title: Phage-displayed peptides as developmental agonists for Phytophthora capsici zoospores.
abstract: As part of its pathogenic life cycle, Phytophthora capsici disperses to plants through a motile zoospore stage. Molecules on the zoospore surface are involved in reception of environmental signals that direct preinfection behavior. We developed a phage display protocol to identify peptides that bind to the surface molecules of P. capsici zoospores in vitro. The selected phage-displayed peptides contained an abundance of polar amino acids and proline but were otherwise not conserved. About half of the selected phage that were tested concomitantly induced zoospore encystment in the absence of other signaling agents. A display phage was shown to bind to the zoospore but not to the cyst form of P. capsici. Two free peptides corresponding to active phage were similarly able to induce encystment of zoospores, indicating that their ability to serve as signaling ligands did not depend on their exact molecular context. Isolation and subsequent expression of peptides that act on pathogens could allow the identification of receptor molecules on the zoospore surface, in addition to forming the basis for a novel plant disease resistance strategy.
authors.affiliation: Department of Plant Microbiology and Patholog, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Bishop-Hurley
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Mounter
authors.forename: James
authors.initials: J
authors.lastname: Laskey
authors.forename: Roy O
authors.initials: RO
authors.lastname: Morris
authors.forename: Jim
authors.initials: J
authors.lastname: Elder
authors.forename: Philip
authors.initials: P
authors.lastname: Roop
authors.forename: Chris
authors.initials: C
authors.lastname: Rouse
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Schmidt
authors.forename: James T
authors.initials: JT
authors.lastname: English
mesh_terms: D019151:Peptide Library; D010455:Peptides / Q000494:pharmacology; D010838:Phytophthora / Q000502:physiology*; D013172:Spores, Fungal / Q000187:drug effects* / Q000502:physiology
chemical_list: D019151:Peptide Library; D010455:Peptides