Effects of abscisic acid treatment on Vitis vinifera L. Savvatiano and Mouchtaro grapes and wine characteristics

L’objectif de l’étude était de connaître le rôle du climat sur les aspects phénologiques du cépage « Moscato bianco » dans les différentes zones de production du vin Moscato d’Asti aocg en Piemonte (Italie) et ses effets sur l’époque de vendange. La représentation cartographique ( échelle 1 :25000) de exposition, altitude, climat, index

Climate change poses several challenges for the wine-industry in the 21st century. Adaptation of viticultural and winemaking practices are therefore essential to preserve wine quality and typicity. Given the complex interactions between physical, biological and human factors at terroir scales, studies conducted at these fine scales allow to better define the local environment and its influences on grapevine growth and berry ripening.

In view of sustainability and zero-waste initiatives, the valorisation of sidestreams is a key emerging topic in the wine industry.

Water status impact in viticulture has been widely explored, as it strongly affects grapevine physiology and grape chemical composition. It is considered as a key component of vitivinicultural terroir. Most of the studies concerning grapevine water status have focused on either physiological traits, or berry compounds, or traits involved in wine quality. Here, the response of grapevine to water availability during the ripening period is assessed through non-targeted metabolomics analysis of grape berries by ultra-high resolution mass spectrometry. The grapevine water status has been assessed during 2 consecutive years (2019 & 2020), through carbon isotope discrimination on juices from berries collected at maturity (21.5 brix approx.) for 2 Vitis vinifera cv. Pinot noir (PN) and Chardonnay (CH). A total of 220 grape juices were collected from 5 countries worldwide (Italy; Argentina; France; Germany; Portugal). Measured δ13C (‰) varied from -28.73 to -22.6 for PN, and from -28.79 to -21.67 for CH. These results also clearly revealed higher water stress for the 2020 vintage. The same grape juices have been analysed by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) and Liquid Chromatography coupled to Mass Spectrometry (LC-qTOF-MS), leading to the detection of up to 4500 CHONS containing elemental compositions, and thus likely tens of thousands of individual compounds, which include fatty acids, organic acids, peptides, phenolics, also with high levels of glycosylation. Multivariate statistical analysis revealed that up to 160 elemental compositions, covering the whole range of detected masses (100 –1000 m/z), were significantly correlated to the observed gradients of water status. Examples of chemical markers, which are representative of these complex fingerprints, include various derivatives of the known abscisic acid (ABA), such as phaesic acid or abscisic acid glucose ester, which are significantly correlated with higher water stress, regardless of the variety. Cultivar-specific behaviours could also be identified from these fingerprints. Our results provide an unprecedented representation of the metabolic diversity, which is involved in the water status regulation at the grape level, and which could contribute to a better knowledge of the grapevine mitigation strategy in a climate change context.

The study analyzes a set of open innovation actions promoted by the innovation environments of the Instituto Federal do Rio Grande do Sul (IFRS), in cooperation with entities, companies in the sector and the Department of Innovation, Science and Technology of Rio Grande do Sul.