Grape Anthocyanins Research Articles

Effects of foliar applications of methyl jasmonate alone or with urea on anthocyanins content during grape ripening

Anthocyanins, the main phenolic compounds responsible for the color of red grapes and wines, exhibit antioxidant and antimicrobial properties and offer various health benefits for humans. Currently, climate change can affect grape quality by causing a decoupling between the technological and phenolic maturities of the grapes. Foliar application of methyl jasmonate (MeJ) and urea (Ur) can be a tool to mitigate the global warming effects in the vineyard. The aim of this work was to study i) the development of anthocyanin content in ‘Tempranillo’ grapes along the ripening process, and ii) the effect of foliar application of MeJ and MeJ+Ur on these phenolic compounds over two vintages (2019 and 2020). Overall, in the first vintage, anthocyanins peaked in their concentrations in the pre-harvest or harvest moments; whereas in the second vintage, the highest contents of these phenolic compounds were reached at harvest time, after that, a maintenance or decreased of their concentrations was observed. In both vintages, non-acylated anthocyanins was the most abundant family of anthocyanins. Foliar application of MeJ+Ur was more effective in enhancing anthocyanin biosynthesis than MeJ treatment, which also increased anthocyanin content compared to control grapes. Therefore, MeJ and Ur foliar treatment could present a synergy in anthocyanin biosynthesis by the plant. Moreover, the impact of these applications varied across vintages, and also the content of anthocyanins in grapes, probably due to different climatological conditions. Consequently, the two foliar treatments, MeJ and MeJ+Ur, could be a suitable tool to increase anthocyanins biosynthesis in grapes, and thus improve grape quality.

Improvement of chlorpyrifos-induced cognitive impairment by mountain grape anthocyanins based on PI3K/Akt signaling pathway

The organophosphorus insecticide Chlorpyrifos (CPF) is widely used worldwide due to its high effectiveness. However, when ingested through the mouth and nose, it can cause severe neurotoxic effects and cognitive impairment. Natural anthocyanins show great potential in improving cognitive impairment. In this paper, we will delve into the protective effect of anthocyanins on CPF-induced cognitive impairment and its mechanism through the PI3K/Akt signaling pathway. Morris water maze, histopathological, ELISA and western blot analyses showed that anthocyanins effectively ameliorated CPF-induced spatial learning memory impairment in mice by ameliorating CPF-induced AChE inhibition, oxidative stress, and neuroinflammation and by modulating the levels of apoptosis (Caspase-3, Caspase-9) and autophagy (LC3II/ LC3I, Beclin1, p62, mTOR) biomarkers, in order to restore damaged hippocampal tissue morphology, neuron and synapse structures. To identify the action pathway of anthocyanins, we used KEGG and GO pathway enrichment analysis for screening prediction and western blot and molecular docking to verify that anthocyanins improve CPF-induced cognitive impairment by activating the PI3K/Akt pathway.

Storage Stability and Sensory Properties of Raha Sweet Colored with Crude and Purified Red Grape Anthocyanins and Synthetic Food Colorant.

Anthocyanins (ANCs) are water-soluble pigments that are useful as nutraceuticals due to their health benefits. This study was performed to evaluate the storage stability of purified and crude red grape ANCs in Raha Sweet (RS) during storage and to evaluate its sensory properties. ANCs were extracted from red grape pomace and purified with a macroporous resin. RS was prepared and colored with a synthetic food dye, Carmoisine (control), and ANCs (crude and purified). Pigments were extracted from RS weekly for a period of seven weeks and the absorbance was read spectrophotometrically. RS colored with ANCs was evaluated for its color and other sensory properties against another RS colored with the control. Results showed that the degradation of ANCs in RS followed the first-order reaction model, unlike the control, which showed no degradation during storage. The half-life of crude ANCs was three times higher than that of the purified ones, and RS colored with ANCs received a significantly (p < 0.05) lower score for color than that of RS colored with the control. ANCs could provide the food industry with a natural alternative to synthetic dyes to color foods with high sugar content that are stored for a short period of time.

Combined Metabolome and Transcriptome Analysis Revealed the Accumulation of Anthocyanins in Grape Berry (Vitis vinifera L.) under High-Temperature Stress.

In grape (Vitis vinifera L.) cultivation, high temperatures (HTs) usually reduce the accumulation of anthocyanins. In order to elucidate the regulatory mechanism of anthocyanin biosynthesis under high-temperature environments, we investigated the effects of HT stress at veraison (5% coloring of grape ears) on fruit coloration and anthocyanin biosynthesis in 'Summer Black' (XH) and 'Flame seedless' (FL) grapevines. Compared to the control group (35 °C), the total anthocyanin content of XH and FL grapes subjected to a high-temperature (HT) treatment group (40 °C) decreased significantly as the HT treatment continued, but showed an upward trend with fruit development. However, the concentration of procyanidins increased significantly following HT treatment but decreased with fruit development. Nonetheless, FL grapes showed some resistance to the HT condition, producing anthocyanin content at ripeness comparable to the control group, demonstrating a greater adaptability to HT conditions than XH grapes. Based on the CIRG index, at stage S4, the fruit of FL was classified as dark red, while XH was classified as blue-black in the control group. Anthocyanin-targeted metabonomics identified eight different types of anthocyanins accumulating in the peels of XH and FL grapes during ripening, including cyanidins, delphinidins, malvidins, pelargonidins, peonidins, petunidins, procyanidins, and flavonoids. Malvidins were the most abundant in the two grape varieties, with malvidin-3-O-glucoside being more sensitive to high temperatures. HT treatment also down-regulated the expression of structural genes and regulators involved in the anthocyanin synthesis pathways. We used the WGCNA method to identify two modules that were significantly correlated with total anthocyanin and procyanidin contents. Among them, MYBCS1, bHLH137, WRKY65, WRKY75, MYB113-like, bZIP44, and GST3 were predicted to be involved in grape anthocyanin biosynthesis. In conclusion, this study conducted in-depth research on the HT inhibition of the biosynthesis of anthocyanins in XH and FL grapes, for reference.

Review of Process and Extraction Effects on the Bioavailability of Anthocyanins in Grapes

Grapes are widely consumed worldwide in various forms, including fresh and dried, or processed into products like juice, vinegar, wine, and so on. Anthocyanins, mainly found in grapes, are responsible for various health-promoting effects and contribute to their colours such as red, purple, and blue. Although grapes contain a high quantity of anthocyanins, their bioavailability is considered limited. Anthocyanins may be absorbed by the gastrointestinal wall, undergo intensive first-pass metabolism, and emerge as metabolites in systemic circulation. A significant percentage of some anthocyanins can enter the large intestine and undergo breakdown induced by digestive system microorganisms. Several factors, such as pH, temperature, light, and solvents, can affect anthocyanin bioavailability, and processing grapes into products may impact their bioavailability. Considering the high market share of grapes and grape products, it is important to understand the effects of processing on anthocyanin bioavailability. This review discusses changes in the bioavailability of anthocyanins found in grapes and grape products during food processing, the effect of extraction conditions on bioavailability, as well as the health-promoting effects of grapes and grape products.

Comparison of Total Antioxidant Capacities and Phenolic Constituents of Grapes Cultivated in Turkey for Wine Production

Grapes are renowned for their health-promoting properties due to polyphenols, particularly anthocyanins in red grapes and flavonols in white grapes. This study evaluated the total antioxidant capacities (TAC) of specific grape varieties (Sultaniye, Chardonnay, Shiraz, Carignan, Alicante Bouschet, and Merlot) using the CUPRAC (CUPric Reducing Antioxidant Capacity) and ABTS/HRP (2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)/horseradish peroxidase) methods. Additionally, total phenolic, flavonoid, and anthocyanin contents were determined via Folin Ciocalteu, AlCl3/NaNO2, and pH differential methods. Primary phenolic compounds were identified with High-Performance Liquid Chromatography-Photodiode Array (HPLC-PDA). TAC values of the grape juices (mmol Trolox L−1) ranked as Alicante > Shiraz > Sultaniye > Carignan > Merlot > Chardonnay by CUPRAC, and Shiraz > Alicante > Merlot > Carignan ≥ Sultaniye > Chardonnay by ABTS/HRP and for skin extracts (mmol Trolox g−1), Carignan > Alicante > Shiraz > Merlot > Chardonnay > Sultaniye by CUPRAC, and Carignan > Shiraz > Alicante > Merlot > Chardonnay > Sultaniye by ABTS/HRP. The study demonstrated a strong correlation between phenolic composition and TAC values in grape samples, with anthocyanins as the predominant family contributing significantly to TAC. Varietal and intra-fruit differences in specific phenolic compounds were found to account for variations in observed TAC levels. Specifically, grape skin samples showed a more robust correlation between antioxidant capacity and total phenolic content (r = 0.986) than grape juices (r = 0.777). These findings underscore the considerable variation in antioxidant potential among grape varieties and emphasize the critical role of phenolic composition in the health-related benefits of grape consumption.

Vine spacing of &lt;i&gt;Vitis vinifera&lt;/i&gt; cv. Shiraz/101-14 Mgt. III. Grape and wine quality

Vine spacing effects of Shiraz/101-14 Mgt on a relatively high potential soil in the Breede River Valley, Robertson, South Africa, on grape composition and wine quality, were investigated. Canopies were VSP trellised and orientated approximately NNE-SSW. Spacing between rows was fixed at 2.2 m. In-row vine spacing changed from 0.3 – 4.5 m with increments of 30 cm (from 15151 – 1010 vines/ha). Grape composition and wine quality were monitored over six seasons and two grape ripeness levels. Decreasing trends of soluble solids (°B) and pH and increasing titratable acidity from narrow to wide spacing were observed. Sugar accumulation of wider spacings seemed delayed. Berry skin total anthocyanin index and phenol content showed virtually no change. Malvidin mono-glucoside and its p-coumaroyl and acetyl derivatives were present in the highest concentrations, followed by peonidin-, petunidin-, delphinidin- and cyanidin mono-glucosides and derivatives, each vine spacing treatment displaying a unique grape anthocyanin profile. The narrower spacing of vines seemed to favour skin anthocyanin accumulation compared to wider spacing. Decreasing trends in wine total anthocyanin intensity, anthocyanin density, and phenols were observed from narrow to wide spacing; all had higher levels in wines from riper grapes. Individual wine anthocyanin concentrations also showed qualitative profile changes. The first regression join points for all anthocyanins occurred around 1.8 – 2.4 m vine spacing; those for malvidin and derivatives consistently appeared at 1.8 m spacing. Although volatile compounds only seemed to respond to ripeness level and not to vine spacing, wine sensory quality generally decreased with wider vine spacing at both grape ripeness levels. Given the changes in biotic and abiotic growth conditions with wider vine spacing, the results likely displayed adaptation to the combined impact of increasing light exposure, berry temperature, physiological functioning, vegetative and reproductive growth ratios, and plant stress. The study showed the prominent role of plant spacing in sustainable grape growing and wine outcomes and thus the importance of judicious decision-making during the establishment and management of vines under any growth conditions and in any terroir.

Phenolic acids and polydatin of grape and products of its processing

The paper established that in the fruits of red grapes and in the products of its processing, the main phenolic acids are not chlorogenic acids (the acylation product of quinic acid by caffeic one), as indicated in a number of publications, but caftaric acid (the acylation product of tartaric acid by caffeic one) and coutaric acid (the acylation product of tartaric acid by p-coumaric one). For chromatographic analysis of the studied samples, the stationary phase Symmetry C18 and the mobile phases of the “acetonitrile – 10 vol.% of HCOOH-water” system were chosen, being convenient for determining grape anthocyanins. It was shown that caftaric acid in all studied mobile phase compositions is completely separated from coutaric acid and from three isomeric monocaffeoylquinic acids (3-caffeoylquinic, 4-caffeoylquinic and 5-caffeoylquinic), i.e. there is no confusion between the retention times of these acids. But for chromatography, mobile phase compositions should be selected in which there is no co-elution of any of these acids with delphinidin-3-glucoside, which is usually present in extracts, juices and wines. Complete separation of these components is possible both with a relatively low acetonitrile content (less than 6 vol. %) in the mobile phase, and with a relatively high (at least 8.5 vol. %) as well. This made it possible to propose a gradient elution option for separating all compounds of interest. A gradient mode was needed to elute all anthocyanins and associated extractives from the column. It turned out that the proposed separation conditions were favorable for the detection of polydatin (one of the isomeric glucosides of resveratrol). This made it possible to establish another common misconception, according to which it is claimed that resveratrol (and not its glucoside) is one of the most important biologically active substances in grapes. Under the proposed conditions, much more strongly retained resveratrol coelutes with one of the acylated anthocyanins, but analysis of the areas of the corresponding peaks indicates that polydatin is the dominant form of resveratrol in grapes

Application of poly(L-lactic acid)-based films for equilibrium modified atmosphere packaging of “Kyoho” grapes and its favorable protection for anthocyanins

Grapes were packaged by different Poly (L-lactic acid)-based packaging films (PLTL-PLEL) and stored at 5 °C for 35 days to investigate the effects of equilibrium modified atmosphere packaging on the quality of “Kyoho” grapes during storage. Changes in physiochemical quality, antioxidant content and senescence of grapes were studied. Furthermore, UPLC-Q-TOF-MS/MS was used to observe and identify key factors influencing the variation of grape anthocyanins under different atmosphere conditions. Alterations in gas components and enzyme activities significantly impacted anthocyanin levels, highlighting oxygen concentration as the primary influence on total anthocyanin levels. The PLTL-PLEL50 packaging resulted in an approximate 5.7% lower weight loss and increased soluble solids by approximately 14.4%, vitamin C, total phenols and flavonoids reaching 60.2 mg/100 g, 8.4 mg/100 g and 7.2 mg/100 g, respectively. This packaging also preserved higher anthocyanin levels, with malvidin-3-glucoside and peonidin-3-glucoside at 0.55 μg/mL and 1.62 μg/mL, respectively, on the 35th day of storage.

Light influences the effect of exogenous ethylene on the phenolic composition of Cabernet Sauvignon grapes.

The gaseous phytohormone ethylene (ETH) plays a key role in plant growth and development, and is a major regulator of phenolic biosynthesis. Light has long been known to influence phytohormone signaling transduction. However, whether light influences the effect of ETH on the phenolic composition of grapes (Vitis vinifera L.) is an open question. Here, the accumulation and composition of anthocyanins and non-anthocyanin phenolics were analyzed in Cabernet Sauvignon grapes under four treatments: light exposure with and without ETH treatment, and box-shading with and without ETH treatment. Both light and ETH promoted ripening, decreased the color index (L*, C*, and h*), and accelerated the color change from green to red and purplish red. Sunlight-exposed grapes had the highest contents of most anthocyanins, flavonols, flavan-3-ols, and hydroxybenzoic acids. In addition, light exposure increased the ratios of 3'5'-substituted/3'-substituted anthocyanins and flavonols, but decreased the ratios of methoxylated/non-methoxylated and acylated/non-acylated anthocyanins and flavan-3-ols. Notably, the effects of ETH were influenced by light exposure. Specifically, ETH treatment promoted anthocyanin and non-anthocyanin biosynthesis in light-exposed grapes, and their increasing multiples were remarkably higher under light-exposed conditions. Furthermore, ETH treatment decreased the ratios of methoxylated/non-methoxylated, 3'5'-substituted/3'-substituted, and acylated/non-acylated anthocyanins and flavan-3-ols in light-exposed grapes, each of which was increased by ETH treatment in shaded grapes. Fifteen differential phenolic components were identified through partial least-squares-discriminant analysis (PLS-DA). Among them, cyanidin-3-O-(cis-6-O-coumaryl)-glucoside, petunidin-3-O-(6-O-acetyl)-glucoside, petunidin-3-O-(trans-6-O-coumaryl)-glucoside, petunidin-3-O-glucoside, myricetin-3-O-galactoside, kaempferol-3-O-galactoside, and kaempferol-3-O-glucoside were the main differential components between ETH treatments under different light conditions. This study contributes to the understanding of the impact of ethylene treatment under dark and light conditions on phenolic synthesis in grape berries.

Using ethanol as postharvest treatment to increase polyphenols and anthocyanins in wine grape

Red wine grapes are qualitatively evaluated for their content in polyphenols and anthocyanins. Due to certain conditions (weather, latitude, temperature), the concentration of these compounds may be not at the right level for reaching a high-quality wine, thus postharvest technologies can be operated as a remediation strategy. Ethanol is a secondary volatile metabolite and its application has been demonstrated to delay fruit ripening, to reduce decay, and to increase secondary metabolites. The present study investigates the effects of ethanol post-harvest application on wine grapes’ metabolism and composition. Red wine grapes (Vitis Vinifera L. cv Aglianico) were exposed to different ethanol doses (0.25, 0.5, or 1 mL L−1) for 12, 24, or 36 h. Ethanol increased sugar concentration, malic acid, free amino nitrogen, polyphenols, and anthocyanins. Particularly, anthocyanins reached an average value of 1820 mg/L in treated samples versus the 1200 mg/L of control grapes already after 12 h whatever the concentration was. Moreover, the highest concentration of ethanol modified berry metabolism shifting from aerobic to anaerobic one. Obtained results suggest that 12 h of ethanol postharvest treatment could be an interesting solution to improve anthocyanins in wine grapes, especially when the quality is not as good as expected.

Effect of using biodegradable film constituting red grape anthocyanins as a novel packaging on the qualitative attributes of emergency food bars during storage.

This study presents a novel packaging film based on whey protein isolate/κ-carrageenan (WC) with red grape pomace anthocyanins (RGA) to investigate its impact on some qualitative attributes of emergency food bars (EFBs) for 6 months at 38°C. Increasing the RGA dose in WC films from 5% (WCA5) to 10% (WCA10) reduced hydrogen bonding between polymers and polymer homogeneity in the matrix according to FTIR and SEM. Tensile strength slightly declined in WCA5 from 7.47 ± 0.26 to 6.97 ± 0.12, while elongation increased from 27.74 ± 1.36 to 32.36 ± 1.25% compared to WC film. The maximum weight loss temperature (TM) increased by incorporating 5 wt% RGA from 182.95°C to 244.36°C, whereas TM declined to 187.19°C in WCA10 film. WVP and OTR slightly changed in WCA5 (from 7.83 ± 0.07 and 2.57 ± 0.18 to 8.41 ± 0.03 g H2O.m/m2.Pa.s × 10-9 and 1.79 ± 0.32 cm3 O2/m2.d.bar, respectively), but significantly impaired in WCA10 compared to WC film. WCA5 and WCA10 films had high AA%, 68.77%, and 79.21%, respectively. WCA10 film presented great antimetrical properties against Staphylococcus aureus with an inhibition zone of 6.00 mm. The light transmission of RGA-contained films in the UV spectrum was below 10%. The WCA5 film effectively restrained moisture loss and hardness increment until the end of the storage period, which were 14.33% and 28.76%, respectively, compared to day 0. Antioxidant films provided acceptable resistance against oxidation to EBF treatment. Sensory panels scored WCA5 and WCA10 higher in overall acceptance with 5.64 and 5.40 values, respectively, while complaining about the hardness of OPP treatment. The results of this investigation demonstrated that incorporating RGA, preferably 5 wt%, into WC-based film effectively improved the qualitative properties of EFB during the 6-month shelf life. This film might be a promising alternative for packaging light and oxygen-sensitive food products.

Timing of leaf removal modulates tannin composition and the level of anthocyanins and methoxypyrazines in Pinot noir grapes and wines

This study aimed to investigate the impact of leaf removal on concentrations of anthocyanin, tannin, and methoxypyrazines (MPs) in Pinot noir grapes and wines. Leaf removal after 7 days (LR7), 30 days (LR30), and 60 days (LR60) of flowering were compared with no leaf removal control (LRC). Grapes and resultant wines were analysed for tannin and aroma composition using liquid chromatography and two-dimensional gas chromatography–mass spectrometry. All leaf removal treatments increased anthocyanin concentration in grapes and reduced MP levels in grape stems compared to LRC, indicating the effectiveness of both early and late leaf removal. Leaf removal after 7 days and 30 days were more effective in enhancing colour density, polymeric pigments, and tannin concentration in wines. Higher grape skin tannin and anthocyanin concentrations, along with lower seed tannin concentration in berries, correlated with higher tannin concentrations in wines. LR7 showed significantly higher skin-originated tannin proportion than LRC, suggesting a useful tool to manage tannin extraction. Aroma composition of resultant wines was influenced by leaf removal, although these differences were not evident in the sensory evaluation.

MiR156b-targeted VvSBP8/13 functions downstream of the abscisic acid signal to regulate anthocyanins biosynthesis in grapevine fruit under drought.

Anthocyanins are the primary color components of grapevine berries and wines. In cultivation practices, a moderate water deficit can promote anthocyanin accumulation in red grape skins. Our previous study showed that abscisic acid (ABA) plays a key role in this process. Herein, we identified a microRNA, vv-miR156b, that is generated in grapevine berries in response to drought stress, along with increasing anthocyanin content and biosynthetic structural gene transcripts. In contrast, vv-miR156b short tandem target mimic (STTM) function-loss callus exhibits the opposite phenotype. Results from in vivo and in vitro experiments revealed that the ABA-signaling-regulated transcription factor VvAREB2 binds directly to the ABA-responsive element (ABRE) of the MIR156b promoter and activates miR156b expression. Furthermore, two miR156b downstream targets, VvSBP8 and VvSBP13, exhibited reduced grape anthocyanin content in their overexpressors but there was a contrary result in their CRISPR-edited lines, the decrease in anthocyanin content was rescued in miR156b and SBP8/13 double overexpressors. We further demonstrated that both VvSBP8 and VvSBP13, encoding transcriptional repressors, displayed sufficient ability to interact with VvMYC1 and VvMYBA1, thereby interfering with MYB-bHLH-WD (MBW) repeat transcriptional complex formation, resulting in the repression of anthocyanin biosynthesis. Our findings demonstrate a direct functional relationship between ABA signaling and the miR156-SBP-MBW complex regulatory module in driving drought-induced anthocyanin accumulation in grape berries.

Effects of laccase from &lt;i&gt;Botrytis cinerea&lt;/i&gt; on the oxidative degradation of anthocyanins

This work aimed to study the degradation kinetics of five grape anthocyanins caused by laccase from Botrytis cinerea. In individual solutions, the anthocyanins with three substituents in the B-ring—petunidin, delphinidin and malvidin 3-O-glucosides—were degraded much faster than those with two substituents. In the latter case, cyanidin 3-O-glucoside did not degrade as quickly, and peonidin-3-O-glucoside, in particular, was not degraded by laccase at all. In contrast, when an equimolar solution of the five anthocyanins was used, the differences in the degradation kinetics of all anthocyanins were lessened, probably because the less reactive anthocyanins were able to polymerise with the quinones formed by the laccase action on the more reactive anthocyanins. Finally, supplementation with (-)-epicatechin, glutathione and especially seed tannins seemed to protect the red colour from laccase.

Cellulose/Salep-based intelligent aerogel with red grape anthocyanins: Preparation, characterization and application in beef packaging

The purpose of this study was to prepare a porous intelligent aerogel for food packaging applications, in particular for monitoring minced beef freshness, using cellulose extracted from grape stalk, Salep as a copolymer, and red grape anthocyanins as a pH-sensitive pigment. Aerogels based on cellulose 1% (w/v) and Salep 1% (w/v) at ratios of 1:3, 3:1, and 1:1 were prepared by lyophilization. Aerogel with high porosity, low density, and higher mean pore size was chosen for preparing intelligent colorimetric aerogel (ICA) with the addition of 0.44 mg/100 mL of anthocyanins. Based on the color parameters, the stability of ICA was satisfactory when exposed to both light and dark conditions, as well as when stored at either 4 or 25 °C. Additionally, X-ray diffraction and thermogravimetric analyses indicated that an amorphous aerogel was formed, with a thermal decomposition temperature of 320 °C. The color of the ICA changed from purple on the first and 3rd days of packaging to blue-gray on the 6th day. As the spoilage process continued, the color of the indicator became dark brown. Taken together, ICA showed a quick response to minced beef spoilage with the ability to differentiate between fresh and spoiled meat during storage at 4 °C.

Genome-Wide Identification of ATP-Binding Cassette (ABC) Transporter Provides Insight to Genes Related to Anthocyanin Transportation in New Teinturier Grape Germplasm ‘ZhongShan-HongYu’

ATP-binding cassette (ABC) transporters are a large class of superfamily involved in a variety of biological processes with multiple functions, including phytohormone transport, heavy metal ion detoxification, and so on. Anthocyanin pigmentation in grapes is a commercially important feature of this superfamily. To elucidate the mechanisms of the VvABC gene at different stages in grape berries, we analyzed and characterized the ABC family in ‘ZhongShan-HongYu’ (ZS-HY) berries using RNA-seq analysis. In this study, a total of 146 VvABC genes were identified by comprehensive bioinformatics analysis, which outlined their gene structure, chromosomal location, conserved domains, phylogenetic relationships, and collinearity analysis. The VvABC family could be divided into eight subfamilies based on the phylogenetic analysis. Fifty-eight VvABC genes were identified from the RNA-seq data, of which 31 belong to the ABCG subfamily, 15 belong to the ABCC subfamily, 8 belong to the ABCB subfamily, 2 belong to the ABCF subfamily, and only 1 belongs to each of the ABCA and ABCD subfamilies. We used qRT-PCR to detect the expression of VvABC genes in different organs and found that it changed significantly in different organs. Phylogenetic analysis showed that genes involved in anthocyanin transport in other species were closely related to members of the ABCC subfamily. Subsequently, analysis of the promoter elements and the protein interactions of the VvABCC genes using RNA-seq was performed. This study has improved our understanding of the functions of the ABC gene family and provided a basis for the role of ABC genes in grape anthocyanin transport.

Omic analysis of anthocyanin synthesis in wine grape leaves under low-temperature

• Low-temperature promotes the accumulation of anthocyanins in grape leaves by up-regulating the expression of structural genes that induce anthocyanin synthesis, related transcription factors and LRR-type receptor-like protein kinases. • Under the same low-temperature environment, the more anthocyanin accumulated in the leaves, the less damage they suffered. • The synthesis and accumulation of anthocyanins promoted the adaptation and resistance of grape leaves to low-temperature environmental conditions. Anthocyanins can be induced by environmental factors such as low- temperature, and play an important role in adapting to abiotic stress. In this study, the leaves of 'Cabernet Gernischt' grapes with different colors under natural low-temperature in autumn were collected and grouped into Green (Gre), Light-red (L-Red), Red (Red), and Dark-red (D-Red). Results showed that the total anthocyanin content and anthocyanin components were increased in turn from Gre to D-red. Under the same low-temperature, Gre was substantially damaged, L-Red was mildly damaged, Red and D-Red had no visible damage. RNA-seq data showed that a total of 3666 DEGs were screened out of all 28,306 genes detected, of which 1936 DEGs were upregulated and 1730 DEGs were downregulated in D-Red vs Gre. Transcriptomics and metabolomics showed that DEGs were significantly enriched in GO terms, such as in defense response, defense response to oomycetes, and response to reactive oxygen species, hydrogen peroxide, heat, salt stress, and biotic stimulus pathways. The KEGG analysis showed that DEGs were mainly enriched in secondary metabolism, carbohydrate metabolism, energy metabolism, and lipid metabolism. Anthocyanin synthesis genes may be regulated by transcription factors such as ERF, MYB, NAC, bHLH and various LRR-type receptor-like protein kinase (LRR-RLK) family genes. In conclusion, the accumulation of anthocyanins significantly increased from green to red in grape leaves during autumn low-temperature, improving the cold resistance of grape leaves.

Soil management affects the nutraceutical properties of Primitivo's grape pomace

Soil management is a sustainable agronomic practice to produce grapes, wine, and grape pomace with a low environmental impact in viticulture, affecting soil microbial biodiversity, organic matter, and healthy roots. Grape pomace is the main by-product of winemaking and a valuable source of natural phytochemicals. This research aimed to evaluate the phenolic content and antioxidant activity of pomace deriving from the microvinification of the Primitivo wine grapes obtained by four different soil management techniques: cover crop (C), soil mechanical tillage (T), green manure (G) and farm soil management (F). The content of total phenolic compounds and anthocyanins in grapes and wines is the highest with the vineyard cover cropping system. Moreover, grape pomace derived by cover crop soil management shows a significant abundance of these molecules and a more elevated antioxidant activity than the other soil technique.

Effect of varying concentrations of melatonin on anthocyanin and sugar metabolism in grapes (Vitis labruscana L.)

Effect of varying concentrations of melatonin on anthocyanin and sugar metabolism in grapes (Vitis labruscana L.)