Research ArticlePLANT SCIENCES

Genome mapping of seed-borne allergens and immunoresponsive proteins in wheat

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Science Advances  17 Aug 2018:
Vol. 4, no. 8, eaar8602
DOI: 10.1126/sciadv.aar8602
  • Fig. 1 The prolamin superfamily and its relation to clinical diseases and allergen protein families.

    (A) Clinical syndromes associated with wheat ingestion or exposure. Mechanisms of wheat-related clinical syndromes, route of exposure, and major allergens and antigens are presented. (B) Protein groups primarily expressed in the seed are highlighted in yellow. Protein types with immunoreactive peptides in their sequence are highlighted in gray, and reference allergen homologs identified based on the AllFam database are highlighted in blue. “Tri a” labeling of the individual groups follows the nomenclature system of the World Health Organization/International Union of Immunological Societies (WHO/IUIS) Allergen Nomenclature Database.

  • Fig. 2 Reference allergen map of bread wheat.

    (A) Genome distribution of food disease–related reference allergens in the wheat genome. Only genes with presence of multiple disease-associated epitopes and over 70% sequence homology to reference allergens are presented. (B) Disease association of reference allergens.

  • Fig. 3 Epitope mapping and phylogenetic analysis in Prolamin clan (CL0482) protein families, HMW glutenins, and ω-gliadins.

    Protein sequences with gliadin (PF13016), protease inhibitor, seed storage and lipid transfer (PF00234), HMW glutenin (PF03157) domains, and ω-gliadins were used to analyze the expansion of the epitope content and composition. Protein sequences were retrieved from UniProt and used along with the reference genome sequence data of bread wheat, T. urartu, A. tauschii, barley, rye, and other grasses such as rice, Brachypodium, maize, and sorghum for phylogenetic analysis. Peptides that induce IFN-γ responses were grouped into six immune response groups (based on median SFU) and colored separately. Linear epitopes related to WDEIA and baker’s asthma are also labeled. The number of peptides per sequence is highlighted by color intensity changes. Linear epitopes related to WDEIA and baker’s asthma are also labeled. SCRP, small cysteine-rich protein.

  • Fig. 4 Quantification and protein profiling of major immunoreactive protein types in Chinese Spring, Bjarne, and Berserk.

    (A) MALDI-TOF analysis of major immunoreactive protein fractions using fractions collected in the RP-HPLC analysis. (B) Peptides measured by R5 and G12 mAbs are characteristic of main immunoreactive proteins related to celiac disease and WDEIA. Expression changes of these proteins were measured in three temperature regimes. m/z, mass/charge ratio.

  • Fig. 5 Effect of cell type, genotype, and temperature on transcript levels of genes encoding grain allergens.

    Heat map showing relative transcript levels of genes encoding reference allergens across cell types, genotypes (BJ, Bjarne; BE, Berserk; and CS, Chinese Spring), and temperatures (CS only). Association of reference allergen transcripts with celiac disease, WDEIA, Baker’s asthma, and food allergy.

  • Fig. 6 Expression profile of the 54 genes encoding the 63 identified immunoreactive gliadin and glutenin peptides in the cells of the endosperm of Bjarne and Berserk at high temperature and Chinese Spring at high, low, and normal temperatures.

    (A) Peptide identity and IFNγ-ELISPOT responses in median SFU values representing the immunoreactivity of peptides against patients’ blood sera according to Tye-Din et al. (15). Dark red represents strong immunoreactivity values, and yellow represents weak values. (B) Heat map showing the relative cumulative expression of the genes encoding each peptide across cell types, genotypes (BJ, Bjarne; BE, Berserk; and CS, Chinese Spring), and temperatures. (C) Heat map showing the scaled average expression level of the immunoreactive peptides across all endosperm cell types. (D) Number and identity of proteins containing the individual immunoreactive peptides.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/8/eaar8602/DC1

    Section S1. Manual annotation and curation of the Prolamin superfamily genes in the reference genome

    Section S2. Organization of major prolamin gene clusters of short arms of chromosomes 1 and 6

    Section S3. Phylogenetic analysis of Prolamin superfamily genes

    Section S4. Phylogenetic analysis of highly immunogenic α-gliadin sequences

    Section S5. Impact of temperature stress on protein composition

    Fig. S1. Chromosomal location of major food disease–related protein families on chromosome groups 1 and 6.

    Fig. S2. Mapping of peptides with known IFNγ-ELISPOT response on the gliadin and glutenin sequences of Chinese Spring.

    Fig. S3. Phylogenetic analysis of prolamin superfamily gene models.

    Fig. S4. Phylogenetic analysis and epitope distribution of highly immunostimulatory gliadin and gliadin proteins in wheat and related species.

    Table S1. Effect of temperature stress on protein content and composition.

    Data file S1. CDS sequences of prolamin superfamily gene models and identified reference allergens in fasta file format.

    Data file S2. Annotation of prolamin superfamily genes and reference allergens used in this study.

    Data file S3. Epitope annotation table of sequences used for the phylogenetic analyses.

    Data file S4. Expression of peptides with known IFNγ-ELISPOT responses.

    Science article authors that are IWGSC members

  • Supplementary Materials

    The PDF file includes:

    • Section S1. Manual annotation and curation of the Prolamin superfamily genes in the reference genome
    • Section S2. Organization of major prolamin gene clusters of short arms of chromosomes 1 and 6
    • Section S3. Phylogenetic analysis of Prolamin superfamily genes
    • Section S4. Phylogenetic analysis of highly immunogenic α-gliadin sequences
    • Section S5. Impact of temperature stress on protein composition
    • Fig. S1. Chromosomal location of major food disease–related protein families on chromosome groups 1 and 6.
    • Fig. S2. Mapping of peptides with known IFNγ-ELISPOT response on the gliadin and glutenin sequences of Chinese Spring.
    • Fig. S3. Phylogenetic analysis of prolamin superfamily gene models.
    • Fig. S4. Phylogenetic analysis and epitope distribution of highly immunostimulatory gliadin and gliadin proteins in wheat and related species.
    • Table S1. Effect of temperature stress on protein content and composition.
    • Legend for Data files S1 to S4

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    Other Supplementary Material for this manuscript includes the following:

    • Data file S1 (.fasta file format). CDS sequences of prolamin superfamily gene models and identified reference allergens in fasta file format.
    • Data file S2 (Microsoft Excel format). Annotation of prolamin superfamily genes and reference allergens used in this study.
    • Data file S3 (Microsoft Excel format). Epitope annotation table of sequences used for the phylogenetic analyses.
    • Data file S4 (Microsoft Excel format). Expression of peptides with known IFNγ-ELISPOT responses.
    • Science article authors that are IWGSC members

    Download Data Files S1 to S4

    Files in this Data Supplement:

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