Nitrogen forms and Iron deficiency: how do Grapevine rootstocks responses change?

Recently, foliar treatments with mineral-based compounds have shown positive effects on grapevine production by protecting grape from thermal excesses and reducing the decoupling between technological and phenolic maturity caused by climate change. Unraveling the effect of mineral particle applications on grape-associated microbes is pivotal for successful wine processing, due to the influence of the microbiota on wine composition and stability. To our knowledge, this is the first work that comprehensively studied the effects of kaolin and chabasite-rich zeolitites treatments on grape-related microorganisms (by real-time PCR quantification of total fungi, Hanseniospora uvarum, Metschnikowia pulcherrima, plant-associated bacteria and lactic acid bacteria), the expression of genes related to the flavonoid biosynthesis (PAL1, CHS1, F3H2, DFR, LDOX, UFGT, MYBA1, GST4, FLS4 genes) and the berry composition (°Brix, pH, acidity and anthocyanin concentrations) in cv. Sangiovese during ripening in two growing seasons (2019 and 2020).

Grape composition is strongly influenced by climate conditions. Their expected modifications in near future, notably because of increased temperatures, could significantly modify the biochemical composition of berries at harvest, and thus wine typicity and quality. Elevated temperatures favor sugar accumulation in grapes, enhance malic acid degradation and modify the amino acid content. They also reduce significantly anthocyanin accumulation in Merlot, leading to the imbalance between anthocyanins and sugars, while no significant effects on final anthocyanin levels were reported in Tempranillo[1] and finally affect aromas or aroma precursors.

The application of remote and proximal sensing is a fast and efficient method to monitor grapevine vegetative and physiological parameters and is considered valuable to derive information on associated yield and quality traits in the vineyard. Further details can be obtained by the application of molecular analysis at the gene expression level aiming at elucidating how pathways controlling the formation of different grape quality traits are influenced by spatial variability. This work aims at evaluating intra-vineyard variability in grape composition at harvest and at comparing this with remotely sensed canopy vegetation data and molecular-based approaches.

The use of oenological additives is becoming a common practice due to the technological and sensory properties they provide to the wines. However, the number of studies focused on the impact that these additives might induce on wine flavor perception during wine tasting is still quite scarce. The aim of this work was to evaluate the effect of three different types of common oenological additives: two oenotannins (ellagitannin and gallotannin) and a commercial preparation of yeast mannoproteins on the long-lasting flavor perception (aroma and astringency).

Tropical fruit aromas in wines are thought to be important to wine consumers, although there is little research to confirm this statement. With so many wine styles available, it has become important to understand the qualities that are desirable to consumers and how to achieve those qualities. Thiols and esters are compounds that have been found to cause tropical fruit aromas in chardonnay (ref). Fermentation temperature gradients and skin contact were found to increase these compounds using micro scale fermentations. This work aimed to scale up these fermentations/operations to determine if the desired tropical fruit aromas could still be achieved and if there is a perceivable difference in tropical fruit aromas, liking, and emotional response in the wines at the consumer level.