A microarray approach to identify genes involved in seed and mesocarp development in peach

Background Field observations and a few physiological studies pointed out that peach embryogenesis and fruit development are strictly related. In fact, attempts to stimulate parthenocarpic fruit development by means of external tools failed. Moreover, physiological disturbances during the early embryo development lead to seed abortion and fruitlet abscission. Later on, the interactions between seed and fruit development become less stringent. Genetic and molecular information about seed and fruit development in peach is limited. Results The isolation of 455 genes differentially expressed in seed and fruit was done by means of a comparative analysis of the transcription profiles carried out in peach (Prunus persica, cv Fantasia) seed and mesocarp throughout development by means of µPEACH 1.0, the first peach microarray. Genes differentially expressed in the two organs and specific of developmental stages had been identified, and some were validated as markers. Genes representative of the main functional categories are present, among which several transcription factors such as MADS-box, bZIP, Aux/IAA, AP2, WRKY, and HD. Some of these showed a similar transcription profile in the two organs, while others displayed an opposite pattern, being more expressed in embryo at early development and in mesocarp at ripening. Conclusions The µPEACH1.0, although developed from ripe fruit ESTs, resulted in being suitable for studying seed/mesocarp interactions. Among the differentially expressed genes, marker genes specific for organ and stage of development have been selected. Comparisons were carried out by pooling stage 1 and 2 (named early development, e) and stage 3 and 4 (named late development, l), separately for mesocarp (M) and seed (S) of cultivar Fantasia, and using a simple loop experimental design. RNA has been extracted from fruit harvest at above-mentioned stages of development. At least four hybridizations have been conducted for a total of four technical replicates (with dye-swap).