Corrigendum

Ethylene signalling receptors and transcription factors over the grape berry development: gene expression profilingVitis 49 (3), 129-136 (2010

Ethylene signalling receptors and transcription factors over the grape berry development: gene expression profiling

The ethylene signalling pathway has never been fully described in grapes. Regarded as a non-climacteric fruit, grape berry seems to ripen independently to ethylene, however 1-methylcyclopropene (1-MCP), a specific inhibitor of ethylene receptors has been shown to alter berry ripening processes. Here, we report profiles of transcript abundance of various receptors and transcription factors, associated with ethylene signalling, throughout berry development. Transcript abundance of ortholog VvETR2 gene showed a transient peak at the inception of ripening in 'Cabernet Sauvignon' berries coinciding with an internal ethylene peak, prior to colour changes. The transcripts of other orthologs such as VvRTE1 and VvEIN4 steadily increased over the berry development, while VvERS1 ortholog transcripts exhibited a peak of accumulation only when the berries were fully coloured. Finally, mRNAs of two transcription factors, VvEIN3 and VvMADS4, showed strong accumulation during the late phase of berry ripening. We also observed inflections of mRNA accumulation after incubating berry clusters with ethylene and 1-MCP (inhibitor of ethylene action). The main effect was observed with VvEIN3 transcripts that showed a significant up-regulation after incubation with 1-MCP. Furthermore, other transcript levels (VvETR2 and VvCTR1) were also increased by exogenous ethylene, once the colour change was initiated (i.e. 10 to 11 weeks after bloom). Some studies have already indicated that non-climacteric fruits shared signalling pathways with climacteric fruits. However, most differences between these ripening classifications remain poorly described at the genetic/molecular level. This data set will contribute to a better understanding on potential involvements of ethylene signalling in a non-climacteric fruit such as grape berry.

XL. New observations on volcanoes and their lava

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Affect and New French Extremity: Aesthetics of Traumatic Memory

This thesis hopes to highlight how a particular film phenomenon in early twenty-first century France demonstrates the concepts of traumatic affect eloquently through its aesthetic and formal tendencies. Commonly known as New French Extremity, this phenomenon touched on transgressive subjects in extreme and often viscerally challenging ways. This work into New French Extremity hopes to bring about a broader understanding of how art communicates traumatic memory through formal elements of storytelling. Ultimately this research seeks to better understand how bodily experience is affectively contagious and how cinema facilitates this communication through formal and aesthetic means

Identification et caractérisation fonctionnelle de deux gènes régulateurs du métabolisme des composés phénoliques de la baie de raisin

Les polyphénols sont des constituants majeurs de la baie de raisin. Ils contribuent de manière prépondérante à la qualité organoleptique, phytosanitaire et à la stabilité d'un vin. Bien que de nombreuses études scientifiques aient permis d'évaluer leur biosynthèse au cours du développement de la baie de raisin, peu de résultats ont été publiés sur les mécanismes moléculaires régulant leur accumulation. Par une approche de gènes candidats, nous avons identifié deux gènes régulateurs (VvMybCs1 et VvMybCs2) dont la sur-expression dans deux systèmes hétérologues (Tabac, Arabidopsis thaliana) a permis de valider leur rôle dans la régulation coordonnée des gènes de la voie de biosynthèse des polyphénols

Timing of ripening initiation in grape berries and its relationship to seed content and pericarp auxin levels

BACKGROUND: Individual berries in a grape (Vitis vinifera L.) cluster enter the ripening phase at different times leading to an asynchronous cluster in terms of ripening. The factors causing this variable ripening initiation among berries are not known. Because the influence via hormonal communication of the seed on fruit set and growth is well known across fruit species, differences in berry seed content and resultant quantitative or qualitative differences in the hormone signals to the pericarp likely influence the relative timing of ripening initiation among berries of the cluster. RESULTS: At the time of the initiation of cluster ripening (véraison), underripe green berries have higher seed content compared to the riper berries and there is a negative correlation between the seed weight-to-berry weight ratio (SB) and the sugar level in berries of a cluster. Auxin levels in seeds relative to the pericarp tissues are two to 12 times higher at pre-ripening stages. The pericarp of berries with high-SB had higher auxin and lower abscisic acid (ABA) levels compared to those with low-SB from two weeks before véraison. In the prevéraison cluster, the expression of auxin-response factor genes was significantly higher in the pericarp of high-SB berries and remained higher until véraison compared to low-SB berries. The expression level of auxin-biosynthetic genes in the pericarp was the same between both berry groups based upon similar expression activity of YUC genes that are rate-limiting factors in auxin biosynthesis. On the other hand, in low-SB berries, the expression of ABA-biosynthetic and ABA-inducible NCED and MYB genes was higher even two weeks before véraison. CONCLUSIONS: Differences in the relative seed content among berries plays a major role in the timing of ripening initiation. Towards the end of berry maturation phase, low and high levels of auxin are observed in the pericarp of low- and high-SB berries, respectively. This results in higher auxin-signaling activity that lasts longer in the pericarp of high-SB berries. In contrast, in low-SB berries, concomitant with an earlier decrease of auxin level, the features of ripening initiation, such as increases in ABA and sugar accumulation begin earlier.Keywords: Vitis vinifera, Seed, Fruit ripening, Auxin, Asynchronous ripeningKeywords: Vitis vinifera, Seed, Fruit ripening, Auxin, Asynchronous ripenin

Water Deficit Increases Stilbene Metabolism in Cabernet Sauvignon Berries

The impact of water deficit on stilbene biosynthesis in wine grape (Vitis vinifera) berries was investigated. Water deficit increased the accumulation of trans-piceid (the glycosylated form of resveratrol) by 5-fold in Cabernet Sauvignon berries but not in Chardonnay. Similarly, water deficit significantly increased the transcript abundance of genes involved in the biosynthesis of stilbene precursors in Cabernet Sauvignon. Increased expression of stilbene synthase, but not that of resveratrol-O-glycosyltransferase, resulted in increased trans-piceid concentrations. In contrast, the transcript abundance of the same genes declined in Chardonnay in response to water deficit. Twelve single nucleotide polymorphisms (SNPs) were identified in the promoters of stilbene synthase genes of Cabernet Sauvignon, Chardonnay, and Pinot Noir. These polymorphisms resulted in eight changes within the predicted cis regulatory elements in Cabernet Sauvignon and Chardonnay. These results suggest that cultivar-specific molecular mechanisms might exist that control resveratrol biosynthesis in grapes

Tissue-specific mRNA expression profiling in grape berry tissues

<p>Abstract</p> <p>Background</p> <p>Berries of grape (<it>Vitis vinifera</it>) contain three major tissue types (skin, pulp and seed) all of which contribute to the aroma, color, and flavor characters of wine. The pericarp, which is composed of the exocarp (skin) and mesocarp (pulp), not only functions to protect and feed the developing seed, but also to assist in the dispersal of the mature seed by avian and mammalian vectors. The skin provides volatile and nonvolatile aroma and color compounds, the pulp contributes organic acids and sugars, and the seeds provide condensed tannins, all of which are important to the formation of organoleptic characteristics of wine. In order to understand the transcriptional network responsible for controlling tissue-specific mRNA expression patterns, mRNA expression profiling was conducted on each tissue of mature berries of <it>V. vinifera </it>Cabernet Sauvignon using the Affymetrix GeneChip^®<it>Vitis </it>oligonucleotide microarray ver. 1.0. In order to monitor the influence of water-deficit stress on tissue-specific expression patterns, mRNA expression profiles were also compared from mature berries harvested from vines subjected to well-watered or water-deficit conditions.</p> <p>Results</p> <p>Overall, berry tissues were found to express approximately 76% of genes represented on the <it>Vitis </it>microarray. Approximately 60% of these genes exhibited significant differential expression in one or more of the three major tissue types with more than 28% of genes showing pronounced (2-fold or greater) differences in mRNA expression. The largest difference in tissue-specific expression was observed between the seed and pulp/skin. Exocarp tissue, which is involved in pathogen defense and pigment production, showed higher mRNA abundance relative to other berry tissues for genes involved with flavonoid biosynthesis, pathogen resistance, and cell wall modification. Mesocarp tissue, which is considered a nutritive tissue, exhibited a higher mRNA abundance of genes involved in cell wall function and transport processes. Seeds, which supply essential resources for embryo development, showed higher mRNA abundance of genes encoding phenylpropanoid biosynthetic enzymes, seed storage proteins, and late embryogenesis abundant proteins. Water-deficit stress affected the mRNA abundance of 13% of the genes with differential expression patterns occurring mainly in the pulp and skin. In pulp and seed tissues transcript abundance in most functional categories declined in water-deficit stressed vines relative to well-watered vines with transcripts for storage proteins and novel (no-hit) functional assignments being over represented. In the skin of berries from water-deficit stressed vines, however, transcripts from several functional categories including general phenypropanoid and ethylene metabolism, pathogenesis-related responses, energy, and interaction with the environment were significantly over-represented.</p> <p>Conclusion</p> <p>These results revealed novel insights into the tissue-specific expression mRNA expression patterns of an extensive repertoire of genes expressed in berry tissues. This work also establishes an extensive catalogue of gene expression patterns for future investigations aimed at the dissection of the transcriptional regulatory hierarchies that govern tissue-specific expression patterns associated with tissue differentiation within berries. These results also confirmed that water-deficit stress has a profound effect on mRNA expression patterns particularly associated with the biosynthesis of aroma and color metabolites within skin and pulp tissues that ultimately impact wine quality.</p

Proteomic analysis of the effects of ABA treatments on ripening Vitis vinifera berries

The control of ripening of the non-climacteric grapevine fruit is still a matter of debate, but several lines of evidence point to an important role for the hormone abscisic acid (ABA). The effects of ABA treatments on Cabernet Sauvignon berries before and at véraison were studied using a 2-DE proteomic approach. Proteins from whole deseeded berries (before véraison) and berry flesh and skin (at véraison) treated with 0.76 mM ABA and collected 24 h after treatment were separated and analysed. A total of 60 protein spots showed significant variations between treated and control berries, and 40 proteins, mainly related to general metabolism and cell defence, were identified by LC MS/MS. Our results show that ABA acts mainly through the regulation of mostly the same proteins which are involved in the ripening process, and that several of these changes share common elements with the ABA-induced responses in vegetative tissues