Influence of the carbonic maceration winemaking method on the colour features of Tempranillo red wines

Heat and water stress can accelerate berry sugar accumulation and lead to excessive sugar-to-acid ratios at harvest, producing bland, overly-alcoholic wines. Selecting grapevines for slower sugar accumulation could help maintain wine quality under future, hotter conditions, but these efforts have been stymied by our limited understanding of the traits determining sugar accumulation rates. Here, we measured traits characterizing the structure and anatomy of the sugar transport system – the phloem – in 16 winegrape cultivars and tested for relationships with sugar accumulation rates and cultivar climate classifications.

In the current scenario of climatic variability, even though the vine (Vitis vinifera) is a species generally considered very fertile, the process of bud differentiation is particularly influenced by the weather trend not only of the current year but also of the previous one.

Acidity adjustments are key to microbial control, sensory quality and wine longevity. Acidification with cation exchange resins -in acid cycle- offers the possibility to reduce the pH by exchanging wine cations, such as potassium (K+), for hydrogen ions (H+). During the exchange process, the removal of potassium and calcium ions contributes to limiting the formation of tartrate salts, thus offering an alternative solution to conventional methods for tartrate stability. Moreover, the reduction of wine pH and the removal of metals catalyzers (e.g. iron) could positively impact the wine’s oxidative stability. Therefore, the aims of this work were (a) to optimize the ion exchange process by testing different volumes and concentrations of sulfuric acid (H2SO4) during the acid cycle, (b) evaluate the effects of the ion exchange process on the formation of tartrate salts, and (c) analyze the oxidative stability of the treated wines.

Grafting plants uses intrinsic healing processes to join two different plants together to create one functional organism. To further our understanding of the molecular changes occurring during graft union formation in grapevine, we characterized the metabolome and transcriptome of intact and wounded cuttings (with and without buds to represent scions and rootstocks respectively), and homo- and heterografts at 0 and 14 days after wounding/grafting. As over-wintering, dormant plant material was grafted, we also characterized the gene expression changes in the wood during bud burst and spring activation of growth. We observed an asymmetrical pattern of gene expression between above and below the graft interface, auxin and sugar related genes were up-regulated above the graft interface, while genes involved in stress responses were up-regulated below the graft interface.

Pest biocontrol strategies are gaining attention as eco-friendly alternatives to the use of synthetic pesticides, including in viticulture.