EXPRESSION OF STRAWBERRY ALLERGEN FRA A 1 GENE DURING FRUIT RIPENING

Consumption of fresh strawberries (Fragaria ×ananassa) can cause oral allergy syndrome for susceptible individuals. To produce strawberries with low allergen contents a selection of hypoallergenic genotypes and the establishment of culture methods are required. Since several studies have reported that Fra a 1 is a major allergen of strawberry, the expression profiling of the Fra a 1 gene could be an indicator of the allergic potential. In this study, the expression of the Fra a 1 gene was investigated in strawberry during fruit (receptacles and achene) development. The fresh weight and anthocyan content of fruits were also measured to assess their potential correlations with Fra a 1 expression. Fruit of the strawberry were harvested for analyses from a working farm at seven different ripening stages. Real-time PCR revealed the transcript level of the Fra a 1 gene was highest at the early stage of ripening and decreased to approximately 1/70th that level by the red-colored stage. Considering that Fra a 1 belongs to the pathogenesis-related protein 10 family, this result was in line with the report that strawberry fruit may be attacked by oxygen species at the early stage of ripening. Additionally, Fra a 1 gene homologues in Fragaria vesca were surveyed to assess the inducibility of their expression. We found that a gene coding Fra a1 a2 seemed to be expressed in response to stress, and it had major stress-related elements in its promoter region. These results indicate that Fra a 1 expression can be induced by stress, and preharvest treatment to reduce the allergen content will be possible by studying the transcriptional activity of Fra a 1.