title: 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.
abstract: 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.
authors.affiliation: Centro de Investigación y Estudios Avanzados del IPN. Unidad Irapuato, Departamento de Ingeniería Genética, Irapuato, Gto., Apdo. Postal 629, C.P. 36500, México. qbpsusy@gmail.com
authors.forename: Susana
authors.initials: S
authors.lastname: De la Torre-Zavala
authors.forename: Selene
authors.initials: S
authors.lastname: Aguilera
authors.forename: Enrique
authors.initials: E
authors.lastname: Ibarra-Laclette
authors.forename: José Luis
authors.initials: JL
authors.lastname: Hernandez-Flores
authors.forename: Alejandro
authors.initials: A
authors.lastname: Hernández-Morales
authors.forename: Jesús
authors.initials: J
authors.lastname: Murillo
authors.forename: Ariel
authors.initials: A
authors.lastname: Alvarez-Morales
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005810:Multigene Family; D009952:Ornithine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D044224:Pseudomonas syringae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C091100:GacA protein, Bacteria; D014157:Transcription Factors; C021234:phaseolotoxin; D009952:Ornithine; C074165:lemA protein, bacterial; D010453:Peptide Synthases