A microarray approach to identify genes involved in seed-pericarp cross-talk and development in peach

Abstract

BackgroundField observations and a few physiological studies have demonstrated that peach embryogenesis and fruit development are tightly coupled. In fact, attempts to stimulate parthenocarpic fruit development by means of external tools have failed. Moreover, physiological disturbances during early embryo development lead to seed abortion and fruitlet abscission. Later in embryo development, the interactions between seed and fruit development become less strict. As there is limited genetic and molecular information about seed-pericarp cross-talk and development in peach, a massive gene approach based on the use of the μPEACH 1.0 array platform and quantitative real time RT-PCR (qRT-PCR) was used to study this process.ResultsA comparative analysis of the transcription profiles conducted in seed and mesocarp (cv Fantasia) throughout different developmental stages (S1, S2, S3 and S4) evidenced that 455 genes are differentially expressed in seed and fruit. Among differentially expressed genes some were validated as markers in two subsequent years and in three different genotypes. Seed markers were a LTP1 (lipid transfer protein), a PR (pathogenesis-related) protein, a prunin and LEA (Late Embryogenesis Abundant) protein, for S1, S2, S3 and S4, respectively. Mesocarp markers were a RD22-like protein, a serin-carboxypeptidase, a senescence related protein and an Aux/IAA, for S1, S2, S3 and S4, respectively.The microarray data, analyzed by using the HORMONOMETER platform, allowed the identification of hormone-responsive genes, some of them putatively involved in seed-pericarp crosstalk. Results indicated that auxin, cytokinins, and gibberellins are good candidates, acting either directly (auxin) or indirectly as signals during early development, when the cross-talk is more active and vital for fruit set, whereas abscisic acid and ethylene may be involved later on.ConclusionsIn this research, genes were identified marking different phases of seed and mesocarp development. The selected genes behaved as good seed markers, while for mesocarp their reliability appeared to be dependent upon developmental and ripening traits. Regarding the cross-talk between seed and pericarp, possible candidate signals were identified among hormones.Further investigations relying upon the availability of whole genome platforms will allow the enrichment of a marker genes repertoire and the elucidation of players other than hormones that are involved in seed-pericarp cross-talk (i.e. hormone peptides and microRNAs).

Immunohistochemical Localization of Endogenous IAA in Peach (Prunus persica L.) Fruit during Development

“…3). Bonghi (2011) determined that during peach fruit development, auxin is transported from the seed to other organs by the apoplastic pathway, which was coincided with our results that IAA was produced in the seed coat, but it was not transported symplastically, indicating that it was likely translocated through the apoplastic pathway.…”

“…These results are consistent with our results determined by the immunohistochemical localization of IAA technique: The content of IAA was highest in seed, whereas it was low in mesocarp and endocarp tissues. Bonghi et al (2011) determined that peach embryogenesis and fruit development are tightly coupled. Moreover, physiological disturbances during early embryo development will lead to seed abortion and fruitlet abscission.…”

“…Torrigiani showed that jasmonic acid and spermine could affect fruit ripening and were related with ethylene and auxin (Torrigiani et al, 2012). Auxin is an important molecule both in early and late development (Bonghi et al, 2011), but the signal generating sites and transport pathway of auxin are poorly understood at present.…”

“…In the early stage of fruit development, a variety of hormones were involved in the cross-talk, and auxin may play a direct role in the signal transduction (Bonghi et al, 2011). In order to explore the source of IAA and observe its spatial distribution and dynamic changes, the immunohistochemical localization of IAA was carried out in different tissues of peach fruits.…”

Early Induction of Apple Fruitlet Abscission Is Characterized by an Increase of Both Isoprene Emission and Abscisic Acid Content

“…Briefly, this bioinformatics tool allows, in terms of correlation (or anticorrelation), the similarity (or dissimilarity) to be described between a query transcriptional response and a transcriptional response typically assessed with a certain hormone treatment as defined by known hormone indexes in Arabidopsis. For a detailed description of the tool, see Volodarsky et al (2009) and recent applications in peach (Bonghi et al, 2011) and grape (Vitis vinifera; Ziliotto et al, 2012). Microarray data produced by Botton et al (2011) were used as input for this analysis (see Supplementary Material for further details), indicating that ABA-related transcriptional indexes were active at both 17 and 19 DAPF.…”