Project description:Noble rot results from atypical infections of ripe grape berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and accumulation of secondary metabolites that enhance wine grape quality. Noble rot-infected berries of SÃ©millon, a white-skinned variety, were collected over three years from a commercial vineyard at the same time fruit were harvested for botrytized wine production. Transcriptomic and metabolomic data were integrated to identify pathways associated with distinct stages of noble rot. Botrytis induced the expression of known key regulators of pathways in secondary metabolism associated with berry ripening. The activation by Botrytis during noble rot of metabolic pathways associated with berry ripening was further supported by comparisons with transcriptomes of red-skinned varieties at vÃ©raison. A prominent and common outcome of noble rot and berry ripening was the enhancement of the phenylpropanoid metabolism. Induced synthesis of stilbenes, flavonoids, and anthocyanins was supported by both transcriptional and metabolite analyses. Enzyme assays and targeted gene expression analyses of samples from the three distinct years confirmed that the activation of central and peripheral phenylpropanoid pathways is a consistent hallmark of noble rot. Finally, we show that the impact of noble rot on grape metabolism is still detectable in botrytized wines. These results demonstrate that despite the late stage of terminal senescence of a plant organ, a biotic stress can cause a major reprogramming of plant metabolism leading, in case of noble rot, to the synthesis of important metabolites for grape berry flavor and aroma. The experimental design consists of 4 treatments, berries at 3 distinct stages of noble rot and berries without apparent symptoms of infection. From each treatment a total of 4 biological replicates were sequenced with RNAseq, each replicate corresponded to independent pools of 10-15 berries harvested from adjacent grapevines.

Project description:Temperature and solar radiation influence Vitis vinifera L. berry ripening. Both environmental conditions fluctuate cyclically on a daily period basis and the strength of this fluctuation affects grape ripening too. Additionally, a molecular circadian clock regulates daily cyclic expression in a large proportion of the plant transcriptome modulating multiple developmental processes in diverse plant organs and developmental phases. Circadian cycling of fruit transcriptomes has not been characterized in detail despite their putative relevance in the final composition of the fruit. Thus, in this study, gene expression throughout 24 h periods in pre-ripe berries of Tempranillo and Verdejo grapevine cultivars was followed to determine whether different ripening transcriptional programs are activated during certain times of day in different grape tissues and genotypes. Results: Microarray analyses identified oscillatory transcriptional profiles following circadian variations in the photocycle and the thermocycle. A higher number of expression oscillating transcripts were detected in samples carrying exocarp tissue including biotic stress-responsive transcripts activated around dawn. Thermotolerance-like responses and regulation of circadian clock-related genes were observed in all studied samples. Indeed, homologs of core clock genes were identified in the grapevine genome and, among them, VvREVEILLE1 (VvRVE1), showed a consistent circadian expression rhythm in every grape berry tissue analysed. Light signalling components and terpenoid biosynthetic transcripts were specifically induced during the daytime in Verdejo, a cultivar bearing white-skinned and aromatic berries, whereas transcripts involved in phenylpropanoid biosynthesis were more prominently regulated in Tempranillo, a cultivar bearing black-skinned berries. Conclusions: The transcriptome of ripening fruits varies in response to daily environmental changes, which might partially be under the control of circadian clock components. Certain cultivar and berry tissue features could rely on specific circadian oscillatory expression profiles. These findings may help to a better understanding of the progress of berry ripening in short term time scales.

Project description:Temperature and solar radiation influence Vitis vinifera L. berry ripening. Both environmental conditions fluctuate cyclically on a daily period basis and the strength of this fluctuation affects grape ripening too. Additionally, a molecular circadian clock regulates daily cyclic expression in a large proportion of the plant transcriptome modulating multiple developmental processes in diverse plant organs and developmental phases. Circadian cycling of fruit transcriptomes has not been characterized in detail despite their putative relevance in the final composition of the fruit. Thus, in this study, gene expression throughout 24 h periods in pre-ripe berries of Tempranillo and Verdejo grapevine cultivars was followed to determine whether different ripening transcriptional programs are activated during certain times of day in different grape tissues and genotypes. Results: Microarray analyses identified oscillatory transcriptional profiles following circadian variations in the photocycle and the thermocycle. A higher number of expression oscillating transcripts were detected in samples carrying exocarp tissue including biotic stress-responsive transcripts activated around dawn. Thermotolerance-like responses and regulation of circadian clock-related genes were observed in all studied samples. Indeed, homologs of core clock genes were identified in the grapevine genome and, among them, VvREVEILLE1 (VvRVE1), showed a consistent circadian expression rhythm in every grape berry tissue analysed. Light signalling components and terpenoid biosynthetic transcripts were specifically induced during the daytime in Verdejo, a cultivar bearing white-skinned and aromatic berries, whereas transcripts involved in phenylpropanoid biosynthesis were more prominently regulated in Tempranillo, a cultivar bearing black-skinned berries. Conclusions: The transcriptome of ripening fruits varies in response to daily environmental changes, which might partially be under the control of circadian clock components. Certain cultivar and berry tissue features could rely on specific circadian oscillatory expression profiles. These findings may help to a better understanding of the progress of berry ripening in short term time scales. A total of 54 samples were hybridized. Three different circadian time course series consisted on six time point each. Series corresponded to pericarp of Verdejo grapevine cultivar and berry flesh and skin in separate of Tempranillo cultivar. Three biological replicates were analyzed for each series.

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Auxin treatment of grapevine (Vitis vinifera L.) berries delays ripening onset by inhibiting cell expansion

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