Freeze-thaw temperature oscillations promote increased differential gene expression during grapevine bud dormancy

Climate change and harvest date decisions have led to the evolution of must quality over the last decades. Increases in must sugar concentrations are among the most obvious consequences, quantitatively. Saccharomyces cerevisiae is a robust and acid tolerant organism. These properties, its sugar to ethanol conversion rate and ethanol tolerance make it the ideal production organism for wine fermentations. Unfortunately, high sugar concentrations may affect S. cerevisiae and lead to growth inhibition or yeast lysis, and cause sluggish or stuck fermentations. Even sublethal conditions cause a hyperosmotic stress response in S. cerevisiae which leads to increased formation of fermentation by-products, including acetic acid, which may exceed legal limits in some wines.

Sulla base del tema assegnatomi è stata forte la tentazione di addentrarmi nel labirinto della regolamentazione comunitaria. Per buona pace degli intervenuti ho ritenuto, pero, poco utile una elencazione di numeri e riferimenti normativi che saranno brevemente riassunti in una tabella (TAB 1),

English version: Result of their history, some famous French wine countries such as Burgundy, Bordeaux or Alsace, have a hierarchical organization of their Appellations of Controlled Origin (AOC): AOC regional, communal, Premier Cru, Grand Cru.

The professional winegrower usually selects the harvest date considering several elements, such as the vine stem and berry colour, the flavour, appearance and grain elasticity. Nowadays these elements have turned old fashioned.

Wine viticulture, being firmly linked to the vine-terroir relationship, has always encountered significant bottlenecks to genetic innovation. Nonetheless, the development of new breeding strategies leading to the selection of stress resilient genotypes is urgent, especially in viticulture, where it would allow reducing the use of chemical treatments adopted to control fungal diseases. Genome editing represents an extremely promising breeding technique. Unfortunately, the well-known recalcitrance of several wine grape cultivars to in vitro regeneration strongly limits the exploitation of this approach, which to our knowledge has so far been developed on table grape genotypes with high regeneration potential.