AOC valorization of terroir nuances at plot scale in Burgundy

Historical terrace vineyards are simultaneously impressive documents of the human inclination to design, sites for the production of high quality wines and habitats for a rich variety of flora and fauna

In the last decades, climate change required already adaptation of vineyard management. Increase in temperature and unexpected weather events cause changes in all phenological stages requiring new management tools. For example, defoliation can be a useful tool to reduce the sugar content in the berries creating differences in the wine profiles. In a ten-year field experiment using Riesling (Vitis vinifera L, planted 1986, Geisenheim, Germany), various mechanical defoliation strategies and different intensities were trialed until 2016 before the vineyard was uprooted. Wood was sampled from the plant compartments root, trunk, cordon and shoot for analyses of physicochemical properties (e.g. lignin and element content, pH, diameter), nonstructural carbohydrates and the microbial communities. The aim of the study was to investigate the influence of reduced canopy leaf area on the sink-source allocation into different compartments and potential changes of the fungal and prokaryotic wood-inhabiting community using a metabarcoding approach. Severe summer pruning (SSP) of the canopy and mechanical defoliation (MDC) above the bunch zone decreased the leaf area by 50% compared to control (C). SSP reduced the photosynthetic capacity, which resulted in an altered source-sink allocation and carbohydrate storage. With lower leaf area, less carbohydrates are allocated. This for example resulted in a decreased trunk diameter. Further, it affected the composition of the grapevine wood microbiota. SSP and MDC management changed significantly the prokaryotic community composition in wood of the root samples, but had no effect in other compartments. In general, this study found strong compartment and less management effects of the microbial community composition and associated physicochemical properties. The highest microbial diversities were identified in the wood of the trunk, and several species were recorded the first time in grapevine.

Grafting Vitis vinifera L. (wine traditional cultivars) onto North American grapevine species or hybrids is a common practice in viticulture given their tolerance against phylloxera (Daktulosphaira vitifoliae). However, rootstock genetic background affects the response of grapevines to environmental stresses and their ability for establishing a symbiotic relationship with the microbial communities, and more specifically with arbuscular mycorrhizal fungi (AMF).
The aim of this study was to evaluate Monastrell variety (clone ENTAV 369) grafted onto three rootstocks (140Ru, 110R and RG8) characterized by a different genetic background, in combination with AMF inoculation (Rhizophagus irregularis) vs. a non-inoculated control with regards to vegetative growth, leaf gas exchange parameters, and mycorrhization.

It is a well-established fact that premature oxidation is noxious for wine aromatic quality and longevity. Although some oxidation-related aroma molecules have been previously identified, there are not works carrying out systematic research about the changes in the profiles of odour-active volatiles during wine oxidation.