Saccharomyces cerevisiae – Oenococcus oeni – Lactiplantibacillus plantarum: focus on malolactic fermentation during production of Catarratto and Riesling white wines

In sparkling wines, foam is a relevant aspect whose measurement method could affect the results. The shaking test (ST) is a simple method measuring foamability1,2

Rootstocks play a key role in the grapevine’s adaptation to the increasing soil water scarcity related to climate change. A pot experiment carried out in 2022 aimed at assessing the physiological responses of seven ungrafted rootstocks to a progressive soil water deficit and a subsequent recovery to field capacity.

Climate transition with frequent heat waves and long drought periods threatens grapevine productivity and wine quality in the Mediterranean regions. Microorganisms are known to contribute to plant fitness and to stimulate plant resilience against biotic and abiotic factors.
In this work, it was assessed the impact of long-term drought on soil microbiome associated to grapevine in open field in Alentejo, renowned Portuguese wine region.
Soil and plant tissues of drought tolerant Syrah cultivar exposed to three irrigation levels (100%- FI, 50%-DI ETc; rain-fed–NI) for 5 years were sampled for two years (2022-2023). Metabarcoding analysis of soil bacteria (16S V4 rRNA) and fungi (ITS sub-region) were integrated with soil physiochemical properties and leaves´ physiological data. Pre-dawn leaf water potential and stomatal conductance confirmed the imposed drought scenarios. Even though, α- and β-diversity of prokaryotic and eukaryotic microbial communities differed more by season than water availability, samples clustered according to soil water content and pH (p<0.05). Fungal communities show higher differences in the structure across treatments than bacteria. In 2023, 16 bacterial against 61 fungal ASVs were significatively different in abundance between NI and FI. Beijerinckiaceae, Bradyrhizobiaceae (Alphaproteobacteria) and Nocardioidaceae, Streptomycetaceae (Actinobacteria) families resulted to be significatively more abundant in NI, while Ascomycota, Basidyomicota and Mortierellomycota are the most important fungal phyla in NI. With culturomics data, this study aims to gather insights into how soil microbiome is remodelled under drought and contribute to select bacterial and fungal taxa with potential to mitigate drought stress in vineyards.

AIM: The diversity and complexity of the fermentation ecosystem during wine making limits the successful prediction of wine characteristics. The use of selected starter cultures has allowed a better control of the fermentation process and the production of wines with established characteristics. Among them, the use of mixed fermentations with Starmerella bacillaris and Saccharomyces cerevisiae yeasts has gained attention in recent years due to the fructophylic nature of the first and the ability of this inoculation protocol to reduce the acetic acid and ethanol content of the wines.

Service crops in vineyard can provide multiple ecosystem services but they can also lead to competition with the grapevine for soil resources in the Mediterranean region due to potential severe droughts (Garcia et al., 2018). One of the levers of action to manage this competition is the choice of species adapted in terms of growth dynamics and water and nutrients’ needs. The objectives of this study were to determine the effect of temporary service crops on grapevine water and nitrogen status and grapevine yield and yield components in a Mediterranean vineyard.