in Red Kidney bean leaves and to multiply to a level 102. to 103-fold lower than that of the wild-type strain. This is the first comprehensive report of the genetic and transcriptional organization of the hrp gene cluster in a phytopathogenic bacterium.The bean halo blight pathogen, Pseudomonas syringae pv. phaseolicola, possesses a group of genes, designated hrp ("harp"), that are essential for the development of disease symptoms and for the elicitation of the hypersensitive reaction on resistant plants. The majority of known hrp genes in this bacterium are clustered in a large genomic region that has been designated the hrp cluster, whereas one locus (hrpM) is located elsewhere in the genome (24,29,31,36). Besides P. syringae pv. phaseolicola, hrp genes and/or gene clusters from several other members of the P. syringae taxon have been described and cloned (5, 13-16, 24, 30, 33, 37-39), as have those from phylogenetically distinct plant pathogens, such as Pseudomonas solanacearum (2, 14), Erwinia amylovora (44, 45), and some pathovars of Xanthomonas campestris (2,6,42). Homology between hrp genes has been reported among members of the P. syringae taxon (8a, 24) as well as between P. solanacearum and members of the X. campestris group (2).The nature and precise role of most hrp gene products in the plant-bacterium interaction are unknown. Three hrp loci have been analyzed in some detail in P. syringae pv. phaseolicola. A locus designated hrpS encodes a protein that shares sequence similarity to NtrC-like regulatory proteins (...

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confidence: 73%

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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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