Differential transcript abundance and genotypic variation of four putative allergen-encoding gene families in melting peach

We analysed the temporal and spatial transcript expression of the panel of 18 putative isoallergens from four gene families (Pru p 1-4) in the peach fruit, anther and leaf of two melting cultivars, to gain insight into their expression profiles and to identify the key family members. Genotypic variation of abundantly expressed genes in mature fruit was further screened in nine additional melting cultivars. In the Pru p 1 family, Pru p 1.01 and Pru p 1.06B were predominant and constitutively expressed in all the tissues, with large difference among cultivars observed in mature fruits. Pru p 1.02 was especially abundant only in the leaf. A new member of the Pru p 1 family, Pru p 1.06D, was identified through peach genome mining. In the Pru p 2 family, Pru p 2.01B was predominant in all tissues, whereas Pru p 2.01A was abundant in a few cultivars and undetectable in others. Pru p 3.01 was the most highly expressed member in all tissues except the mesocarp, while the other two members exhibited tissue specificity: Pru p 3.02 was highly expressed in the leaf, and Pru p 3.03 in the anther. Both Pru p 4 isoallergen genes were equally expressed in all tissues of both cultivars. There was high expression variability of Pru p 1 and Pru p 2 members in mature fruits among 11 cultivars, while relative lower for Pru p 3 and Pru p 4. The location, arrangement and features of peach isoallergen genes on the peach genome scaffolds were illustrated