Project description:Fleshy fruit help in reproduction by developing structures that, reached a given maturity stage, become attractive to animals that, feeding on them, spread the contained seeds in the environment. According to the species, seed development can be at the same pace with the pericarp, or be ready for dispersion before or after the ripening of the fruit. In peach, seed and mesocarp maturation are on pace in mid-season cultivars, while in early ripening ones the seed is not mature at ripening, with the endosperm not yet fully reabsorbed. On the contrary, slow ripening genotypes show the opposite, i.e. a mature seed in a fruit unable to fully ripen. To gain insights on the molecular control of peach fruit development and ripening and on the interactions between the seed and the mesocarp, genome wide transcriptional changes of the two fruit parts have been investigated throughout development from flower anthesis up to commercial ripening in the mid-season cultivar Fantasia. Besides flower, six time points encompassing the four fruit developmental stages were investigated.
Project description:Manipulating the crop load in peach trees determines carbon supply and optimum balance between fruit yield and quality potentials. The impact of carbon supply on peach fruit quality was assessed in three development stages (S2, S3, S4) on fruit of equal maturity from trees that were carbon (C) starved (unthinned) and sufficient (thinned). Previous studies determined that primary metabolites of peach fruit mesocarp are mainly linked with developmental processes, thus, the secondary metabolite profile was assessed using non-targeted liquid chromatography mass-spectrometry (LC-MS). Carbon sufficient (C-sufficient) fruit demonstrated superior quality attributes as compared to C-starved fruit. Early metabolic shifts in the secondary metabolome appear to prime quality at harvest. Enhanced C-availability facilitated the increased and consistent synthesis of flavonoids, like catechin, epicatechin and eriodyctiol, via the phenylpropanoid pathway, providing a link between the metabolome and fruit quality, and serving as signatures of C-sufficiency during peach fruit development.
Project description:The fruit of melting-flesh peach cultivars produce high levels of ethylene caused by high expression of PpACS1, resulting in rapid fruit softening at the late-ripening stage. In contrast, the fruit of stony hard peach cultivars do not soften and produce little ethylene due to low expression of PpACS1. To elucidate the mechanism for suppressing PpACS1 expression in stony hard peaches, a microarray analysis was performed. Several genes that displayed similar expression patterns as PpACS1 were identified and shown to be IAA-inducible genes. Change in gene expression according to growth of fruits in 'melting peach M-bM-^@M-^XAkatsukiM-bM-^@M-^Y fruit sampled at 92, 98, 104 and 106 day after full bloom (DAB). Propylene induced gene expression stony peach M-bM-^@M-^XManamiM-bM-^@M-^Y and M-bM-^@M-^XOdorokiM-bM-^@M-^Y harvested at commercial maturity (Tatsuki et al., 2006).
Project description:The aim of this study was to elucidate the potential use of microarray technology, developed in model species, in related, yet phenotypically distinct, species where few or no information are available. Considering the high degree of sequence conservation within the Rosaceae family and, in particular, among the Prunus species we employed the first available peach oligonucleotide microarray (µPEACH 1.0) for studying the transcrptomic profile during apricot fruit development (Prunus armeniaca L., cv. 'Goldrich'). Fruit material was harvested at three distinct stages, corresponding to immature-green stage (6 weeks before fully-ripe stage), mature-firm-ripe stage (change of peel color, 1 week before fully-ripe stage) and at fully-ripe stage and designated as S1, S2 and S3 stages, respectively. Apricot targets cDNA, when applied the µPEACH1.0, were showing significant hybridization with an average of 43% of spotted targets validating the use of μPEACH1.0 to profile the transcriptome of apricot fruit during development and ripening. Microarray analysis carried out on immature and ripe peach and apricot fruit separately pointed out that 70% of genes differentially expressed was detectable the same pattern of expression in both species. This result indicates that the transcriptome of immature and ripe fruit are quite similar in apricot and peach, but also highlighted the presence of transcript changes specie-specific. When μPEACH1.0 was used to profile apricot developing fruit were identified 400 and 74 genes differetially expressed during the transition from S1 to S2 stage and from S2 to S3 stage, respectively. Intriguingly, a considerable number of auxin action regulators (AUX/IAA) and of genes coding heat shock proteins (hsp) were highly up-regulated at the onset and late of ripening phase, respectively.The comparison between the expression profiles of these apricot genes and their peach hortologues showed a similar pattern for AUX/IAA and quite different for hsps. This result suggests a similar role for AUX/IAA in both species and a more important involvement for hsps in the apricot fruit ripening.
Project description:The fruit of melting-flesh peach cultivars produce high levels of ethylene caused by high expression of PpACS1, resulting in rapid fruit softening at the late-ripening stage. In contrast, the fruit of stony hard peach cultivars do not soften and produce little ethylene due to low expression of PpACS1. To elucidate the mechanism for suppressing PpACS1 expression in stony hard peaches, a microarray analysis was performed. Several genes that displayed similar expression patterns as PpACS1 were identified and shown to be IAA-inducible genes.
Project description:Thinning is indispensable practice in peach cultivation aiming to reduce fruit number per plant, promoting sink-source balance and reducing competition among fruit, which results in bigger fruit and the improvement of other fruit-quality parameters. Inhibition of floral induction by GAs has been largely demonstrated and commercial products based on GAs have been used to this aim. We tested a product GA4/7 based in different moments after full bloom in peach to reduce the number of flowers in the following season. Return to bloom and transcriptome analysis were performed to identify the best moment for the treatment, increasing the product efficacy and understanding the product action at genetic level.
Project description:In peach, the flat phenotype is caused by a partially dominant allele in heterozygosis (Ss), fruits from homozygous trees (SS) abort a few weeks after fruit setting. Previous research has identified a SSR marker (UDP98-412) highly associated with the trait, found suitable for marker assisted selection (MAS). Here we report a ?10?Kb deletion affecting the gene PRUPE.6G281100, 400?Kb upstream of UDP98-412, co-segregating with the trait. This gene is a leucine-rich repeat receptor-like kinase (LRR-RLK) orthologous to the Brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) group. PCR markers suitable for MAS confirmed its strong association with the trait in a collection of 246 cultivars. They were used to evaluate the DNA from a round fruit derived from a somatic mutation of the flat variety 'UFO-4', revealing that the mutation affected the flat associated allele (S). Protein BLAST alignment identified significant hits with genes involved in different biological processes. Best protein hit occurred with AtRLP12, which may functionally complement CLAVATA2, a key regulator that controls the stem cell population size. RT-PCR analysis revealed the absence of transcription of the partially deleted allele. The data support PRUPE.6G281100 as a candidate gene for flat shape in peach.
Project description:We performed small RNA deep sequencing and identified 47 peach-specific and 47 known miRNAs or families with distinct expression patterns. Together, the identified miRNAs targeted 80 genes, many of which have not been reported previously. Like the model plant systems, peach has two of the three conserved trans-acting siRNA biogenesis pathways with similar mechanistic features and target specificity. Unique to peach, three of the miRNAs collectively target 49 MYBs, 19 of which are known to regulate phenylpropanoid metabolism, a key pathway associated with stone hardening and fruit color development, highlighting a critical role of miRNAs in regulation of peach fruit development and ripening. We also found that the majority of the miRNAs were differentially regulated in different tissues, in part due to differential processing of miRNA precursors. Up to 16% of the peach-specific miRNAs were differentially processed from their precursors in a tissue specific fashion, which has been rarely observed in plant cells. The miRNA precursor processing activity appeared not to be coupled with its transcriptional activity but rather acted independently in peach. Collectively, the data characterizes the unique expression pattern and processing regulation of peach miRNAs and demonstrates the presence of a complex, multi-level miRNA regulatory network capable of targeting a wide variety of biological functions, including phenylpropanoid pathways which play a multifaceted spatial-temporal role in peach fruit development. Identification of peach miRNAs and their targets from four different tissues