2,302 research outputs found
Peaches harvested at advanced ripening stage: postharvest for maintaining quality
No full textConsumers of peaches and nectarines often complain of the low eating quality of these fruits that, for commercial purposes, are harvested before their physiological maturation is completed on the tree. The higher quality attained by delaying harvest contradicts the possibility of prolonging shelf-life, particularly for those varieties characterised by a very rapid softening process. In previous works (Tonutti et al., 1998; Bonghi et al., 1999) we have shown that Ultra Low Oxygen (ULO) postharvest treatments (up to 48h) without refrigeration are effective in reducing the softening rate in Springcrest peaches. Considering the differences existing among peach varieties in terms of ripening physiology, the aim of the present work was to evaluate the effects of a short-term ULO treatment on white (WF) and yellow (YF) flesh peach varieties harvested at an advanced ripening stage
Impiego dei fitoregolatori in viticoltura: potenzialità e problematiche.
No full textThe use of plant bioregulators to regulate
physiological process occurring during plant growth
and development may represent an important tool for
growers. In viticulture, hormone treatments have been
mainly addressed to the reproductive developmental
cycle, taking into account that grapevine vegetative
activity can be successfully controlled by training
systems and agricultural practices. In this review we
discuss the role of various hormones in the control of
inflorescence development and berry growth and ripening.
The control of these processes may have relevant
implications for disease control in the vineyard
considering that the susceptibility of different grape
cultivars to Botrytis bunch rot, powdery mildew and
downey mildew attacks is closely correlated with
bunch architecture. The timing and the extent of ripening
is of considerable scientific interest, but has also
implications for the various grape industries (fresh
market, winery logistic and processing, as well as
grape withering). In viticulture several bioregulators
can be used to regulate events of reproductive developmental
cycle. However, the most important applications
regard the use of gibberellins to modify inflorescence
length and bunch architecture as well as
berry size in seedless varieties, and abscissic acid,
ethylene and brassinosteroids to improve quality traits
of berries. Auxins can be mainly used as inhibitors of
ripening; therefore, they can be applied to delay the
vintage without significant changes of global quality of
berries. A delayed ripening can be also achieved by
spraying 1-methylcyclopropene, an inhibitors of ethylene
action. The knowledge of these effects has been
significantly improved in the last years thanks to the
increasing availability of information concerning the
molecular basis of hormone action. In the future, this
information could be used to develop new strategies
in the control of reproductive developmental cycle. In
addition, crystallography X-ray is an important tool to
elucidate the structure of plant hormone receptors
and thus to select, from chemical libraries, small biomolecules
able to interact with them. This is a crucial
point to develop new molecules with a lower synthesis
cost, which is often the main constraint on the introduction
of new plant bioregulators
Il controllo genetico-molecolare della maturazione e della qualità dei frutti
No full textIl completamento di progetti di sequenziamento dei genomi delle diverse specie frutticole consentirà di ampliare notevolmente le conoscenze sui processi di maturazione e sui meccanismi fisiologici e molecolari più rilevanti per la definizione della qualità dei frutti. Ciò permetterà di mettere a punto strumenti molecolari utilizzabili in programmi di miglioramento genetico assistito e di razionalizzare le tecnologie di produzione e di conservazione dei prodotti ortofrutticoli
The use of microarray μpeach 1.0 to investigate the transition from pre-climacteric to climacteric phase in peach fruit
No full textThe transition from preclimacteric to climacteric phase is a critical step during fruit development and ripening. An holistic approach to study this transition has been undertaken using the first peach microarray (μpeach 1.0) containing 4800 oligos corresponding to an equal number of genes expressed at preclimacteric and climacteric stages. Microarray hybridization indicated that 260 and 98 genes are up- and down-regulated, respectively. According to the TAIR Gene Ontology, genes have been classified into three main ontologies named cellular localization, molecular function and biological process. Considering the cellular localization the most significant up-and down-regulated gene products belong to cell wall and chloroplast. As far as cell wall is concerned major up-regulated genes encode pectinesterases and expansins, while down-regulation regards genes involved in cell wall growth and lignification. Among genes localized at chloroplast level a dramatic up-regulation of those controlling isoprenoids biosynthesis has been observed. Considering ontologies concerning molecular functions and biological process, a dramatic up-regulation has been detected for genes encoding transcription factors and enzymes involved in ethylene biosynthesis and action. Among transcription factors members of the APETALA and AUX/IAA families are the most represented, while within the family of ethylene receptors a peach new member has been described
Genomic tools for a better understanding of the fruit ripening process
No full textPurpose of the review: Increased understanding of fruit ripening is feasible with high-throughput methodologies for comprehensive transcriptome analyses. This article reviews main results gained by transcript profiling methods in the identification of genes involved in the regulation of fleshy-fruit ripening, and outlines potential applications of genomic tools developed in model species and already available in some important fruit crops.
Main findings: Global transcript profiling methods allowed the association of newly identified genes, such as some transcription factors, with the ripening syndrome. Furthermore, they helped in the functional characterisation of genes important for quality traits, such as aroma evolution and pigmentation. Comparative genomics carried out by digital analysis of expressed sequence tag repertoires and microarray analyses indicated that groups of genes responsible for regulatory mechanisms are shared between climacteric and non-climacteric fruits.
Direction for the future research: Gene sequences are important for fruit characteristics and can be useful in marker-assisted selection of new varieties. Further information on regulation of fruit ripening requires an extensive analysis of the proteome. Comparative proteomics is an efficient strategy that could be used to achieve this goal. The identification of differentially-expressed protein is becoming easier as a result of the rapid growth of plant DNA databases that allow association of a protein sequence with its cognate gene
Genomics approaches for better understanding the biological basis of fruit ripening and quality
No full textGenomics tools are nowadays commonly used in many plant science labs and are rapidly spreading for studying transcriptome profiles throughout fruit development and discovering new genes involved in processes modulating quality traits. In fact, transcript profiling (TP) has the potential to reveal transcriptional hierarchy during development for thousands of genes, as well as providing expression data for many genes of unknown or putative function. By using both direct and indirect TP methods, a body of new information is now available concerning ripening regulation in both climacteric and non-climacteric fruits, and a number of genes differentially expressed during the transition from unripe to ripe fruit and related to the evolution of quality parameters have been identified. Concerning direct TP methods, isolated ESTs have been used for digital expression analysis throughout fruit development in several fruit species and for comparative genomics investigations. The comparative approach has allowed to identify genes putatively encoding transcription factors induced at ripening in both grapes and peaches indicating that some regulatory elements are in common in non-climacteric and climacteric fruits. Among direct TP analyses, cDNA-AFLP has been widely used in several fruit types including grape berry: using this technique, we have identified 92 and 82 genes differentially regulated in skins of grape berries during extended ripening off- (detachment) and on- (late harvest) plant, respectively. Some of these genes are in common but others are specifically induced or repressed by each treatment and may be responsible for some quality traits characterizing late-harvest or partially dehydrated grape berries. Considering the indirect analyses, the first peach microarray (μPEACH 1.0) containing oligo-probes corresponding to 4806 unigenes has been constructed and used for comparing transcriptome of pre-climacteric and climacteric peach fruit: 267 and 109 genes appear up- and down-regulated, respectively, during this transition. Among these, genes responsible for typical peach fruit traits (pulp pigmentation) and others, already associated to ripening in other species, but never studied in peach have been identified
La regolazione ormonale dell’invaiatura della bacca di vite: un possibile modello basato sull’analisi dei profili trascrizionali di bacche trattate con acido naftalenacetico
No full textI meccanismi regolativi attivi durante la maturazione della bacca d’uva sono prevalentemente basati sulle interazioni tra auxina, etilene, acido abscissico (ABA) e brassinosterodi (BR). In particolare, le auxine agiscono come repressori della maturazione, mentre etilene, ABA e BR operano come induttori. Per apportare nuove informazioni sulle interazioni ormonali presenti all’avvio della maturazione (invaiatura) è stato effettuato un trattamento con auxina sintetica (acido naftalacetico, NAA), una settimana prima dell’invaiatura. Il trattamento causa un forte ritardo della progressione degli eventi associati alla maturazione: aumento di dimensione della bacca, accumulo di antociani e zuccheri e riduzione degli acidi organici. Questi eventi sono accompagnati da significative variazioni della trascrizione di geni associati ai metabolismi primario, secondario e ormonale. I dati relativi a questi ultimi sono stati analizzati mediante HORMONOMETER, uno strumento bioinformatico che consente di valutare gli effetti dell’applicazione di ormoni e le loro interazioni sulla base di dati trascrittomici. I risultati ottenuti evidenziano che, a sette giorni dal trattamento, le concentrazioni di auxina tornano a livelli biologicamente compatibili grazie all’attivazione di un processo di omeostasi. Questa ipotesi è suffragata da analisi di trascritti (via qPCR) che mostrano un’induzione di geni coinvolti nella coniugazione (GH3-like) della auxine e di quelli che ne regolano l’azione (IAA4- e IAA31-like). Per quanto attiene alle interazioni è stato osservato che l’NAA induce i geni della biosintesi dell’etilene (ACS e ACO) ma esercita un forte effetto negativo su quelli associati alla sua percezione (EIN4) ed azione (ERFs). A questo si contrappone un inaspettato effetto sinergico, seppur limitato, delle auxine sulla catena trasduttiva dell’ABA. L’insieme dei dati ottenuti è stato organizzato in un modello della regolazione ormonale dell’invaiatura che sarà presentato e discusso
Peaches harvested at advanced ripening stage: postharvest treatment for maintaining quality
No full textConsumers of peaches and nectarines often complain of the low eating quality of these fruits that, for commercial purposes, are harvested before their physiological maturation is completed on the tree. The higher quality attained by delaying harvest contradicts the possibility of prolonging shelf-life, particularly for those varieties characterised by a very rapid softening process. In previous works (Tonutti et al., 1998; Bonghi et al., 1999) we have shown that Ultra Low Oxygen (ULO) postharvest treatments (up to 48h) without refrigeration are effective in reducing the softening rate in Springcrest peaches. Considering the differences existing among peach varieties in terms of ripening physiology, the aim of the present work was to evaluate the effects of a short-term ULO treatment on white (WF) and yellow (YF) flesh peach varieties harvested at an advanced ripening stage
Postharvest water loss induces marked changes in transcript profiling in skins of wine grape berries
No full textA large-scale transcriptome analysis was conducted using an oligo-based microarray (14,562 probes) on skins of wine grape (Vitis vinifera L.) berries dehydrated at different rates (slow, S and rapid, R) after harvest up to 10 and 30% of weight loss (WL). At 10% WL, a total of 84 and 68 probes were differentially expressed following S and R dehydration, respectively. At 30% WL, 309 and 262 differentially expressed probes were detected in S and R samples, respectively, indicating that grape berries are still reactive at advanced stages of postharvest dehydration. Bioinformatic analysis revealed that about 70% of the differentially expressed probes could be annotated and putative functions were assigned. Functional characterization highlighted that, independently of the rate and intensity of dehydration, differential expression occurred in particular for genes associated with general metabolism, regulatory processes, and responses to biotic and abiotic stimuli. A total of 16 (induced) and 10 (repressed) probes, common to all four dehydrated samples, were associated with hormone (ethylene) metabolism, transcription factors, carbohydrate and secondary (polyphenols) metabolism, transport and stress responses. Together with the total number of differentially expressed probes, enhancing the dehydration level from 10 to 30% WL also affected the distribution of genes within functional categories: this behaviour was observed in particular for R samples. A higher level of water stress in grapes appears to be associated with modification to the expression of genes mainly involved in hormone and sugar metabolism, and defence mechanisms. Besides the intensity of dehydration, a significant effect on gene expression was also associated with rate of water loss: an increase in the percentage incidence of differentially expressed probes was present for categories involved in defence and environmental stress when comparing R and S samples. The microarray data, validated by RT-PCR analyses, represent robust evidence for the marked effects of postharvest water loss on metabolic processes in fruit tissues
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