Vitis vinifera L. cv. 'Agiorgitiko' is one of the most important red grape varieties of Greece, cultivated almost exclusively in the region of Nemea in north-eastern Peloponnese. This work aimed to ...study the influence of some commonly applied viticultural practices on the polyphenolic composition of 'Agiorgitiko'. Leaf removal at veraison, irrigation, and a combination of both, were applied and the phenolic content of the grapes and of the produced wines was compared. The results showed that leaf removal decreased berry size, enhanced total anthocyanin, total phenol and malvidin 3-O-monoglucoside accumulation in skins and increased the amount of extractable anthocyanins in the juice. The combination of irrigation and leaf removal caused a significant increase in total phenols in the skin and in the amount of extractable anthocyanins in juice. As far as the produced wines were concerned, color intensity, tannin content and total polyphenols were increased due to leaf removal. Both irrigation and leaf removal resulted in wines with the highest concentration of malvidin 3-O-monoglucoside, although neither practice resulted in any significant difference in anthocyanin concentration of the wines. Vines where only irrigation was applied produced berries with reduced extractable anthocyanins, increased seed total phenols and lower wine total tannins. The study showed that increasing cluster sun exposure of 'Agiorgitiko' vines may be, overall, beneficial to the quality of the produced wine.
•Red Tempranillo yielded more than white Tempranillo.•Drought combined with elevated temperature reduced growth and bunch weight.•Elevated CO2 attenuated the negative effect of drought.•Grape yield ...was less affected by the stress factors than vegetative growth.•Effects of climate change on grape quality were cultivar dependent.
In the Mediterranean area, climate change is associated with atmospheric CO2 concentration increases, enhanced temperatures and scarce water availability, limiting seriously crop yield and decreasing quality. The aim of this study was to investigate the effects of elevated CO2, elevated temperature and water deficit, acting individually and/or interacting, on vegetative and reproductive growth, substrate and plant water status, and must quality in fruit-bearing cuttings of two grapevine (Vitis vinifera L.) cultivars (red and white Tempranillo). In four temperature gradient greenhouses, eight treatments were applied, from fruit set to maturity: CO2 level (400 versus 700μmolmol−1), temperature (ambient versus ambient +4°C), and water availability (full irrigation versus cyclic drought). Effects of climate change on grape yield and quality were cultivar dependent. Generally, red Tempranillo had more vegetative growth and grape yield than the white cultivar. Also, grape yield was less affected by the treatments than vegetative growth. Drought, especially under elevated temperature, drastically reduced vegetative growth, bunch fresh and dry weights in both cultivars. Interestingly, elevated CO2 attenuated these negative effects of drought. The effects of climatic factors on yield were not associated with a worse water status of the vegetative or reproductive organs. In red Tempranillo, the combination of elevated CO2, elevated temperature and drought reduced total polyphenol index (TPI), malic acid and increased color density, but did not modify anthocyanin concentration. In white Tempranillo, the combined action of the three factors associated with climate change modified only tartaric acid. In this latter cultivar, drought increased TPI under ambient temperature, regardless of CO2 level, when compared with full-irrigated plants. In conclusion, climate change-related factors (elevated CO2, elevated temperature and water deficit) individually (especially drought) and/or interacting affected to different extent red and white Tempranillo vegetative growth and yield. Drought combined with elevated temperatures reduced grapevine performance, and elevated CO2 mitigated such deleterious effect.
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•Naturalized grapevines selected from hyper-arid Chile were assessed as rootstocks•Syrah and Cabernet Sauvignon grafted vines were submitted to deficit irrigation•R32 rootstock ...induced higher performance through root traits in both cultivars•Major scion-driven transcriptional changes occurred at rootstock level•R32 was for near-iso / anisohydric vines as adaptive strategy to climate constrains
Viticulture is facing water deficit problems related to climate change, new extremes in heat and precipitation regimes and drought events. Rootstocks use was assessed as strategy for enhancing performance of Cabernet Sauvignon (CS) and Syrah (Sy) under water deficit. Vines were grafted onto naturalized grapevines selected from hyper-arid Chile, and compared to own-grafted and commercial Ruggeri 140. Plants were submitted to optimal (100 % ETc) and deficit (30 % ETc) irrigation throughout two seasons at field conditions. Functional traits along both seasons were determined. Water deficit reduced all growth and physiological traits especially in CS. R32 rootstock induced significantly higher values for most traits irrespective of cv and seasons associated to higher root growth. Transcriptomic analysis was further performed in both cultivars grafted over R32 rootstock by RNA-Seq, determining that gene up-regulation extent was higher in Sy. More stable transcriptional landscape was determined in CS than Sy, which might be linked to its hydric strategy. Unexpectedly, major differences in transcriptional behaviour were detected in R32 rootstock, revealing major transcriptional changes occurring at root level, suggesting scion-driven transcriptional regulation in response to stress. Finally, R32 rootstock can be considered for both near iso and anisohydric grapevines as adaptive strategy for climate constrains.
Grape (Vitis vinifera L.) seed oil was studied for physicochemical characteristics and
chemical composition. Through the gas chromatography-flame ionization (GC-FID)
process, the fatty acid ...composition in the oil was analysed, revealing that the oil is very
rich in linoleic (65.3%), linolenic (0.43%), and oleic (17.56%) acid. The physicochemical
properties of the oil were also examined, including viscosity (87.8±2.75 cP), acid value
(2.25±0.75 mg KOH/g), saponification content (185.5±7.45 mg KOH/g) and iodine value
(176.4±5.85 g I2/100 g). The results also indicated that grape seed is a health-beneficial oil
due to the high contents of polyunsaturated fatty acids. This research also provided an
important base for further investigations on the production of relevant high-value
products, such as analysis of other minor nutrients of grape seed oil originated in Vietnam
and study of the beneficial effects of grapeseed oil on human health and its application in
the cosmetic industry.
•Irrigation treatments had no impact on canopy architecture, but mechanical canopy management treatments were effective in controlling it.•Stronger plant water stress between fruit set and veraison ...reduced yield, with greater anthocyanin, tannin and total phenolics in berry; the results were confirmed in wine with greater β-damascenone.•Higher amount of precipitation at fruit set increased concentration of 3-isobutyl-2-methoxypyrazine, but the concentration of terpenes and norisoprenoids was lower.•In typical years, where no precipitation is received in the SJV of California during the season, light mechanical shoot thinning and water stress between fruit set and veraison contributed to improved berry and wine phenolics as well as reducing IBMP in wine.
A field study was conducted in north-central San Joaquin Valley of California to deduce the interactive effects of irrigation and mechanical canopy management on the phenolic composition of grape and wine, and volatile compounds of the wines produced from Syrah (Vitis vinifera L.). The irrigation treatments consisted of a grower control of 70% crop evapotranspiration (ETc) replacement (IRR-I) from anthesis to harvest, compared to a stronger plant water stress between fruit set and veraison with 50% ETc replacement, otherwise 70% ETc replacement rest of the season (IRR-II). Four canopy management treatments were crossed with the irrigation design. A control treatment was pruned by hand to 22 two-node spurs (C) with no further manipulation. Experimental canopy management treatments (CM) consisted in mechanically box pruning the vines to a 0.10m hedge combined with 3 levels of mechanically shoot thinning: heavy shoot thinning (M1), light shoot thinning (M2) and no shoot thinning (M3). In this two-year study, the irrigation treatments had no impact on the canopy architecture, but mechanization treatments were effective. However, this study reports sensitivity of canopy management to weather conditions in previous and current year, therefore to vintage effect. The irrigation treatments affected berry composition more than mechanization, and the effect was insensitive of the vintage effect. The IRR-II reduced berry weight, resulting in reduced yield and crop load in both years but greater berry anthocyanins, tannins and total phenolics. For anthocyanins, this result was also confirmed on wine. One year was characterized by higher amount of precipitation at fruit set, and in this year the concentration in 3-isobutyl-2-methoxypyrazine was higher, but the concentration of terpenes and norisoprenoids was lower, with the exception of β-damascenone that was stable between years but increased with IRR-II. In typical years, where no precipitation is received in the San Joaquin Valley from fruit set to veraison, the M2 and IRR-II method may contribute to improve berry skin and wine phenolics as well as to reducing IBMP in wine while achieving high yields. This trial showed that precipitation can modulate the impact of cultural practices on grape and wine composition, and that lower irrigation amounts do not correspond to reduced wine quality even in the semi-arid and warm conditions of Central California.
Withering processes have a strong impact on the phenolic composition of winegrapes and related wines. Even if attention has often been focused on other phenolics, a great number of studies have ...included phenolic acids because of their quantitative and qualitative modifications during dehydration-withering processes. A systematic review that provides a concise overview of the extensive literature available on this important topic is lacking.
This review identified 39 articles to answer the research question: What changes occur in phenolic acids after the withering process of winegrapes? The expected contribution of this systematic review is to have a full view of the worthwhile recent findings on these often-overlooked compounds to manage the technological process with new awareness and to find eventual weaknesses in this field to highlight new questions and research directions.
The research yielded useful results for withering and winemaking management. Phenolic acids are well represented in certain special productions to be proposed as markers of wine authenticity. Hydroxycinnamic and hydroxybenzoic acids and their derivatives are often affected differently by the withering process. Their evolution during grape withering is a complex phenomenon that is affected by many varietal and technological variables. In particular, the withering conditions applied and grape genotype play an important role in the changing amounts of phenolic acids, but there is still much to be understood, especially related to the combined effect of both factors through genetic responses to environmental stresses and their respective chemical implications.
•Phenolic acids are represented by hydroxybenzoic and hydroxycinnamic compounds•Their evolution during withering involves a complex balance of different processes•Concentration effect usually prevails in withered grapes increasing their contents•Withering conditions and genetic regulation are relevant in determining the content•Phenolic acids have been proposed as authenticity markers for icewines
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•A UV-B supplement was applied to grapevine via a new mechanical method in the field.•The UV-B supplement’s effects on grape skins and resulting wines were investigated.•Flavonols and ...antioxidant capacity increased in UV-B-supplemented skins and wines.•Six volatile organic compounds increased in wines made of UV-B-supplemented grapes.•UV-B supplementation is a new promising agricultural practice for use in vineyards.
Ultraviolet-B (UV-B) supplements have been applied to grapevine in controlled environments but not under field conditions, which would be the only way to manipulate UV-B to provide tangible agronomic benefits. Further, the effects of UV-B supplements should be investigated not only in grapes but also resulting wines, to check whether possible beneficial effects incurred by the raw material are conserved in the elaborated product. In this study, a UV-B supplement was applied to Tempranillo grapes under commercial field conditions, to test its effects on (1) the phenolic composition of grape skins and the resulting wines in two different seasons and (2) the volatile organic compounds (VOCs) of the wines. The UV-B supplement was applied mechanically, using a manufactured lamp mounted on a tractor, to make the application method more realistically viable at a crop scale.
Flavonols and antioxidant capacity, and to a lesser extent phenolic acids and flavanols, increased in UV-B-supplemented grape skins and their resulting wines, thus enhancing the quality of both components in wine production. In particular, the augmented flavonols could improve the health properties of grapes and wines, while also contributing to wine color stabilization. In addition, six VOCs were found elevated in the wines elaborated with UV-B-supplemented grapes. Following from these results, we discuss whether these changes were more likely attributable to the irradiance peaks of the supplemental UV-B than to the additional UV-B dose applied. In conclusion, we propose the mechanical application of UV-B supplements on grapevine plants at a crop scale as a new agricultural practice with promising utility, such as counteracting deficits of natural UV-B in specific locations or years.
Drought tolerance varies greatly across Vitis vinifera cultivars, depending on physiological responses and structural and morphological adaptations. In this study, responses to water stress were ...examined in three extensively cultivated varieties from Northern Italy. Over the course of two seasons, mature potted vines were subjected to a 12 or 13‐day period of water restriction. Vine water relations were investigated using measures of water potential, gas exchanges, and leaf ABA content. Leaf angle response to increasing water stress was analysed in the four cultivars as a mechanism that improves stress tolerance. Different physiological responses were observed among cultivars, suggesting a near‐isohydric water‐use strategy for Moscato and a near‐anisohydric one for Garganega, Glera and Merlot. Results of leaf ABA analysis highlighted a variability among the studied varieties, indicating higher contents and lower sensitivity to ABA for the anisohydric ones. In all varieties, a similar increase in midday leaf inclination was observed in response to decreasing stem water potentials, indicating that leaf angle adjustments may represent a common adaptive response to drought. These findings increase the understanding of the leaf physiological and structural mechanisms that contribute to water stress tolerance in grapevine, supporting a more efficient cultivar selection to cope with the expected changes in Mediterranean climate.
Grapevine leafroll is the most complex and intriguing viral disease of grapevine (
Vitis
spp.). Several monopartite closteroviruses (family
Closteroviridae
) from grapevines have been molecularly ...characterized, yet their role in disease etiology is not completely resolved. Hence, these viruses are currently designated under the umbrella term of Grapevine leafroll-associated viruses (GLRaVs). This review examines our current understanding of the genetically divergent GLRaVs and highlights the emerging picture of several unique aspects of the leafroll disease pathosystem. A systems biology approach using contemporary technologies in molecular biology, -omics, and cell biology aids in exploring the comparative molecular biology of GLRaVs and deciphering the complex network of host-virus-vector interactions to bridge the gap between genomics and phenomics of leafroll disease. In addition, grapevine-infecting closteroviruses have a great potential as designer viruses to pursue functional genomics and for the rational design of novel disease intervention strategies in this agriculturally important perennial fruit crop.
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