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Background: Weed control is essential for agricultural floor management in vineyards and the inter-row mulching is an eco-friendly practice to inhibit weed growth via filtering out photosynthetically active radiation. Besides weed suppression, inter-row mulching can influence grapevine growth and the accumulation of metabolites in grape berries. However, the complex interaction of multiple factors in the field challenges the understanding of molecular mechanisms on the regulated metabolites. In the current study, black geotextile inter-row mulch (M) was applied for two vintages (2016–2017) from anthesis to harvest. Metabolomics and transcriptomics analysis were conducted in two vintages, aiming to provide insights into metabolic and molecular responses of Cabernet Sauvignon grapes to M in a semi-arid climate. Results: Upregulation of genes related to photosynthesis and heat shock proteins confirmed that M weakened the total light exposure and grapes suffered heat stress, resulting in lower sugar-acid ratio at harvest. Key genes responsible for enhancements in phenylalanine, glutamine, ornithine, arginine, and C6 alcohol concentrations, and the downward trend in ε-viniferin, anthocyanins, flavonols, terpenes, and norisoprenoids in M grapes were identified. In addition, several modules significantly correlated with the metabolic biomarkers through weighted correlation network analysis, and the potential key transcription factors regulating the above metabolites including VviGATA11, VviHSFA6B, and VviWRKY03 were also identified. Conclusion: This study provides a valuable overview of metabolic and transcriptomic responses of M grapes in semi-arid climates, which could facilitate understanding the complex regulatory network of metabolites in response to microclimate changes. [ABSTRACT FROM AUTHOR]

This two-consecutive-year study aimed to evaluate the effects of ground management methods on the volatomics of 'Cabernet Sauvignon' grapes and wines in Northwest China, in which inner-row crop covering with purslane (GRASS) and mulching with black plastic film (FILM) treatments were carried out, respectively. Compared with clean tillage (CK), the GRASS and FILM treatments changed the microclimates of grapevine fruit zones and rhizospheres, which delayed the ripening of grape berries and affected the accumulation of aroma substances in the mature grapes effectively. GRASS increased the concentration of terpenes and C13-norisoprenoids in berries and gave more floral, fruity, and caramel fragrances to wines, while FILM had the opposite effect of significantly increasing the synthesis of C6/C9 compounds and brought more green leaf flavors, showing that inner-row purslane covering is a potential and stable viticultural practice to improve the wine quality in this booming wine region. [ABSTRACT FROM AUTHOR]

This study aimed to clarify how microclimate diversity altered volatilomics in Cabernet Sauvignon grapes and wines. Four row-oriented vineyards were selected, and metabolites of grapes and wines were determined from separate canopy sides. Results showed that shaded sides received 59% of the solar radiation and experienced 55% of the high-temperature days compared to the exposed sides on average. Grape primary metabolites were slightly affected by the canopy side. Herbaceous aromas were consistently more abundant in grapes and wines from shaded clusters. Heat-stressed canopy sides accelerated terpenoid loss and increased norisoprenoid levels in grapes, while β -damascenone in north-side wines was 13%–32% higher than that in south-side wines of the east-west vineyard. The northeast-southwest vineyard showed the most notable variation in taste and aroma sensory scores, with four parameters significantly different. There were 32 aroma series identified in wines, and banana, pineapple, and strawberry odors were highly correlated with aroma sensory score. • Herbaceous, grass, and woody odors were higher in wines from shaded canopy sides. • Grape norisoprenoids were more abundant in exposed and heat-stressed canopy sides. • Phloematic transport dampened variation in primary metabolites, especially sugars. [ABSTRACT FROM AUTHOR]

• An effective deacidification of KHCO 3 addition in wine was investigated. • pH adjustment helped to initiate malo-lactic acid conversion in V. amurensis wines. • The addition of KHCO 3 after alcoholic fermentation enhanced wine aroma. • The pH of alcoholic fermentation dominated the level of esters and higher alcohols. • Sufficient malolactic fermentation helps to enhanced the global aroma. To produce quality dry red wines with high-acidity grapes of Vitis amurensis , an experiment was designed to adjust pH during winemaking by adding KHCO 3 at two time points and two pH levels in conjunction with malolactic fermentation (MLF). The organic acids and volatiles were detected by HPLC and GC–MS separately, combing with the color characteristic and sensory evaluation, we investigated the quality of V.amurensis wines under pH adjustment. Results showed that the pH adjustment weakened the wine color slightly but helped to initiate MLF. The low pH value of alcoholic fermentation favored the development of esters and higher alcohols. Higher pH levels promoted a sufficient MLF and enhanced the global aroma levels by 1.14–1.25 times, which led to higher sensory scores. In conclusion, KHCO 3 addition and MLF improved the quality of V. amurensis dry red wines, chemical addition after alcoholic fermentation was more effective for cold regions. [ABSTRACT FROM AUTHOR]

Severe shoot topping (SST) is a viticultural technique that has been proposed to face global warming in recent years. In the present study, a three-year study (2018–2020) was performed to investigate the comprehensive impact of SST on vine physiology, berry sugar accumulation rate and flavoromics of Cabernet Sauvignon grapes in a semi-arid climate. Results showed that manipulating different SST treatments could cause a reduction of 0.4–1.7 mg/berry/d (0.02–0.11°Brix/d) in grape sugar accumulation without affecting the yield. Photosynthetic compensation was found in consecutively SST-treated vines across vintages. The berry skin anthocyanins and flavanols showed lower concentrations in SST grapes than in the control. However, the individual flavonols, including myricetin-based and kaempferol-based flavonols, had higher concentrations in SST grapes. A minor difference was found in aroma compounds regarding the SST influence, which seemed vintage-dependent. Through principal component analysis, the metabolites that showed high correlations with vintages, SST treatment (SST vs control) and different SST time were evaluated. Our results provided an available viticultural strategy to face climate change in the semi-arid region. [Display omitted] • SST reduced grape sugar accumulation by 0.4–1.7 mg/berry/d without affecting yield. • Photosynthetic compensation was found in consecutively SST-treated vines. • Delaying harvest caused declined concentrations of berry anthocyanins and flavanols. • SST increased the concentration of berry myricetin- and kaempferol-based flavonols. • Delayed harvest caused by SST was meaningful in avoiding grape heat stress. [ABSTRACT FROM AUTHOR]

• Grape and wine volatomics varied from different cluster growing spatial positions. • Microclimate and vine growth of different positions lead to the heterogeneity. • Terpenes and norisoprenoids responded differently to light than C 6 /C 9 compounds. • The herbaceous aroma was more prominent in lower-positioned wines. • Hexanal in grape was negatively correlated with terpenes and norisoprenoids in wine. The cluster-zone of the fan training system with multiple trunks (F-MT) distribute >1.5 m vertically and 1.0 m horizontally, which leads to microclimate heterogeneity around clusters. In the current study, clusters were divided into eight spatial positions according to the cluster growing height and light conditions, and the aroma profiles of grapes and wines were evaluated by HS-SPME-GC-MS. Results showed that the microclimate varied in different spatial positions. Light exposure promotes the accumulation of terpenes and C 13 -norisoprenoids, while inhibiting C 6 /C 9 compounds in grape berries. Zone 2 wine presented the highest global aroma concentration. Floral and fruity were the main aromas in F-MT wines, but the herbaceous was more prominent in lower-position wines. C 6 /C 9 compounds in grapes negatively correlated with terpenes and C 13 -norisoprenoids in wines. In conclusion, the aroma profiles of grapes and wines varied from different cluster positions, and graded harvesting will be helpful to produce quality wines. [ABSTRACT FROM AUTHOR]

• Grape and wine quality varied from different cluster growing spatial positions. • Microclimate and vine growth of different positions lead to the heterogeneity. • Light promotes the accumulation of flavonols and 3′-hydroxylated anthocyanins. • Wines made from upper clusters had higher alcohol degree and lightness. • Lower clusters give the wine a higher total acidity and red color component. The fan training system with multiple trunks (F-MT) is widely used in the northern China winegrape region with high yield and convenience for burying soil to prevent winter cold. However, the wide distribution of clusters under F-MT usually leads to variations in berry compositions. In two consecutive years, clusters from different spatial positions were collected to determine the phenolic composition in grapes and resultant wines by HPLC-QqQ-MS/MS. Results showed that light exposure promotes the accumulation of flavonols and 3′-hydroxylated anthocyanins in berries. Wines made from upper clusters had higher alcohol degree, lightness, monomeric anthocyanins and flavonols, whereas wines made from lower clusters had relatively higher total acidity, red color component, polymeric anthocyanin and total flavanols. Most of the wine parameters were also significantly affected by vintage. In conclusion, the quality of grapes and wines varied from different cluster positions, graded harvesting helps to maximize the characteristics of grape berries. [ABSTRACT FROM AUTHOR]

[Display omitted] • The region had the greatest influence on the content and distribution of elements in wine, followed by vintage and grape maturity. • Similar terroir conditions shape similar petiole elemental composition, and the petiole element can likewise be used as an indication of origin traceability. • Al, B, Ba, K, Pb, Mn, Sr and Rb were significantly positively correlated with soil pH and K in wine was significantly positively correlated with element K in the soil. The ionic elements in wine and in vineyards are gaining attention due to characterization of the wine traits, wine origin tracing, and vine nutrient judging. In this experiment, 19 elements were detected by inductively coupled plasma mass spectrometry (ICP-MS) in 69 wine samples from 4 regions, 3 vintages, and 3 grape maturity levels. Furthermore, the elements related to vine development, such as N, P, K, Ca, Mg, Cu, Fe, Zn and Cu in the vineyard soil and petioles were determined. Two orthogonal partial least squares discriminant analysis (O2PLS-DA) showed that K, Mn, Co, Sr, B, Si, Pb, Ni, Cu, and Zn were important elements in distinguishing the regions. High-temperature vintages can bring wines with high levels of Sr in wine. Na, Ca, K, Mg, Rb, Al, Rb, Pb and Fe can be used as signature elements to distinguish wines made from 2 grape maturities. And Cu, Zn, and Mn were the key elements used to differentiate the petioles in the 4 regions. Partial square regression (PLSR) analysis showed that soil pH was positively correlated with Al, B, Ba, K, Pb, Mn, Sr and Rb in wine, and K in wine was significantly positively correlated with element K in the soil. In conclusion, the elemental contents in wine are shaped by the combination of origin, vintage and grape maturity, while some key elements can be used as indicators of origin traceability. [ABSTRACT FROM AUTHOR]