Influence of Reverse Osmosis Process in Different Operating Conditions on Phenolic Profile and Antioxidant Activity of Conventional and Ecological Cabernet Sauvignon Red Wine

Red wine polyphenols are responsible for its colour, astringency, and bitterness. They are known as strong antioxidants that protect the human body from the harmful effects of free radicals and prevent various diseases. Wine phenolics are influenced by viticulture methods and vinification techniques, and therefore, conventionally and ecologically produced wines of the same variety do not have the same phenolic profile. Ecological viticulture avoids the use of chemical adjuvants in vineyards in order to minimise their negative influence on the environment, wine, and human health. The phenolic profile and antioxidant activity of wine can also be influenced by additional treatments, such as concentration by reverse osmosis. The aim of this study was to investigate the influence of four different pressures (2.5, 3.5, 4.5, and 5.5 MPa) and two temperature regimes (with and without cooling) on the phenolic profile and antioxidant activity of conventional and ecological Cabernet Sauvignon red wine during concentration by reverse osmosis. The results showed that retention of individual phenolic compounds depended on the applied processing parameters, chemical composition of the initial wine, and chemical properties of a compound. Higher pressure and retentate cooling favoured the retention of total polyphenols, flavonoids, and monomeric anthocyanins, compared to the opposite conditions. The same trend was observed for antioxidant activity.

Comparative Proteomics Reveals Differential Mechanism of Root Cold-resistance between Vitis. Riparia × V. Labrusca and Cabernet Sauvignon

Grapevines, containing large amounts of bioactive metabolites that offer health benefits, are widely cultivated around the world. The cold damage of growing outside with extreme low temperature during overwintering stage limits the expansion of production. Although the levels of morphological, biochemical and molecular in different Vitis species exposure to different temperatures have been investigated, differential expression of proteins in roots is still limited. Here, the roots of cold-resistant (Vitis. riparia × V. labrusca, T1) and cold-sensitive varieties (Cabernet Sauvignon, T3) at −4°C as well as of the former at −15°C (T2) were measured by iTRAQ-based proteomic analysis, expression levels of genes encoding candidate proteins were validated by qRT-PCR. The results showed that the root activity of cold-resistant variety was stronger than that of cold-sensitive variety, and it declined with the decrease of temperature. A total of 25 proteins were differentially co-expressed at T2 versus (vs) T1 and T1 vs T3, and these proteins were involved in stress response (e.g. DHN1, SHSPCP and USPCP), bio-signaling (e.g. PKCP, S/TPP and nsS/TP), metabolism (e.g. GluP, GluBE and PE), energy (e.g. AAC, AAACP and NADCP), and translation (e.g. rpL14, rpS21 and PPI). The relative expression levels of the candidate 13 genes were consistent with their fold-change values of proteins. The signature translation pattern for the roots at spatio-temporal treatments of varieties and temperatures provides insight into the differential mechanism of cold resistance of grapevines.

Characterization and Evolution of Volatile Compounds of Cabernet Sauvignon Wines from Two Different Clones during Oak Barrel Aging

Xinjiang is a major wine-making region in China, but its hot climate in summer and intense sun exposure negatively affect the aroma quality of Cabernet Sauvignon wine. The aim of this study was to characterize and differentiate the volatile composition of Cabernet Sauvignon wines from two clones (169 and 191) in Xinjiang, and to study their aromatic profile evolution during 12-month oak barrel aging period. Results showed that before aging, clone 169 wine contained higher concentrations of several alcohols and ethyl esters, while acetate esters and furanic compounds were higher in clone 191 wine. After aging, levels of many terpenes, norisoprenoids, volatile phenols and phenolic aldehydes were significantly higher in clone 169 wine than 191 wine. Aroma series analysis revealed that clone 169 wine exhibited higher floral and roasty aromas after aging, while clone 191 wine had stronger chemical aroma. Principal component analysis indicated that aging process played a primary role in the alteration of volatile profile in these wines. Clone played a secondary role and oak barrel had a tertiary contribution to the variation. The present work indicates that clone 169 is a better choice for producing high-quality aged Cabernet Sauvignon wine with intense and elegant aroma in Xinjiang.

Flavor Chemical Profiles of Cabernet Sauvignon Wines: Six Vintages from 2013 to 2018 from the Eastern Foothills of the Ningxia Helan Mountains in China

The eastern foothills of the Helan Mountains in the Ningxia region (Ningxia), is a Chinese wine-producing region, where Cabernet Sauvignon is the main grape cultivar; however, little compositional or flavor information has been reported on Ningxia wines. Oenological parameters, volatile profiles, and phenolic profiles were determined for 98 Ningxia Cabernet Sauvignon wines from the 2013–2018 vintages, as well as 16 from Bordeaux and California, for comparison. Ningxia wines were characterized by high ethanol, low acidity, and high anthocyanin contents. Multivariate analysis revealed that citronellol and 12 characteristic phenolic compounds distinguish Ningxia wines from Bordeaux and California wines. The concentrations of most phenolic compounds were highest in the 2018 Ningxia vintage and decreased with the age of the vintage. To our knowledge, this is the first extensive regionality study on red wines from the Ningxia region.

First report of grapevine polerovirus 1 from a grapevine in China

Xinjiang Uygur Autonomous Region is the largest grape-producing area in China, with a grape output of 3.05 million tons in 2020, accounting for nearly 20% of the total grape output in China (National Bureau of Statistics, 2021). Viral disease is a major factor threatening the grape industry and results in large economic losses by affecting the quality of grapes and wines. Actually, nearly 80 different viruses have been recorded in grapevine (Fuchs, 2020). To identify viruses that infect grapevine in Xinjiang, leaves of four vines of cultivar Cabernet Sauvignon with symptoms of chlorotic spots and crinkling were collected from a vineyard at Shihezi University in Shihezi City in May 2019 and pooled for total RNA extraction (Invitrogen™ PureLink ® Plant RNA Reagent, USA). After ribodepletion, a cDNA library was prepared using the Ribo-ZeroTM Kit (Illumina, San Diego, USA) and subjected to high-throughput sequencing (HTS) on the Illumina NovaSeq 6000 platform (Novogene, China). In total, 41,799,420 paired-end reads (150 nt × 2) were obtained after performing quality control using Trimmomatic version 0.39 (Bolger et al., 2014). These reads were de novo assembled into 154,716 contigs using the rnaSPAdes method in SPAdes software with default parameters (Bankevich et al., 2012). BLASTn analysis of these contigs led to the identification of 59 viral-related contigs from 248 -18476 bp. These contigs belonged to six positive-stranded RNA viruses, namely, grapevine polerovirus 1 (GPoV-1; 2 contigs), grapevine berry inner necrosis virus (GBINV; 4 contigs), grapevine leafroll-associated virus 3 (GLRaV-3; 2 contigs), grapevine Pinot gris virus (GPGV; 3 contigs), grapevine rupestris stem pitting-associated virus (GRSPaV; 4 contigs), and grapevine fleck virus (GFkV; 17 contigs); one DNA virus, grapevine geminivirus A (GGVA; 2 contigs); and one viroid, Australian grapevine viroid (AGVd; 1 contig). Among them, GPoV-1 is a newly discovered grape-infecting virus that has recently been reported from Japan and France (Candresse et al., 2020; Chiaki and Ito, 2020). The two contigs of GPoV-1 were assembled manually into a 5627-nt scaffold that covers 99.6% of the genome of the reference GPoV-1 isolate (MT008025). The scaffold shared 98.5% and 98.2% nucleotide (nt) sequence identities with the French GPoV-1 isolate KT (MT008025) and the Japanese GPoV-1 isolate KC (LC505098), respectively. To confirm the GPoV-1 infection of the grapevines used for HTS analysis, we designed a primer pair targeting the coding region of the P1 protein GP30F (5′-CCTCTTTCGCTGCCATAGGC-3′) and GP2180R (5′-CCTGGAGCCTTAAGCTGGTG-3′) and applied them in revere transcription (RT)-PCR using a PrimeScriptTM One Step RT–PCR Kit (Takara, China) to detect GPoV-1. The expected 2151-bp fragment was amplified from one of the four grapevine samples. The amplicon was cloned into the pMD19-T vector (TaKaRa, China) and Sanger sequenced. BLASTn analysis showed that the sequence of the amplicon (GenBank accession no. OK574336) shared 98% identity with the scaffold obtained from HTS and shared 98.5% and 97.4% identity with the GPoV-1 isolates KT and KC, respectively. To determine the occurrence of GPoV-1 in the vineyard, 8 and 20 leaves were randomly collected from grapevines of cvs. Black Monukka and Cabernet Sauvignon, respectively. We designed a primer pair of GPoV4264F (5′-ACTGCACAGACTCTCACACG-3′) and GPoV4657R (5′- TCCTTCGCGCAGTCACTATC-3′), which target the coding region of the P3-P5 fusion protein. An expected 394-bp amplicon was detected in 2 out of the 8 Black Monukka and 7 out of the 20 Cabernet Sauvignon leaf samples. Sanger sequencing confirmed the GPoV-1 identity of the amplicons. Although all the samples used for HTS analysis displayed symptoms, 4 of 9 samples in which GPoV-1 infection was detected were asymptomatic, suggesting that GPoV-1 may be latent, as reported previously (Candresse et al., 2020). To the best of our knowledge, this is the first report of GPoV-1 infection of grapevine in China. Although most members of the genus Polerovirus (family Solemoviridae) are transmitted by aphids, how GPoV is transmitted remains unknown, representing an increased risk for its spread. Therefore, attention should be given to reducing the prevalence of GPoV-1 in grape-producing areas in China, especially in Xinjiang.

Application of different fertilizers to cabernet sauvignon vines: Effects on grape aroma accumulation

BACKGROUND: Vine nutrition affects the composition of grapes, but how it impacts the aroma of grapes is largely unknown. OBJECTIVE: This work aimed to investigate the effect of different fertilizers: chemical fertilizer (CF), sheep manure-based organic fertilizer (OF), 50% organic fertilizer + 50% chemical fertilizer (O + C), 25% organic fertilizer + 25% chemical fertilizer [1/2(O + C)], and soil conditioner (SC) on the aroma accumulation of Cabernet Sauvignon grapes. METHODS: The treatments were applied and samples were collected in 2019 at weekly intervals from August 7 to September 22. The grapes’ chemical characteristics and volatile compounds were analyzed. RESULTS: The chemical results showed that the treatments had a positive effect on grapes, with a strong preference for the 1/2(O + C) treatment. Grape aroma results showed that the concentrations of grape aromas in O + C-treated samples were lower than the other treatments. The OF treated samples had comparatively high (24.8%) volatile concentrations during maturity compared to other treatments, including the control (15.9%). Throughout development, samples treated with OF (17.4%) and CF (15.7%) had higher volatile concentrations than samples treated with SC (14.4%), 1/2(O + C) (12.8%), and O + C (12.4%). However, compared to SC-treated samples, samples treated with 1/2(O + C) increased the accumulation of terpenes and esters. The principal component analysis (PCA) results showed that samples treated with OF were strongly correlated to carbonyls, terpenes, and esters during maturity. CONCLUSION: The type and ratio of fertilizer used had a significant impact on the aroma profile of Cabernet Sauvignon grapes.

First Report of Diaporthe ambigua associated with dead arm disease on grapevine in Chile

Grapevine (Vitis vinifera L.) is one of the most important fruit crops in Chile based on economic value. Phaeomoniella chlamydospora and Botryosphaeriaceae species have been reported as the major causal agents associated with dieback symptoms in Chile commercial vineyards (Díaz and Latorre 2014; Besoain, 2018; Larach et al. 2020). Recently Eutypa lata has been reported attacking Chilean vineyards with dieback symptoms (Lolas et al. 2020). In this study, two commercial cv. Cabernet Sauvignon vineyards, located in O'Higgins Region of Chile, showing dead cordons, dead spur with a grayish color, canker, and vascular necrosis were sampled in fall 2018, with a high incidence of symptoms was observed. Four symptomatic wood samples were analyzed from these vineyards. Pieces of wood (<1 cm2) were taken from the advance zone of the canker lesions, disinfected with 70% ethanol, rinsed in sterile distilled water, dried, and transferred to two media in Petri plates, potato dextrose agar acidified with 0.5 ml of 96% lactic acid (APDA) and malt extract agar, and incubated for at least seven days at 24°C in darkness. From mycelium obtained from monosporic culture, two isolates were selected and morphologically identified as Diaporthe sp. To induce sporulation, these two isolates were grown in APDA under near-ultraviolet light (λ = 320 nm) at room temperature. After 30 days, the development of pycnidia was observed. Both Diaporthe sp. isolate presented alpha-conidia ellipsoidal with an obtuse apex, biguttulate (n=30) of 6.7 µm ± 0.33 µm x 3.3 µm ± 0.32 µm. No Beta-conidia or perhitecia were observed. DNA was extracted from the monosporic mycelium. The ribosomal internal transcribed spacer (ITS), β-tubulin (BT) gene, and elongation factor (EF) gene were amplified using ITS4/ITS5, Bt2a/Bt2b, and EF1-728F/EF1-986R primer pairs, respectively. PCR products were sequenced and identified as Diaporthe ambigua Nitschke (PUCV2140 and PUCV2141), showing 100% sequence identity with ITS MH864620.1, 99.8% with BT MG281142.1, and 100% with EF KC343738.1 sequences from D. ambigua. Sequences were deposited in GenBank (ITS: accession numbers MW301136, MW301137; BT: MW323445, MW323446 and EF: MW308305, MW308306). Two pathogenicity tests were performed with strains PUCV2140 and PUCV2141 using 2-year-old V.vinifera cv. Cabernet Sauvignon. In each test, three plants were used per isolate, considering one plant as an experimental unit. In the first test, a 5 mm mycelial plug from a 6-day-old APDA culture was inoculated using an oblique cut made in the bark with a sterile scalpel and done at the middle of the trunk. In the second test, the trial was done under the same described conditions previously, but in this case, one-year-old semi-lignified shoots were inoculated between two internodes, using mycelial plugs, one shoot for each plant. Injured plants but treated with sterile APDA plugs were used as controls. Plants were placed in natural conditions, and after three months from inoculations, plants showed a cortical canker and brown vascular lesions. Non-inoculated plants remained asymptomatic. The lengths of the cankers were 22.0 ± 1.8 mm and 10.5 ± 0.6 mm, after inoculations of the trunk and cane, respectively. The vascular lesions were 37.0 ± 3.3 and 18.0 ± 2.0 mm, in trunk and cane inoculations, respectively. D. ambigua was re-isolated and reidentified morphologically from the inoculated symptomatic plants, confirming Koch’s postulate. Also, the plants inoculated on the trunk showed premature leaf drop. To our knowledge, this is the first report of D. ambigua associated with dieback affecting grapevines in Chile. Previous D. ambigua was reported causing fruit rots (Auger et al. 2013; Díaz et al. 2017) and cordon dieback in kiwifruit (Díaz and Latorre, 2018), and stem canker and dieback in blueberry (Elfar et al. 2013) in Chile. This study reports a new species of fungi for Chile associated with the dead arm in vineyards. D. ambigua is a pathogen in essential crops in our country. Therefore, it is important to study its prevalence in the future.