Project description:Background Grapes (Vitis vinifera L.) are economically the most important fruit crop worldwide. However, the complexity of molecular and biochemical events that lead to the onset of ripening of nonclimacteric fruits is not fully understood which is further complicated in grapes due to seasonal and cultivar specific variantion. The Portuguese wine variety Trincadeira gives rise to high quality wines but presents extremely irregular berry ripening among seasons probably due to high susceptibility to abiotic and biotic stresses. Results Ripening of Trincadeira grapes was studied taking into account the transcriptional and metabolic profilings complemented with biochemical data. The mRNA expression profiles of four time points spanning developmental stages from pea size green berries, through veraison and mature berries (EL 32, EL 34, EL 35 and EL 36) and in two seasons (2007 and 2008) were compared using the Affymetrix GrapeGen® genome array containing 23096 probesets corresponding to 18726 unique sequences. Over 50% of these probesets were significantly differentially expressed (1.5 fold) between at least two developmental stages. A common set of modulated transcripts corresponding to 5862 unigenes indicates the activation of common pathways in between years despite the irregular development of Trincadeira grapes. These unigenes were assigned in the functional categories of “metabolism, development”, “cellular process”, “diverse functions”, “regulation overview”, “response to stimulus, stress”, “signaling”, “transport overview”, “xenoprotein, transposable element” and “unknown”. Metabolic profiling using 1H NMR spectroscopy associated to two-dimensional techniques showed the importance of metabolites related to oxidative stress response, amino acid and sugar metabolism as well as secondary metabolism in grape ripening. This information was integrated with transcriptional profiling obtained using genome array and qRT-PCR for five developmental stages (EL 32, EL 34, EL 35, EL 36 and EL 38). Conclusions Altogether the results provide new information regarding the network of events leading to grape ripening as well as highlight features that may be cultivar specific namely in what concerns the role of carbohydrates and growth regulators´ metabolism as well as epigenetic factors and signaling pathways.

Project description:Plants must continuously react to the ever-fluctuating nature of their environment. Repeated exposure to stressful conditions can lead to priming, whereby prior encounters heighten a plant’s ability to respond to future events. A clear example of priming is provided by the model plant species Arabidopsis thaliana (Arabidopsis), in which photosynthetic and photoprotective responses are enhanced following recurring light stress. While there are various post-translational mechanisms underpinning photoprotection, an unresolved question is the relative importance of transcriptional changes towards stress priming and, consequently, the potential contribution from DNA methylation – a heritable chemical modification of DNA capable of influencing gene expression. Here, we systematically investigate the potential molecular underpinnings of physiological priming against recurring excess light (EL), specifically DNA methylation and transcriptional regulation: the latter having not been examined with respect to EL priming. The capacity for physiological priming of photosynthetic and photoprotective parameters following a recurring EL treatment was not impaired in Arabidopsis mutants with perturbed establishment, maintenance and removal of DNA methylation, nor was the transmission of this priming into naive tissues developed in the absence of excess light. Importantly, no differences in developmental or basal photoprotective capacity were identified in the mutants that may confound the above result. Little evidence for a causal transcriptional component of physiological priming was identified; in fact, most alterations in primed plants presented as a transcriptional ‘dampening’ in response to an additional EL exposure, likely a consequential of physiological priming. However, a set of transcripts uniquely regulated in primed plants provide preliminary evidence for a novel transcriptional component of recurring EL priming, independent of physiological changes. Thus, we propose that physiological priming of recurring EL in Arabidopsis occurs independently of DNA methylation; and that the majority of the associated transcriptional alterations are a consequence, not cause, of this physiological priming.

Project description:Background Grapes (Vitis vinifera L.) are economically the most important fruit crop worldwide. However, the complexity of molecular and biochemical events that lead to the onset of ripening of nonclimacteric fruits is not fully understood which is further complicated in grapes due to seasonal and cultivar specific variantion. The Portuguese wine variety Trincadeira gives rise to high quality wines but presents extremely irregular berry ripening among seasons probably due to high susceptibility to abiotic and biotic stresses. Results Ripening of Trincadeira grapes was studied taking into account the transcriptional and metabolic profilings complemented with biochemical data. The mRNA expression profiles of four time points spanning developmental stages from pea size green berries, through veraison and mature berries (EL 32, EL 34, EL 35 and EL 36) and in two seasons (2007 and 2008) were compared using the Affymetrix GrapeGen® genome array containing 23096 probesets corresponding to 18726 unique sequences. Over 50% of these probesets were significantly differentially expressed (1.5 fold) between at least two developmental stages. A common set of modulated transcripts corresponding to 5862 unigenes indicates the activation of common pathways in between years despite the irregular development of Trincadeira grapes. These unigenes were assigned in the functional categories of “metabolism, development”, “cellular process”, “diverse functions”, “regulation overview”, “response to stimulus, stress”, “signaling”, “transport overview”, “xenoprotein, transposable element” and “unknown”. Metabolic profiling using 1H NMR spectroscopy associated to two-dimensional techniques showed the importance of metabolites related to oxidative stress response, amino acid and sugar metabolism as well as secondary metabolism in grape ripening. This information was integrated with transcriptional profiling obtained using genome array and qRT-PCR for five developmental stages (EL 32, EL 34, EL 35, EL 36 and EL 38). Conclusions Altogether the results provide new information regarding the network of events leading to grape ripening as well as highlight features that may be cultivar specific namely in what concerns the role of carbohydrates and growth regulators´ metabolism as well as epigenetic factors and signaling pathways. 4 time points in 2007 season. 3 time points in 2008 season. 3 biological replicates.

Dataset Information

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets