Mathematical modeling of fermentation kinetics: a tool to better understand interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae in mixed cultures

Actually, many countries around the world are studying different strategies for adapting winegrowing regions to climate changes, focusing on a sustainable viticulture.

Climate change presents a challenge for agriculture worldwide. Yet, crop productivity is negatively impacted by abiotic hazards such as high temperatures and water deficit.

Phenolic compounds are very importants in crop plants, which is why there have been the subject of a large number of studies

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.

Climate change is increasing the frequency of water deficit in many grape-growing regions. Grapevine varieties differ in their stomatal behavior during water deficit, and their ability to regulate water potential under dry soil conditions is commonly differentiated using the concept of isohydricity. It remains unclear whether stomatal behavior, water potential regulation, and the resulting degree of isohydricity has a relationship with changes to fruit growth during water deficit. This study was conducted on four varieties (`Cabernet Franc`, `Semillon`, `Grenache`, and `Riesling`) subjected to both short-term, severe water deficit and long-term, moderate water deficit applied at both pre- and post-veraison.