Gene expression of Pht cluster genes and a putative non-ribosomal peptide synthetase required for phaseolotoxin production is regulated by GacS/GacA in Pseudomonas syringae pv. phaseolicola

• Published in: Research in microbiology Vol. 162; no. 5; pp. 488 - 498
• Main Authors: De la Torre-Zavala, Susana, Aguilera, Selene, Ibarra-Laclette, Enrique, Hernandez-Flores, José Luis, Hernández-Morales, Alejandro, Murillo, Jesús, Alvarez-Morales, Ariel
• Format: Journal Article
• Language: English
• Published: Issy-les-Moulineaux Elsevier SAS 01.06.2011; Elsevier Masson
• Subjects: arginine; Bacterial plant pathogens; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; beans; Biological and medical sciences; biosynthesis; blight; chromosomes; Fundamental and applied biological sciences. Psychology; GacA; GacS; gene expression; Gene Expression Regulation, Bacterial; genes; Gram-negative bacteria; Microbiology; Miscellaneous; Multigene Family; mutants; Ornithine - analogs & derivatives; Ornithine - biosynthesis; ornithine carbamoyltransferase; Peptide Synthases - genetics; Peptide Synthases - metabolism; Phaseolotoxin; Phaseolus vulgaris; phenotype; Pht cluster; Phytopathology. Animal pests. Plant and forest protection; Pseudomonas syringae; Pseudomonas syringae - enzymology; Pseudomonas syringae - genetics; Pseudomonas syringae - metabolism; Pseudomonas syringae pv. phaseolicola; signal transduction; Transcription Factors - genetics; Transcription Factors - metabolism; transcriptomics; virulence; GacA; GacS; Phaseolotoxin; Pseudomonas syringae pv. phaseolicola; Pht cluster; Pseudomonadales; Gene cluster; Plant pathogen; Peptides; Enzyme; Gene expression; phaseolicola; Pseudomonas syringae pv; Regulation(control); Ligases; Pseudomonas syringae; Bacteria; Pseudomonadaceae
• ISSN: 0923-2508; 1769-7123; 1769-7123
• DOI: 10.1016/j.resmic.2011.04.010

Pseudomonas syringae pv. phaseolicola is the causal agent of halo blight disease of beans ( Phaseolus vulgaris L.), which is characterized by watersoaked lesions surrounded by a chlorotic halo resulting from the action of a non-host specific toxin known as phaseolotoxin. This toxin inhibits the enzyme ornithine carbamoyltransferase involved in the arginine biosynthesis pathway. It was previously reported that genes within the Pht cluster were involved in the regulation and synthesis of phaseolotoxin. The GacS/GacA two-component signal transduction system controls important pathogenicity and virulence mechanisms in several Gram-negative bacteria. Tox − phenotype gacA − and gacS − mutants were obtained and gacA − transcriptome analysis revealed that this response activator controls expression of genes within the Pht cluster as well as another gene located in a different region in the bacterial chromosome and that has been unambiguously shown to be directly involved in phaseolotoxin biosynthesis. Results presented in this work suggest that phaseolotoxin biosynthesis involve elements within and outside the Pht Cluster, and that the GacS/GacA two-component system exerts control over them.