title: A protein key to plant virus transmission at the tip of the insect vector stylet.
abstract: Hundreds of species of plant viruses, many of them economically important, are transmitted by noncirculative vector transmission (acquisition by attachment of virions to vector mouthparts and inoculation by subsequent release), but virus receptors within the vector remain elusive. Here we report evidence for the existence, precise location, and chemical nature of the first receptor for a noncirculative virus, cauliflower mosaic virus, in its insect vector. Electron microscopy revealed virus-like particles in a previously undescribed anatomical zone at the extreme tip of the aphid maxillary stylets. A novel in vitro interaction assay characterized binding of cauliflower mosaic virus protein P2 (which mediates virus-vector interaction) to dissected aphid stylets. A P2-GFP fusion exclusively labeled a tiny cuticular domain located in the bottom-bed of the common food/salivary duct. No binding to stylets of a non-vector species was observed, and a point mutation abolishing P2 transmission activity correlated with impaired stylet binding. The novel receptor appears to be a nonglycosylated protein deeply embedded in the chitin matrix. Insight into such insect receptor molecules will begin to open the major black box of this scientific field and might lead to new strategies to combat viral spread.
authors.affiliation: Unité Mixte de Recherche, Biologie et Génétique des Interactions Plante-Parasite, Institut National de la Recherche Agronomique, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Agro Montpellier, Montpellier, France.
authors.forename: Marilyne
authors.initials: M
authors.lastname: Uzest
authors.forename: Daniel
authors.initials: D
authors.lastname: Gargani
authors.forename: Martin
authors.initials: M
authors.lastname: Drucker
authors.forename: Eugénie
authors.initials: E
authors.lastname: Hébrard
authors.forename: Elisa
authors.initials: E
authors.lastname: Garzo
authors.forename: Thierry
authors.initials: T
authors.lastname: Candresse
authors.forename: Alberto
authors.initials: A
authors.lastname: Fereres
authors.forename: Stéphane
authors.initials: S
authors.lastname: Blanc
mesh_terms: D000818:Animals; D001042:Aphids / Q000821:virology*; D007303:Insect Vectors; D010942:Plant Viruses / Q000502:physiology*