title: Down-regulation of the strawberry Bet v 1-homologous allergen in concert with the flavonoid biosynthesis pathway in colorless strawberry mutant.
abstract: Proteomic screening of strawberry (Fragaria ananassa) yielded a 58% success rate in protein identification in spite of the fact that no genomic sequence is available for this species. This was achieved by a combination of MALDI-MS/MS de novo sequencing of double-derivatized peptides and indel-tolerant searching against local protein databases built on both EST and full-length nucleotide sequences. The amino acid sequence of a strawberry allergen, homologous to the well-known major birch pollen allergen Bet v 1, was partially determined. This strawberry allergen, named Fra a 1 according to the nomenclature for allergen proteins, showed sequence identity of 54 and 77%, respectively, with corresponding allergens from birch and apple. Differential expression, as evaluated by 2-D DIGE, occurred in 10% of protein spots when red strawberries were compared to a colorless (white) strawberry mutant. White strawberries, known to be tolerated by individuals affected by allergy, were found to be virtually free from the strawberry allergen. Also several enzymes in the pathway for biosynthesis of flavonoids, to which the red color pelargonidin belongs, were down-regulated. This approach to assess differential protein expression without access to genomic sequence information can also be applied to other crop plants and phenotypic traits.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Karin
authors.initials: K
authors.lastname: Hjernø
authors.forename: Rikard
authors.initials: R
authors.lastname: Alm
authors.forename: Björn
authors.initials: B
authors.lastname: Canbäck
authors.forename: Rune
authors.initials: R
authors.lastname: Matthiesen
authors.forename: Karin
authors.initials: K
authors.lastname: Trajkovski
authors.forename: Lars
authors.initials: L
authors.lastname: Björk
authors.forename: Peter
authors.initials: P
authors.lastname: Roepstorff
authors.forename: Cecilia
authors.initials: C
authors.lastname: Emanuelsson
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D003116:Color; D030562:Databases, Protein; D015536:Down-Regulation; D015180:Electrophoresis, Gel, Two-Dimensional; D020224:Expressed Sequence Tags; D005419:Flavonoids / Q000096:biosynthesis*; D005512:Food Hypersensitivity; D031985:Fragaria / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D016415:Sequence Alignment
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C501561:Bet v 1 protein, Fragaria; D005419:Flavonoids; D010940:Plant Proteins; D020033:Protein Isoforms