Exploring diversity of grapevine responses to Flavescence dorée infection

The increasing frequency of wildfires in grape-growing regions is seen as a significant risk for the grape and wine industry.

The results of the first step of the zoning study carried out in Bolghery appellation area (Castagneto Carducci, Tuscany) in the 1993-1995 period have been recently published. Quality factors of Bolgheri appellation and different “terroirs ” were identified.

The frequency of bushfires close to wine regions around the world has increased in the last two decades. The economic losses incurred when grapes and wines are discarded due to ‘smoke taint’ are substantial (i.e., hundreds of millions of dollars). Efforts to mitigate and ameliorate smoke taint are therefore crucial. Chardonnay, rosé and cabernet sauvignon wines made from grapes exposed to smoke during the 2020 wildfires in eastern Australia were subjected to various amelioration techniques: the addition of activated carbons, molecularly imprinted polymers (mips), and a proprietary resin (either directly, or following membrane filtration); spinning cone column (scc) distillation; and finally, transformation into vinegar.

Over the last decade, the use of non-Saccharomyces yeasts in the winemaking process has been re-assessed and accepted by winemakers. These yeasts can be used to achieve specific objectives such as lowering the ethanol content, preventing wine spoilage and increasing the production of specific aroma compounds. Since these species are unable to complete alcoholic fermentation, strategies of co- and sequential inoculation of non-Saccharomyces and Saccharomyces cerevisiae have been developed. However, when mixed starter cultures are used, several parameters (e.g. strain yeast, inoculation timing and nutrient competitions) impact the growth of the individual yeasts, the fermentation kinetics and the metabolites/aroma production. In particular, competition for nitrogen compounds could have a major impact, potentially leading to sluggish fermentation when the yeast assimilable nitrogen (YAN) availability is low. Moreover, many aroma compounds produced by the yeasts are directly produced and influenced by nitrogen metabolism such as higher alcohols, acetate esters and ethyl esters which participate in the organoleptic complexity of wine.

The phenolic profiles of little known red grape cultivars, namely Garnacho, Moribel and Tinto Fragoso, which are autochthonous from the Spanish region of La Mancha (ca. 600,000 ha of vineyards) have been studied over the consecutive seasons of years 2013 and 2014. The study was separately performed over the skins, the pulp and the seeds, and comprised the following phenolic types: anthocyanins, flavonols, hydroxycinnamic acid derivatives (HCADs), total proanthocyanidins (PAs) and their structural features. The selected grape cultivars belong to the Vine Germplasm Bank created in this region in order to preserve the great diversity of genotypes grown in La Mancha.