scholarly journals Ornithine carbamoyltransferase genes and phaseolotoxin immunity in Pseudomonas syringae pv. phaseolicola

1987 ◽  
Vol 6 (12) ◽  
pp. 3585-3591 ◽  
Author(s):  
Richard C. Peet ◽  
Nickolas J. Panopoulos
Keyword(s):  
Pseudomonas Syringae ◽  
Ornithine Carbamoyltransferase

scholarly journals The Global Arginine Regulator ArgR Controls Expression of argF in Pseudomonas syringae pv. phaseolicola but Is Not Required for the Synthesis of Phaseolotoxin or for the Regulated Expression of argK

2004 ◽  
Vol 186 (11) ◽  
pp. 3653-3655 ◽  
Author(s):  
José Luis Hernández-Flores ◽  
Karina López-López ◽  
Rogelio Garcidueñas-Piña ◽  
Alba E. Jofre-Garfias ◽  
Ariel Alvarez-Morales
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Syringae ◽  
Ornithine Carbamoyltransferase ◽  
Regulated Expression

ABSTRACT In Pseudomonas syringae pv. phaseolicola the enzyme ornithine carbamoyltransferase (OCTase), encoded by argF, is negatively regulated by argR, similar to what has been reported for Pseudomonas aeruginosa. However, production of the phaseolotoxin-resistant OCTase encoded by argK, synthesis of phaseolotoxin, and infectivity for bean pods occur independently of the ArgR protein.

scholarly journals In Pseudomonas syringae pv. phaseolicola, Expression of the argK Gene, Encoding the Phaseolotoxin-Resistant Ornithine Carbamoyltransferase, Is Regulated Indirectly by Temperature and Directly by a Precursor Resembling Carbamoylphosphate

2004 ◽  
Vol 186 (1) ◽  
pp. 146-153 ◽  
Author(s):  
Karina López-López ◽  
José Luis Hernández-Flores ◽  
Marisa Cruz-Aguilar ◽  
Ariel Alvarez-Morales
Keyword(s):  
Pseudomonas Syringae ◽  
Regulatory Mechanisms ◽  
Ornithine Carbamoyltransferase ◽  
Wild Type ◽  
Gene Encoding ◽  
Null Mutants

ABSTRACT Pseudomonas syringae pv. phaseolicola synthesizes a non-host-specific toxin, phaseolotoxin, and also synthesizes a phaseolotoxin-resistant ornithine carbamoyltransferase (ROCT) to protect itself from its own toxin. ROCT is encoded by argK, which is expressed coordinately with phaseolotoxin synthesis at 18°C. To investigate the regulatory mechanisms of this system, null mutants were constructed for argK, argF (encoding the phaseolotoxin-sensitive OCTase [SOCT]), and amtA (encoding an amidinotransferase involved in phaseolotoxin synthesis). The argF mutant did not exhibit arginine auxotrophy when grown in M9 medium at 28°C, because under this condition SOCT was replaced by ROCT. This loss of thermoregulation of argK was apparently caused by accumulation of carbamoylphosphate, one of the substrates of SOCT. Carbamoylphosphate, which has a structure similar to that of the inorganic moiety of phaseolotoxin, was used in induction assays with wild-type P. syringae pv. phaseolicola and was shown to be able to induce argK expression in M9 medium at 28°C. These results indicate that argK expression is independent of temperature and is regulated directly by a compound resembling the inorganic moiety of phaseolotoxin.

scholarly journals Molecular Analysis of Thermoregulation of Phaseolotoxin-Resistant Ornithine Carbamoyltransferase (argK) from Pseudomonas syringae pv. phaseolicola

2000 ◽  
Vol 13 (10) ◽  
pp. 1071-1080 ◽  
Author(s):  
Karla B. Rowley ◽  
Ronghui Xu ◽  
Suresh S. Patil
Keyword(s):  
Pseudomonas Syringae ◽  
Tandem Repeats ◽  
Genomic Library ◽  
Protein S ◽  
Dnase I ◽  
Ornithine Carbamoyltransferase ◽  
Core Motif ◽  
Sequence Elements ◽  
Multiple Copies

The phaseolotoxin-resistant ornithine carbamoyltransferase (ROCT) and phaseolotoxin are produced by Pseudo-monas syringae pv. phaseolicola at 18°C but not at 28°C. At 28°C, the pathogen produces a protein(s) that binds (in vitro) to a 485-bp fragment (thermoregulatory region, TRR) from a heterologous clone from the pathogen genomic library, which in multiple copies overrides thermoregulation of phaseolotoxin production in wild-type cells (K. B. Rowley, D. E. Clements, M. Mandel, T. Humphreys, and S. S. Patil, Mol. Microbiol. 8:625-635, 1993). We report here that DNase I protection analysis of the 485-bp fragment shows that a single site is protected from cleavage by the protein in the 28°C extract and that this site contains two repeats of a core motif G/C AAAG separated by a 5-bp spacer. Partially purified binding protein forms specific complexes with a synthetic oligonucleotide containing four tandem repeats of this motif. A 492-bp upstream fragment from argK encoding ROCT also forms specific complexes with the protein in the 28°C crude extract, and a 260-bp subfragment from the TRR containing the binding site cross competes with the argk fragment, indicating that the same protein binds to nucleotides in both fragments. DNase I protection analysis of the fragment from argK revealed four separate protected sequence elements, with element III containing half of the core motif sequence (CTTTG), and the other elements containing similar sequences. Gel shift assays were done with DNA fragments from which one or all of the sites were removed as competitor DNAs against the argK probe. The results of these experiments confirmed that the binding sites (in argK) are necessary for the protein to bind to the argK fragment in a specific manner. Taken together, the results of studies presented here suggest that in cells of P. syringae pv. phaseolicola grown at high temperature argK may be negatively regulated by the protein produced at this temperature.

Effects of the pseudomonad phytotoxin coronatine on tomato leaf structure and ultrastructure

1995 ◽  
Vol 53 ◽  
pp. 862-863
Author(s):  
D.A. Palmer ◽  
C.L. Bender
Keyword(s):  
Pseudomonas Syringae ◽  
Membrane Integrity ◽  
Leaf Tissue ◽  
Cell Number ◽  
Cell Ultrastructure ◽  
Response To Treatment ◽  
Prominent Symptom ◽  
Chlorophylls A And B ◽  
Cell Dimensions ◽  
Structure And Ultrastructure

Coronatine is a non-host-specific phytotoxin produced by several members of the Pseudomonas syringae group of pathovars. The toxin acts as a virulence factor in P. syringae pv. tomato, allowing the organism to multiply to a higher population density and develop larger lesions than mutant strains unable to produce the toxin. The most prominent symptom observed in leaf tissue treated with coronatine is an intense spreading chlorosis; this has been attributed to a loss of chlorophylls a and b in tobacco. Coronatine's effects on membrane integrity and cell ultrastructure have not been previously investigated. The present study describes changes in tomato leaves in response to treatment with purified coronatine, infection by a coronatine-producing strain of P. syringae pv. tomato, and infection by a cor" mutant.In contrast to H2O-treated tissue, coronatine-treated tissue showed a diffuse chlorosis extending approximately 5 mm from the inoculation site. Leaf thickness, cell number, and cell dimensions were similar for both healthy and coronatine-treated, chlorotic tissue; however, the epidermal cell walls were consistently thicker in coronatine-treated leaves (Figs, la and lb).

Exemplar Abstract for Pseudomonas syringae van Hall 1902 (Approved Lists 1980).

2003 ◽  
Author(s):  
Charles Thomas Parker ◽  
Dorothea Taylor ◽  
George M Garrity
Keyword(s):  
Pseudomonas Syringae

Exemplar Abstract for Pseudomonas syringae van Hall 1902 (Approved Lists 1980).

2003 ◽  
Author(s):  
Charles Thomas Parker ◽  
Dorothea Taylor ◽  
George M Garrity
Keyword(s):  
Pseudomonas Syringae
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