title: Pseudomonas syringae type III effector repertoires: last words in endless arguments.
abstract: Many plant pathogens subvert host immunity by injecting compositionally diverse but functionally similar repertoires of cytoplasmic effector proteins. The bacterial pathogen Pseudomonas syringae is a model for exploring the functional structure of such repertoires. The pangenome of P. syringae encodes 57 families of effectors injected by the type III secretion system. Distribution of effector genes among phylogenetically diverse strains reveals a small set of core effectors targeting antimicrobial vesicle trafficking and a much larger set of variable effectors targeting kinase-based recognition processes. Complete disassembly of the 28-effector repertoire of a model strain and reassembly of a minimal functional repertoire reveals the importance of simultaneously attacking both processes. These observations, coupled with growing knowledge of effector targets in plants, support a model for coevolving molecular dialogs between effector repertoires and plant immune systems that emphasizes mutually-driven expansion of the components governing recognition.
authors.affiliation: Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA.
authors.forename: Magdalen
authors.initials: M
authors.lastname: Lindeberg
authors.forename: Sébastien
authors.initials: S
authors.lastname: Cunnac
authors.forename: Alan
authors.initials: A
authors.lastname: Collmer
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D058947:Bacterial Secretion Systems; D054884:Host-Pathogen Interactions; D010935:Plant Diseases / Q000382:microbiology*; D044224:Pseudomonas syringae / Q000378:metabolism* / Q000472:pathogenicity*; D037521:Virulence Factors / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D037521:Virulence Factors