Project description:Seedless varieties are of particular importance to the table-grape and raisin industries. Gibberellin (GA) application is widely used in the early stages of seedless berry development to increase berry size and economic value. However, the underlying mechanism of GA induction of berry enlargement is not well understood. Here, RNA-sequencing analysis of âCentennial Seedlessâ (Vitis vinifera L.) berries treated with GA3 12 days after flowering is reported.
Project description:Auxin treatment of grape (Vitis vinifera L.) berries delays ripening by inducing changes in gene expression and cell wall metabolism and could combat some deleterious climate change effects. Auxins are inhibitors of grape berry ripening and their application may be useful to delay harvest to counter effects of climate change. However, little is known about how this delay occurs. The expression of 1892 genes was significantly changed compared to the control during a 48 h time-course where the auxin 1-naphthaleneacetic acid (NAA) was applied to pre-veraison grape berries. Principal component analysis showed that the control and auxin-treated samples were most different at 3 h post-treatment when approximately three times more genes were induced than repressed by NAA. There was considerable cross-talk between hormone pathways, particularly between those of auxin and ethylene. Decreased expression of genes encoding putative cell wall catabolic enzymes (including those involved with pectin) and increased expression of putative cellulose synthases indicated that auxins may preserve cell wall structure. This was confirmed by immunochemical labelling of berry sections using antibodies that detect homogalacturonan (LM19) and methyl-esterified homogalacturonan (LM20) and by labelling with the CMB3a cellulose-binding module. Comparison of the auxin-induced changes in gene expression with the pattern of these genes during berry ripening showed that the effect on transcription is a mix of changes that may specifically alter the progress of berry development in a targeted manner and others that could be considered as non-specific changes. Several lines of evidence suggest that cell wall changes and associated berry softening are the first steps in ripening and that delaying cell expansion can delay ripening providing a possible mechanism for the observed auxin effects.
Project description:SuperSAGE is a method of digital gene expression profiling that allows isolation of 26bp tag fragments from expressed transcripts. Because its tag size is larger than that of conventional SAGE, SuperSAGE allowed a secure tag-to-gene annotation using BLAST search against grape genome databases.Transcript profiles in nine samples of grape berry tissues under different light conditions were obtained by SuperSAGE analysis and used for screening the genes which have co-ordinated transcript profiles with the change in the flavonoid composition in the samples analyzed. Candidate genes related to flavonoid biosynthesis and regulation were identified. Nine different grape samples, i.e., flowers, grape berries of Cabernet Sauvignon at 2, 7, 9 weeks after flowering (WAF), berry skins at 17 days after flowering (DAF) shaded after flowering, and berry skins at 17DAF shaded from flowering to 14DAF and then light exposed, were analyzed.
Project description:Grapevine cluster compactness is a multi-componential trait of agronomical interest; it greatly influences the vineyard management and the visual aspect of table grape. Clusters with greater compactness are more susceptible to disease. The compactness can be break down in a patchwork of agronomical traits, each having agronomical importance that includes parameters related to inflorescence and cluster architecture (cluster length and width, length of pedicels, etc.), fruitfulness (number of berries, number of seeds) and berry (size, shape, volume...). Through visual evaluation of a collection of 730 clones from the cultivar Tempranillo and 501 clones from Garnacha Tinta we identified and fully phenotyped distinct clones which transcriptomes were compared at key developmental stages in order to identify the genes playing a role in mechanisms involved in cluster compactness such as the ones determining number of berries, cluster length or berry size. Key genes involved in this process were identified. The findings lead us to hypothesize that berry size and/or number at ripening are greatly influenced by the rate of cell replication in flowers during the first stages after pollination.
Project description:Grapevine is a perennial crop often cultivated by grafting a scion cultivar on a suitable rootstock. Rootstocks influence scions, particularly with regard to water uptake and vigor. Therefore, one of the possibilities to adapt viticulture to the extended drought stress periods is to select rootstocks conferring increased tolerance to drought. However, the molecular mechanisms associated with the ability of rootstock/scion combination to influence grape berry metabolism under drought stress are still poorly understood. The transcriptomic changes induced by drought stress in grape berries (cv. Pinot noir) from vines grafted on either 110R (drought tolerant) or 125AA (drought sensitive) rootstock were compared. The experiments were conducted in the vineyard for two years and two grape berry developmental stages (50% and 100 % veraison. The genome-wide microarray approach showed that water stress strongly impacts gene expression in the berries, through ontology categories that cover cell wall metabolism, primary and secondary metabolism, signalling, stress, and hormones, and that some of these effects strongly depend on the rootstock genotype. Indeed, under drought stress, berries from vines grafted on 110R displayed a different transcriptional response compared to 125AA concerning genes related to jasmonate, phenylpropanoid metabolism and PR-proteins. The data also suggests a link between jasmonate and secondary metabolism in water-stressed berries. Overall, genes related to secondary metabolism and jasmonate are more induced and/or less repressed by drought stress in the berries grafted on the drought-sensitive rootstock 125AA. These rootstock-dependent gene expression changes are relevant for berry composition and sensory properties.
Project description:White grape (Vitis vinifera cv. Furmint) berry samples subjected to natural noble rot were collected in a vineyard in Mád, Hungary (Tokaj wine region). Raw data include grapevine and Botrytis cinerea sequence reads.