Dataset Information

Volatile profiles and transcriptomic variation in Cabernet Sauvignon grapes in response to various sunlight exposure strategies in a warm climate

ABSTRACT: Basal leaf removal has been widely practiced to increase cluster sunlight exposure, control berry rot and eventually improve grape berry quality. Early leaf removal performed in cool region appeared to benefit the accumulation of norisoprenoids and monoterpenes. However, effects of this canopy management and leaf moving on volatile profiles and transcriptome of grape berry in warm region characterized with strong sunshine and arid climate were paid less attention. To cope with multiple possible effects caused by global warming, researches in warm region are urgently needed to provide a guide for adjusting the sunlight exposure treatment to adapt the climate change.In Manas county of Xinjiang province, sunlight exposure treatments performed in this study resulted in decreased β-carotene and lutein, which mainly responsible for the reduced norisoprenoids in ripening grapes. Substrate competition due to the up-regulation of VvTPS-a and VvNCED3 may contribute to the decreased concentration of monoterpenes in exposed berries. The notable increased C6 alcohols in the grape berries treated by leaf removal applied at veraison (LR-V), was mainly attribute to the enhanced substrate availability of linoleic acid and linolenic acid together with the higher expression of VvLOXO and VvADH1. Free C6 aldehyde was reduced by half leaf removal applied at veraison (HLR-V), leaf moving at veraison (LM-V) and leaf removal applied at berry pepper-corn size (LR-PS). Moreover, transcriptomic analysis indicated that both LR-V and LM-V treated grape berry implemented multiple stress-mitigation strategies to acclimate the improved sunlight exposure. Interestingly, photosynthesis-related genes in grape berry were primarily up-regulated by LR-V as a consequence of carbohydrate source removal rather than improved sunlight exposure. Weighted gene co-expression network analysis (WGCNA) suggested that the genes encoding malate synthase and 3-oxoacyl-(acyl carrier protein) reductase show a significant correlation with the accumulation of C6 alcohol.

ORGANISM(S): Vitis vinifera

PROVIDER: GSE121146 | GEO | 2018/10/14

REPOSITORIES: GEO

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Project description:Leaf removal is a grapevine canopy management technique widely used to modify the source-sink balance and/or microclimate around berry clusters to optimize fruit composition. In general, the removal of basal leaves before flowering reduces fruit set, hence achieving looser clusters, and improves grape composition since yield is generally curtailed more than proportionally to leaf area itself. Albeit responses to this practice seem quite consistent, overall vine performance is affected by genotype, environmental conditions, and severity of treatment. The physiological responses of grape varieties to defoliation practices have been widely investigated, and just recently a whole genome transcriptomic approach was exploited showing an extensive transcriptome rearrangement in berries defoliated before flowering. Nevertheless, the extent to which these transcriptomic reactions could be manifested by different genotypes and growing environments is entirely unexplored. To highlight general responses to defoliation vs. different locations, we analyzed the transcriptome of cv. Sangiovese berries sampled at four development stages from pre-flowering defoliated vines in two different geographical areas of Italy. We obtained and validated five markers of the early defoliation treatment in Sangiovese, an ATP-binding cassette transporter, an auxin response factor, a cinnamyl alcohol dehydrogenase, a flavonoid 3-O-glucosyltransferase and an indole-3-acetate beta-glucosyltransferase. Candidate molecular markers were also obtained in another three grapevine genotypes (Nero d'Avola, Ortrugo, and Ciliegiolo), subjected to the same level of selective pre-flowering defoliation (PFD) over two consecutive years in their different areas of cultivation. The flavonol synthase was identified as a marker in the pre-veraison phase, the jasmonate methyltransferase during the transition phase and the abscisic acid receptor PYL4 in the ripening phase. The characterization of transcriptome changes in Sangiovese berry after PFD highlights, on one hand, the stronger effect of environment than treatment on the whole berry transcriptome rearrangement during development and, on the other, expands existing knowledge of the main molecular and biochemical modifications occurring in defoliated vines. Moreover, the identification of candidate genes associated with PFD in different genotypes and environments provides new insights into the applicability and repeatability of this crop practice, as well as its possible agricultural and qualitative outcomes across genetic and environmental variability.

Project description:Studying the effect of varying durations (1, 7 and 14 days) of locally applied heat stress on grape berries at three developmental stages (middle green, veraison and middle ripening). Among various environmental factors, temperature is a major regulator affecting plant growth, development and fruit composition. Reproductive development of grapevine and berry composition, are both highly influenced by temperature. To date, the molecular mechanisms involved in grapevine berries tolerance to high temperatures (HS) are poorly understood. Although recent data addressed the consequences on berry development of elevated temperatures applied at the whole plant level, the present work particularly focuses on the fruit responses triggered by direct exposure to heat stress. In the context of climate change, this work focused on microclimate effect is of particular interest to better understand the consequences of leaf removal (a common viticultural practice) on berry development. HS (+ 8°C) was locally applied to clusters from Cabernet Sauvignon fruiting cuttings at three different developmental stages (middle green, véraison and middle ripening). Samples were collected 1, 7 and 14 days after treatment and used for metabolic and transcriptomic analyses. The results showed dramatic and specific biochemical and transcriptomic changes in heat exposed berries, depending on the developmental stage and the stress duration. When applied at the herbaceous stage, HS delayed the onset of véraison. Heating also strongly altered the berry concentration of amino acids and organic acids (e.g. PHE, GABA, and malate) and decreased the anthocyanin content at maturity. These physiological alterations could be partly explained by the deep remodelling of transcriptome in heated berries. More than 7000 genes were deregulated in at least one of the nine experimental conditions. The most affected processes belong to the categories “stress responses”, “protein metabolism” and “secondary metabolisms”, highlighting the intrinsic capacity of grape berries to perceive heat stress and to build adaptive responses. Additionally, important changes in processes related to “transport”, “hormone” and “transcription” might contribute to the postponing of véraison. Finally, opposite effects depending on heating duration were observed for genes encoding enzymes of the general phenylpropanoid pathway, suggesting that the HS-induced decrease in anthocyanin content may result from a combination of transcript abundance and product degradation.

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Volatile profiles and transcriptomic variation in Cabernet Sauvignon grapes in response to various sunlight exposure strategies in a warm climate

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