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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., This work has been carried out thanks to funding from the Ministerio de Ciencia, Innovación y Universidades through the Project RTI2018-096549-B-I00.

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., This work has been carried out thanks to funding from the Ministerio de Ciencia, Innovación y Universidades through the Projects RTI2018-096549-B-I00 and RTI-2018-095794-A-C22.

[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., Financial support was given by Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)‐Gobierno de La Rioja under project RTA2013‐00053‐C03‐01. GG‐G is grateful for the financial support given by CONICYT through BCH/Doctorado 72170532. JP and TG‐C wish to thank INIA‐Gobierno de La Rioja and the European Social Fund for their contracts. TG‐C also thanks MINECO for funding her Ramón y Cajal contract.

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.

The aromas of the grape are compounds that are directly related to the quality of the must and the wine. In this work, the effect of foliar application of phenylalanine (Phe), methyl jasmonate (MeJ) and a mixture of both (Phe + MeJ) on the content of volatile compounds in grapes of the Grenache variety has been studied. The results showed that the most effective treatment in order to improve the content of terpenoids and C13 norisoprenoids was MeJ; while, for enhancement of the benzenoid compounds and the total positive compounds was Phe. In the case of terpenoids and benzenoids, the treatment based on Phe + MeJ was the one that most potentiated their increase. C6 compounds, which contribute to the wine herbaceous aromas considered as negative, did not increase with any treatment. In conclusion, all treatments applied in the vineyard improved the content of volatile compounds in grapes of Grenache variety., Financial support was given by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) under the project RTA2013-00053-C03-01. S. M.-S.-R. thanks Gobierno de La Rioja for her predoctoral contract. T. G.-C., P. R.-B. and E.P. P.-Á. thank the MINECO for her postdoctoral contracts.

Elicitors play a key role against pathogen infestation, becoming as an alternative to chemical pesticides by the improving secondary metabolites synthesis. Their effect on grape volatile compounds has been little investigated. This field trial aimed to study the foliar application of methyl jasmonate (MeJ), chitosan (CHT), and a yeast extract (YE) on grape volatile compounds by HS-SPME-GC–MS. The results showed that, in general, foliar elicitor application decreased the synthesis of grape volatile compounds. Depending of the treatment, MeJ and CHT showed the lowest total amounts of terpenoids, C13 norisoprenoids, benzenoids, and esters, together with the highest levels of C6 compounds. YE treatment applied to the grapevines barely affected the synthesis of volatile compounds in grapes. The importance of this work is to add information about the effects of elicitors on grape volatile composition in Tempranillo grapevines., Financial support was given by Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)-Gobierno de La Rioja under the project RTA2013-00053-C03-01. G. G.-G. thanks for the financial support given by CONICYT through, BCH/Doctorado-72170532. T. G.-C., P. R.-B., and E.P. P.-Á. also thank MINECO for funding their postdoctoral contracts.

[Aim] The study of elicitors in grapevines has focused on inducing resistance to diseases and improving phenolic and volatile composition of grapes and wines. Due to the importance of nitrogen compounds in grape quality, the aim of this work was to study the effect of methyl jasmonate (MeJ) applied to two grapevine varieties on grape amino acid content during two consecutive seasons. [Methods and results] Amino acids were analyzed by HPLC-DAD. The results showed that MeJ applications to Tempranillo grapevines decreased the concentration of certain amino acids during both seasons, but did not affect total amino acid content. Moreover, MeJ applications to Graciano grapevines increased the concentration of several amino acids during the second season. [Conclusions] The effects of MeJ on grape amino acid concentration were conditioned by variety and vintage. Significance and impact of the study: The importance of this work is to provide more information with respect to the effects of elicitors on grape quality for good viticultural management., Financial support was provided by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)-Gobierno de La Rioja under project RTA2013-00053-C03-01. G. G.-G. thanks for the financial support given by CONICYT through BCH/Doctorado-72170532. E.P. P.-Á., P. R.-B., and T. G.-C. also thank MINECO for funding.

Photosynthetic pigments, including carotenoids are important secondary metabolites, which play a key role in photosynthesis. There is little information about the effects of nitrogen and elicitor applications on chlorophyll and carotenoid concentrations in grapes. The aim of this work was therefore to study the effects of the foliar application of nitrogen sources and elicitors to Tempranillo, Garnacha and Graciano (Vitis vinifera L.) grapevines on chlorophyll and carotenoid contents. The results showed that β-carotene and lutein were the most abundant carotenoids in all the samples, ranging from 1336 and 227 to 7054 and 1382 μg/g, respectively. The applied treatments had greater impact on chlorophyll and carotenoid contents in Tempranillo grapes than in Graciano and Garnacha varieties. The content of chlorophyll was determined by the variety factor, while the concentration of carotenoids was influenced by the interaction of variety and treatment factors, depending on the type of foliar application., Financial support was given by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)-Gobierno de La Rioja under the project RTA2013-00053-C03-01. E. P. P.-Á., P. R.-B. and T. G.-C. thank the MINECO for her contracts. G. G.-G. acknowledges the financial support given by CONICYT through, BCH/Doctorado – 72170532.

Proanthocyanidins or “condensed tannins” play an important role in the organoleptic properties of wines, and their levels in both grapes and wines can be achieved by several means. One such way is based on the use of elicitors, agrochemicals which were originally designed to improve resistance to plant pathogens, but whose action mechanism has also been found to increase polyphenol levels. Among these chemical elicitors, jasmonic acid and, especially, its methyl ester, methyl jasmonate (MeJ), can increase the production of secondary metabolites such as anthocyanins, flavonoids, phenolic acids, and other antioxidant molecules, enhancing the fruit quality and post-harvest life, as well as increasing their health-related properties. The objective of this study was to determine whether the application during two consecutive years of MeJ to Monastrell and Tempranillo varieties at the veraison period had any effect on the accumulation of proanthocyanidins and subsequently on their extractability into wine. The results obtained indicated that treatments increased the grape proanthocyanidin content only in one of the years but for both varieties tested, as well as their levels in the corresponding wines., This work was made possible by financial assistance from the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria. RTA2013-00053-C03-02 and RTA2013-00053-C03-01. J. P. and T. G.-C. also wish to thank the INIA-Gobierno de La Rioja and European Social Fundfor their contracts. T. G.-C. also thanks MINECO for funding her Ramón y Cajal contract.

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., Many thanks for the financial support given by the Gobierno de La Rioja to R-08-13 and R-11-14 projects and by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) under the project RTA2013-00053-C03-01. T. G.-C., P. R.-B., and E.P. P.-Á. wish to thank Ministerio de Economía y Competitividad (MINECO) for her contracts. G. G.-G. thanks for the financial support given by CONICYT (Chile), BCH/Doctorado-72170532.

Trabajo presentado en el 10th In Vino Analytica Scientia Symposium, celebrado en Salamanca (España), del 17 al 20 de julio de 2017, 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., Many thanks for the financial support given by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)-Gobierno de La Rioja under the project RTA2013-00053-C03-01. J. P. and T. G.-C. also wish to thank the INIA-Gobierno de La Rioja and European Social Fund for their contracts. T. G.-C. was also supported by the Ramón y Cajal program from the Spanish MINECO.

Vine foliar applications of phenylalanine (Phe) or methyl jasmonate (MeJ) could improve the synthesis of secondary metabolites. However, there are no reports focusing on the effects of elicitation supported by precursor feeding on must amino acid composition in grapevines. The aim of this research was to study the effect of the elicitation of methyl jasmonate (MeJ) supported by phenylalanine (Phe) as a precursor feeding (MeJ + Phe) and its application individually on must amino acid composition. Results showed that foliar Phe and MeJ treatments decreased the concentration of most of the studied amino acids with respect to the control (p ≤ 0.05). MeJ + Phe treatment did not affect must nitrogen content. Musts obtained from MeJ + Phe showed higher concentration of several amino acids than samples from Phe and MeJ applications. Therefore, other sources of precursor feeding could support elicitation, to improve amino acid composition and be considered as a tool for viticulture., Financial support was given by Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)-Gobierno de La Rioja under the project RTA2013-00053-C03-01. G. G.-G. thanks for the financial support given by CONICYT through, BCH/Doctorado - 72170532. J. P. and T. G.-C. wish to thank the INIA-Gobierno de La Rioja and European Social Fund for their contracts. T. G.-C. also thanks MINECO for funding her Ramón y Cajal contract.

Elicitors play an important role in the defense against pathogens as an alternative to chemical pesticides by increasing secondary metabolites. Their effect on grape amino acid has been little investigated. Thus, the aim of this research was to study the influence of methyl jasmonate (MeJ), chitosan (CHT), and a yeast extract (YE) on grape amino acid composition, through foliar applications to grapevines. The must amino acid concentration was analyzed by HPLC. The results showed that CHT and YE treatments decreased the must concentration of several amino acids, affecting total amino acid content (from 2364 to 1961, and 1818 mg/L, respectively). However, MeJ treatment had a slight effect on grape amino acid content, increasing the concentration of Met (from 8.95 to 12.13 mg/L) and Phe (from 7.96 to 9.29 mg/L). It seems to be that, the resistance induction through CHT and YE treatments results in physiological costs to grapevines associated with a decrease on grape amino acid concentration. Consequently, MeJ applications, as a viticultural practice, could be a better tool than CHT and YE treatments, because did not affect grape amino acid concentration., Financial support was given by Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)-Gobierno de La Rioja under the project RTA2013-00053-C03-01. G. G.-G. thanks for the financial support given by CONICYT through, BCH/Doctorado - 72170532. J. P. and T. G.-C. wish to thank the INIA-Gobierno de La Rioja and European Social Fund for their contracts. T. G.-C. also thanks MINECO for funding her Ramón y Cajal contract.

Two preharvest treatments (methyl jasmonate or cell wall yeast) of grapevines (Monastrell and Tempranillo) were applied during two vintages (2014 and 2015) to check whether these elicitors enhanced stilbene accumulation in berries at the moment of harvest and in the corresponding wines elaborated with them. The main objective was checking the effect of treatment, variety and year on stilbene composition due to the interesting health-related properties of these compounds in both grapes and wines. The results pointed to inter-varietal and inter-annual differences, and that the treatments generally enhanced the stilbene composition of grapes and, particularly, of wines. The increase was more evident in Monastrell variety than in Tempranillo variety and in their wines more than their grapes during 2014 vintage but not during 2015 vintage., This work was made possible by financial assistance from the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) (RTA2013-00053-C03-02 and RTA2013-00053-C03-01). T. G.-C. wishes to thank INIA-Gobierno de La Rioja and Ministerio de Economía y Competitividad for her INIA-Doc and Ramón y Cajal contracts, respectively.