title: A multiplex-PCR assay for identification of the quarantine plant pathogen Xanthomonas axonopodis pv. phaseoli.
abstract: In this study we developed an algorithm to screen for all exact molecular signatures of the quarantine pathogen Xanthomonas axonopodis pv. phaseoli (Xap), based on available data of the presence or absence of virulence-associated genes. The simultaneous presence of genes avrBsT and xopL is specific to Xap. Therefore we developed a multiplex PCR assay targeting avrBsT and xopL for the molecular identification of Xap. The specificity of this multiplex was validated by comparison to that of other molecular identification assays aimed at Xap, on a wide collection of reference strains. This multiplex was further validated on a blind collection of Xanthomonas isolates for which pathogenicity was assayed by stem wounding and by dipping leaves into calibrated inocula. This multiplex was combined to the previously described X4c/X4e molecular identification assay for Xap. Such a combination enables the molecular identification of all strains of Xanthomonas pathogenic on bean. Results also show that assay by stem wounding does not give reliable results in the case of Xap, and that pathogenicity assays by dipping should be preferred.
authors.affiliation: Université d'Angers, UMR1345 IRHS, Institut de Recherches en Horticulture et Semences, SFR4207 QUASAV, PRES L'UNAM, F-49071 Beaucouze Cedex, France. tristan.boureau@univ-angers.fr
authors.forename: T
authors.initials: T
authors.lastname: Boureau
authors.forename: M
authors.initials: M
authors.lastname: Kerkoud
authors.forename: F
authors.initials: F
authors.lastname: Chhel
authors.forename: G
authors.initials: G
authors.lastname: Hunault
authors.forename: A
authors.initials: A
authors.lastname: Darrasse
authors.forename: C
authors.initials: C
authors.lastname: Brin
authors.forename: K
authors.initials: K
authors.lastname: Durand
authors.forename: A
authors.initials: A
authors.lastname: Hajri
authors.forename: S
authors.initials: S
authors.lastname: Poussier
authors.forename: C
authors.initials: C
authors.lastname: Manceau
authors.forename: F
authors.initials: F
authors.lastname: Lardeux
authors.forename: F
authors.initials: F
authors.lastname: Saubion
authors.forename: M-A
authors.initials: MA
authors.lastname: Jacques
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods*; D010935:Plant Diseases / Q000382:microbiology; D010944:Plants / Q000382:microbiology; D011790:Quarantine; D037521:Virulence Factors / Q000235:genetics*; D053532:Xanthomonas axonopodis / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D037521:Virulence Factors