The role of phytoplasma effector interaction with phosphoglucomutase in the pathogenicity of ‘Candidatus Phytoplasma solani’ in grapevine 

Tannins are very important for grape and wine quality, since they participate in several organoleptic wine characteristics such as astringency perception, bitterness, and the colour stability. The compositions in tannins in grapes and wines differs between seeds and skins. Tannin seeds contain a higher concentration of tannins than skin and has been associated with a coarse and more tannic notes in wines, by contrast, tannin skin are related to a greater softness in the wines.

Yeast-derived aroma compounds are the result of different and complex biochemical pathways that mainly occur during alcoholic fermentation. Many of them are related -but not limited- to the availability of nutrients in the fermentation medium and linked to nitrogen metabolism and biomass produced. Besides, the metabolic phase of yeast also regulates the expression of many enzymes involved in the formation of aroma active compounds. The work investigates the overall effect of continuous supplementation of nutrients during alcoholic fermentation of a grape must on the volatile composition of wines.

SO2 is used during winemaking for its anti-oxidative and anti-microbial properties. A high SO2 concentration in the wine has negative impacts by hiding wine aromas and delaying malolactic fermentation.

Temperature and yeast nutrition profoundly impact wine quality and sensory attributes by modulating yeast aroma production and release during fermentation. While temperature and nitrogen’s individual effects are well-studied, their combined influence, including nutrient type and addition timing, remains underexplored. hence, this study aimed to investigate the simultaneous effects of these factors on fermentation kinetics, aroma production and sensory profile, particularly in a Chardonnay wine production selected as a quite aromatically neutral base.

Vegetative propagation of grapevines can generate spontaneous somatic variations, providing a valuable source for cultivar improvement. In this context, natural variation in the composition of phenolic compounds in grapevine berries and seeds stands as a pivotal factor in crafting wines with diverse oenological profiles from the same cultivar. To deepen on the understanding of the physiological and genetic mechanisms driving somatic variation in grape phenolics, here we characterized a somatic variant from Tempranillo Tinto, the clone VN21, that exhibits an intense reduced berry skin cuticle and increased extractability of phenolic compounds during wine fermentation.