title: Pseudomonas viridiflava and P. syringae--natural pathogens of Arabidopsis thaliana.
abstract: We report the isolation and identification of two natural pathogens of Arabidopsis thaliana, Pseudomonas viridiflava and Pseudomonas syringae, in the midwestern United States. P. viridiflava was found in six of seven surveyed Arabidopsis thaliana populations. We confirmed the presence in the isolates of the critical pathogenicity genes hrpS and hrpL. The pathogenicity of these isolates was verified by estimating in planta bacterial growth rates and by testing for disease symptoms and hypersensitive responses to A. thaliana. Infection of 21 A. thaliana ecotypes with six locally collected P. viridiflava isolates and with one P. syringae isolate showed both compatible (disease) and incompatible (resistance) responses. Significant variation in response to infection was evident among Arabidopsis ecotypes, both in terms of symptom development and in planta bacterial growth. The ability to grow and cause disease symptoms on particular ecotypes also varied for some P. viridiflava isolates. We believe that these pathogens will provide a powerful system for exploring coevolution in natural plant-pathogen interactions.
authors.affiliation: Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA.
authors.forename: Katrin
authors.initials: K
authors.lastname: Jakob
authors.forename: Erica M
authors.initials: EM
authors.lastname: Goss
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Araki
authors.forename: Tam
authors.initials: T
authors.lastname: Van
authors.forename: Martin
authors.initials: M
authors.lastname: Kreitman
authors.forename: Joy
authors.initials: J
authors.lastname: Bergelson
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology*; D007113:Immunity, Innate / Q000235:genetics; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology*; D011549:Pseudomonas / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics