Drought affects vineyard soil microbiome: approach to select micro-organisms adapted to drought

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.

AIM: Proteins in white wine can cause cloudiness or haze after bottling, which consumers may consider an indicator of poor quality. . As a consequence, winemakers often use bentonite, a clay-based material that binds protein, to remove proteins and achieve protein stabilisation. However, removing bentonite from wine after treatment can result in a 3-10% loss of wine (1)…

Developing technologies that help vines survive and produce in quantity and quality within current times is mandatory. In this sense, in the 2021/2022 agricultural harvest, the influence of the foliar application of seaweed – Laminaria japonica was studied, aiming at productivity and quality of the must in the ‘Merlot’ grape. In the city of “Santana do Livramento”, “Rio Grande do Sul” (RS), Brazil; in a 15-year-old commercial vineyard of ‘Merlot’ clone ENTAV-INRA® 347, grafted onto ‘SO4’ rootstock, the following treatments were applied on 6 occasions: No treatment (control) and; Foliar application of Laminaria japonica seaweed (commercial product: Exal (ALAS), 2 kg ha-1).

The purpose of this research study is to consider new solutions for distillate ageing, in alternative to conventional oak chips or barrels in particular sliced wood and peeled wood were compared to oak cubes, normally employed during both wine and distillate ageing.

Germicidal ultraviolet-C (UV-C) light has shown promising results for suppression of several plant-pathogenic microorganims, including Erysiphe necator, which attacks grapevine. In Washington State the majority of winegrape production is in a semi-arid steppe environment, with historically low powdery mildew disease pressure, making it a promising area to deploy UV-C as a disease management tool. Trials focusing on UVC application timing and frequency will assist in developing regionally-appropriate application recommendations for eastern Washington State.