Haplotype-resolved genome assemblies of Chasselas and Ugni Blanc

AIM: Biofilm is a resistance mechanism deployed by microorganisms to adapt to stresses, leading to their persistence in the environment. In the case of Brettanomyces bruxellensis, a wine spoilage yeast, knowledge about its capacity to form biofilm remains limited although this potential strategy could explain its recurring presence in cellars.

The designations of origin of the Loire Valley wine have been recognized according to customs and notoriety established over the centuries since the Middle Ages. There are four main production basins going up the Loire, from Nantes to the Sancerrois region: Nantes, Anjou-Saumur, Touraine and the vineyards of the Centre. In each of these basins, there is a wide range of appellations of origin which has been established according to a logic which may not seem obvious to the uninformed.

Soil is a reservoir of microorganisms playing important roles in biogeochemical cycles and interacting with plants whether in the rhizosphere or in the root endosphere. Through rhizodeposition, plants regulate their associated microbiome composition depending on the environment and plant factors, including genotypes. Since the phylloxera crisis, Vitis vinifera cultivars are mainly grafted onto American Vitis hybrids. Rootstocks play a pivotal role in the grapevine development, as the interface between the scion and the soil.

During wine aging, several complex phenomena of gas transfer take place in barrels due to the wine/oak contact. The efficiency of this gas transfer varies according to oak wood’s intrinsic physical properties. This research aims to better understand oxygen transfer phenomena through dry oak staves and especially through stave gaps, in order to reevaluate the importance of barrel-making on a barrel’s supply of oxygen. Experimentation was based on the development of an innovative permeameter of laboratory scale, for which the principal operating conditions concerning applied pressure, the choice of liquid phase/gas phase, and the grain type of oak are taken into account and investigated. With a specially developed tightening system, the existing pressure at stave gaps in a barrel could be reproduced on a laboratory scale in order to estimate its influence on oxygen transfer efficiency.

Riesling wines are appreciated for their diverse aromas, ranging from the fruity fresh characters in young vintages to the fragrant empyreumatic notes developed with aging. Wine tasters often refer to Riesling wines as prime examples showcasing terroir, with their typical aroma profiles reflecting the geographical provenance of the wine. However, the molecular basis of the distinctive aromas of these varietal wines from major Riesling producing regions in Europe have not been fully elucidated. In this study, new lights were shed on the chemical characterization and the sensory contribution of volatile thiols to Riesling wines from Rheingau, Mosel, and Alsace. First, Riesling wines (n = 46) from the three regions were collected and assessed for their aroma typicality by an expert panel.