Research article

Genomic characterization of putative allergen genes in peach/almond and their synteny with apple

Lin Chen^1,2 , Shuiming Zhang^1,5 , Eudald Illa³ , Lijuan Song¹ , Shandong Wu² , Werner Howad³ , Pere Arús³ , Eric van de Weg⁴ , Kunsong Chen¹ and Zhongshan Gao^1,2

¹  Institute of Fruit Science, The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Biotechnology, Zhejiang University, Hangzhou, 310029, PR China

²  Allergy Research Center, Zhejiang University, Hangzhou, 310058, PR China

³  IRTA. Centre de Recerca en Agrigenòmica CSIC-IRTA-UAB, Carretera de Cabrils Km2; 08348 Cabrils (Barcelona), Spain

⁴  Plant Research International, Wageningen University and Research Centre, PO box 16, 6700AA, Wageningen, The Netherlands

⁵  Key Laboratory of Pomology, Anhui Agricultural University, Hefei 230036, PR China

author email corresponding author email

BMC Genomics 2008, 9:543doi:10.1186/1471-2164-9-543

Published:	17 November 2008

Abstract

Background

Fruits from several species of the Rosaceae family are reported to cause allergic reactions in certain populations. The allergens identified belong to mainly four protein families: pathogenesis related 10 proteins, thaumatin-like proteins, lipid transfer proteins and profilins. These families of putative allergen genes in apple (Mal d 1 to 4) have been mapped on linkage maps and subsequent genetic study on allelic diversity and hypoallergenic traits has been carried out recently. In peach (Prunus persica), these allergen gene families are denoted as Pru p 1 to 4 and for almond (Prunus dulcis)Pru du 1 to 4. Genetic analysis using current molecular tools may be helpful to establish the cause of allergenicity differences observed among different peach cultivars. This study was to characterize putative peach allergen genes for their genomic sequences and linkage map positions, and to compare them with previously characterized homologous genes in apple (Malus domestica).

Results

Eight Pru p/du 1 genes were identified, four of which were new. All the Pru p/du 1 genes were mapped in a single bin on the top of linkage group 1 (G1). Five Pru p/du 2 genes were mapped on four different linkage groups, two very similar Pru p/du 2.01 genes (A and B) were on G3, Pru p/du 2.02 on G7,Pru p/du 2.03 on G8 and Pru p/du 2.04 on G1. There were differences in the intron and exon structure in these Pru p/du 2 genes and in their amino acid composition. Three Pru p/du 3 genes (3.01–3.03) containing an intron and a mini exon of 10 nt were mapped in a cluster on G6. Two Pru p/du 4 genes (Pru p/du 4.01 and 4.02) were located on G1 and G7, respectively. The Pru p/du 1 cluster on G1 aligned to the Mal d 1 clusters on LG16; Pru p/du 2.01A and B on G3 to Mal d 2.01A and B on LG9; the Pru p/du 3 cluster on G6 to Mal d 3.01 on LG12; Pru p/du 4.01 on G1 to Mal d 4.03 on LG2; and Pru p/du 4.02 on G7 to Mal d 4.02 on LG2.

Conclusion

A total of 18 putative peach/almond allergen genes have been mapped on five linkage groups. Their positions confirm the high macro-synteny between peach/almond and apple. The insight gained will help to identify key genes causing differences in allergenicity among different cultivars of peach and other Prunus species.