Methyl jasmonate foliar application to Tempranillo vineyard improved grape and wine phenolic content

Berry secondary metabolites and leaf physiological parameters are independently regulated by exogenous methyl jasmonate application in Sangiovese grapevines (Vitis vinifera L.)

The role of jasmonates as elicitor of secondary metabolites is well known, and many experiments have been conducted in grapevine to evaluate their effects on berry and wine quality. Even though most of these studies used foliar jasmonates applications, little investigations have been done to assess the effects on leaves which, in turn, may indirectly affect grape metabolism potentially involving a long distance signaling or crosstalk. In this experiment we jointly investigated the specific effect of jasmonates on grape berry secondary metabolites and leaf physiological parameters to better comprehend their elicitation mechanisms in grapevine. A 10 mM methyl jasmonate (MeJA) solution was applied during the lag-phase only on the leaves or only on the clusters and compared to an untreated control. The MeJA specifically affected leaf physiological parameters and berry metabolism in the treated area. When applied only on the leaves, gas exchange parameters and leaf efficiency were reduced, stimulating the senescence mechanisms, without affecting berry metabolism. On the contrary, MeJA applied on the clusters significantly delayed berry ripening, leading to hypothesize a re-route of the berry carbon resources through the biosynthesis of volatile organic compounds which were strongly increased, especially the monoterpenes in their glycosylated form.

Vine Foliar Treatments at Veraison and Post-Veraison with Methyl Jasmonate Enhanced Aromatic, Phenolic and Nitrogen Composition of Tempranillo Blanco Grapes

Methyl jasmonate (MeJ) is an elicitor that, when applied in the vineyard, can improve grape quality. There are several studies about the MeJ influence on red grape varieties; however, to our knowledge, there is little information about white grape varieties, specifically Tempranillo Blanco. Therefore, the aim of this work is to evaluate the effect of MeJ foliar treatments, carried out at veraison and post-veraison, on the aromatic, phenolic and nitrogen composition of Tempranillo Blanco grapes. The results showed that grape volatile compounds content increased after MeJ application, especially terpenoids, C13 norisoprenoids, benzenoids and alcohols, and, in general, mainly at post-veraison. Regarding phenolic and nitrogen compounds, their concentrations were enhanced after MeJ treatments, regardless of application time. Consequently, MeJ treatment improved grape volatile, phenolic and nitrogen composition, particularly when this elicitor was applied post-veraison. Therefore, this is a good and easy tool to modulate white grape quality.

Influence of foliar treatments with methyl jasmonate and methyl jasmonate-doped nanoparticles on nitrogen composition of Tempranillo grapes during two vintages

Nanoparticles are emerging as a cutting-edge technology to improve crop agricultural input efficiency and reduce biotic and abiotic stresses. In viticulture, nanoparticles hold promise for the sustainable application of an elicitor (methyl jasmonate, MeJ), allowing a considerable dosage reduction. Herein, the influence of the foliar application of free MeJ (10 mM) and MeJ nanoformulation (ACP-MeJ, 1 mM MeJ) on Tempranillo grape amino acids content over two vintages (2019 and 2020) was evaluated. While both MeJ treatments provided a significant increase of the amino nitrogen and yeast assimilable nitrogen in the must in 2019, there were no significant differences on these parameters in 2020. In 2019, MeJ treatment enhanced the synthesis of most of the amino acids included in this study, while ACP-MeJ promoted the formation of six amino acids. Hence, the content of total amino acids, with and without proline, was higher after applying MeJ than in the control musts. However, these values were higher for control must than for MeJ samples in 2020. The multivariable analysis confirmed that the vintage factor had a more prominent effect on the overall parameters of the musts. This strong influence of the vintage could be related to the higher rainfall in 2020.

Different response of proanthocyanidins from Vitis vinifera cv. Monastrell depending on time of elicitor application

BACKGROUND

Proanthocyanidins (PAs) are phenolic compounds present in skins and seeds of wine grapes and have great implications for plant physiology and wine quality. There are several strategies to increase PA concentration, such as application of elicitors methyl jasmonate (MeJ) and benzothiadiazole (BTH), compounds that can stimulate defence responses like phenolic compound biosynthesis in wine grapes, which have been applied mainly at veraison (beginning of ripening). We recently evaluated the application of MeJ and BTH on Vitis vinifera cv. Monastrell grapes during veraison and mid-ripening (3 weeks after veraison). Grapes treated at mid-ripening showed higher anthocyanin concentrations than those at veraison. In this trial, over two seasons, we evaluated whether time of application (veraison or mid-ripening) of MeJ and BTH on 'Monastrell' grapes is a determining factor in the biosynthesis and composition of PAs in grapes and their subsequent release into wines.

RESULTS

Application of elicitors at different ripening times produced significant differences in the PAs of 'Monastrell' grapes, since those treated at mid-ripening recorded a higher PAs concentration in skin and seeds, and then in the wines produced, compared to grapes treated at veraison.

CONCLUSION

Results suggest that despite different environmental conditions endured in each of the two seasons evaluated, application of elicitors at mid-ripening of Monastrell grapes could be used to harvest grapes with higher PA concentration, increasing the functional value of the wines, without altering their organoleptic quality. © 2022 Society of Chemical Industry.

MeJA regulates the accumulation of baicalein and other 4'-hydroxyflavones during the hollowed root development in Scutellaria baicalensis

The dried roots of Scutellaria baicalensis are important traditional Chinese medicine used to treat liver and lung inflammation. An anomalous structure, hollowed root, was discovered in perennial cultivated Scutellaria baicalensis. The presence of the hollow may change the contents of bioactive metabolites, such as baicalein, and other 4'-hydroxyflavones in Scutellaria baicalensis roots, but the relationship between the hollowed root and bioactive metabolite contents is poorly understood. In this study, we identified the anatomical structure of the hollowed root and detected differentially accumulating flavonoid metabolites and enzymes related to 4'-hydroxyflavone biosynthesis in 3-year-old roots with a hollow. We confirmed that methyl jasmonate (MeJA) induced the accumulation of 4'-hydroxyflavones and the expression of enzymes related to 4'-hydroxyflavone biosynthesis in hydroponically cultured Scutellaria baicalensis roots. The development of the hollowed root were divided into 4 stages. The 4'-hydroxyflavone contents and expression of enzymes related to 4'-hydroxyflavone biosynthesis increased synchronously with the content of MeJA during the development of hollowed root. Pathogen and programed-cell-death related genes were induced during hollowed root development. Taken together, our results provide novel insight into the importance of MeJA in the development of hollowed root and the accumulation of 4'-hydroxyflavones in Scutellaria baicalensis roots. Our results suggest that a pathogen and senescence are the two major causes for the development of hollowed root in Scutellaria baicalensis roots.

Effects of the application of forchlorfenuron (CPPU) on the composition of verdejo grapes

The application of cytokinins such as forchlorfenuron (CPPU) has been widely used in table grape varieties to increase yield and berry size. However, the potential interest of these phytoregulators in wine grapes have been scarcely analyzed. The objective of this study has been to evaluate the influence of CPPU treatment on the agronomic performance and composition of Verdejo grapes. The trial was conducted in 2021, in the Protected Designation of Origin “Rueda” (Spain). CPPU was applied using a concentration of 15 mg/L, by spraying the bunches when the berries were 5-6 mm in diameter. The photosynthesis rates and the stem water potential, measured after the application, tended to decrease in the treated plants without modify the values ​​of vine yield and vigour. The treatment significantly affected the content of soluble solids and total polyphenols of the grape must, detecting increases of 15.4% and 7%, respectively, compared to the controls. Preliminary results suggest that the application of CPPU on the bunches could improve the quality of the Verdejo grapes. The treatment would be interesting to apply in cultivation conditions where the harvest has difficulties to reach an adequate level of maturity, such as excessive vigour or too cold climate.

Application of Elicitors, as Conventional and Nano Forms, in Viticulture: Effects on Phenolic, Aromatic and Nitrogen Composition of Tempranillo Wines

The phenolic, aromatic and nitrogen composition of a wine determines its organoleptic profile and quality. Elicitors have been used as a tool to stimulate the plant’s defense systems, favoring the synthesis of secondary metabolites. In this pioneering study, the elicitor methyl jasmonate in conventional form (MeJ) and in nanoparticle form (ACP-MeJ), with a concentration ten times lower, was applied in a Tempranillo vineyard over two seasons. The phenolic, nitrogen and volatile composition and the sensory properties of the MeJ-based wines were determined. The results showed that the effects of foliar applications of MeJ modify the wine composition. Thus, although the total concentration of most of the groups of phenolic compounds was not altered, several compounds, such as petunidin-3-glucoside, quercetin-3-glucoside, epigallocatechin and most of the stilbenes, increased, in both years, in the treated wines. Amino acids were influenced differently in each of the years studied, and volatile compounds generally did not improve in the treated wines. However, the ACP-MeJ wines were the best rated by the tasters, highlighting their equilibrium on the taste and their genuineness and odor quality. Therefore, foliar applications of ACP-MeJ can be considered a useful tool to improve wine quality.

Effect of Methyl Jasmonate and Methyl Jasmonate Plus Urea Foliar Applications on Wine Phenolic, Aromatic and Nitrogen Composition

Foliar application has been studied to enhance grape composition and, therefore, wine quality. This work examined, for first time, the effects of foliar applications of methyl jasmonate (MeJ) and methyl jasmonate plus urea (MeJ+Ur) to Tempranillo vineyard on wine phenolic, aromatic and nitrogen composition over two vintages (2019 and 2020). A reduction in alcoholic degree was observed in MeJ and MeJ+Ur wines. The effect of foliar treatments was season-dependent. MeJ and MeJ+Ur wines were characterized, in the first vintage, by a higher content of total acylated anthocyanins, but a low content of total esters, alcohols and acids when compared with control wines. MeJ+Ur wines presented a higher total amino acids content than control and MeJ wines. However, in the second vintage, MeJ and MeJ+Ur wines presented an increase in some non-acylated anthocyanins, but only MeJ+Ur treatment increased the total content of flavonols, flavanols, hydroxycinnamic acids, stilbenes and total amino acids when compared with control wines. MeJ wines presented a low content of esters and acids, whereas MeJ+Ur did not show differences with control wines. Overall, the effect of MeJ+Ur foliar treatment was greater than the effect of MeJ application in order to improve the wine chemical composition.

Effects of Methyl Jasmonate and Nano-Methyl Jasmonate Treatments on Monastrell Wine Volatile Composition

The application of methyl jasmonate (MeJ) as an elicitor to enhance secondary metabolites in grapes and wines has been studied, but there is little information about its use in conjunction with nanotechnology and no information about its effects on wine volatile compounds. This led us to study the impact of nanoparticles doped with MeJ (Nano-MeJ, 1mM MeJ) on the volatile composition of Monastrell wines over three seasons, compared with the application of MeJ in a conventional way (10 mM MeJ). The results showed how both treatments enhanced fruity esters in wines regardless of the vintage year, although the increase was more evident when grapes were less ripe. These treatments also achieved these results in 2019 in the cases of 1-propanol, ß-phenyl-ethanol, and methionol, in 2020 in the cases of hexanol and methionol, and in 2021, but only in the case of hexanol. On the other hand, MeJ treatment also increased the terpene fraction, whereas Nano-MeJ, at the applied concentration, did not increase it in any of the seasons. In summary, although not all families of volatile compounds were increased by Nano-MeJ, the Nano-MeJ treatment generally increased the volatile composition to an extent similar to that obtained with MeJ used in a conventional way, but at a 10 times lower dose. Therefore, the use of nanotechnology could be a good option for improving the quality of wines from an aromatic point of view, while reducing the necessary dosage of agrochemicals, in line with more sustainable agricultural practices.

Two-Step PEF Processing for Enhancing the Polyphenol Concentration and Decontaminating a Red Grape Juice

This study’s aim is to evaluate Pulsed Electric Fields (PEF) technology as an alternative method for the processing of red grape juice. For this purpose, two PEF treatments were applied: first to grapes for polyphenol enrichment of the juice, and subsequently for microbial decontamination of the obtained juice. Juice obtained from PEF-treated grapes (5 kV/cm, 63.4 kJ/kg) had the polyphenol content 1.5-fold higher and colour intensity two times higher of control juices by spectrophotometric measurement (p ≤ 0.05). A subsequent decontamination treatment by PEF (17.5 kV/cm and 173.6 kJ/kg) achieved inactivation of the present microbiota (yeasts, moulds, and vegetative mesophilic bacteria) below detection level (<30 CFU/mL). Furthermore, PEF-treated juices were microbiologically stable up to 45 days, even at abusive refrigeration storage temperatures (10 °C). PEF juice quality and sensory characteristics were similar to a fresh juice; they were neither affected by the PEF decontamination treatment, nor by storage time and temperature. Results obtained in this study demonstrate the considerable potential of PEF for the production of a polyphenol-enriched and microbially stabilized red grape juice as a unique and sustainable alternative for the juice industry, while avoiding enzymatic and heat treatments.

Near-harvest application of methyl jasmonate affected phenolic content and antioxidant properties in "Thompson Seedless" grape

The influence of methyl jasmonate (MJ) preharvest treatment was investigated on some polyphenols and antioxidant systems in the "Thompson Seedless" table grape. The clusters were sprayed in the vineyard 2 days before harvest with 0, 1, 5, and 10 mM MJ. After picking, berries were stored for 6 days at 15°C, simulating marketing conditions. Total phenols and flavonoids were affected by MJ treatment, especially at 10 mM concentration, whereas total tannins were found to be unchanged. Antioxidant activity of the treated skin was noticeably higher compared with the control, together with PAL and POD activity. Although MJ had little effect on catechin and epicatechin, the levels of quercetin and rutin were noticeable. In addition, 5 and 10 mM MJ exerted a pronounced effect on transresveratrol content. These data showed that a single preharvest application close to the harvest time could be an effective treatment to promote the antioxidant properties of the grape.

Biogenic volatile organic compounds in the grapevine response to pathogens, beneficial microorganisms, resistance inducers, and abiotic factors

The synthesis of volatile organic compounds (VOCs) in plants is triggered in response to external stimuli, and these compounds can migrate to distal tissues and neighbouring receivers. Although grapevine VOCs responsible for wine aroma and plant-insect communications are well characterized, functional properties of VOCs produced in response to phytopathogens, beneficial microorganisms, resistance inducers, and abiotic factors have been less studied. In this review, we focused on the emission patterns and potential biological functions of VOCs produced by grapevines in response to stimuli. Specific grapevine VOCs are emitted in response to the exogenous stimulus, suggesting their precise involvement in plant defence response. VOCs with inhibitory activities against pathogens and responsible for plant resistance induction are reported, and some of them can also be used as biomarkers of grapevine resistance. Likewise, VOCs produced in response to beneficial microorganisms and environmental factors are possible mediators of grapevine-microbe communications and abiotic stress tolerance. Although further functional studies may improve our knowledge, the existing literature suggests that VOCs have an underestimated potential application as pathogen inhibitors, resistance inducers against biotic or abiotic stresses, signalling molecules, membrane stabilizers, and modulators of reactive oxygen species. VOC patterns could also be used to screen for resistant traits or to monitor the plant physiological status.

A Jasmonate-Induced Defense Elicitation in Mature Leaves Reduces Carbon Export and Alters Sink Priority in Grape (Vitis vinifera Chardonnay)

This work aims to understand how Vitis vinifera (Chardonnay) vines prioritise the export and distribution of recently fixed photoassimilate between root tissue, fruit, and defence, following the elicitation of a defence response. Jasmonic acid (JA) and its methyl ester, MeJA, are endogenous plant hormones, known collectively as jasmonates, that have signalling roles in plant defence and consequently are often used to prime plant defence systems. Here, we use exogenous jasmonate application to mature source leaves of Chardonnay grapevines to elucidate the prioritisation strategy of carbon allocation between plant defence and growth. Our results demonstrate that jasmonate application to Chardonnay leaves can elicit a defence response to Botrytis cinerea, but the effect was localised to the jasmonate-treated area. We found no evidence of a systemic defence response in non-treated mature leaves or young growing tissue. JA application reduced the photosynthetic rate of the treated leaf and reduced the export rate of recently fixed carbon-11 from the leaf. Following JA application, a greater proportion of available recently fixed carbon was allocated to the roots, suggesting an increase in sink strength of the roots. Relative sink strength of the berries did not change; however, an increase in berry sugar was observed seven days after JA treatment. We conclude that the data provide evidence for a “high sugar resistance” model in the mature treated leaves of the vine, since the export of carbon was reduced to ensure an elevated defence response in the treated leaf. The increase in berry sugar concentration seven days after treatment can be explained by the initial prioritisation of a greater portion of the exported carbon to storage in the roots, making it available for remobilisation to the berries once the challenge to defence had passed.

Methyl jasmonate elicits distinctive hydrolyzable tannin, flavonoid, and phyto-oxylipin responses in pomegranate (Punica granatum L.) leaves

Transcriptome and biochemical analyses suggested that, while suppression of multiple flavonoids and anthocyanins occurs at least partially at the transcriptional level, increased biosynthesis of non-jasmonate phyto-oxylipins is likely controlled non-transcriptionally. Methyl jasmonate (MeJA) produced in plants can mediate their response to environmental stresses. Exogenous application of MeJA has also shown to activate signaling pathways and induce phytoalexin accumulation in many plant species. To understand how pomegranate plants respond biochemically to environmental stresses, metabolite analysis was conducted in pomegranate leaves subjected to MeJA application and revealed unique changes in hydrolyzable tannins, flavonoids, and phyto-oxylipins. Additionally, transcriptome and real-time qPCR analyses of mock- and MeJA-treated pomegranate leaves identified differentially expressed metabolic genes and transcription factors that are potentially involved in the control of hydrolyzable tannin, flavonoid, and phyto-oxylipin pathways. Molecular, biochemical, and bioinformatic characterization of the only lipoxygenase with sustained, MeJA-induced expression showed that it is capable of oxidizing polyunsaturated fatty acids, though not located in the subcellular compartment where non-jasmonate (non-JA) phyto-oxylipins were produced. These results collectively suggested that while the broad suppression of flavonoids and anthocyanins is at least partially controlled at the transcriptional level, the induced biosynthesis of non-JA phyto-oxylipins is likely not regulated transcriptionally. Overall, a better understanding of how pomegranate leaves respond to environmental stresses will not only promote plant health and productivity, but also have an impact on human health as fruits produced by pomegranate plants are a rich source of nutritional compounds.

Effects of Water Deficit Irrigation on Phenolic Composition and Antioxidant Activity of Monastrell Grapes under Semiarid Conditions

The high phenolic compound content of grapes makes them an important source of natural antioxidants, among other beneficial health properties. Vineyard irrigation might affect berry composition and quality. Regulated deficit irrigation (RDI) is a widely used strategy to reduce the possible negative impact of irrigation on grapes, improving grape composition and resulting in water savings. Monastrell grapevines (Vitis vinifera L.) grown in eastern Spain were subjected to two water regime strategies: rainfed (non-irrigation) and RDI. The content of anthocyanins, flavonols, flavanols, hydroxybenzoic and hydroxycinnamic acids, and stilbenes was determined by HPLC and was related with total phenolic content and three antioxidant activity methods (ABTS, DPPH, and ORAC). The study aimed to evaluate and compare the phenolic composition and antioxidant potential of Monastrell grapes. The rainfed regime concentrated grapes in terms of phenolic compounds. Thus, total content of anthocyanins, flavonols, flavanols, hydroxybenzoic acids, and total phenols were higher in the rainfed grapes than in the RDI ones. Besides, the rainfed grapes doubled their antioxidant potential with respect to the RDI grapes with the ORAC method. Total phenolic content and antioxidant activity by ORAC assay positively correlated with most of the total phenolic compounds analyzed. This study demonstrates how field practices can modulate final grape composition in relation to their antioxidant activity.

Chitosan-Phenylalanine Nanoparticles (Cs-Phe Nps) Extend the Postharvest Life of Persimmon (Diospyros kaki) Fruits under Chilling Stress

There are high levels of damage imposed on persimmon fruit postharvest, especially after storing it in cold storage, which causes chilling injury (CI). To reduce this stress on the fruit, the conventional way is to use chemical treatments. Since there is a limitation in the use of chemical materials, it is necessary to apply non-harmful treatments to decrease chilling injury and maintain the quality of persimmon in cold storage. The aim of this study is to investigate the effects of chitosan-loaded phenylalanine nanoparticles (Cs-Phe NPs) (2.5 and 5 mM) on physiochemical and quality factors of persimmon (Diospyros kaki) during 45 days of storage at 4 °C (38 °F) and evaluate the impact of Cs-Phe NPs on the preserving quality in order to reduce the chilling injury of this fruit. The experiment was conducted using a completely randomized design with three replications. Treatments were applied at 15, 30, and 45 days after storage at 4 °C with ≥90% relative humidity. The size of Cs-Phe NPs was less than 100 nm, approximately. The results showed that application of 5 mM of Cs-Phe NPs delayed the negative effects of chilling stress and enhanced antioxidant capacity, firmness, and total soluble solids of persimmon fruit. Lower H2O2 and malonaldehyde (MDA) accumulation along with higher soluble tannin and total carotenoid accumulation in persimmon fruit treated with 5 mM Cs-Phe NPs was also observed. Fruit coated using Cs-Phe NPs in both concentrations (2.5 and 5 mM) showed the highest antioxidant enzyme activity for superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and the lowest for polyphenol oxidase (PPO) and chilling injury during storage. According to our results, 5 mM of Cs-Phe NPs could be considered as the best treatment under chilling-stress conditions.

Methyl Jasmonate Applications in Viticulture: A Tool to Increase the Content of Flavonoids and Stilbenes in Grapes and Wines

Recently, the interest in methyl jasmonate (MeJ) has increased in viticulture due to its effects on the synthesis of phenolic secondary metabolites in grapes, especially of anthocyanins, flavonols, and stilbenes derivatives, naturally occurring or synthesized, in berries in response to MeJ application to grapevines. These metabolites help to define sensory characteristics of wines by contributing to their color, flavor and mouthfeel properties, and to derive potential beneficial health effects due to their consumption. This review offers an overview of the importance of these phenolic compounds in grape and wine quality, in association with the MeJ supplementation to grapevines, and also considers their natural biosynthesis in grapes. On the other hand, this review describes the adaptation mechanisms induced after the grapevine elicitation. In addition, this report addresses the effects of MeJ over other aspects of Vitis immunity and its association with phenolic compounds and summarizes the recently published reports about the effects of exogenous MeJ applications to grapevines on grape and wine quality.

Application of Elicitors in Two Ripening Periods of Vitis vinifera L. cv Monastrell: Influence on Anthocyanin Concentration of Grapes and Wines

In recent years, it has been demonstrated that the application of elicitors such as methyl-jasmonate (MeJ) and benzothiadiazole (BTH) to wine grapes can increase their phenolic and aromatic compounds if they are treated at the beginning of ripening (veraison). However, the veraison period is short, and it is not always possible to apply the treatments in a few days. Therefore, it would be of great interest to optimize the moment of elicitor application or extend the treatment period. The aim of this paper was to analyze during two consecutive years (2016–2017) the foliar application of MeJ, BTH, and a combination of both, during two different ripening periods of Monastrell grapes (veraison and mid-ripening), and determine the more appropriate moment to increase the concentration of anthocyanins. To carry out this aim, analysis of anthocyanins by HPLC in grapes and wines was mainly performed. The most suitable period for the application of MeJ, BTH, and MeJ + BTH was at mid-ripening, since the grapes showed a greater accumulation of anthocyanins at harvest. However, the MeJ + BTH treatment applied during veraison also obtained similar results, which would allow extending the application period if necessary. However, the increase in the anthocyanin content of grapes was not reflected in all the wines, which may have been due to reinforcement of the skin cell wall as a result of the application of elicitors. Further analysis is needed to improve the maceration process of the Monastrell grapes and the extraction of the anthocyanins that were increased by the treatments applied in the vineyard.

Three Types of Elicitors Induce Grapevine Resistance against Downy Mildew via Common and Specific Immune Responses

Three recognized plant defense stimulators (PDS), methyl jasmonate (MeJA), benzothiadiazole (BTH) and phosphonates (PHOS), were sprayed on grapevine Vitis vinifera cuttings and conferred resistance to the biotrophic pathogen Plasmopara viticola. The effects on molecular defense-related genes and polyphenol content (stilbenes and flavanols) were revealed at 6 and 8 days post-elicitation. The transcript accumulation was consistent with the signaling pathway specific to the elicitor, salicylic acid for BTH, and jasmonic acid for MeJA, with some cross-talks. PHOS tended to modulate the defense responses like BTH. Moreover, in response to a downy mildew inoculation, the leaves pre-treated with PHOS and BTH overproduced pterostilbene, and after MeJA treatment, piceids and ε-viniferin, compared to uninoculated elicitor-treated leaves. These results provide evidence of the different modes of action of PDS and their role in sustainable viticulture.

Ethephon foliar application: Impact on the phenolic and technological Tempranillo grapes maturity

In recent years, there has been increasing concern about the impact of climate change on viticulture, in particular regarding its influence on grape maturity and quality. Extensive research has shown that the rise of temperatures during grape ripening accelerates the accumulation of sugars while reducing the synthesis of phenolic and aromatic compounds. The aim of this study was to investigate whether the foliar application of the plant growth regulator ethephon might delay technological grape maturity and increase grape phenolic content, improving wine quality. For this, different concentrations of ethephon were applied during two vintages to the Tempranillo grape variety at the onset of veraison. Results showed that grape sugar accumulation was delayed in one of the two vintages, whereas the treatment favored the accumulation of phenolic compounds in both vintages. In conclusion, the application of ethephon at the onset of veraison to Tempranillo grapevines helped to couple grape phenolic and technological maturity, leading to more balanced wines, either by delaying sugar accumulation or by enhancing the synthesis of anthocyanins and phenolic compounds. PRACTICAL APPLICATION: Due to the current climate change, phenolic maturity of grapes does not match with their technological maturity, which means that harvested grapes are usually very sweet but without enough color and aroma. The foliar application of the plant growth regulator-ethephon-delays technological grape maturity and increases grape phenolic content, improving wine quality and creating wines that are more balanced.

Oenological potential and health benefits of Chinese non-Vitis vinifera species: An opportunity to the revalorization and to breed new varieties

The wine industry is focused on the producing wine mostly from European grapevine varieties (Vitis vinifera L.). China has experienced a significant growth of the vineyard surface, based on the cultivation of these grapevine varieties. Currently, China has become one of the countries with the largest surface of planted vineyards in the world. In the last years, there has been a trend to oenologically and viticulturally revalorize certain autochthonous grapevine species. China holds a great diversity of Vitis species, which are being the focus of study. This could be an important alternative for the diversification of wine production, providing new products with a strong identity. Additionally, the varietal homogenization has increased the vineyard genetic vulnerability in relation to the emergence of grapevine diseases and their resistance to chemical fungicides. In this way, non-Vitis vinifera species are characterized by having a high resistance to a wide range of biotic and abiotic factors, which can bring an opportunity to breed new varieties. However, there is little available information about the oenological potential of these species, which makes it a current interesting topic. Therefore, this review aims to summarize the oenological potential of non-Vitis vinifera species found in China, discussing their potential effects on human health and thus, to propose some Chinese wild grapes for their use in breeding programs.

Foliar-sprayed manganese sulfate improves flavonoid content in grape berry skin of Cabernet Sauvignon (Vitis vinifera L.) growing on alkaline soil and wine chromatic characteristics

Flavonoids are key determinants of grape quality and wine color. Grapevines growing in alkaline soil are prone to manganese deficiency, which can decrease the contents of secondary metabolites, including flavonoids. We determined the effects of a foliar Mn treatment (MnSO₄·H₂O) of Cabernet Sauvignon grapevines (V. vinifera L.) growing in alkaline soil on the flavonoid contents in grape skin, and the quality of wine. The Mn treatments were applied in 2017 and 2018, and tended to increase the grape sugars, berry weight, and the contents of phenolic compounds from veraison until harvest. The Mn treatments increased the amounts of acetylated, methylated, and total anthocyanins, as well as the total flavonol contents in grape berry skin at harvest. The wines prepared from these grapes had a higher color intensity than those prepared from grapes from control vines. Foliar-applied MnSO₄·H₂O can promote flavonoid biosynthesis in grape berries, and improve the color of wine.

Phenolic composition of Tempranillo Blanco (Vitis vinifera L.) grapes and wines after biostimulation via a foliar seaweed application

BACKGROUND

Seaweeds are defined as novel elicitors in many crops, allowing the synthesis of secondary metabolites to be triggered in different plant tissues. Currently, the phenolic composition of Tempranillo Blanco grapes and wines is unreported. The present study aimed to investigate the effects of an Ascophyllum nodosum seaweed extract applied to Tempranillo Blanco grapevines, at low (Ld) and high (Hd) dosages, on grape and wine phenolic compounds during two consecutive seasons (2017-2018).

RESULTS

The results obtained showed that catechin was the most abundant phenolic compound in Tempranillo Blanco grapes and wines. Season affected the weight of 100 berries and some enological parameters. Catechin and flavonols concentrations in grapes were increased after Hd application to grapevines, independently of season. The concentration of hydroxycinnamic and hydroxybenzoic acids in wines was affected by vintage, probably as a result of oxidation reactions, as well as pinking phenomena, whereas the stilbenes content in wines was conditioned by the affect of cryptogamic diseases in grapes.

CONCLUSION

Seaweeds might act as an elicitor of several phenolic compounds in grapes, enhancing the content of some phenolic compounds in wines. © 2019 Society of Chemical Industry.

LC-MS untargeted approach showed that methyl jasmonate application on Vitis labrusca L. grapes increases phenolics at subtropical Brazilian regions

INTRODUCTION

Vitis labrusca L. grapes are largely cultivated in Brazil, but the tropical climate negatively affects the phenols content, especially anthocyanin. According to the projections of the incoming climatic changes, the climate of several viticulture zone might change to tropical. Therefore, researches are focusing on increasing grape phenols content; with methyl jasmonate application (MeJa) is considered a good alternative.

OBJECTIVES

The aim was to investigate with an untargeted approach the metabolic changes caused by the MeJa pre-harvest application on two Vitis labrusca L. cultivars grapes, both of them grown in two Brazilian regions.

METHODS

Isabel Precoce and Concord grapes cultivated under subtropical climate, in the south and southeast of Brazil, received MeJa pre-harvest treatment. Grape metabolome was extracted and analyzed with a MS based metabolomics protocol by UPLC-HRMS-QTOF.

RESULTS

Unsupervised data analysis revealed a clear separation between the two regions and the two cultivars, while supervised data analysis revealed biomarkers between the MeJa treatment group and the control group. Among the metabolites positively affected by MeJa were (a) flavonoids with a high degree of methylation at the B-ring (malvidin and peonidin derivatives and isorhamentin) for Isabel Precoce grapes; (b) glucosides of hydroxycinnamates, gallocatechin, epigallocatechin and cis-piceid for Concord grapes; and (c) hydroxycinnamates esters with tartaric acid, and procyanidins for the Southeast region grapes.

CONCLUSION

These results suggest that MeJa can be used as elicitor to secondary metabolism in grapes grown even under subtropical climate, affecting phenolic biosynthesis.

Chitosan Upregulates the Genes of the ROS Pathway and Enhances the Antioxidant Potential of Grape (Vitis vinifera L. 'Touriga Franca' and 'Tinto Cão') Tissues

Chitosan is an environmentally-friendly active molecule that has been explored for numerous agricultural uses. Its use in crop protection is well-known, however, other properties, such as bioactivity, deserve attention. Moreover, the modes of actions of chitosan remain to be elucidated. The present study assessed the levels of total phenolic compounds, the antioxidant potential, and the expression of reactive oxygen species (ROS) scavenging genes in the berries (skins and seeds), leaves, cluster stems, and shoots upon chitosan application on two red grapevine varieties (Touriga Franca and Tinto Cão). The application of chitosan on the whole vine before and after veraison led to the increased levels of polyphenols, anthocyanins, and tannins in Tinto Cão berries, and polyphenols and tannins in Touriga Franca berries, respectively. CUPric Reducing Antioxidant Capacity (CUPRAC) and Ferric Reducing Antioxidant Power (FRAP) assays indicated an increase in the antioxidant potential of berries. With the exception of ascorbate peroxidase (APX), all the ROS pathway genes tested, i.e., iron-superoxide dismutase (Fe-SOD), copper-zinc-superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione reductase (GR), glutaredoxin (Grx), respiratory burst oxidase (Rboh), amine oxidase (AO), peroxidase (POD) and polyphenol oxidase (PPO), were found up-regulated in chitosan-treated berries. Results from the analyses of leaves, stems, and shoots revealed that chitosan not only induced the synthesis of phenolic compounds but also acted as a facilitator for the transfer of polyphenols from the leaves to the berries.

Pre-harvest methyl jasmonate treatments increase antioxidant systems in lemon fruit without affecting yield or other fruit quality parameters

BACKGROUND

Jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA) are hormones involved in the regulation of many processes in plants and act (when applied as a post- or pre-harvest treatment) to increase fruit bioactive compounds with antioxidant potential. However, there is no literature available regarding the effect of pre-harvest MeJA treatment on lemon fruit antioxidant systems, which was the aim of the present study.

RESULTS

MeJA treatment (0.1, 0.5 and 1.0 mmol L^-1 ) increased antioxidant compounds, such as phenolics, in the juice and flavedo of 'Fino' and 'Verna' lemons at harvest, with the most effective concentration being 0.1 mmol L^-1 in both cultivars. In addition, catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities were also increased by MeJA treatment, with the highest increases being also found with 0.1 mmol L^-1 . The increases in APX and CAT were maintained from one treatment to another during fruit development on the tree, whereas the increase on POD disappeared after 8-10 days of each treatment. For both antioxidant systems, the highest increases were found in lemon harvested at the commercial ripening stage. By contrast, crop yield, fruit ripening process and quality parameters were generally not affected by MeJA treatment.

CONCLUSION

Preharvest MeJA treatment could be a useful tool for increasing antioxidant potential and the health beneficial effects of lemon fruit consumption, given the relationship between these properties and phenolic content. Moreover, the increased concentration of phenolics and the activity of antioxidant enzymes in the flavedo of MeJA treated fruit could increase lemon tolerance to chilling injury and decay during postharvest storage. © 2019 Society of Chemical Industry.

Production of Stilbenes in Callus Cultures of the Maltese Indigenous Grapevine Variety, Ġellewża

The production of secondary metabolites in tissue culture has been considered as an alternative to the cultivation and harvesting of crops intended for this purpose. The present study was aimed at the growth of callus and production of polyphenolic compound of callus derived from a Maltese indigenous grapevine variety, Ġellewża. Callus was inoculated onto plant growth regulators-enriched Murashige Skoog media (MSm) to determine whether polyphenols are produced in vitro as well as to determine the best combination of plant growth regulators needed for the production of these metabolites. From results obtained, it was observed that the best callus production was obtained by auxin-enriched MSm. In fact, indole acetic acid and indole acetic acid /6-benzyl aminopurine enhanced biomass accumulation (3.04 g and 3.39 g) as opposed to the others (<1.97 g). On the other hand, parameters showing the presence of flavonoids (tonality, 3.80), particularly anthocyanins (24.09 mg/kg) and total polyphenols (1.42 mg/g), were optimum in the presence of cytokinins, particularly 6-benzyl aminopurine. Analysis for single polyphenols revealed a high amount a particular stilbene: polydatin (glucoside of resveratrol). Resveratrol and other typical polyphenols, found in mature berries, were also found in significant quantities, while the other polyphenolic compounds were found in minimal quantities. This is the first study to describe the production and composition of polyphenols in Ġellewża callus cultures. From the results obtained, it can be seen that this grape tissue is an excellent alternative for the production of polyphenols from the stilbene group, which can be upscaled and exploited commercially.

A review of the use of biostimulants in the vineyard for improved grape and wine quality: effects on prevention of grapevine diseases

Foliar application of biostimulants (including resistance inducers or elicitors) in the vineyard has become an interesting strategy to prevent plant diseases and improve grape quality on the grapevine. This also represents a partial alternative to soil fertilisation, avoiding some of the negative effects to the environment from leaching of nutrients into the groundwater. The foliar applications that most promote the synthesis of secondary metabolites in grape berries are treatments with nitrogen, elicitors, other biostimulants, and waste from the agricultural industry. However, the impact of their use in the vineyard depends on a number of conditions, including mainly the type of compound, application rate, timing and number of applications, and cultivar. This review thus summarises the influence of biostimulants as foliar applications to grapevines on grape amino acids and their phenolic and volatile concentrations, to define the most important factors in their effectiveness. © 2018 Society of Chemical Industry.

Biochemical and molecular effects of yeast extract applications on anthocyanin accumulation in cv. Sangiovese

The effect of biotic and abiotic elicitors on the secondary metabolism in grapevine is gaining a lot of interest, as it has been shown that they can increase the accumulation of phenolic compounds and anthocyanins in particular. The aim of this research was to verify the biochemical and molecular effects of the application of LalVigne™ MATURE (Lallemand, St. Simon, France), 100% inactivated natural yeast (Saccharomyces cerevisiae) on the anthocyanin accumulation in potted plants of Sangiovese. In both years, LVM plants did not differ from C in technological ripening at harvest. A significant increase in anthocyanin concentration and the expression of genes involved in their biosynthesis was found in 2016 in LVM grapes compared to C, while in 2017, a year with extremely warm temperatures, the anthocyanins of C and LVM were comparable, despite a slight increase in LVM after the second treatment.

Foliar applications of iron promote flavonoids accumulation in grape berry of Vitis vinifera cv. Merlot grown in the iron deficiency soil

Flavonoids are important compounds for grape and wine quality. Foliar fertilization with iron compounds has been reported to have a substantial impact on grape composition in the grapevines growing in calcareous soil. However, much less is known about its real impact on flavonoid composition. In the present study, Ferric ethylenediamine di (O-hydroxyphenylacetic) acid (Fe-EDDHA) was foliar applied to Merlot (Vitis vinifera L.) grapevines growing in calcareous soil over two consecutive vintages in order to study its effect on grape flavonoid composition. Fe-EDDHA foliar supply tended to increase grape sugar, anthocyanin and flavonol content, decrease acid content and enhance the juice pH when compared to the control. Principal component analysis showed that the vintage also had influence on grape quality. The results suggested that Fe-EDDHA foliar application had an enhancement effect on grape secondary metabolism, and the effect increased the nutritional value of the consequent grapes and wines.

Influence of methyl jasmonate foliar application to vineyard on grape volatile composition over three consecutive vintages

An alternative to improve grape quality is the elicitor application to the vineyard due its implication to induce defense mechanisms involved in the synthesis of secondary metabolites. There are few studies about the influence of elicitors on grape volatile composition. The aim of this work was to investigate the influence of methyl jasmonate (MeJ) foliar application to Tempranillo grapevines on grape aroma composition over three consecutive vintages. In the first vintage, MeJ treatment improved p-cymene, methyl jasmonate, and hexanal synthesis, and degraded 2-hexen-1-ol acetate, (Z)-3-hexen-1-ol, and n-hexanol. In the second season, the content of several terpenes, β-damascenone, methyl jasmonate, esters, benzenoids and (Z)-3-hexen-1-ol was diminished after MeJ application. In the third vintage, the synthesis of several volatile compounds considered positive contributors for grape aroma was improved by MeJ application. In conclusion, the effect of MeJ foliar application on grape volatile content was mainly dependent on the vintage.

Elicitor and nitrogen applications to Garnacha, Graciano and Tempranillo vines: effect on grape amino acid composition

BACKGROUND

Elicitors and nitrogen foliar applications to vineyards could regulate grape nitrogen composition, which has an important effect on grape and wine quality. Thus the aim of this research was to study the effect of foliar elicitor treatments, methyl jasmonate (MeJ) and yeast extract (YE), and foliar nitrogen applications, urea (Ur) and phenylalanine (Phe), to Garnacha, Graciano and Tempranillo vines on grape amino acid composition.

RESULTS

The results showed that elicitor and nitrogen foliar applications to Garnacha and Tempranillo grapevines decreased the must amino acid concentration. However, Phe application to these two grapevines increased the must Phe content. The treatments applied to Graciano grapevines barely effected the grape amino acid content. According to the percentage of variance attributable, the variety had a higher impact on the must amino acid composition than the treatments and their interaction, except in certain amino acids such as Phe.

CONCLUSION

The influence of elicitor and nitrogen foliar applications to grapevines on grape amino acid concentration was strongly conditioned by the variety. © 2017 Society of Chemical Industry.

Evaluation of Grenache, Graciano and Tempranillo grape stilbene content after field applications of elicitors and nitrogen compounds

BACKGROUND

Stilbenes have a significant biological activity and are one of the most important non-flavonoid contributors to grape and wine health-related properties. The accumulation of this class of compounds could be favored by viticultural practices such as the application of biostimulants. However, stilbene concentration also depends on several factors, including, for example, grape variety. Therefore, the aim of this work was to study the influence of foliar treatments carried out with elicitors (methyl jasmonate (MeJ) and a commercial foliar spray (YD)) and nitrogen compounds (phenylalanine and urea) on the grape stilbene composition of three varieties: Grenache, Graciano and Tempranillo. An ultra-high-pressure liquid chromatographic methodology was validated for stilbene determination.

RESULTS

Results showed that, despite the huge influence of the grape variety, YD significantly improved stilbene composition in Grenache and Graciano, while MeJ increased the stilbene content in Graciano and Tempranillo. As for the nitrogen treatments, phenylalanine significantly increased the stilbene concentration in Graciano, while urea treatment increased it in Tempranillo. However, the application of elicitors had a greater effect than the nitrogen compounds.

CONCLUSION

Overall, the foliar application of the elicitors could be a suitable practice for increasing the amount of stilbenes in grape and, therefore, its nutraceutical properties. © 2017 Society of Chemical Industry.

Characterization of phenolic composition in Carignan noir grapes (Vitis vinifera L.) from six wine-growing sites in Maule Valley, Chile

BACKGROUND

Among Chilean varieties, Carignan noir has had a major resurgence due to its rediscovered wine quality potential. For this, the aim of this study was to characterize phenolic composition of grapes grown in six sites from the Maule Valley.

RESULTS

The data showed that myricetin-3-glc and catechin were the most important flavonol and flavanol, respectively. Anthocyanin and flavonol composition was correlated with biologically effective degree days, exhibiting a relationship with grape maturity. Flavanol and hydroxycinnamic acid composition was inversely correlated to the average maximum temperature of the warmest month, showing that their synthesis is favored by cooler temperatures during the warmest month.

CONCLUSION

These results have enological and viticultural interest for grape growers as vineyard site selection for this cultivar can confer differentiable attributes in terms of grape composition and quality. On the other hand, understanding the effects of climate on the synthesis of phenolic compounds may be useful for managing the vineyards with the aim of improving grape quality. © 2017 Society of Chemical Industry.

Preharvest Application of Methyl Jasmonate as an Elicitor Improves the Yield and Phenolic Content of Artichoke

The effects of methyl jasmonate (MeJa) treatment as an elicitor of artichoke plants [Cynara cardunculus var. scolymus (L.) Fiori] on the yield and quality attributes of artichokes, especially those related to individual phenolic content and antioxidant activity, at two harvest dates and along storage were analyzed in this research. Plants treated gave a higher yield of artichokes in comparison to control plants, with 0.55 kg more per plant. MeJa treatment also increased artichoke quality and phenolic content in the edible fraction at harvest and during storage at 2 °C for 28 days as a result of the accumulation of hydroxycinnamic acids and luteolin derivatives. In addition, antioxidant activity was enhanced by MeJa treatment and correlated with the total phenolic content. Results suggest that MeJa foliar application could be a simple and practical tool to improve the yield and phytochemical content on artichokes, with elicitation being a cheap and environmentally friendly procedure to improve the health-beneficial effects of artichoke consumption.

Evaluation of Tempranillo and Albariño SO2-free wines produced by different chemical alternatives and winemaking procedures

In this work physical and chemical alternatives to produce SO₂ free wines are shown. The use of inactive yeast strains enriched in glutathione, chitosan, dimethyldicarbonate and different hydrolysable and condensed tannins were assessed in Tempranillo and Albariño wines. The time of addition, mixtures of additives and the use of inert gases were evaluated. In general, no significant differences on the sensory quality were shown when compared sulphited and non-sulphited wines. Both physical and chemical treatments were more effective for Tempranillo wines. In the two studied vintages, non-sulphited Tempranillo wines were better valuated than controls, even when wines were produced only using the application of inert gases. No differences were observed when argon was used instead of carbon dioxide as inert gas. Mixtures of seed and skin tannins with inactive dry yeast enriched in glutathione were the most effective treatments. This work may help winemakers to elaborate healthier wines meeting the current consumer demands.

Elicitation with methyl jasmonate supported by precursor feeding with phenylalanine: Effect on Garnacha grape phenolic content

Recent works showed that elicitation, supported by precursor feeding, could be a strategy to increase phenolic content. However, these studies have never been conducted in viticulture. This strategy could be of greater interest in Garnacha, a grape variety characterized by its low phenolic content. Therefore, this work studied elicitation with methyl jasmonate (MeJ), supported by precursor feeding with phenylalanine (Phe), in order to improve Garnacha grape phenolic content. Results showed that Phe+MeJ treatment did not improve phenolic content to a greater extent than the corresponding individual treatments. Overall, the greatest improvement was obtained with MeJ application, followed by Phe+MeJ; while Phe treatment barely increased phenolic compounds. Consequently, it was not possible to confirm the hypothesis that elicitation by MeJ could be supported by precursor feeding with Phe, when both applied together. This is the first study dealing with this matter under field conditions serving as basis for future works.

Effect of elicitors on the evolution of grape phenolic compounds during the ripening period

BACKGROUND

The effect of the application of benzothiadiazole (BTH) and methyl jasmonate (MeJ) at veraison on the phenolic composition of grapes from three varieties (Monastrell, Syrah and Merlot) was studied during the ripening period, using HPLC techniques to measure flavonols, anthocyanins and tannins.

RESULTS

The effects of the treatments differed in the three varieties, and the maximum concentration of phenolic compounds was not always reached at the end of the ripening period but some days before harvest. At the end of ripening both treated Syrah grapes only differed from control grapes in the flavonol concentration, whereas MeJ-treated Merlot grapes presented higher anthocyanin and skin tannin contents than the control and BTH-treated grapes. Only the anthocyanin content was significantly higher in treated Monastrell grapes at the moment of harvest.

CONCLUSION

The results indicate that the moment of elicitor treatment should be more studied since differences between treated and control grapes were, in general greater several days before harvest in all three varieties. © 2016 Society of Chemical Industry.

Synthesis, Biological Evaluation, and Molecular Modeling Studies of New Oxadiazole-Stilbene Hybrids against Phytopathogenic Fungi

Natural stilbenes (especially resveratrol) play important roles in plant protection by acting as both constitutive and inducible defenses. However, their exogenous applications on crops as fungicidal agents are challenged by their oxidative degradation and limited availability. In this study, a new class of resveratrol-inspired oxadiazole-stilbene hybrids was synthesized via Wittig-Horner reaction. Bioassay results indicated that some of the compounds exhibited potent fungicidal activity against Botrytis cinerea in vitro. Among these stilbene hybrids, compounds 11 showed promising inhibitory activity with the EC₅₀ value of 144.6 μg/mL, which was superior to that of resveratrol (315.6 μg/mL). Remarkably, the considerably abnormal mycelial morphology was observed in the presence of compound 11. The inhibitory profile was further proposed by homology modeling and molecular docking studies, which showed the possible interaction of resveratrol and oxadiazole-stilbene hybrids with the cytochrome P450-dependent sterol 14α-demethylase from B. cinerea (BcCYP51) for the first time. Taken together, these results would provide new insights into the fungicidal mechanism of stilbenes, as well as an important clue for biology-oriented synthesis of stilbene hybrids with improved bioactivity against plant pathogenic fungi in crop protection.

Effect of methyl jasmonate application to grapevine leaves on grape amino acid content

Over the last few years, considerable attention has been paid to the application of elicitors to vineyard. However, research about the effect of elicitors on grape amino acid content is scarce. Therefore, the aim of this study was to evaluate the influence of foliar application of methyl jasmonate on must amino acid content. Results revealed that total amino acid content was not modified by the application of methyl jasmonate. However, the individual content of certain amino acids was increased as consequence of methyl jasmonate foliar application, i.e., histidine, serine, tryptophan, phenylalanine, tyrosine, asparagine, methionine, and lysine. Among them, phenylalanine content was considerably increased; this amino acid is precursor of phenolic and aromatic compounds. In conclusion, foliar application of methyl jasmonate improved must nitrogen composition. This finding suggests that methyl jasmonate treatment might be conducive to obtain wines of higher quality since must amino acid composition could affect the wine volatile composition and the fermentation kinetics.

Improvement of grape and wine phenolic content by foliar application to grapevine of three different elicitors: Methyl jasmonate, chitosan, and yeast extract

Phenolic compounds play a key role in grape and wine organoleptic properties, being therefore a key parameter in wine quality. Elicitor application constitutes an interesting field of research since it is indirectly involved in the accumulation of phenolic compounds. The aim of this study was to compare the effect of the application of three different elicitors on both grape and wine phenolic content. Methyl jasmonate, chitosan, and a commercial yeast extract were applied to the canopy at veraison and one week later. Results showed that foliar treatments carried out with methyl jasmonate and yeast extract achieved the best results, increasing grape and wine anthocyanin content when compared to the control. Moreover, the application of the yeast elicitor also enhanced grape stilbene content. In contrast, the chitosan treatment did not have a substantial impact on the phenolic compounds. The results of this study indicate that methyl jasmonate and yeast extract applications could be a simple practice to increase grape and wine phenolic content.