Changes of Anthocyanin Component Biosynthesis in 'Summer Black' Grape Berries after the Red Flesh Mutation Occurred

Metabolomics of Vitis davidii Foëx. grapes from southern China: Flavonoids and volatiles reveal the flavor profiles of five spine grape varieties

The spine grapes (Vitis davidii Foëx.) are wild grape species that grow in southern China, and can be used for table grapes, juicing and winemaking. To systematically investigate the flavor profiles of spine grapes, flavonoids and volatile compounds were detected in five spine grape varieties (Seputao, Ziqiu, Miputao, Tianputao and Baiputao) using HPLC-QqQ-MS/MS and GC-MS. The content of flavonoids highly depended on the variety, such as the total concentrations of anthocyanins (91.43-328.85 mg/kg FW) and flavonols (33.90 to 83.16 mg/kg FW). The volatile compounds with higher odor active value were selected to describe the aroma of spine grapes. Hexanal, (E)-2-hexenal and (E, Z)-2,6-nonadienal contributed to the higher herbaceous flavor to Baiputao and Ziqiu. β-Damascenone and (E)-2-nonenal gave Baiputao a flavor with more floral, fruity and earthy. Their characteristic flavor compounds were subsequently revealed using multivariate statistical analysis. The results helped producers to further develop and utilize the spine grapes.

Methylation of AcGST1 Is Associated with Anthocyanin Accumulation in the Kiwifruit Outer Pericarp

Most red-fleshed kiwifruit cultivars, such as Hongyang, only accumulate anthocyanins in the inner pericarp; the trait of full red flesh becomes the goal pursued by breeders. In this study, we identified a mutant "H-16" showing a red color in both the inner and outer pericarps, and the underlying mechanism was explored. Through transcriptome analysis, a key differentially expressed gene AcGST1 was screened out, which was positively correlated with anthocyanin accumulation in the outer pericarp. The result of McrBC-PCR and bisulfite sequencing revealed that the SG3 region (-292 to -597 bp) of AcGST1 promoter in "H-16" had a significantly lower CHH cytosine methylation level than that in Hongyang, accompanied by low expression of methyltransferase genes (MET1 and CMT2) and high expression of demethylase genes (ROS1 and DML1). Transient calli transformation confirmed that demethylase gene DML1 can activate transcription of AcGST1 to enhance its expression. Overexpression of AcGST1 enhanced the anthocyanin accumulation in the fruit flesh and leaves of the transgenic lines. These results suggested that a decrease in the methylation level of the AcGST1 promoter may contribute to accumulation of anthocyanin in the outer pericarp of "H-16".

Independent flavonoid and anthocyanin biosynthesis in the flesh of a red-fleshed table grape revealed by metabolome and transcriptome co-analysis

BACKGROUND

Red flesh is a desired fruit trait, but the regulation of red flesh formation in grape is not well understood. 'Mio Red' is a seedless table grape variety with light-red flesh and blue-purple skin. The skin color develops at veraison whereas the flesh color develops at a later stage of berry development. The flesh and skin flavonoid metabolomes and transcriptomes were analyzed.

RESULTS

A total of 161 flavonoids were identified, including 16 anthocyanins. A total of 66 flavonoids were found at significantly different levels in the flesh and skin (fold change ≥ 2 or ≤ 0.5, variable importance in projection (VIP) ≥ 1). The main anthocyanins in the flesh were pelargonidin and peonidin, and in the skin were peonidin, delphinidin, and petunidin. Transcriptome comparison revealed 57 differentially expressed structural genes of the flavonoid-metabolism pathway (log₂fold change ≥ 1, FDR < 0.05, FPKM ≥ 1). Two differentially expressed anthocyanin synthase (ANS) genes were annotated, ANS2 (Vitvi02g00435) with high expression in flesh and ANS1 (Vitvi11g00565) in skin, respectively. One dihydro flavonol 4-reductase (DFR, Vitvi18g00988) gene was differentially expressed although high in both skin and flesh. Screened and correlation analysis of 12 ERF, 9 MYB and 3 bHLH genes. The Y1H and dual luciferase assays showed that MYBA1 highly activates the ANS2 promoter in flesh and that ERFCBF6 was an inhibitory, EFR23 and bHLH93 may activate the DFR gene. These genes may be involved in the regulation of berry flesh color.

CONCLUSIONS

Our study revealed that anthocyanin biosynthesis in grape flesh is independent of that in the skin. Differentially expressed ANS, MYB and ERF transcription factors provide new clues for the future breeding of table grapes that will provide the health benefits as red wine.

Integrative analysis of grapevine (Vitis vinifera L) transcriptome reveals regulatory network for Chardonnay quality formation

Anthocyanins, total phenols, soluble sugar and fruit shape plays a significant role in determining the distinct fruit quality and customer preference. However, for the majority of fruit species, little is known about the transcriptomics and underlying regulatory networks that control the generation of overall quality during fruit growth and ripening. This study incorporated the quality-related transcriptome data from 6 ecological zones across 3 fruit development and maturity phases of Chardonnay cultivars. With the help of this dataset, we were able to build a complex regulatory network that may be used to identify important structural genes and transcription factors that control the anthocyanins, total phenols, soluble sugars and fruit shape in grapes. Overall, our findings set the groundwork to improve grape quality in addition to offering novel views on quality control during grape development and ripening.

Influence of rootstock on endogenous hormones and color change in Cabernet Sauvignon grapes

Different rootstocks for grapes can significantly affect fruit color and quality, possibly by affecting hormone contents, related genetic pathways, and fruit coloring mechanisms in skin. 'Cabernet Sauvignon' was grafted to '5BB', 'SO4', '140R', 'CS', '3309M' and 'Vitis riparia' rootstocks, with self-rooting seedlings as the control (CS/CS), and sampled from the early stage of veraison to the ripening stage. The effects of rootstock on the contents of gibberellin (GA₃), auxin (IAA), and abscisic acid (ABA) in grape skin were determined alongside the expression levels of eight anthocyanin synthesis related genes using real-time fluorescence quantitative PCR methods. The rootstock cultivars exhibited accelerated fruit color change, and the CS/140R combination resulted in grapes with more color than the control group in the same period. With the development of fruit, the IAA and GA₃ contents in the skin of different rootstock combinations showed trends of increasing initially, then decreasing, while the ABA content decreased initially and then increased. During the verasion (28 July), the various 'Cabernet Sauvignon' rootstock combinations exhibited varying degrees of increases in GA₃, ABA, and IAA contents; correlation analysis showed that, at the start of veraison, the expression levels of the anthocyanin synthesis-related genes VvCHS, VvDFR, and VvUFGT had strong positive correlations with hormone contents, which indicated they are key genes involved in the endogenous hormone responsive anthocyanin biosynthesis pathway. The results of this study showed that rootstock regulates the fruit coloring process by influencing the metabolism level of peel hormones in the 'Cabernet Sauvignon' grape.

Integrated metabolomic and transcriptomic analysis reveals the mechanism underlying the accumulation of anthocyanins and other flavonoids in the flesh and skin of teinturier grapes

Vitis vinifera 'Yan73' is a teinturier grape cultivar with red flesh. To explore the mechanism of berry color development, we performed an integrated flavonoid-targeted analysis of the metabolome and transcriptome of the skin and flesh of Yan73 berries collected at three phenological stages (E-L 31, E-L 35, and E-L 38). We identified 234 flavonoid-related metabolites, including 61 flavonols, 22 anthocyanins, and 61 other flavonoids. Most flavonoid metabolites accumulated continuously during berry development and attained the highest contents in the skin at E-L 38. The transcript level of crucial genes (C4H, CHS, and GST) was highest in the skin at E-L 38. Seventeen distinct modules were identified in a weighted gene correlation network analysis. The MEcoral1 module was probably correlated with flavonoid metabolism and comprised 623 unigenes. The findings provide insights into the regulation of flavonoid metabolites during berry development of Yan73 grape.

Integrative Analysis of Fruit Quality and Anthocyanin Accumulation of Plum cv. 'Cuihongli' (Prunus salicina Lindl.) and Its Bud Mutation

Fruit color is one of the quality indicators to judge the freshness of a plum. The coloring process of plum skin is valuable for research due to the high nutritional quality of anthocyanins found in plums. 'Cuihongli' (CHL) and its precocious mutant variety 'Cuihongli Red' (CHR) were used to analyze the changes of fruit quality and anthocyanin biosynthesis during plum development. The results showed that, during the development of the two plums, the total soluble solid and soluble sugar contents were highest at the mature stage, as the titratable acid trended gradually downward as the fruits of the two cultivars matured, and the CHR fruit showed higher sugar content and lower acid content. In addition, the skin of CHR turned red in color earlier than CHL. Compared with CHL, the skin of CHR had higher anthocyanin concentrations, higher activities of phenylalanine ammonia-lyase (PAL), chalcone isomerase (CHI), dihydroflavonol-4-reductase (DFR), and UDPglucose: flavonoid-3-O-glucosyltransferase (UFGT), and higher transcript levels of genes associated with anthocyanin production. In the flesh of the two cultivars, no anthocyanin content was detected. Taken together, these results suggest that the mutation exerted a major effect on anthocyanin accumulation via modification of the level of transcription; thus, CHR advances the ripening period of 'Cuihongli' plum and improves the fruit quality.

Assessment of 'Cabernet Sauvignon' Grape Quality Half-Véraison to Maturity for Grapevines Grown in Different Regions

Grapes are widely cultivated around the world and their quality has distinct regional characteristics. In this study, the qualitative characteristics of the 'Cabernet Sauvignon' grape variety in seven regions, from half-véraison to maturity, were analyzed comprehensively at physiological and transcriptional levels. The results indicated that the quality traits of 'Cabernet Sauvignon' grapes in different regions were significantly different with obvious regionality. Total phenols, anthocyanins, and titratable acids were the main factors of the regionality of berry quality, which were very sensitive to changes in the environment. It should be noted that the changes in titrating acids and total anthocyanin of berries vary greatly from half-véraison to maturity between regions. Moreover, the transcriptional analysis showed that the co-expressed genes between regions characterized the core transcriptome of berry development, while the unique genes of each region reflected the regionality of berries. The differentially expressed genes (DEGs) between half-véraison and maturity can be used to demonstrate that the environment of the regions could promote or inhibit gene expression. The functional enrichment suggested that these DEGs help to understand the interpretation of the plasticity of the quality composition of grapes according to the environment. Taken together, the information generated by this study could contribute to the development of viticultural practices aimed at making better use of native varieties for the development of wines with regional characteristics.

Review: Status and prospects of association mapping in grapevine

Thanks to current advances in sequencing technologies, novel bioinformatics tools, and efficient modeling solutions, association mapping has become a widely accepted approach to unravel the link between genotype and phenotype diversity in numerous crops. In grapevine, this strategy has been used in the last decades to understand the genetic basis of traits of agronomic interest (fruit quality, crop yield, biotic and abiotic resistance), of special relevance nowadays to improve crop resilience to cope with future climate scenarios. Genome-wide association studies have identified many putative causative loci for different traits, some of them overlapping well-known causal genes identified by conventional quantitative trait loci studies in biparental progenies, and/or validated by functional approaches. In addition, candidate-gene association studies have been useful to pinpoint the causal mutation underlying phenotypic variation for several traits of high interest in breeding programs (like berry color, seedlessness, and muscat flavor), information that has been used to develop highly informative and useful markers already in use in marker-assisted selection processes. Thus, association mapping has proved to represent a valuable step towards high quality and sustainable grape production. This review summarizes current applications of association mapping in grapevine research and discusses future prospects in view of current viticulture challenges.

Comparative study of phenolic compounds reveals a positive relationship between astringency and the phenolic composition in table grape varieties

Phenolic compounds and their derivatives play a major role in the intensity and characteristics of grape (Vitis vinifera) astringency. The present study investigated the relationship between phenolic composition and astringency of six commercial table grape varieties (two of each white-, red-, and black-skinned). Qualitative and quantitative liquid chromatography-mass spectrometry analysis was used to identify the variety-specific phenolic profiles in the skins and total astringency intensity was assessed and described by a trained sensory panel. Thirty phenolic compounds were identified among the six varieties. Principal component analysis of the phenolic profiles revealed that the intensity of astringency of grape skin was positively correlated with catechin, epicatechin, epicatechin-3-O-gallate, and proanthocyanidin dimers B1, B2, and B3. A further orthogonal partial least-squares discrimination analysis of these compounds showed that catechin was the substance most strongly and positively correlated (R = 0.904) with grape skin astringency. PRACTICAL APPLICATION: This study provided a better understanding of the relationships between phenolic composition and table grape astringency and highlighted a potential metabolic marker that could be used as a predictor for the complex astringency sensory attributes of table grape berries.

Anthocyanins: Metabolic Digestion, Bioavailability, Therapeutic Effects, Current Pharmaceutical/Industrial Use, and Innovation Potential

In this work, various concepts and features of anthocyanins have been comprehensively reviewed, taking the benefits of the scientific publications released mainly within the last five years. Within the paper, common topics such as anthocyanin chemistry and occurrence, including the biosynthesis of anthocyanins emphasizing the anthocyanin formation pathway, anthocyanin chemistry, and factors influencing the anthocyanins' stability, are covered in detail. By evaluating the recent in vitro and human experimental studies on the absorption and bioavailability of anthocyanins present in typical food and beverages, this review elucidates the significant variations in biokinetic parameters based on the model, anthocyanin source, and dose, allowing us to make basic assumptions about their bioavailability. Additionally, special attention is paid to other topics, such as the therapeutic effects of anthocyanins. Reviewing the recent in vitro, in vivo, and epidemiological studies on the therapeutic potential of anthocyanins against various diseases permits a demonstration of the promising efficacy of different anthocyanin sources at various levels, including the neuroprotective, cardioprotective, antidiabetic, antiobesity, and anticancer effects. Additionally, the studies on using plant-based anthocyanins as coloring food mediums are extensively investigated in this paper, revealing the successful use of anthocyanins in coloring various products, such as dietary and bakery products, mixes, juices, candies, beverages, ice cream, and jams. Lastly, the successful application of anthocyanins as prebiotic ingredients, the innovation potential of anthocyanins in industry, and sustainable sources of anthocyanins, including a quantitative research literature and database analysis, is performed.

Comparative Study on Grape Berry Anthocyanins of Various Teinturier Varieties

The red-fleshed grape cultivars, called teinturier or dyer grapes, contain anthocyanins in both the skin and flesh. These phenolic compounds exhibit excellent coloring ability, and as antioxidants, they are important bioactive compounds in food crops. In this work, anthocyanin patterns of grape berries of fifteen teinturier varieties collected from the gene bank located at Pécs in the southwest of Hungary were compared. Anthocyanin profiles of numerous varieties originating from Hungary such as 'Bíborkadarka', 'Kármin', 'Kurucvér', and 'Turán' are reported for the first time. Anthocyanins extracted separately from the skin and juice were analyzed using high-performance liquid chromatography coupled with a photodiode array detector. For the identification of compounds, high-resolution orbitrap mass spectrometry was used. All in all, twenty-one anthocyanins were identified and quantified. We found that anthocyanin patterns differed significantly in the skin and juice for all investigated cultivars. For Vitis vinifera varieties, the predominant anthocyanin in the skin was malvidin-3-O-glucoside, while the main pigment in the juice was peonidin-3-O-glucoside. For the first time, a significant amount of diglucosides was detected in two Vitis Vinifera cultivars with a direct relationship. In general, the pigment composition of the skin was much more complex than that of the juice. The comparative study with presented patterns gives valuable and beneficial information from a chemotaxonomical point of view. Our results also help to choose the appropriate teinturier varieties with the desired anthocyanins for food coloring or winemaking purposes.

First investigation on polyphenols and glycosidic aroma precursors in a spontaneous colour mutant of 'Glera', the principal grape variety of Prosecco sparkling wine

BACKGROUND

Somatic mutations in Vitis spp. are relatively frequent and can generate new agronomically interesting phenotypes. We report the discovery, genetic and chemical characterization of 'Glera rosa', a mutant for the berry skin colour of 'Glera', the main white cultivar used to produce Prosecco wine.

RESULTS

We ascertained the relationship between the skin colour of 'Glera rosa' and the polymorphisms in the Myb-gene transcription factors involved in polyphenol biosynthesis. We established that VvMybA1 was homozygous (VvMybA1a/VvMybA1a) in 'Glera' but heterozygous (VvmybA1a/VvmybA1b) in the 'Glera rosa' mutant. We verified that the VvMybA1a non-functional allele contained Grapevine Retrotransposon 1 (Gret1), while in the VvmybA1b allele Gret1 was missing, and the gene function was partially restored. The effects of mutation on 'Glera rosa' grape metabolites were studied by high-resolution mass spectrometry and gas chromatography/mass spectrometry analysis. Fifteen anthocyanins and five unique flavonols were found in the 'Glera rosa' mutant. The mutation also increased the contents of trans-resveratrol and its derivatives (i.e., piceatannol, E-ε-viniferin, cis- and trans-piceid) and of some flavonols in grape. Finally, the mutation did not significantly affect the typical aroma precursors of Glera grape such as glycosidic monoterpenes, norisoprenoids and benzenoids.

CONCLUSION

'Glera rosa' could be an interesting genetic source for the wine industry to produce Prosecco DOC rosé typology (made by adding up to 15% of 'Pinot Noir'), which was introduced to the market in 2020 with a worldwide massive success. © 2022 Society of Chemical Industry.

Effects of UVA disappearance and presence on the acylated anthocyanins formation in grape berries

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UVA block inhibited acylated anthocyanin formation.

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UVA presence promoted acylated anthocyanin formation.

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Peonidin for acetylation and p-coumaroylation primarily respond to UVA.

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A total of 3962 DEGs and 136 DAMs were identified.

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VvMYBA1 played a key role in co-expression network.

Ultraviolet A (UVA), the major component of the UV, plays a crucial role in formatting the characteristics of color in wine grapes by influencing its anthocyanin composition and contents. Results showed that anthocyanin biosynthesis was suppressed by UVA screening and enhanced by irradiation. The acetylation and p-coumaroylation of anthocyanins were more pronounced and showed positive correlation with a* and negative correlation with L*, b*, C*, and h, thereby leading to changes in color. Weighted gene co-expression network analysis showed that two modules (red and turquoise) were significantly related to the acetylation and p-coumaroylation of peonidin. In addition, relative gene expression assays and correlation analysis also indicated that VvMYBA1 might influence anthocyanin accumulation by directly regulating VvOMT expression and increasing the flux to the vacuole through VvGST4. In conclusion, the results helped in improving our understanding of the role of UVA in skin color formation.

Transcriptome and metabolite integrated analysis reveals that exogenous ethylene controls berry ripening processes in grapevine

Although grapevine (Vitis vinifera L.) is generally classified as a non-climacteric fruit, the regulatory mechanisms of ethylene in the ripening of non-climacteric fruit are still poorly understood. In this study, exogenous ethephon (ETH) strongly stimulated fruit color and anthocyanin accumulation, which was consistent with the increased expression of anthocyanin structural, regulatory, and transport genes. ETH application increased ABA content and decreased IAA content by coordinating ABA and auxin biosynthesis regulatory network. ETH treatment also accelerated sugar (glucose and fructose) accumulation by enhancing the gene expression involved in sugar transport and sucrose cleavage. ETH treatment blocked the synthesis of cellulose and accelerated the degradation of pectin, which was strongly associated with berry softening. To further confirm the function of ethylene biosynthesis and signaling genes, transient overexpression of VvACO4 and VvEIL3 were performed in both in tomato and strawberry fruits. These findings of the ethylene cascade add to our understanding of ethylene in non-climacteric berry ripening regulation and revealed a complex involvement of ethylene and its interplay with phytohormones during grapevine berry ripening.

Metabolomic profiling of brassinolide and abscisic acid in response to high-temperature stress

Hormone treatment enhanced the content of osmotic substances under high-temperature conditions. The effect of ABA and BR treated separately is better than treated together. To determine the effect of abscisic acid (ABA), brassinolide (BR) and ABA + BR on grape quality under high-temperature stress, various metabolites were analyzed. Compared with the control (CK), DL-tryptophan, D-raffinose, geniposidic acid, dodecanedioic acid and polyphenols were found to be higher after ABA treatment. After BR treatment, amino acids and poricoic acid B were higher than in CK. And carbohydrates and amino acids were up-regulated after ABA + BR treatment. BR and ABA + BR treatment also induced higher endogenous ABA and epibrassinolide contents. In addition, treated grape had higher soluble solid concentrations and soluble sugar content, and delayed the degradation of middle lamella and microfibrils. Antioxidant and heat shock-related genes were examined, which significantly increased in treated grape. The finding of this study suggested that ABA, BR and ABA + BR are very useful for alleviating high-temperature damage by increasing the accumulation of osmotic adjustment substances, and endogenous hormones content.

Strawberry Proteome Responses to Controlled Hot and Cold Stress Partly Mimic Post-harvest Storage Temperature Effects on Fruit Quality

To determine the effect of different temperature on strawberry after harvest, physiological indicator analysis and proteomics analysis were conducted on ripened strawberry (“Sweet Charlie”) fruit stored at 4, 23, and 37°C for 10 or 20 days. Results showed that 4°C maintained a better visual quality of strawberry, and the weight loss and firmness remained stable within 3 days. Low temperature negatively affected anthocyanin but positively affected soluble sugars. Though anthocyanin content was higher with increasing temperature, anthocyanin synthesis related proteins were downregulated. Higher indole-acetic acid (IAA) content in seeds and lower abscisic acid (ABA) content were found in berry at 4°C. Antioxidant related proteins were upregulated during storage, showing a significant up-regulation of peroxidase (POD) at 4°C, and ascorbate-glutathione (AsA-GSH) cycle related proteins and heat shock proteins (HSPs) at 37°C. In addition, overexpressed sugar phosphate/phosphate translocator, 1-aminocyclopropane-1-carboxylate oxidase, and aquaporin PIP2-2 had a positive effect in response to low temperature stress for containing higher protopectin content and POD activity.

Dual Application of Waste Grape Skin for Photosensitizers and Counter Electrodes of Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs), a powerful system to convert solar energy into electrical energy, suffer from the high cost of the Pt counter electrode and photosensitizer. In this study, the dual application of waste grape skin is realized by employing the grape skin and its extract as the carbon source of the carbon-based counter electrode and photosensitizer, respectively. The ultraviolet–visible absorption and Fourier transform infrared spectroscopy verify the strong binding between the dye molecules (anthocyanins) in the extract and the TiO₂ nanostructure on the photoanode, contributing to a high open-circuit voltage (V_OC) value of 0.48 V for the assembled DSSC device. Moreover, the waste grape skin was subjected to pyrolysis and KOH activation and the resultant KOH-activated grape skin-derived carbon (KA-GSDC) possesses a large surface area (620.79 m² g⁻¹) and hierarchical porous structure, leading to a high short circuit current density (J_SC) value of 1.52 mA cm⁻². Additionally, the electrochemical impedance spectroscopy reveals the efficient electron transfer between the electrocatalyst and the redox couples and the slow recombination of electrolytic cations and the photo-induced electrons in the conduction band of TiO₂. These merits endow the DSSC with a high photovoltaic efficiency of 0.48%, which is 33% higher than that of a common Pt-based DSSC (0.36%). The efficiency is also competitive, compared with some congeneric DSSCs based on other natural dyes and Pt counter electrode. The result confirms the feasibility of achieving the high-value application of waste grape skin in DSSCs.

Effects of ethylene on berry ripening and anthocyanin accumulation of 'Fujiminori' grape in protected cultivation

BACKGROUND

Although the grape berries are deliberated as a non-climacteric fruit, ethylene seems to be involved in grape berry ripening. However, the precise role of ethylene in regulating the ripening of non-climacteric fruits is poorly understood.

RESULTS

Exogenous ethephon (ETH) can stimulate the concentration of internal ethylene and accelerate the accumulation of anthocyanins in berries of 'Fujiminori', including malvidin-, delphinidin-, and petunidin-derivatives (3',4',5'-trihydroxylated anthocyanins) and cyanidin-derivatives (3',4'-dihydroxylated anthocyanins). The content of 3',4',5'-trihydroxylated anthocyanins was extremely higher than 3',4'-dihydroxylated anthocyanins, and ethylene did not affect the composition of anthocyanins in grape. Furthermore, we observed the expression of anthocyanin structural and regulatory genes as well as ethylene biosynthesis and response genes in response to ETH treatment. The anthocyanins accumulation is significantly associated with increased expression of anthocyanin structural (VvPAL, Vv4CH, VvCHS, VvCHI, VvF3H, and VvUFGT) and regulatory genes (VvMYBA1, VvMYBA2, and VvMYBA3), which persisted over the 12 days. In addition, exogenous ETH affected the endogenous ethylene biosynthesis (VvACO2 and VvACO4) and the downstream ethylene regulatory network (VvERS1, VvETR2, VvCTR1, and VvERF005).

CONCLUSIONS

These findings bring new insights into the physiological and molecular function of ethylene during berry development and ripening in grapes. © 2021 Society of Chemical Industry.

An Insight into Anti-Inflammatory Activities and Inflammation Related Diseases of Anthocyanins: A Review of Both In Vivo and In Vitro Investigations

Anthocyanin is a type of flavonoid pigment widely present in fruits and vegetables. It can not only be used as natural pigment, but also has a variety of health functions, for instance, anti-oxidant, anti-inflammatory, anti-tumor, and neuroprotective activities. Persistent proinflammatory status is a major factor in the development, progression, and complications of chronic diseases. Not surprisingly, there are thus many food ingredients that can potentially affect inflammation related diseases and many studies have shown that anthocyanins play an important role in inflammatory pathways. In this paper, the inflammation related diseases (such as, obesity, diabetes, cardiovascular disease, and cancer) of anthocyanins are introduced, and the anti-inflammatory effect of anthocyanins is emphatically introduced. Moreover, the anti-inflammatory mechanism of anthocyanins is elaborated from the aspects of NF-κB, toll like receptor, MAPKs, NO, and ROS and the main efficacy of anthocyanins in inflammation and related diseases is determined. In conclusion, this review aims to get a clear insight into the role of anthocyanins in inflammation related diseases.

Profiling Analysis of Volatile and Non-volatile Compounds in Vitis Vinifera Berries (cv. Chardonnay) and Spontaneous Bud Mutation

A novel clonal variety of Vitis vinifera was identified from “Chardonnay” using inter-simple sequence repeat (ISSR) markers and called “bud mutation. ” The metabolomic profiles in Chardonnay and bud mutation berries indicated essential differences in the expression of key genes in the pathways of 2-C-methyl-D-erythritol-4-phosphate (MEP) and lipoxygenase-hydroperoxide lyase (LOX-HPL). Bud mutation fruits also matured 10 days earlier than Chardonnay and have higher carotenoid, sugar, and acidic compound contents. Furthermore, the gene expression was examined in the biosynthetic pathways of two ripening-associated hormones, abscisic acid (ABA) and jasmonic acid (JA), which significantly increased in bud mutation compared with the Chardonnay fruit. The synthesis and metabolism of amino acids, terpenes, fatty acids, volatile components, and specialized metabolites significantly increased in bud mutation. Therefore, in comparison with Chardonnay, bud mutation is considered a highly aroma-producing grape variety for an improvement in the beverage industry.

Molecular Evaluation of Kyoho Grape Leaf and Berry Characteristics Influenced by Different NPK Fertilizers

Fertilization, a fundamental aspect of a plant’s life, has been of great concern for agricultural specialists to minimize the yield gap between actual and potential yield. Around the globe, fertilizers with different NPK ratios are being used to attain a better yield of grape. To find the suitable commercially available fertilizer for quality grape production, a 2 years (2017–2018) study was conducted for the evaluation of 10 fertilizers with different NPK ratios. Commercial fertilizers included were Zhanlan (16:16:16), Garsoni (15:15:15), Acron (16:16:16), Norway (21:7:12), Peters 1 (30:10:10), Nutrivant (14:14:30), Peters 2 (20:20:20), UMAX (15:15:15), G2 (20:20:20), and Yara (15:15:15). The fertilizer application rate was 20 g plant⁻¹, and each was applied at L-29, L-33, and L-36 phenological stages. Chlorophylls, carotenoids, macro/micronutrients in leaf, and anthocyanin derivatives in grape peel were evaluated. Expression levels of 24 genes, including nitrogen, phosphorous, potassium, and anthocyanin pathways in leaf, peel, and pulp were validated by qPCR at L-29, L-33, and L-36 stages. Results indicated that Norway (21:7:12) and Peters 1 (30:10:10) increased carotenoids, chlorophylls, and anthocyanins in leaves, while Zhanlan (16:16:16) improved fruit biochemical attributes, and anthocyanin (cyanidin, delphinidin, petunidin, malvidin, peonidin, and pelargonidin contents). However, a better grape yield was obtained by the application of Peters 1 (30:10:10). Potassium pathway genes were upregulated by Nutrivant (14:14:30), phosphorous pathway genes by Peters 2 (20:20:20), and nitrogen pathway genes by Peters 1 (30:10:10), while Nutrivant (14:14:30) upregulated anthocyanin pathway genes and simultaneously enhanced anthocyanin biosynthesis in berry peels. Results of two years’ study concluded that Peters 1 (30:10:10) was proved better to increase yield, while Zhanlan (14:14:30) was superior in improving anthocyanin biosynthesis.

Metabolomic profile combined with transcriptomic analysis reveals the value of UV-C in improving the utilization of waste grape berries

Table grape is a popular fruit worldwide. The quality of the appearance of table grapes directly affects their commercial value. Table grape bunches are usually carefully managed during production. At different developmental stages, a large number of grape berries are pruned as waste for commercial appearance, which leads to wasted resources. Ultraviolet-C (UV-C) can regulate the accumulation of secondary metabolites in fruits. In this study, metabolomic profile was combined with transcriptomic analysis technology to explore the value of UV-C in improving the utilization of waste grapes. The berries of the 'Jumeigui' grape were subjected to UV-C radiation treatment in the green-berry stage, veraison stage, and maturation stage. The results showed that UV-C could brown grape berries and decrease their sugar content at different developmental stages. Compared with other samples, those treated with UV-C in the veraison stage had the most upregulated metabolites, while samples in the green-berry stage had the most down-regulated metabolites. UV-C promoted the accumulation of stilbenes and some flavonoids in the berries at each developmental stage (especially at the green-berry and veraison stages). Compared with other stages, UV-C treatment during the veraison stage led to the highest number of upregulated genes related to transcription factors, protein modification, indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin acid (GA), receptor kinases, and Ascorbic acid/Glutathione (Ascorb/Gluath). UV-C might promote the accumulation of phenolic components by upregulating the expression of their biosynthesis related genes. UV-C may be an effective in vitro approach for improving the application value of waste grape berries by enhancing the accumulation of the nutritious phenolic components.

Molecular and Hormonal Mechanisms Regulating Fleshy Fruit Ripening

This article focuses on the molecular and hormonal mechanisms underlying the control of fleshy fruit ripening and quality. Recent research on tomato shows that ethylene, acting through transcription factors, is responsible for the initiation of tomato ripening. Several other hormones, including abscisic acid (ABA), jasmonic acid (JA) and brassinosteroids (BR), promote ripening by upregulating ethylene biosynthesis genes in different fruits. Changes to histone marks and DNA methylation are associated with the activation of ripening genes and are necessary for ripening initiation. Light, detected by different photoreceptors and operating through ELONGATED HYPOCOTYL 5(HY5), also modulates ripening. Re-evaluation of the roles of 'master regulators' indicates that MADS-RIN, NAC-NOR, Nor-like1 and other MADS and NAC genes, together with ethylene, promote the full expression of genes required for further ethylene synthesis and change in colour, flavour, texture and progression of ripening. Several different types of non-coding RNAs are involved in regulating expression of ripening genes, but further clarification of their diverse mechanisms of action is required. We discuss a model that integrates the main hormonal and genetic regulatory interactions governing the ripening of tomato fruit and consider variations in ripening regulatory circuits that operate in other fruits.

Postharvest Dehydration Temperature Modulates the Transcriptomic Programme and Flavonoid Profile of Grape Berries

Raisins are a popular and nutritious snack that is produced through the dehydration of postharvest grape berries under high temperature (HT). However, the response of the endogenous metabolism of white grape varieties to postharvest dehydration under different temperature have not been fully elucidated to date. In this study, the white grape cultivar ‘Xiangfei’ was chosen to investigate the effect of dehydration at 50 °C, 40 °C, and 30 °C on the transcriptomic programme and metabolite profiles of grape berries. Postharvest dehydration promoted the accumulation of soluble sugar components and organic acids in berries. The content of gallic acid and its derivatives increased during the dehydration process and the temperature of 40 °C was the optimal for flavonoids and proanthocyanidins accumulation. High-temperature dehydration stress might promote the accumulation of gallic acid by increasing the expression levels of their biosynthesis related genes and regulating the production of NADP⁺ and NADPH. Compared with that at 30 °C, dehydration at 40 °C accelerated the transcription programme of 7654 genes and induced the continuous upregulation of genes related to the heat stress response and redox homeostasis in each stage. The results of this study indicate that an appropriate dehydration temperature should be selected and applied when producing polyphenols-rich raisins.

Transcriptomic and Metabolomic Basis of Short- and Long-Term Post-Harvest UV-C Application in Regulating Grape Berry Quality Development

In this study, ultraviolet-C (UV-C) was utilized to improve the quality of post-harvest grape berries, and the transcriptomic and metabolomic basis of this improvement was elucidated. Berries of the red grape variety ‘Zicui’ and the white variety ‘Xiangfei’ were chosen to evaluate the effect of short- and long-term UV-C irradiation. Post-harvest UV-C application promoted malondialdehyde (MDA) and proline accumulation, and reduced the soluble solid content in berries. Both the variety and duration of irradiation could modulate the transcriptomic and metabolomic responses of berries to UV-C. Compared with the control, the differentially expressed genes (DEGs) identified under UV-C treatment were enriched in pathways related to metabolite accumulation, hormone biosynthesis and signal transduction, and reactive oxygen species (ROS) homeostasis. Flavonoid biosynthesis and biosynthesis of other secondary metabolites were the shared pathways enriched with differential metabolites. After long-term UV-C irradiation, cis-resveratrol accumulated in the berries of the two varieties, while the differential chalcone, dihydroflavone, flavonoid, flavanol, and tannin components primarily accumulated in ‘Xiangfei’, and some flavonols and anthocyanins primarily accumulated in ‘Zicui’. Based on an exhaustive survey, we made a summary for the effect of UV-C in regulating the quality development of post-harvest grape berries. The results of this study may help to elucidate the mechanism by which UV-C functions and support its efficient application.

Comparative transcriptomic analysis between 'Summer Black' and its bud sport 'Nantaihutezao' during developmental stages

4-coumarate-CoA ligase (VIT_02s0109g00250) and copper amine oxidase (VIT_17s0000g09100) played essential roles in contributing to the total soluble solid and total anthocyanin variations induced by bud sport in grape berries. Taste and color, which are important organoleptic qualities of grape berry, undergo rapid and substantial changes during development and ripening. In this study, we used two cultivars 'Summer Black' and its bud sport 'Nantaihutezao' to explore and identify differentially expressed genes associated with total soluble solid and anthocyanin during developmental stages using RNA-Seq. Overall, substantial differences in expression were observed across berry development between the two cultivars. 5388 genes were detected by weighted gene co-expression network analysis (WGCNA) associated with the total soluble solid (TSS) and anthocyanin contents variations. Several of these genes were significantly enriched in the phenylalanine metabolism pathway; two hub genes 4-coumarate-CoA ligase (VIT_02s0109g00250) and copper amine oxidase (VIT_17s0000g09100) played the most essential roles in relating to the total soluble solid and total anthocyanin variations induced by bud sport through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and co-expression network analysis. These findings provide insights into the molecular mechanism responsible for the bud sport phenotype.

Brassinosteroid Regulates 3-Hydroxy-3-methylglutaryl CoA Reductase to Promote Grape Fruit Development

Brassinosteroids (BRs) are known to regulate plant growth and development. However, only little is known about their mechanism in the regulation of berry development in grapes. This study demonstrates that BR treatment enhances the accumulation of fruit sugar components, reduces the content of organic acids (e.g., tartaric acid), promotes coloration, and increases the anthocyanin content in grape berries at the onset of the veraison, half veraison, and full veraison stages at the rate of 0.0998, 0.0560, and 0.0281 mg·g^-1_, respectively. In addition, BR treatment was also found to accelerate the biosynthesis of terpenoid aroma components, such as α-pinene, d-limonene, and γ-terpinene, which influence the aromatic composition of grapes. BRs can negatively regulate the expression of VvHMGR, a key gene involved in the mevalonate (MVA) pathway, and reduce the activity of 3-hydroxy-3-methylglutaryl CoA reductase (HMGR). Inhibiting the expression of HMGR promoted the accumulation of anthocyanins and fruit coloration. Meanwhile, after the inhibition, the contents of auxin indole-3-acetic acid (IAA), abscisic acid (ABA), and brassinosteroid (BR) increased, while gibberellin (GA₃) and zeatin riboside (ZR) decreased, and its aromatic composition also changed. Therefore, it may be concluded that BRs inhibited HMGR activity and cooperated with VvHMGR to regulate the formation of color, aroma, and other quality characteristics in fruits.

Color Intensity of the Red-Fleshed Berry Phenotype of Vitis vinifera Teinturier Grapes Varies Due to a 408 bp Duplication in the Promoter of VvmybA1

Grapevine (Vitis vinifera) teinturier cultivars are characterized by their typical reddish leaves and red-fleshed berries due to ectopic anthocyanin formation. Wines of these varieties have economic importance as they can be used for blending to enhance the color of red wines. The unique and heritable mutation has been known for a long time but the underlying genetic mechanism still is not yet understood. Here we describe the association of the red-fleshed berry phenotype with a 408 bp repetitive DNA element in the promoter of the VvmybA1 gene (grapevine color enhancer, GCE). Three different clones of ‘Teinturier’ were discovered with two, three and five allelic GCE repeats (MybA1t2, MybA1t3 and MybA1t5). All three clones are periclinal chimeras; these clones share the same L1 layer, but have distinct L2 layers with different quantities of GCE repeats. Quantitative real time PCR and HPLC analysis of leaf and berry samples showed that the GCE repeat number strongly correlates with an increase of the expression of VvmybA1 itself and the VvUFGT gene regulated by it and the anthocyanin content. A model is proposed based on autoregulation of VvmybA1t to explain the red phenotype which is similar to that of red-fleshed apples. This study presents results about the generation and modes of action of three MybA1t alleles responsible for the red-fleshed berry phenotype of teinturier grapevines.

The Effect of Ethylene on the Color Change and Resistance to Botrytis cinerea Infection in 'Kyoho' Grape Fruits

The formation of grape quality and the mechanism of resistance against foreign pathogens affect the storage stability of fruits during post-harvest handling. Ethylene plays a crucial role in regulating the ripeness of fruits and can be used as an exogenous regulator to resist exogenous pathogens. In this study, we used different concentrations of ethephon for treatment of grape fruits before veraison, analyzed the anthocyanin content, soluble solids, titratable acid, and determined fruit firmness and cell wall metabolism-related enzymes during fruit development. Results showed that exogenous ethephon promoted the early coloration of grape fruits and increased the coloring-related genes myeloblastosis A1(MYBA1), myeloblastosis A2(MYBA2), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonoid 3’-hydroxylase gene (F3’H), flavonoid 3’, 5’hydroxylase (F3’5’H), 3-O-flavonoid glucosyltransferase (UFGT), and glutathione S-transferase (GST), softening related genes Polygalacturonase(PG), pectinate lyases(PL) and Pectin methylesterase( PME, as well as ethylene metabolism pathway-related genes 1-aminocyclopropane-1-carboxylic acid synthase 1(ACS1), 1-aminocyclopropane-1-carboxylic acid oxidase 2 (ACO2), ethylene receptor gene(ETR2), and ethylene-insensitive 3 (EIN3). Ethephon treatment also increased soluble solids and decreased titratable acid in grape fruit. Fruits pretreated with ethephon were inoculated with Botrytis cinerea, which led to resistance in grape fruit through activation of the antioxidant system. The expression levels of disease resistance-related genes including VvPAD4, VvPIP1, VvNAC26, VvDREB, VvAPX, Vvpgip, VvWRKY70, VvMYC2, VvNPR1 also increased in inoculated fruit with pathogen following ethephon pretreatment. Furthermore, we monitored ethylene response factor 1(ERF1) transcription factor, which could interact with protein EIN3 during ethylene signal transduction and mediate fruit resistance against B. cinerea infection. Meanwhile, overexpression of VvERF1 vectorin strawberry fruits reduced the susceptibility to B. cinerea infection. We suggest that ethylene can induce resistance in ripened fruits after B. cinerea infection and provide adequate postharvest care.

Anthocyanin Biosynthesis and Methylation of the MdMYB10 Promoter Are Associated with the Red Blushed-Skin Mutant in the Red Striped-Skin "Changfu 2" Apple

The color of apple skin, particularly anthocyanin-based coloration, is a key factor determining market acceptance. The mechanisms of anthocyanin accumulation in apples with different skin color patterns (i.e., striped and blushed) were analyzed. In total, 14 anthocyanins and 5 procyanidins were simultaneously assayed in red blushed-skin mutants (CF-B1 and CF-B2) and red striped-skin parents (CF-S1 and CF-S2), and 13 significant differences were revealed. Anthocyanin accumulation was significantly higher in the red blushed-skin apples than it was in the parents. The transcript levels of anthocyanin biosynthesis genes and regulatory factors (MdMYB10, MdbHLH3, and MdWD40) were associated with different skin color patterns during the coloring period at 4, 6, and 8 days after the fruits were debagged. The methylation levels of the MdMYB10 promoter regions -1203 to -779 bp, -1667 to -1180 bp, and -2295 to -1929 bp were associated with different skin color patterns, and there was more methylation in red striped-skin apples. These results improve our understanding of anthocyanin accumulation and its underlying molecular mechanism in apples with different skin color patterns, thereby providing valuable information for apple breeding.

Exposure to endophytic fungi quantitatively and compositionally alters anthocyanins in grape cells

Anthocyanins contribute greatly to the organoleptic and biochemical properties of grapes and wines. Although there are broadly documented factors involved in grape anthocyanin synthesis, the present work focused on fungal endophytes and their possible role in grape coloration. Our results showed that exposure to endophytic fungi within a dual culture system differentially affected total anthocyanin concentrations and PAL activities in grape cells. Grape cells dual cultured with fungal strains XH-2, R2-21 and B2-17 showed significant differences of their anthocyanin concentrations were subjected to further analysis of their anthocyanidin compositions. Compared to the no-fungus controls, grape cells exposed to fungal strains XH-2 and R2-21 exhibited quantitative promotion of their total anthocyanidin concentrations by 74% and 28%, respectively, whereas treatment with the fungus B2-17 reduced the anthocyanidin content by 19%. A total of 14 species of anthocyanidins were detected from the grape cells in these experiments. Most interestingly, exposure to any of these fungal strains differentially modified the compositional patterns of grape cellular anthocyanidins. The obvious upregulation of the transcription of VvMYB in grape cells treated with fungal strains XH-2 and R2-21 implies that the increased anthocyanin levels in these grape cells may be due to the activated transcriptional factors. In addition, the exposure of grape cells to extracts of these fungi initiated similar responses of anthocyanin contents and PAL activities to exposure to the living fungi and appeared obvious dosage effects. The influence of fungal endophytes on the coloration of grape berries was also examined in this study.