Exogenous dsRNA applications to identify novel candidate susceptibility genes to downy mildew

OTA occurrence in wine is well-documented, with higher levels typically found in red (< 0.01-7.63 μg/l), followed by rose (0.01-2.40 μg/l) and white wine (<0.01-1.72 μg/l). Incidence rates are nOTAble, with studies showing OTA present in 53% of 521 red wines, 69% of 98 rose, and 61% of 301 white wines analysed. In europe, wine is estimated to be the second source of OTA intake after cereals. Since 2006, the maximum allowable limit for OTA in wine is 2 μg/l, according to regulation (ec) no. 1881/2006.

The increasing vulnerability of viticulture to climate change necessitates innovative solutions to improve its sustainability and resilience.

The paper presents results that develop the results of studies carried out in 2022-2023 under the OIV grant on the topic of distribution of deuterium (2H(D)) in the intracellular water of grapes and wines, taking into account the impact of natural, climatic and technogenic factors using quantitative nuclear magnetic resonance spectroscopy (qNMR).

Sulphur dioxide (SO2) seems indispensable in winemaking because of its properties. However, a current increasing concern about its allergies effects in food product has addressed the international research efforts on its replacement. This supposes a sufficient knowledge of its properties and conditions of use. Several studies compared SO2 properties against new alternatives that are supposed to overcome SO2 disadvantages. Firstly, the state of art on SO2 wine replacements is revised, and secondly, the last promising results using natural enriched polyphenol extracts are shown.

Water is the main limiting factor for yield in viticulture. Improving drought adaptation in viticulture will be an increasingly important issue under climate change. Genetic variability of water deficit responses in grapevine partly results from the rootstocks, making them an attractive and relevant mean to achieve adaptation without changing the scion genotype. The objective of this work was to characterize the rootstock effect on the diurnal regulation of scion transpiration. A large panel of 55 commercial genotypes were grafted onto Cabernet Sauvignon. Three biological repetitions per genotype were analyzed. Potted plants were phenotyped on a greenhouse balance platform capable of assessing real-time water use and maintaining a targeted water deficit intensity. After a 10 days well-watered baseline period, an increasing water deficit was applied for 10 days, followed by a stable water deficit stress for 7 days. Pruning weight, root and aerial dry weight and transpiration were recorded and the experiment was repeated during two years. Transpiration efficiency (ratio between aerial biomass and transpiration) was calculated and δ13C was measured in leaves for the baseline and stable water deficit periods. A large genetic variability was observed within the panel. The rootstock had a significant impact on nocturnal transpiration which was also strongly and positively correlated with maximum daytime transpiration. The correlations with growth and water use efficiency related traits will be discussed. Transpiration data were also related with VPD and soil water content demonstrating the influence of environmental conditions on transpiration. These results highlighted the role of the rootstock in modulating water deficit responses and give insights for rootstock breeding programs aimed at identifying drought tolerant rootstocks. It was also helpful to better define the mechanisms on which the drought tolerance in grapevine rootstocks is based on.