title: The twin arginine protein transport pathway exports multiple virulence proteins in the plant pathogen Streptomyces scabies.
abstract: Summary Streptomyces scabies is one of a group of organisms that causes the economically important disease potato scab. Analysis of the S. scabies genome sequence indicates that it is likely to secrete many proteins via the twin arginine protein transport (Tat) pathway, including several proteins whose coding sequences may have been acquired through horizontal gene transfer and share a common ancestor with proteins in other plant pathogens. Inactivation of the S. scabies Tat pathway resulted in pleiotropic phenotypes including slower growth rate and increased permeability of the cell envelope. Comparison of the extracellular proteome of the wild type and DeltatatC strains identified 73 predicted secretory proteins that were present in reduced amounts in the tatC mutant strain, and 47 Tat substrates were verified using a Tat reporter assay. The DeltatatC strain was almost completely avirulent on Arabidopsis seedlings and was delayed in attaching to the root tip relative to the wild-type strain. Genes encoding 14 candidate Tat substrates were individually inactivated, and seven of these mutants were reduced in virulence compared with the wild-type strain. We conclude that the Tat pathway secretes multiple proteins that are required for full virulence.
authors.affiliation: Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Madhumita V
authors.initials: MV
authors.lastname: Joshi
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Mann
authors.forename: Haike
authors.initials: H
authors.lastname: Antelmann
authors.forename: David A
authors.initials: DA
authors.lastname: Widdick
authors.forename: Joanna K
authors.initials: JK
authors.lastname: Fyans
authors.forename: Govind
authors.initials: G
authors.lastname: Chandra
authors.forename: Matthew I
authors.initials: MI
authors.lastname: Hutchings
authors.forename: Ian
authors.initials: I
authors.lastname: Toth
authors.forename: Michael
authors.initials: M
authors.lastname: Hecker
authors.forename: Rosemary
authors.initials: R
authors.lastname: Loria
authors.forename: Tracy
authors.initials: T
authors.lastname: Palmer
mesh_terms: D017360:Arabidopsis / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology*; D002463:Cell Membrane Permeability; D015180:Electrophoresis, Gel, Two-Dimensional; D055786:Gene Knockout Techniques; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology*; D021381:Protein Transport; D020543:Proteome / Q000032:analysis; D011198:Solanum tuberosum / Q000382:microbiology; D013302:Streptomyces / Q000737:chemistry / Q000201:enzymology* / Q000254:growth & development / Q000472:pathogenicity*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D020543:Proteome; D037521:Virulence Factors