Analysis of major paralogs encoding the Fra a 1 allergen based on their organ-specificity in Fragaria × ananassa

• Published in: Plant cell reports Vol. 37; no. 3; pp. 411 - 424
• Main Authors: Ishibashi, Misaki, Nabe, Takeshi, Nitta, Yoko, Tsuruta, Hiroki, Iduhara, Miho, Uno, Yuichi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2018; Springer Nature B.V
• Subjects: Accumulation; Allergens; Allergens - genetics; Allergens - immunology; Allergens - metabolism; Allergies; Amino Acid Sequence; Animals; Antigens, Plant - classification; Antigens, Plant - genetics; Antigens, Plant - metabolism; Bet v 1 antigen; Biomedical and Life Sciences; Biotechnology; Cell Biology; Fragaria - genetics; Fragaria - metabolism; Fragaria ananassa; Fruit - genetics; Fruit - metabolism; Fruits; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Plant; Gene sequencing; Genes; Genomes; Guinea Pigs; Humans; Immune Sera - immunology; Immunoblotting; Immunoglobulin E; Immunoglobulin E - immunology; Life Sciences; Organ Specificity - genetics; Organs; Original Article; Phylogeny; Plant Biochemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Sciences; Pollen; Proteins; Receptacles; Ribonucleic acid; RNA; Sequence Analysis, RNA; Sequence Homology, Amino Acid; Transcription; RNA sequencing; Cultivated strawberry; IgE binding capacity; Organ localization; Pathogenesis-related protein; Oral allergic syndrome
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-017-2237-6

Key message Fra a 1 protein in strawberry causes oral allergic syndrome. Over 39 Fra a 1 paralogs have been identified in strawberry genome. Fra a 1.01 is major accumulating protein in edible organs. Strawberry fruits contain allergenic proteins that cause oral allergic syndrome. The hypothesized major allergen is Fra a 1, an ortholog of the birch pollen allergen protein Bet v 1. We organized Fra a 1 genes and analyzed their localizations at the transcriptional and translational levels. In total, 15 new Fra a 1 proteins were identified from the genomic database, increasing the total number of Fra a 1 to 30 proteins encoded by 39 genes. Fra a 1.02 was mostly expressed in receptacles, and Fra a 1.01 in achenes, when analyzed by RNA sequencing. Immunoblotting showed that the Fra a 1.01 protein was broadly accumulated in strawberry organs, while the Fra a 1.02 protein was mostly expressed in receptacles. Recombinant Fra a 1.01 strongly reacted with human IgE. The mRNA and protein expression levels of Fra a 1 did not correlate, indicating the importance of protein levels when evaluating the abundance of allergens in strawberry. Based on the localizations, accumulation levels and reactivity to human IgE, we determined that Fra a 1.01 was the most important allergen, followed by Fra a 1.02, and then other Fra a 1 proteins. The information obtained here will be useful for selecting the target Fra a 1 paralogs when breeding hypoallergenic strawberry.