Mobilizing endogenous transposable elements for grapevine improvement: a genomic and epigenomic approach in New Zealand Sauvignon Blanc

Retrotransposons, particularly of the Ty-Copia and Ty-Gypsy superfamilies, represent the most abundant and widespread transposons in many plant genomes. Grapevine is no exception and it is clear that these mobile elements have played a major role in the evolution of Vitaceae genomes. While speculation abounds around the possible role of transposons in plant genomes, outside of the rather obvious involvement of retrotransposition in fueling genome expansion, there is little clarity of the actual role these elements have in both developing new genetic variation and in modulating epigenetic responses within genomes to changing climate. To this end we have been exploring de-novo assembled Sauvignon blanc and Pinot noir genomes with a view to catalogue retrotransposon loci to determine the structural intactness and thus age of insertion variation across a small number of clonal linages of these 2 varietals in an attempt to identify ‘live’ TE loci.

The cultivar with a greater oenological potential was ‘Monastel’, which showed overall better values than ‘Tempranillo’ in colour intensity, total polyphenol index, wine colour, total anthocyanins, resveratrol and gallic acid.

The designations of origin of the Loire Valley wine have been recognized according to customs and notoriety established over the centuries since the Middle Ages. There are four main production basins going up the Loire, from Nantes to the Sancerrois region: Nantes, Anjou-Saumur, Touraine and the vineyards of the Centre. In each of these basins, there is a wide range of appellations of origin which has been established according to a logic which may not seem obvious to the uninformed.

This study investigated if compositional differences between Shiraz and Cabernet Sauvignon grape varieties could influence the production of yeast-derived compounds. This work was based on the analysis of 40 experimental red wines made in triplicate fermentations from grapes harvested from two consecutive vintages in New South Wales (Australia). Grapes were picked at three maturity stages using berry sugar accumulation as physiological indicator, from nine commercial vineyards located in three different climatic regions (temperate, temperate-warm and warm-hot). A range of 30 yeast-derived wine volatiles including esters and alcohols were quantified by HS/SPME-GC/MS. Ammonia, amino-acids and lipids were analysed in the corresponding grapes. The juice total soluble solids (°Brix) in addition to the wine alcohol and residual sugar levels were also measured. The influence of grape maturity on wine ester composition was also variety dependent, particularly for higher alcohol acetate and ethyl ester of branched acids. This study highlights that varietal differences observed in Shiraz and Cabernet Sauvignon wines involve fermentation-derived compounds irrespective of the site (soil, climate, viticultural practices).

After the onset of grape berry ripening, phloem unloading follows an apoplasmic route into the mesocarp tissue. In the apoplast, most of the unloaded sucrose is cleaved by cell wall invertases