Inter- and Intra-Varietal Genetic Variability in Vitis vinifera L.

Grapevine (Vitis vinifera L.) is the most economically important and widely cultivated fruit crop in the world and its domestication produced cultivars suited to a wide diversity of climates and tastes In effect this genus shows a wide morphological and genetic variability that is causing confusions and ambiguity for biotypes and clones identification, in particular considering varieties that are widely distributed and cultivated for centuries. Ampelography, ampelometry, and biochemical traits analysis have been traditionally employed to identify the different biotypes in viticulture. However, these analyses are based on phenotypic characteristics which can be affected by environmental conditions The DNA molecular analyses are essential for internationally accepted grapevine identification and the investigation of genetic differences among the Vitis vinifera L. clones. Methods based on DNA analysis have been used with varying degrees of success. Simple sequence repeat (SSR) markers are universally used for the identification of the grape varieties. A molecular strategy to obtain DNA polymorphisms of Vitis vinifera genotypes from the same cultivar to study the intra- and inter- varietal genetic variability, to discriminate accessions, clones, and biotypes of a same grape variety, and to analyze the relationships between molecular profiles and some environmental parameters (i.e., geographic site) or morphological traits is described. This approach uses four different molecular marker systems (i.e., AFLP amplified fragment length polymorphism, SAMPL selective amplification of microsatellite polymorphic loci, M-AFLP microsatellites amplified fragment length polymorphism, and ISSR inter simple sequenced repeat)

Role of chitosan against grapevine downy mildew

The study of environmentally friendly active principles against downy mildew represents one of the main challenges in viticulture. In this context, the aim of the present trial was to investigate the efficacy of chitosan as a resistance elicitor against downy mildew and to study the metabolites involved in the interaction plant-chitosan-pathogen by a metabolomics approach. The experiments were carried out on potted vines of Merlot R18 grafted on SO4 rootstock, Guyot trained, during 2022. Leaf disks pre-treated with chitosan were infected by Plasmopara viticola sporangia in 3 phenological phases and the development of infection was recorded. The most significant findings were: 1) Chitosan resulted as an effective elicitor of defense mechanism against Plasmopara viticola. 2) The elicitor activity of chitosan was explained mainly through the induction of some secondary metabolites (terpenes and resveratrol), fatty acids (involved in the biosynthesis of sterols), and hormones (brassinosteroids and abscisic acid). 3) The best efficacy corresponded to the application of chitosan 48 hours before the infection. The timing of the treatment was, therefore, one of the key factors for the success of chitosan treatment

Polyphenol metabolomics of twenty Italian red grape varieties

“Suspect screening analysis”method to study grape metabolomics, was performed. This method is a middle-way “targeted” and “untargeted”approach aiming at identifying the largest number of metabolites in grape samples. A new database of putative grape and wine metabolites (GrapeMetabolomics), which currently contains around 1,100 compounds, was constructed by CREA at Conegliano. By performing high-resolution mass spectrometry analysis of the grape extract in both positive and negative ionization mode, averaging 320- 450 putative compounds are identified. Most of them are grape polyphenols, such as anthocyanins, flavonols and stilbene derivatives. By performing PCA and Cluster Analysis the composition in anthocyanins and flavonols of 20 Italian red grape varieties, was studie

Characterization of some Italian V. vinifera L. grape varieties on the basis of their flavonol profile

"Suspect screening metabolomics" is a mid-way approach between "targeted" and "untargeted" analysis. For this aim, a new database of putative grape and wine metabolites (GrapeMetabolomics ) was expressly constructed. Currently, this database contains around 1,100 compounds. By performing UHPLC/QTOF mass spectrometry analysis in both positive and negative ionization mode, in a grape extract averaging 320–450 putative compounds are identified. Most of these compounds are important grape metabolites, including flavonols, anthocyanins, and stilbene derivatives. In the present study, this approach was focalized on the characterization of flavonols of 18 important Italian red and white grape varieties and the method provided the identification of 15 flavonols. By performing statistical analysis (Principal Component Analysis and Cluster Analysis), the effect of the variety on the flavonol composition of the grapes was studied. Both the red and white samples fell into three different groups, respectively, on the basis of their flavonol profiles. Because the samples were cultivated in the same vineyard, their profile potentially was not affected by cultural or environmental factors. Anyway, these preliminary results will have to be confirmed by the study of grape samples collected in different years and from different vineyards

Wine Resveratrol: From the Ground Up

The ability of the grapevine to activate defense mechanisms against some pathogens has been shown to be linked to the synthesis of resveratrol and other stilbenes by the plant (inducible viniferins). Metabolized viniferins may also be produced or modified by extracellular enzymes released by the pathogen in an attempt to eliminate undesirable toxic compounds. Because of the important properties of resveratrol, there is increasing interest in producing wines with higher contents of this compound and a higher nutritional value. Many biotic and abiotic elicitors can trigger the resveratrol synthesis in the berries, and some examples are reported. Under the same elicitation pressure, viticultural and enological factors can substantially affect the resveratrol concentration in the wine. The production of high resveratrol-containing grapes and wines relies on quality-oriented viticulture (suitable terroirs and sustainable cultural practices) and winemaking technologies that avoid degradation of the compound. In general, the oenological practices commonly used to stabilize wine after fermentation do not affect resveratrol concentration, which shows considerable stability. Finally the paper reports on two sirtuin genes (SIRT) expressed in grapevine leaves and berries and the role of resveratrol on the deacetylation activity of the encoded enzymes

Role of chitosan against grapevine downy mildew

The study of environmentally friendly active principles against downy mildew represents one of the main challenges in viticulture. In this context, the aim of the present trial was to investigate the efficacy of chitosan as a resistance elicitor against downy mildew and to study the metabolites involved in the interaction plant-chitosan-pathogen by a metabolomics approach. The experiments were carried out on potted vines of Merlot R18 grafted on SO4 rootstock, Guyot trained, during 2022. Leaf disks pre-treated with chitosan were infected by Plasmopara viticola sporangia in 3 phenological phases and the development of infection was recorded. The most significant findings were: 1) Chitosan resulted as an effective elicitor of defense mechanism against Plasmopara viticola. 2) The elicitor activity of chitosan was explained mainly through the induction of some secondary metabolites (terpenes and resveratrol), fatty acids (involved in the biosynthesis of sterols), and hormones (brassinosteroids and abscisic acid). 3) The best efficacy corresponded to the application of chitosan 48 hours before the infection. The timing of the treatment was, therefore, one of the key factors for the success of chitosan treatment

Clima e profilo sensoriale dei vini

Effetti del cambio climatico sulle caratteristiche compositive dell’uva e del vino ed i metodi per ovviare ai problemi post