Environmental factors affecting the expression of apple (Malus X domestica L. Borkh) allergen-encoding genes

Apples can cause allergic reactions in the worldwide population because of the presence of four classes of allergens (Mal d 1, Mal d 2, Mal d 3, and Mal d 4), and their cross-reactivity with sensitising allergens in other species. Knowledge of the factors that affect the allergenic potential of apples would provide important information to apple growers and consumers for the adoption of agronomic practices to decrease the allergenic potential, and for the consumption of fruits with reduced levels of allergens. Expression studies oil apple genes that encode allergens were performed by means of real-time PCR. Samples were collected from fruit in different trials set up to assess the effects of shading, elevation, storage. and water stress on the expression of apple allergen genes. Shading, elevation, and storage significantly affected the transcription of all genes encoding allergens, whereas water stress had only a slight influence oil the expression of the Mal d 4 family of genes. The implications of these results for growers and consumers are critically discussed.