title: Pseudomonas syringae pv. phaseolicola can be separated into two genetic lineages distinguished by the possession of the phaseolotoxin biosynthetic cluster.
abstract: The bean (Phaseolus spp.) plant pathogen Pseudomonas syringae pv. phaseolicola is characterized by the ability to produce phaseolotoxin (Tox(+)). We recently reported that the majority of the Spanish P. syringae pv. phaseolicola population is unable to synthesize this toxin (Tox(-)). These Tox(-) isolates appear to lack the entire DNA region for the biosynthesis of phaseolotoxin (argK-tox gene cluster), as shown by PCR amplification and DNA hybridization using DNA sequences specific for separated genes of this cluster. Tox(+) and Tox(-) isolates also showed genomic divergence that included differences in ERIC-PCR and arbitrarily primed-PCR profiles. Tox(+) isolates showed distinct patterns of IS801 genomic insertions and contained a chromosomal IS801 insertion that was absent from Tox(-) isolates. Using a heteroduplex mobility assay, sequence differences were observed only among the intergenic transcribed spacer of the five rDNA operons of the Tox(-) isolates. The techniques used allowed the unequivocal differentiation of isolates of P. syringae pv. phaseolicola from the closely related soybean (Glycine max) pathogen, P. syringae pv. glycinea. Finally, a pathogenicity island that is essential for the pathogenicity of P. syringae pv. phaseolicola on beans appears to be conserved among Tox(+), but not among Tox(-) isolates, which also lacked the characteristic large plasmid that carries this pathogenicity island. It is proposed that the results presented here justify the separation of the Tox(+) and Tox(-) P. syringae pv. phaseolicola isolates into two distinct genetic lineages, designated Pph1 and Pph2, respectively, that show relevant genomic differences that include the pathogenicity gene complement.
authors.affiliation: Instituto de Agrobiotecnología y Recursos Naturales, CSIC-UPNA, and Laboratorio de Patología Vegetal, Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Oguiza
authors.affiliation: Instituto de Agrobiotecnología y Recursos Naturales, CSIC-UPNA, and Laboratorio de Patología Vegetal, Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain.
authors.forename: Arantza
authors.initials: A
authors.lastname: Rico
authors.affiliation: Instituto de Agrobiotecnología y Recursos Naturales, CSIC-UPNA, and Laboratorio de Patología Vegetal, Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Rivas
authors.affiliation: UMR de Pathologie Végétale INRA-INH-Université, Beaucouzé, 49071 France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Sutra
authors.affiliation: Centre for Research in Plant Science, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Vivian
authors.affiliation: Instituto de Agrobiotecnología y Recursos Naturales, CSIC-UPNA, and Laboratorio de Patología Vegetal, Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Murillo
mesh_terms: D001483:Base Sequence; D017124:Conserved Sequence; D017931:DNA Primers; D005098:Exotoxins / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D009952:Ornithine / Q000031:analogs & derivatives; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D044224:Pseudomonas syringae / Q000145:classification / Q000235:genetics* / Q000254:growth & development
chemical_list: D017931:DNA Primers; D005098:Exotoxins; C021234:phaseolotoxin; D009952:Ornithine