title: The mangotoxin biosynthetic operon (mbo) is specifically distributed within Pseudomonas syringae genomospecies 1 and was acquired only once during evolution.
abstract: Mangotoxin production was first described in Pseudomonas syringae pv. syringae strains. A phenotypic characterization of 94 P. syringae strains was carried out to determine the genetic evolution of the mangotoxin biosynthetic operon (mbo). We designed a PCR primer pair specific for the mbo operon to examine its distribution within the P. syringae complex. These primers amplified a 692-bp DNA fragment from 52 mangotoxin-producing strains and from 7 non-mangotoxin-producing strains that harbor the mbo operon, whereas 35 non-mangotoxin-producing strains did not yield any amplification. This, together with the analysis of draft genomes, allowed the identification of the mbo operon in five pathovars (pathovars aptata, avellanae, japonica, pisi, and syringae), all of which belong to genomospecies 1, suggesting a limited distribution of the mbo genes in the P. syringae complex. Phylogenetic analyses using partial sequences from housekeeping genes differentiated three groups within genomospecies 1. All of the strains containing the mbo operon clustered in groups I and II, whereas those lacking the operon clustered in group III; however, the relative branching order of these three groups is dependent on the genes used to construct the phylogeny. The mbo operon maintains synteny and is inserted in the same genomic location, with high sequence conservation around the insertion point, for all the strains in groups I and II. These data support the idea that the mbo operon was acquired horizontally and only once by the ancestor of groups I and II from genomospecies 1 within the P. syringae complex.
authors.affiliation: Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.
authors.forename: Víctor J
authors.initials: VJ
authors.lastname: Carrión
authors.forename: José A
authors.initials: JA
authors.lastname: Gutiérrez-Barranquero
authors.forename: Eva
authors.initials: E
authors.lastname: Arrebola
authors.forename: Leire
authors.initials: L
authors.lastname: Bardaji
authors.forename: Juan C
authors.initials: JC
authors.lastname: Codina
authors.forename: Antonio
authors.initials: A
authors.lastname: de Vicente
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Cazorla
authors.forename: Jesús
authors.initials: J
authors.lastname: Murillo
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics*; D053898:Biosynthetic Pathways; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D005838:Genotype; D008969:Molecular Sequence Data; D009876:Operon; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D044224:Pseudomonas syringae / Q000145:classification / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D001427:Bacterial Toxins; D017931:DNA Primers; D004269:DNA, Bacterial; C574905:mangotoxin, Pseudomonas syringae