Anthocyanin profi les and color properties of red wines made from Vitis davidii and Vitis vinifera grapes

Spine grape(Vitis davidii Foex.)is an important wild grape species native to China.Fifteen red spine grape clones and three red Vitis vinifera grape varieties were used to evaluate the differences in the anthocyanin profiles and color properties of wines made from V.davidii and V.vinifera grapes.Among spine wines,‘Junzi#2’wine had the highest total phenolic and total anthocyanin,‘Xiangzhenzhu’wine had the highest total flavonoids,and‘Junzi#1’wine had the highest total tannin.The anthocyanin compositions of all of the spine wines were dominated by Mv-3,5-diglucoside.The total individual anthocyanin contents in spine wines,except‘Gaoshan#5’,‘Junzi#5055’,‘Junzi#5061’,and‘Junzi#5044’,were signifi cantly higher than in V.vinifera wines.Most of the spine wines had a stronger red intensity and a brighter chroma with a bluer hue than V.vinifera wines.Correlation analysis revealed that the color properties were closely related to the anthocyanin composition.These results suggest that wines made from spine grapes may be useful for the wine industry for their color properties and high individual anthocyanin contents.

Comparison of phenolic profiles and antioxidant activities in skins and pulps of eleven grape cultivars(Vitis vinifera L.)

Eleven grape cultivars were analysed to explore the variety differences of fresh grape phenolic profiles. The results showed that free phenolics were predominant in grape skins and pulps, and showed the higher antioxidant activities than bound. In 11 cultivars, Muscat Kyoho extracts had the highest total phenolic content in skins(10.525 mg GAE g^(–1) FW) and pulps(1.134 mg GAE g^(–1) FW), and exhibited the highest DPPH radical scavening capacity(EC_(50)=11.7 μg mL^(–1)) and oxygen radical absorbance capacity(ORAC) value(190.57 μmol TE g^(–1) FW) of free phenolic in skin. In addition, the most abundant phenolics in grape skins were found to be flavonoids such as kaempferol in Kyoho skin(541.2 μg g^(–1) FW), rutin, catechin and epicatechin in Muscat Kyoho skin(262.3, 86.3 and 70.0 μg g^(–1) FW, respectively). Furthermore, the principal component analysis showed a strong difference of phenolic profiles with the cultivars, existing forms and distributions. Pearson correlation coefficient analysis showed a significant linear correlation between total phenolic content and antioxidant activity(P<0.05). Therefore, both skins and pulps were rich sources of bioactive phenolic compounds, and Muscat Kyoho was the ideal source among all samples.

The potential role of grape (Vitis vinifera L.) in prevention of threatened abortion via immunomodulatory and anti-inflammatory abilities: a hypothesis

Threatened abortion is a common problem in early pregnancy. This early vaginal bleeding happens in about 25% of pregnant women. The medications including progesterone, uterine muscle relaxant or human chorionic gonadotropin have essential effects in developing pregnancy, but the clinical data are insufficient to prescribe them. In recent decades, medicinal herbs can help us to present new treatments. Grape (Vitis vinifera L.) can protect the fetus from the perspective of Persian medicine. So, we hypothesize about the salutary effects of grape in miscarriage prevention. We found five standard expected mechanisms of grape to prevent threatened abortion: immunomodulatory and anti-inflammatory, anti-oxidant, anti-contraction, hormonal and anti-stress activities. Grape reduces nitric oxide, prostaglandin E2, expression of nuclear factor κB and other pro-inflammatory cytokines like IL (Interleukin)-1β, IL-6, IL-8, and tumor necrosis factor-α. It also elevates anti-inflammatory mediators and expression of peroxisome proliferator-activated receptor-γ. Grape polyphenols have a crucial role in fetus protection with high antioxidant power and other functions such as prevention of stress-triggered abortion with proanthocyanidins, or hormonal effects and inhibition of uterine contractions with resveratrol. So according to these studies, grape probably has effects on the immune and endocrine factors involved in threatened miscarriage.

The Effect of Vineyard Cover Crop on Main Monomeric Phenols of Grape Berry and Wine in Vitis viniferal L. cv. Cabernet Sauvignon

This study was conducted to determine the effect of cover crop inter-row in vineyard on main mono-phenol content of grape berry and wine. Three such cover crops, two perennial legumes （white clover and alfalfa） and a perennial gramineous grass （tall fescue） were sown in vineyard. The main phenolic compounds of mature grape berry and wines vinified under the same conditions were extracted with ethyl acetate and diethyl ether and analyzed by high- performance liquid chromatography （HPLC） by comparing to soil tillage. A total of ten phenolic compounds were identified and quantified in the different grape berry and wines, including nonflavonoids （hydroxybenzoic and hydroxycinnamic acids） and flavonoids （flavanols and flavonols）. The concentration of flavonoid compounds （409.43 to 538.63 mg kg^-1 and 56.16 to 81.30 mg L^-1） was higher than nonflavonoids （76.91 to 98.85 mg kg^-1 and 30.65 to 41.22 mg L^-1） for Cabernet Sauvignon grape and wine under different treatments, respectively. In the flavonoid phenolics, Catechin was the most abundant in the different grapes and wines, accounting for 74.94 to 79.70% and 48.60 to 50.62% of total nonanthocyanin phenolics quantified, respectively. Compared to soil tillage, the sward treatments showed a higher content of main mono-phenol and total nonanthocyanin phenolics in grapes and wines. There were significant differences between two cover crop treatments （tall fescue and white clover） and soil tillage for the content of benzoic acid, salicylic acid, caffeic acid, catechin, and total phenolics in the grape berry （P 〈 0.05 or P〈0.01）. The wine from tall fescue cover crop had the highest gallic acid, caffeic acid and catechin. Cover crop system increased the total nonanthocyanin phenolics of grapes and wines in order of the four treatments： tall fescue, white clover, alfalfa, and soil tillage （control）. Cover crop in vineyard increased total phenols of grape berry and wine, and thus improved the quality of wine evidently.

Genome and transcriptome analysis of the grapevine(Vitis vinifera L.) WRKY gene family

The plant WRKY gene family represents an ancient and complex class of zinc-finger transcription factors(TFs)that are involved in the regulation of various physiological processes,such as development and senescence,and in plant response to many biotic and abiotic stresses.Despite the growing number of studies on the genomic organisation of WRKY gene family in different species,little information is available about this family in grapevine(Vitis vinifera L.).In the present study,a total number of 59 putative grapevine WRKY transcription factors(VvWRKYs)were identified based on the analysis of various genomic and proteomic grapevine databases.According to their structural and phylogentic features,the identified grapevine WRKY transcription factors were classified into three main groups.In order to shed light into their regulatory roles in growth and development as well as in response to biotic and abiotic stress in grapevine,the VvWRKYs expression profiles were examined in publicly available microarray data.Bioinformatics analysis of these data revealed distinct temporal and spatial expression patterns of VvWRKYs in various tissues,organs and developmental stages,as well as in response to biotic and abiotic stresses.To also extend our analysis to situations not covered by the arrays and to validate our results,the expression profiles of selected VvWRKYs in response to drought stress,Erysiphe necator(powdery mildew)infection,and hormone treatments(salicilic acid and ethylene),were investigated by quantitative real-time reverse transcription PCR(qRT-PCR).The present study provides a foundation for further comparative genomics and functional studies of this important class of transcriptional regulators in grapevine.

Cgr1,a ripe rot resistance QTL in Vitis amurensis‘Shuang Hong’grapevine

Ripe rot is a serious grapevine disease in Vitis L.and Muscadinia(Planch.)Small.However,resistance to this disease has been reported in some oriental Vitis species.To identify resistance-related Quantitative Trait Loci(QTLs)from the Chinese grape species V.amurensis,an F1 population of V.vinifera‘Cabernet Sauvignon’×V.amurensis‘Shuang Hong’was used to map the ripe rot resistance loci expected in‘Shuang Hong’grape.A total of 7598 single nucleotide polymorphisms(SNPs)between the parents were identified in our previous study,and 934 SNPs were selected for genetic map construction.These SNPs are distributed across the 19 chromosomes covering a total of 1665.31 cM in length,with an average of 1.81 cM between markers.Ripe rot resistance phenotypes among the hybrids were evaluated in vitro using excised leaves for three consecutive years from 2016 to 2018;a continuous variation was found among the F1 hybrids,and the Pearson correlation coefficients of the phenotypes scored in all three years were significant at the 0.01 level.Notably,the first QTL reported for resistance to grape ripe rot disease,named Cgr1,was identified on chromosome 14 of‘Shuang Hong’grapevine.Cgr1 could explain up to 19.90%of the phenotypic variance.In addition,a SNP named‘np19345’was identified as a molecular marker closely linked to the peak of Cgr1 and has the potential to be developed as a marker for the Cgr1 resistance haplotype.

Identification and Characterization of MicroRNAs and Their Targets in Grapevine(Vitis vinifera)

MicroRNAs （miRNAs） are a class of newly identified, small, non-coding RNAs that play vital roles in regulation. Based on miRNAs unique features of expression pattern, evolutionary conservation, secondary structure and genetic requirements for biogenesis, computational predication strategy is adopted to predicate the novel miRNAs. In this research, potential miRNAs and their targets in grapevine （Vitis vinifera） were predicted. We used previously known plant miRNAs against grapevine genome sequence databases to search for potential miRNAs. A total of 81 potential miRNAs were detected following a range of strict filtering criteria. Using these potential miRNA sequences, we could further blast the mRNA database to find the potential targets in this species. Comparative analysis of miRNAs in grapevine and other species reveals that miRNAs exhibit an evolutional conservation, the number and function of miRNAs must have significantly expanded during the evolution of land plants. Furthermore divergence made versatile functions of miRNAs feasible. Cluster of miRNAs likely represents an ancient expression mechanism. Predicted target genes include not only transcription factors but also genes implicated in floral development, signal transduction, diseases and stress response. Till now, little is known about experimental or computational identification of miRNA in grapevine species. Increased knowledge of the biological mechanisms of the grapevine will allow targeted approaches to increase the quality of fruit and reduce the impact of parasites together with stress, which could enable a sustainable, environmentally-sound, farming policv.

CRISPR/Cas9-mediated mutagenesis of VvMLO3 results in enhanced resistance to powdery mildew in grapevine(Vitis vinifera)

Grapevine(Vitis vinifera),one of the most economically important fruit crops in the world,suffers significant yield losses from powdery mildew,a major fungal disease caused by Erysiphe necator.In addition to suppressing host immunity,phytopathogens modulate host proteins termed susceptibility(S)factors to promote their proliferation in plants.In this study,CRISPR/Cas9(clustered regularly interspaced short palindromic repeats/CRISPR-associated 9)technology was used to enable the targeted mutagenesis of MLO(mildew resistance Locus O)family genes that are thought to serve as S factors for powdery mildew fungi.Small deletions or insertions were induced in one or both alleles of two grapevine MLO genes,VvMLO3 and VvMLO4,in the transgenic plantlets of the powdery mildew-susceptible cultivar Thompson Seedless.The editing efficiency achieved with different CRISPR/Cas9 constructs varied from 0 to 38.5%.Among the 20 VvMLO3/4-edited lines obtained,one was homozygous for a single mutation,three harbored biallelic mutations,seven were heterozygous for the mutations,and nine were chimeric,as indicated by the presence of more than two mutated alleles in each line.Six of the 20 VvMLO3/4-edited grapevine lines showed normal growth,while the remaining lines exhibited senescence-like chlorosis and necrosis.Importantly,four VvMLO3-edited lines showed enhanced resistance to powdery mildew,which was associated with host cell death,cell wall apposition(CWA)and H2O2 accumulation.Taken together,our results demonstrate that CRISPR/Cas9 genome-editing technology can be successfully used to induce targeted mutations in genes of interest to improve traits of economic importance,such as disease resistance in grapevines.

CRISPR/Cas9-mediated VvPR4b editing decreases downy mildew resistance in grapevine(Vitis vinifera L.)

Downy mildew of grapevine(Vitis vinifera L.),caused by the oomycete pathogen Plasmopara viticola,is one of the most serious concerns for grape production worldwide.It has been widely reported that the pathogenesis-related 4(PR4)protein plays important roles in plant resistance to diseases.However,little is known about the role of PR4 in the defense of grapevine against P.viticola.In this study,we engineered loss-of-function mutations in the VvPR4b gene from the cultivar“Thompson Seedless”using the CRISPR/Cas9 system and evaluated the consequences for downy mildew resistance.Sequencing results showed that deletions were the main type of mutation introduced and that no off-target events occurred.Infection assays using leaf discs showed that,compared to wild-type plants,the VvPR4b knockout lines had increased susceptibility to P.viticola.This was accompanied by reduced accumulation of reactive oxygen species around stomata.Measurement of the relative genomic abundance of P.viticola in VvPR4b knockout lines also demonstrated that the mutants had increased susceptibility to the pathogen.Our results confirm that VvPR4b plays an active role in the defense of grapevine against downy mildew.

Not All Shrivels Are Created Equal—Morpho-Anatomical and Compositional Characteristics Differ among Different Shrivel Types That Develop during Ripening of Grape (<i>Vitis vinifera</i>L.) Berries

An understanding of physiological disorders associated with ripening of fruits triggered by abiotic stress relies on anatomical and physico-chemical analyses, as it provide insights into their origin and probable causes. The objective of this study was to analyze different ripening disorders of grape (Vitis vinifera L.) berries by dissecting their morpho-anatomy, shriveling nature, and composition. Four well-defined disorders—sunburn, prolonged dehydration (PD), late-season bunch stem necrosis (LBSN), and berry shrivel (BS) were analyzed in field-grown grapevines of the cultivar Cabernet Sauvignon. Early bunch stem necrosis (EBSN) that occurred before ripening was also included in the study. Unlike healthy spherical berries, the pericarp of disordered berries except for sunburn shriveled causing concomitant reductions in fresh weight and volume. The exocarp of PD berries developed well-ordered indentations as distinct from the wrinkles in LBSN berries, whereas BS berries were flaccid with numerous skin folds. The epicuticular wax occurred as upright platelets in all shrivel forms excluding the sun-exposed hemisphere of sunburned berries. A chlorophyllous inflorescence framework persisted in all shrivel forms but in LBSN, wherein the necrotic regions developed tylosis. Unlike the translucent mesocarp of healthy, sunburned, and PD berries, the mesocarp was collapsed in BS and LBSN berries, nevertheless all had well-developed seeds. The composition of healthy berries was optimal, whereas the disordered berries were compositionally distinct from each other, which as a whole differed from the healthy berries. The BS berries had the lowest sugar content, and although sugar concentration was higher in LBSN, sunburned and PD berries, sugar amount per berry was highest in the healthy berries, the same was true for hexoses. Healthy and BS berries exhibited highest amounts of tartaric acid followed by sunburn and PD berries, whereas the LBSN berries had the lowest values. Conversely, healthy and PD berries had the highest amounts of malic acid followed by LBSN, sunburn and BS berries, which collectively displayed similar amounts. The PD berries exhibited the highest calcium content followed by LBSN, healthy, and finally BS and sunburned berries. A linear relationship existed between potassium (K) and pH of the berries. The PD berries had the highest amounts of K followed by healthy, sunburn, LBSN, and BS berries. Overall, the results reported here provided combined morpho-anatomical and compositional analyses of different shrivel types that occurred during a single growing season. Such analysis is needed to make a progress on understanding these ripening disorders culminating in the development of remedial measures.

Relative quantification of phosphoproteomic changes in grapevine (Vitis vinifera L.) leaves in response to abscisic acid

In a previous transcriptomic analysis,abscisic acid(ABA)was found to affect the abundance of a number of transcripts in leaves of Cabernet Sauvignon grapevines with roots that had been exposed to 10μM ABA for 2 h.Other work has indicated that ABA affects protein abundance and protein phosphorylation as well.In this study we investigated changes in protein abundance and phosphorylation of Cabernet Sauvignon grapevine leaves.Protein abundance was assessed by both label-free and isobaric-label quantitive proteomic methods.Each identified common proteins,but also additional proteins not found with the other method.Overall,several thousand proteins were identified and several hundred were quantified.In addition,hundreds of phosphoproteins were identified.Tens of proteins were found to be affected in the leaf after the roots had been exposed to ABA for 2 h,more than half of them were phosphorylated proteins.Many phosphosites were confirmed and several new ones were identified.ABA increased the abundance of some proteins,but the majority of the proteins had their protein abundance decreased.Many of these proteins were involved in growth and plant organ development,including proteins involved in protein synthesis,photosynthesis,sugar and amino-acid metabolism.This study provides new insights into how ABA regulates plant responses and acclimation to water deficits.

Variation of Polyphenols, Anthocyanins and Antioxidant Power in the Strawberry Grape (<i>Vitis labrusca</i>) after Simulated Gastro-Intestinal Transit and Evaluation of <i>in Vitro</i>Antimicrobial Activity

The influence of a simulated digestive process on some biochemical and biological aspects of strawberry grape (Vitis labrusca) was investigated. The amount of total polyphenols and anthocyanins as well as the antioxidant power were evaluated. Results evidenced that the simulated gastrointestinal transit caused a decrease of the polyphenols content and total anthocyanins;these last, however, were more resistant than polyphenols, decreasing only of 50% respect to the initial value (31.50 μg/ml of extract). The extract exhibited an excellent antioxidant power (EC50 3.8 mg/ml), which decreased of about four times after the simulated gastrointestinal transit. The antimicrobial activity of the extract, evaluated against three Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus pathogen strains was enhanced by the simulated digestion, with an increase of the inhibition halo.

QTL detection and candidate gene analysis of grape white rot resistance by interspecific grape (Vitis vinifera L. × Vitis davidii Foex.) crossing

Grape white rot,a devastating disease of grapevines caused by Coniella diplodiella(Speg.)Sacc.,leads to significant yield losses in grape.Breeding grape cultivars resistant to white rot is essential to reduce the regular use of chemical treatments.In recent years,Chinese grape species have gained more attention for grape breeding due to their high tolerance to various biotic and abiotic factors along with changing climatic conditions.In this study,we employed whole-genome resequencing(WGR)to genotype the parents of‘Manicure Finger’(Vitis vinifera,female)and‘0940’(Vitis davidii,male),along with 101 F1 mapping population individuals,thereby constructing a linkage genetic map.The linkage map contained 9337 single-nucleotide polymorphism(SNP)markers with an average marker distance of 0.3 cM.After 3 years of phenotypic evaluation of the progeny for white rot resistance,we confirmed one stable quantitative trait locus(QTL)for white rot resistance on chromosome 3,explaining up to 17.9%of the phenotypic variation.For this locus,we used RNA-seq to detect candidate gene expression and identified PR1 as a candidate gene involved in white rot resistance.Finally,we demonstrated that recombinant PR1 protein could inhibit the growth of C.diplodiella and that overexpression of PR1 in susceptible V.vinifera increased grape resistance to the pathogen.

Transcriptome of Erysiphe necator-infected Vitispseudoreticulata leaves provides insight into grapevineresistance to powdery mildew

Powdery mildew(PM),which is caused by the pathogen Erysiphe necator(Schw.)Burr.,is the single most damaging disease of cultivated grapes(Vitis vinifera)worldwide.However,little is known about the transcriptional response of grapes to infection with PM.RNA-seq analysis was used for deep sequencing of the leaf transcriptome to study PM resistance in Chinese wild grapes(V.pseudoreticulata Baihe 35-1)to better understand the interaction between host and pathogen.Greater than 100 million(M)90-nt cDNA reads were sequenced from a cDNA library derived from PM-infected leaves.Among the sequences obtained,6541 genes were differentially expressed(DEG)and were annotated with Gene Ontology terms and by pathway enrichment.The significant categories that were identified included the following:defense,salicylic acid(SA)and jasmonic acid(JA)responses;systemic acquired resistance(SAR);hypersensitive response;plant–pathogen interaction;flavonoid biosynthesis;and plant hormone signal transduction.Various putative secretory proteins were identified,indicating potential defense responses to PMinfection.In all,318 putative R-genes and 183 putative secreted proteins were identified,including the defense-related R-genes BAK1,MRH1 and MLO3 and the defense-related secreted proteins GLP and PR5.The expression patterns of 16 genes were further illuminated by RT-qPCR.The present study identified several candidate genes and pathways that may contribute to PM resistance in grapes and illustrated that RNA-seq is a powerful tool for studying gene expression.The RT-qPCR results reveal that effective resistance responses of grapes to PM include enhancement of JA and SAR responses and accumulation of phytoalexins.

Identification of UGT85A glycosyltransferases associated with volatile conjugation in grapevine(Vitis vinifera × Vitis labrusca)

Glycosylated volatiles are considered as hidden aroma precursors that affect fruit flavor and are involved in plant defense response. Several uridine-diphosphate(UDP)-glycosyltransferase(UGT) members related to the glycosylation of volatiles have been identified from grapevine berries. Although grapevine leaves produced much higher levels of glycosylated volatiles than berries, UGTs responsible for the production of glycosylated volatiles in leaves have not yet been identified. Here, eight novel UGT genes were cloned, among these four members that belong to UGT85A family(named UGT85A24, UGT85A25, UGT85A26, and UGT85A27) were localized in the cytoplasm and their recombinant proteins showed activity toward volatiles detected in grapevine, with geraniol as the preferred substrate in vitro. Two UGT genes with 98.1% homology differ in R/S-linalool selection. The UGT85A26-catalyzed substrate showed enrichment in S-linalool, whereas UGT85A27 showed a strong preference for R-linalool. UGT85A24 and UGT85A25 were expressed mainly in berries, and UGT85A26 and UGT85A27 were expressed predominantly in grapevine mature leaves and correlated with the highest content of glycosylated volatiles in the mature leaves. Methyl jasmonate(MeJA) induced the expression of UGT85A26 and UGT85A27 as well as the production of linalyl-β-glucoside, citronellyl-β-glucoside and phenethyl-β-glucoside. Transient overexpression of UGT85A26 and UGT85A27 in tobacco leaves led to the accumulation of linalyl-β-glucoside and an increase in citronellyl-β-glucoside in vivo. These results indicate that the expression of UGT85A26 and UGT85A27 is a major regulator affecting the content of glycosylated volatiles in grapevine.

Divergent molecular and growth responses of young“Cabernet Sauvignon”(Vitis vinifera)plants to simple and mixed infections with Grapevine rupestris stem pitting-associated virus

Grapevine rupestris stem pitting associated virus(GRSPaV)is one of the most widely distributed viruses;even so,little is known about its effect on Vitis vinifera.To provide new insights,the effects of single and mixed GRSPaV infections on the V.vinifera cultivar“Cabernet Sauvignon”were studied by evaluating growth parameters,such as measurements of the total plant length,the number and distance of internodes and the number of leaves per shoot.In addition,parameters relating to gas exchange,i.e.,the stomatal conductance,net photosynthetic rate,internal CO2 concentration and leaf transpiration,were also assessed.All the measurements were performed in one-and two-yearold plants with a single GRSPaV infection or mixed infections of GRSPaV and Grapevine fanleaf virus(GFLV).The results show that the plant phytosanitary status did not significantly alter the growth and gas exchange parameters in oneyear-old plants.However,in two-year-old plants,single GRSPaV infections increased shoot elongation,which was accompanied by the overexpression of genes associated with the gibberellic acid response pathway.The gas exchange parameters of these plants were negatively affected,despite exhibiting higher LHCII gene expression.Plants with mixed infections did not have modified growth parameters,although they presented a greater reduction in the primary photosynthetic parameters evaluated with no change in LHCII expression.The results presented here confirm the co-evolution hypothesis for V.vinifera and GRSPaV during the early stages of plant development,and they provide new evidence about the effects of GRSPaV and GFLV co-infections on the“Cabernet Sauvignon”cultivar.

The use of widely targeted metabolite profiling to reveal the senescence changes in postharvest 'Red Globe'(Vitis vinifera) grape berries

Changes in the metabolites of table grapes(Vitis vinifera) reportedly occur during postharvest senescence. The aim of this study was to determine the metabolomic differences in postharvest table grapes(‘Red Globe’) after being subjected to different senescence periods. To this end, we used widely targeted metabolomics based on ultra-performance liquid chromatography and tandem mass spectrometry. A total of 135 differential metabolites were identified. During postharvest senescence, the levels of most differential flavonoids(e.g., pelargonidin 3-O-glucoside, quercetin-3-O-glucoside, and cyanidin 3-O-glucoside) and L-aspartic acid decreased, while the levels of phenolic acids(e.g., trans-4-hydroxycinnamic acid methyl ester) and pantothenol increased. During early and late senescence, the levels of most differential lipids, especially LysoPC, as well as those of nucleotides and their derivatives, such as uridine, decreased and increased, respectively. Collectively, the findings of this study provide fundamental insights into the reasonable control of table grape fruit postharvest senescence and lay a solid foundation for further research.

Understanding Differential Responses of Grapevine (Vitis vinifera L.) Leaf and Fruit to Water Stress and Recovery Following Re-Watering

Among all fruit crops of horticultural importance, grapevines (Vitis vinifera L.) stand out as the most drought tolerant crop species whose tolerance is credited to their proficiency to recover from water stress in both the natural and vineyard growing conditions. However, information on the recovery responses is relatively scant. Studies were conducted to address this issue using potted vines of the grapevine cultivar, Cabernet Sauvignon, which was subjected to water stress and along with anatomical and ultrastructural characterizations, physiological status was assessed in healthy and water stressed vines, and following recovery via rewatering from the water stressed vines. Water stress induced wilting of leaves, drooping of tendrils, and desiccation followed by abscission of shoot tip leaving behind a brown scar at the shoot apex. The wilted leaves accumulated ABA, which correspondingly reduced stomatal conductance and leaf water potential. Upon re-watering, both these parameters made a recovery with values similar to healthy leaves. Likewise, leaf anatomical features following rewatering resembled to that of healthy leaves. In clusters, water stress caused shriveling of preveraison (unripened) berries, which regained full turgor following water resupply, whereas the postveraison (ripening) berries in the same cluster remained unaffected as evidenced by the presence of viable mesocarp cells and epicuticular wax in the form of platelets. The study revealed that shoot tip with leaf primordia was most sensitive to water stress followed by fully expanded leaves and preveraison berries, whereas the postveraison berries remained unaffected. This information could be valuable to implementing irrigation strategies towards sustaining grape production in existing vineyards experiencing episodic droughts and targeted areas prone to drought.

Low Cost Process for Phenolic Compounds Extraction from Cabernet Sauvignon Grapes (<i>Vitis vinifera</i>L. cv. Cabernet Sauvignon). Optimization by Response Surface Methodology

Phenolic compounds are naturally extracted molecules used nowadays for several industrial applications such as food preservatives and neutraciticals;thus industrial needs are in constant growth. Optimization of phenolic compounds (PC) and monomeric anthocyanins (MA) extraction from grape berries using response surface methodology was here achieved. Cabernet Sauvignon (CS) wine grapes (Vitis vinifera L. cv. Cabernet Sauvignon) are a rich source of anti-radical phe- nols, extractable as dietary supplements. However, efficiency of extraction strongly depends on specific experimental conditions. In this work, the comparison between two extraction mixtures, Acetone/Water (A/W) and Methanol/Water (M/W) and the effects of three critical variables—Extraction Time (between 8 and 88 h), Extraction Temperature (between 1?C and 35?C) and Solvent Content (between 63% and 97%)—on Phenolic Compounds Yield (PCY) and Monomeric Anthocyanins Yield (MAY) were studied using Response Surface Methodology (RSM). Process conditions maximizing the PCY were found to be 87% A/W solvent content, after 88 h incubation at 26?C, and those of the MAY were found to be 97% M/W solvent content, after 8 h incubation at 1?C. In addition, chromatographic profiles of extracts showed very different affinities of the phenolic compounds families to the experimental conditions employed. This process advantages are: low percentage of organic solvent used, high quality of extracted molecules thanks to low temperature treatment, very low energy consumption and low cost of needed machinery. At industrial scale, it may be used as promising technique for the extraction of bioactive compounds from plant or byproduct material such as from wine or grape juice industries.

Flavonoid Profiles of Wild Grapes Native to Japan: <i>Vitis coignetiae </i>Pulliat and<i>Vitis ficifolia </i>Bunge var. <i>ganebu</i>Hatusima

Flavonoids are a group of natural compounds in plants with versatile health benefits for humans. Grapes are a dietary source of flavonoids and the flavonoid components in grape berries can depend on the grape species and cultivar. In this experiment, proanthocyanidins, flavonols, and anthocyanins were analyzed in Vitis coignetiae and V. ficifolia var. ganebu, wild grapes native to Japan, and compared with those in V. labruscana cv. Muscat Bailey A, to evaluate the potential of the wild grapes as a grape resource. Proanthocyanidin contents in seeds were lower in the two wild grapes than in Muscat Bailey A. However, the skin of V. ficifolia var. ganebu was the richest source of proanthocyanidins. Flavonol levels in the skins of the two wild grapes were lower than that in the skin of Muscat Bailey A. Colorimetry determined that the total anthocyanin content in the skin of V. ficifolia var. ganebu was 6 times and 7 times higher, respectively, than those of V. coignetiae and Muscat Bailey A. Although monoglucoside anthocyanin levels analyzed by high-pressure liquid chromatography (HPLC) were in the order Muscat Bailey A > V. ficifolia var. ganebu > V. coignetiae, most of the diglucoside and acylated monoglucoside and diglucoside anthocyanin levels identified by HPLC-mass spectrometry were highest in V. ficifolia var. ganebu. These data suggest that V. ficifolia var. ganebu might be a novel source of flavonoids and superior to V. coignetiae as a source of flavonoids.