237 Factors Affecting Gene Expression of Lipid Transfer Protein (LTP), the Major Allergen of Peach Fruit A. Botton, M. Begheldo, A. Rasori, C. Bonghi and P. Tonutti Department of Environmental Agronomy and Crop Science University of Padova Via Romea, 16 Agripolis, 35020 Legnaro (Padova) Italy Keywords: allergy, epicarp, fruit storage, Prunus persica, ripening Abstract Considering the increase of fruit allergy diseases, a specific research on some molecular aspects of Lipid Transfer Protein (LTP), the major allergen of peach, has been carried out. Fruits of four peach cultivars (Sentry, Royal Gemm, Summered, Tardiva Zuliani) were harvested in correspondence of commercial ripeness and stored at 20°C or at 4°C. A 269bp cDNA fragment (named Pp-LTP1) was PCR- synthesized from poly A+ mRNA extracted from epicarp of cv Sentry, using degenerated primers. Sequencing analysis revealed that Pp-LTP1 encodes a protein belonging to the LTP family. Southern analysis indicated that Pp-LTP1 belongs to a small multigenic family of at least three members. Expression analysis showed that Pp-LTP1 mRNA is present in epicarp but not in mesocarp of ripe fruit and that specific transcript accumulation remains unchanged throughout postharvest ripening at 20°C. Storage at low temperatures induced a decrease of Pp-LTP1 transcript accumulation in cv Sentry and Tardiva Zuliani but not in Royal Gemm and Summered. INTRODUCTION An increasing number of people show adverse reactions to foods, often represented by fruits and vegetables. Allergies are the most common food-related pathologies occurring when the immune system reacts to a certain food by producing specific antibodies named immunoglobulin E (IgE). When IgE react with allergens, that are proteins, histamine and other chemicals (called mediators) are produced causing the symptoms of allergic reactions. Considering allergies to fruit, the Rosaceae botanical family has been increasingly reported as involved in adverse reactions (Rodriguez et al., 2000). Peach is one of the most frequent causes of food allergy in Europe, in both the Northern regions and Mediterranean area (Pastorello et al., 1999). Recently, it has been shown that the major allergen of peach is a Lipid Transfer Protein (LTP) with a low molecular weight (9KDa) (Pastorello et al., 1999; Sànchez-Monge et al., 1999), stable following heat treatment (Brenna et al., 2000), and under acid and proteasic conditions of the stomach (Asero et al., 2000). LTPs form a broad family of proteins widespread in nature. Plant LTPs show common features, as eight conserved cysteines forming disulfide bridges, basic isoelectric point and similar crystallographic structure. Their function was initially associated with the in vitro properties of transferring lipids between membranes (Kader, 1996), but further studies have stressed the possible role of LTPs in the defense mechanisms. The hypothesis of a multiple role played by LTPs is supported by the presence of multigenic families formed by two or more (up to 14 in Pinus spp) genes (Kader, 1996). In several plant species (tobacco, spinach, barley, cotton, tomato), expression analysis showed that LTP transcripts are present only in aerial plant parts and particularly in epidermic and cutinized layers (Sossountzov et al., 1991; Kader, 1996). Aim of the present work was to isolate cDNAs coding for peach LTPs and evaluate specific transcript accumulation in ripe fruit belonging to different peach Proc. 5 th IS on Peach Eds. R.S. Johnson & C.H. Chrisosto Acta Hort. 592, ISHS 2002