Characterization of Red and White Colored Strawberries Including a New White Colored Fragaria Accession on DNA, RNA and Protein Level

Food allergy reactions in Northern Europe are often caused by allergens that are homologous to the birch-pollen allergen Bet v 1. Also strawberries contain one of these homologous proteins, Fra a 1, which leads to allergic reactions due to IgE-cross reactivity. White strawberries are supposed to be low in allergen content. However, many possible explanations for white colored strawberries have been addressed in the literature: mutations in genes of the anthocyanin pathway, reduced level of Fra a 1, Fra a 2 and Fra a 3 or changes in the MYB transcription factors regulating the anthocyanin pathway. To detect the reasons for the missing pigmentation and to analyze the allergen content of red and white strawberries we investigated the following five diploid cultivars on DNA, RNA and protein level: “Red Baron Solemacher”, “Woodland strawberry”, a new and non commercial white colored accession, “White Hagmann” and “Yellow Wonder”. The allergen genes fra a1, fra a2 and fra a3 were sequenced and the expression of Fra a 1 was immunological analyzed in different developmental stages of the fruits. To our surprise also the white colored strawberries contained considerable amounts of the allergen Fra a 1. On the transcription level, genes of the anthocyanin pathway, MYB1 and the allergen genes were investigated in the red and white colored strawberries. Furthermore the new accession was characterized using SSR-markers and cytological analyses. Cross combinations between red and white colored strawberries were performed, verified by SSR-markers and are now available for further analyses.