title: Grapevine Downy Mildew Plasmopara viticola Infection Elicits the Expression of Allergenic Pathogenesis-Related Proteins.
abstract: BACKGROUND
  Downy mildews are a group of microorganisms belonging to the Chromista kingdom that can infect specific plants. When growing on plant tissues these microbes can elicit the expression of pathogenesis-related proteins (PRs), a group of stress-induced proteins frequently described as allergens in many plant species. Our aim was to verify by a proteomic approach whether the allergic reactions experienced by a farmer working in a vineyard infected by Plasmopara viticola (Pv), the etiological agent of downy mildew, are elicited by PRs expressed by the grapevine upon infection or by allergens present in Pv.
  
  
  METHODS
  A skin prick test and prick-to-prick test with infected field grapevine leaves and control leaves were carried out. Field leaves and ad hoc Pv-inoculated leaves were compared by SDS-PAGE and IgE-immunoblotting with extracts from control leaves and Pv sporangia. IgE-binding proteins were further separated by two-dimensional electrophoresis and the positive spots analyzed by nanoHPLC-Chip and tandem mass spectrometry (MS/MS) for identification.
  
  
  RESULTS
  Only infected leaves showed IgE-binding protein bands at 42 and 36 kDa. This agreed with the positive skin prick test experienced by the patient only with the infected leaves extract. Two-dimensional electrophoresis followed by MS/MS analysis led to the identification of PR-2 (β-1,3-glucanase) and harpin-binding protein 1 as putative allergens, the latter having never been reported before.
  
  
  CONCLUSIONS
  The results indicate that Pv infection might represent a new source of plant allergens.
authors.affiliation: Department of Biotechnology, University of Verona, Verona, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Rossin
authors.forename: Danilo
authors.initials: D
authors.lastname: Villalta
authors.forename: Paola
authors.initials: P
authors.lastname: Martelli
authors.forename: Daniela
authors.initials: D
authors.lastname: Cecconi
authors.forename: Annalisa
authors.initials: A
authors.lastname: Polverari
authors.forename: Gianni
authors.initials: G
authors.lastname: Zoccatelli
mesh_terms: D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009868:Oomycetes; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000276:immunology*; D040901:Proteomics; D012882:Skin Tests; D027843:Vitis / Q000276:immunology / Q000382:microbiology*
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D010940:Plant Proteins; D007073:Immunoglobulin E