title: A functional screen for the type III (Hrp) secretome of the plant pathogen Pseudomonas syringae.
abstract: Type III secreted "effector" proteins of bacterial pathogens play central roles in virulence, yet are notoriously difficult to identify. We used an in vivo genetic screen to identify 13 effectors secreted by the type III apparatus (called Hrp, for "hypersensitive response and pathogenicity") of the plant pathogen Pseudomonas syringae. Although sharing little overall homology, the amino-terminal regions of these effectors had strikingly similar amino acid compositions. This feature facilitated the bioinformatic prediction of 38 P. syringae effectors, including 15 previously unknown proteins. The secretion of two of these putative effectors was shown to be type III--dependent. Effectors showed high interstrain variation, supporting a role for some effectors in adaptation to different hosts.
authors.affiliation: Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada. guttman@botany.utoronto.ca
authors.forename: David S
authors.initials: DS
authors.lastname: Guttman
authors.forename: Boris A
authors.initials: BA
authors.lastname: Vinatzer
authors.forename: Sara F
authors.initials: SF
authors.lastname: Sarkar
authors.forename: Max V
authors.initials: MV
authors.lastname: Ranall
authors.forename: Gregory
authors.initials: G
authors.lastname: Kettler
authors.forename: Jean T
authors.initials: JT
authors.lastname: Greenberg
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D029681:Arabidopsis Proteins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D019295:Computational Biology; D004251:DNA Transposable Elements; D005798:Genes, Bacterial; D023281:Genomics; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020543:Proteome; D011549:Pseudomonas / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014774:Virulence
chemical_list: D000596:Amino Acids; D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D010940:Plant Proteins; D020543:Proteome; C089426:RPS2 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; C420919:avrRpt2 protein, Pseudomonas syringae