Search

The aim of this paper is to provide a detailed characterisation of grape lipidome. To achieve this objective, it starts by describing a pipeline implemented in R software to allow the semi-automatic annotation of the detected lipid species. It also provides an extensive description of the different properties of each molecule (such as retention time dependencies, mass accuracy, adduct formation and fragmentation patterns), which allowed the annotations to be made more accurately. Most annotated lipids in the grape samples were (lyso)glycerophospholipids and glycerolipids, although a few free fatty acids, hydroxyceramides and sitosterol esters were also observed. The proposed pipeline also allowed the identification of a series of methylated glycerophosphates never previously observed in grapes. The current results highlight the importance of expanding chemical analyses beyond the classical lipid categories., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The ascomycete Erysiphe necator is a serious pathogen in viticulture. Despite the fact that some grapevine genotypes exhibit mono-locus or pyramided resistance to this fungus, the lipidomics basis of these genotypes' defense mechanisms remains unknown. Lipid molecules have critical functions in plant defenses, acting as structural barriers in the cell wall that limit pathogen access or as signaling molecules after stress responses that may regulate innate plant immunity. To unravel and better understand their involvement in plant defense, we used a novel approach of ultra-high performance liquid chromatography (UHPLC)-MS/MS to study how E. necator infection changes the lipid profile of genotypes with different sources of resistance, including BC4 ( Run1 ), "Kishmish vatkhana" ( Ren1 ), F26P92 ( Ren3 ; Ren9 ), and "Teroldego" (a susceptible genotype), at 0, 24, and 48 hpi. The lipidome alterations were most visible at 24 hpi for BC4 and F26P92, and at 48 hpi for "Kishmish vatkhana". Among the most abundant lipids in grapevine leaves were the extra-plastidial lipids: glycerophosphocholine (PCs), glycerophosphoethanolamine (PEs) and the signaling lipids: glycerophosphates (Pas) and glycerophosphoinositols (PIs), followed by the plastid lipids: glycerophosphoglycerols (PGs), monogalactosyldiacylglycerols (MGDGs), and digalactosyldiacylglycerols (DGDGs) and, in lower amounts lyso-glycerophosphocholines (LPCs), lyso-glycerophosphoglycerols (LPGs), lyso-glycerophosphoinositols (LPIs), and lyso-glycerophosphoethanolamine (LPEs). Furthermore, the three resistant genotypes had the most prevalent down-accumulated lipid classes, while the susceptible genotype had the most prevalent up-accumulated lipid classes.

Lipids are important constituents of plant and animal cells, being essential due to their biological functions. Despite the significant role of these compounds in grape berries, knowledge of grape lipid composition is still limited. This study addresses the free fatty acid composition and other lipids in skins and seeds of several Vitis vinifera grape cultivars using LC-MS/MS. A different profile of free fatty acids was determined in the grape tissues, showing a higher proportion of unsaturated fatty acids in seeds (ca. 60%). Lignoceric acid was one of the main free saturated fatty acids found in grape skins, together with palmitic and stearic acids. Berry skins showed similar ranges of C18-unsaturated fatty acids, whereas linoleic acid was predominant in the seed fatty acid composition. Higher content of glycerophospholipids was determined in grape seeds. Uvaol and oleanolic acid were only quantified in skins (1.5-3.9 and 38.6-57.6 mg/kg fresh weight, respectively). These preliminary results suggest a certain diversity in grape lipids according to their location in the berry tissues and cultivar, providing useful information for the fermentation process due to their role in wine sensory profile and yeast growth., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Glycosides are ubiquitous plant secondary metabolites consisting of a non-sugar component called an aglycone, attached to one or more sugars. One of the most interesting aglycones in grapes and wine is methyl salicylate (MeSA), an organic ester naturally produced by many plants, particularly wintergreens. To date, nine different MeSA glycosides from plants have been reported, mainly spread over the genera Gaultheria, Camellia, Polygala, Filipendula , and Passiflora. From a sensorial point of view, MeSA has a balsamic-sweet odor, known as Wintergreen. MeSA was found in V itis riparia grapes, in V itis vinifera sp . and in the Frontenac interspecific hybrid. We found that the MeSA glycosides content in Verdicchio wines and in some genetically related varieties (Trebbiano di Soave and Trebbiano di Lugana) was very high. In order to understand which glycosides were present in wine, the methanolic extract of Verdicchio wine was injected into a UPLC-Q-TOF-HDMS and compared to the extracts of different plants rich in such glycosides. Using pure standards, we confirmed the existence of two glycosides in wine: MeSA 2- O --d-glucoside and MeSA 2- O --d-xylopyranosyl (1-6) -d-glucopyranoside (gaultherin). For the first time, we also tentatively identified other diglycosides in wine: MeSA 2- O --l-arabinopyranosyl (1-6)--d-glucopyranoside (violutoside) and MeSA 2- O --d-apiofuranosyl (1-6)--d-glucopyranoside (canthoside A), MeSA 2- O --d-glucopyranosyl (1-6)- O --d-glucopyranoside (gentiobioside) and MeSA 2- O --l-rhamnopyranosyl (1-6)--d-glucopyranoside (rutinoside). Some of these glycosides have been isolated from Gaultheria procumbens leaves by preparative liquid chromatography and structurally annotated by 1 H- and 13 C-NMR analysis. Two of the peaks isolated from Gaultheria procumbens leaves, namely MeSA sambubioside and MeSA sophoroside, were herein observed for the first time. Six MeSA glycosides were quantified in 64 Italian white wines, highlighting the peculiar content and pattern in Verdicchio wines and related cultivars. The total concentration in bound and free MeSA in Verdicchio wines varied in the range of 456-9796 g/L and 5.5-143 g/L, respectively, while in the other wines the bound and free MeSA was below 363 g/L and 12 g/L, respectively. As this compound's olfactory threshold is between 50 and 100 g/L, our data support the hypothesis that methyl salicylate can contribute to the balsamic scent, especially in old Verdicchio wines., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Metabolic changes can occur in plants in response to abiotic stress. Extensive use of leaf discs (mechanical wounding) in studies regarding the effect on the biochemical response of the grapevine to different types of biotic stress makes it necessary to understand metabolic perturbation after injury. In this study, we investigate how mechanical wounding can affect the metabolism of grapevine leaf tissue using Bianca variety as case study. Two sizes of leaf discs (1.1 and 2.8 cm in diameter) were excised from leaves, and phenol, lipid and carotenoid perturbation were investigated 0, 6, 12, 24, 48, 96 and 120 h post cutting. In our study, we found an accumulation of molecules belonging to stilbenoid and stilbene classes such as trans-resveratrol, trans-piceide, Z-miyabenol C, E-cis-miyabenol C and ampelopsin D + quadrangularin A after abiotic stress. The increase in fatty acids such as linoleic acid, linolenic acid and oleic + cis-vaccenic acid during the first 12 h after injury, followed by a return to basal level, allowed us to surmise their role in response to abiotic stress, in particular to mechanical wounding in grapevine leaves. Different-sized discs caused a different response to the tissue, with a higher accumulation in 1.1-cm-diameter discs, especially of phenol compounds. The results of this work can be used to better understand metabolic changes due to biotic stress, having previous knowledge about the perturbation caused by abiotic stress.

The abundance of lipids in plants is influenced by genotype and phenotype. Despite being a very important class of plant metabolites, knowledge of grape lipids is still very limited to date, with the exception of those located in seeds. Few investigations of grape lipids have shown that their profile depends on grape maturity, the variety and their location in the berry. Recent advances in liquid chromatography coupled to mass spectrometry have paved the way for faster analysis of lipids with minimal sample preparation. Here we describe a validation method for the extraction, identification and quantification of different classes of grape lipids: fatty acids, sterols, glycerolipids, glycerophospholipids and sphingolipids using liquid chromatographic electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The method was validated for 33 lipids, with linearity range (R(2)=0.95-1.00), LOQ (0.003-14.88 ng mL(-1)) and intraday and interday repeatability being evaluated for each lipid. The lipid profiling method developed was successfully applied to the analysis of 18 grape samples (10 red grape and 8 white grape varieties) from 4 different genetic groups: Vitis vinifera, Vitis non-vinifera, Muscat and hybrid; 33 lipids were identified and quantified. This method, which can be easily expanded to include further compounds and other plant tissues, is the starting point for analysis of the lipid profile in different grape tissues, an essential goal for better understanding the role of lipids in grape physiology., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Nowadays the trend in analytical chemistry is clearly towards the creation of multiple methods with extended coverage, enabling the determination of many different classes of compounds in a single analysis in which virtually all classes of different compounds are included in a single run. The aim of this study was to develop and validate a versatile and selective GC/MS/MS method for metabolite profiling of volatile compounds in apples, raspberries and grapes. Validation of the method was performed in terms of the limit of detection, limit of quantification, linearity range, and inter and intraday precision. Confirmation of the identity of the compounds in samples was carried out by checking compliance of the q/Q ratio of samples and reference standards. The multiple reaction monitoring with selection of two transition ions, one for quantification and one for confirmation, provided excellent selectivity and sensitivity, using the q/Q ratio as a confirmatory parameter. A multi target method was developed and validated for the simultaneous quantification and confirmation of 160 volatile compounds of raspberries, apples and grapes. The main classes were esters (42), alcohols (32), monoterpenes (31), aldehydes (17), ketones (12), norisoprenoids (8), acids (8), sesquiterpenes (7), pyrazines (3) and ethers (1) allowing the detection and quantification of 69 compounds in apples, 122 in grapes and 42 in raspberries. Moreover, the method developed can be easily extended to volatile compounds in other fruits and can therefore be widely used for quantification/profiling studies in the field of fruit aroma., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Gibberellins (GAs) are involved in the regulation of flowering and fruit-set in grapes (Vitis vinifera L.), but the molecular mechanisms behind this process are mostly unknown. In this work, the family of grapevine GA oxidases involved in the biosynthesis and deactivation of GAs was characterized. Six putative GA 20-oxidase (GA20ox), three GA 3-oxidase (GA3ox), and eight GA 2-oxidase (GA2ox) proteins, the latter further divided into five C19-GA 2ox and three C20-GA2ox proteins, were identified. Phylogenetic analyses suggest a common origin of the GA3ox and C19-GA2ox groups and challenge previous evolutionary models. In vitro analysis revealed that all GA3ox and GA20ox enzymes prefer substrates of the non-13-hydroxylation pathway. In addition, ectopic expression of GA2ox genes in Arabidopsis thaliana confirmed the activity of their encoded proteins in vivo. The results show that bioactive GA1 accumulates in opening grapevine flowers, whereas at later developmental stages only GA4 is detected in the setting fruit. By studying the expression pattern of the grapevine GA oxidase genes in different organs, and at different stages of flowering and fruit-set, it is proposed that the pool of bioactive GAs is controlled by a fine regulation of the abundance and localization of GA oxidase transcripts.

In the Vitaceae, viniferins represent a relatively restricted group of trans-resveratrol oligomers with antifungal properties, thus enabling plants to cope with pathogen attack. The aim of this study was to perform isolation and structural characterization of the whole class of viniferins accumulating in the leaves of hybrid Vitis vinifera (Merzling × Teroldego) genotypes infected with Plasmopara viticola . Infected leaves of resistant plants were collected 6 days after infection, extracted with methanol, and prepurified by flash chromatography using ENV+ and Toyopearl HW 40S resins. Further fractionation using normal-phase preparative chromatography and then reversed-phase preparative chromatography allowed isolation of 14 peaks. The isolated compounds were identified using advanced mass spectrometry techniques and extensive one- and two-dimensional nuclear magnetic resonance measurements, UV, CD, optical properties, and molecular mechanic calculations. The results demonstrated the presence in infected leaves of seven dimers (six stilbenes and one stilbenoid), of which four were new in grapevine (ampelopsin D, quadrangularin A, E-ω-viniferin, and Z-ω-viniferin), four trimers (three stilbenes and one stilbenoid), of which two (Z-miyabenol C and E-cis-miyabenol C) were new in grapevine, three tetramer stilbenoids, all new in grapevine, isohopeaphenol, ampelopsin H, and a vaticanol C-like isomer. The isolation of a dimer deriving from the condensation of (+)-catechin with trans-caffeic acid also indicated that other preformed phenolics are structurally modified in tissues infected with P. viticola.