Project description:The ripening of climacteric fruits, such as peach, is a complex process regulated by internal signals and external stimuli. Ultraviolet-C (UV-C) irradiation has been shown to delay fruit ripening, yet the mechanisms underlying this phenomenon remain poorly understood. RNA interference (RNAi)-mediated silencing of ERF1A supported its crucial role in UV-C-mediated ripening delay, as evidenced by changes in ethylene production, ripening-associated metabolites, fruit softening and the fluorescent immunolocalization of cell wall matrix components, particularly arabinogalactan, pectin and xyloglucan epitopes. Levels of auxin and salicylic acid were increased while abscisic acid was reduced in ERF1A silencing peels. Suppression of ERF1A altered the biosynthesis of peel-derived volatile compounds. Proteomic analysis identified several ERF1A-target genes and highlighted that the UV-C delayed ripening could be reversed by ERF1A silencing. Evidence is also presented supporting that PpCXE11, PpCXE13 and PpSABP2 are target of ERF1A transcription. These findings provide insights into the mechanisms driving UV-C-induced ripening delay in peach and underscore the central role of ERF1A in modulating this process.
Project description:A transcriptome analysis was applied on two peach (Prunus persica L.) cultivars with different sensitivity to low temperature regimes to identify cold-responsive genes that might be involved in tolerance to long low temperature storage. Peach fruit from ‘Morettini No2’ and ‘Royal Glory’, a sensitive and a tolerant, to chilling injury cultivars, respectively, were harvested at commercial maturity stage and allowed to ripen at room temperature (25°C) or subjected to 4 and 6-weeks of cold storage (0°C, 95% R.H.) followed by ripening at room temperature. Microarray experiments, employing the peach microarray platform (μ PEACH 1.0), were carried out by comparing harvested fruit against 4- and 6-week cold-stored fruit. The analysis identified 173 and 313 genes that were differentially expressed in ‘Morettini No2’ and ‘Royal Glory’ fruit after 4 weeks, respectively. However, the 6 weeks cold storage provoked a decrease in the total number of genes differentially expressed in both cultivars. RNA blot analysis validated the differential expression of certain genes showed in microarray data. Among these genes, two heat shock proteins (hsps), a putative β-D-xylosidase, an expansin, a dehydrin and a pathogenesis-related protein PR-4B precursor were induced during cold storage in both cultivars. The induction of hsps and the putative β-D-xylosidase appeared to be independent on the duration of postharvest treatment. On the other hand, transcript levels of lipoxygenase were quite constant during postharvest ripening, while a strong reduction or disappearance was observed after cold storage. A dehydration-induced RD22-like protein showed a reduction in the accumulation of transcripts during postharvest ripening independently on the temperature conditions. Overall, the current study shed some light on the molecular aspects of cold stress in peach fruit quality and identified some ripening and/or cold-induced genes which function need further elucidation.
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: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: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.
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
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: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: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.