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

Under standard wine tasting conditions, volatile organic compounds (VOCs) responsible for the wine’s bouquet progressively invade the glass headspace above the wine surface. Most of wines being complex water/ethanol mixtures (with typically 10-15 % ethanol by volume), gaseous ethanol is therefore undoubtedly the most abundant VOC in the glass headspace [1]. Yet, gaseous ethanol is known to have a multimodal influence on wine’s perception [2]. Of particular importance to flavor perception is the effect of ethanol on the release of aroma compounds into the headspace of the beverage [1].

New Plant Breeding Techniques (NPBTs) have arisen with the objective of surmounting the constraints inherent in conventional breeding methodologies, thereby enhancing plant resilience against both biotic and abiotic stresses. To date the application of genome editing in grapevine is still limited by the necessity to overcome recalcitrance to produce embryogenic calli and to regenerate plants. In our studies, we developed a smart and versatile genetic transformation system carrying all the most promising features of different genome editing approaches. In specific, we joined the GRF-GIF expression to improve regeneration, the systemic movement of the editing transcripts through tRNA-like sequences (TLS) and the cisgenic-like approach to remove transgenes.

Vineyards are strongly exposed to fungal diseases, attacks from insects and competition with weeds. Most treatments used on grape vines contain synthetic active substances, which may be transferred to the wine. Such pesticides have a negative image because many active substances are potential health hazards. A specific oenological treatment allowing the reduction of pesticide residues in wine based on activated vegetable fibres (AVF) is under examination by the International Organisation for Vine and Wine. This technique works efficiently and alters the wine only little (Lempereur et al. 2014).

This study aims at evaluating the effects of different refermentation methods (Martinotti/Charmat vs. Classic) on the chemical composition, aroma profile and sensory characteristics of Ribolla Gialla sparkling wines; furthermore, certain winemaking practices (skin contact and use of pectolytic enzymes) were investigated considering the extraction of varietal aromas and aroma precursors. METHODS: Sparkling wines were produced at pilot-plant scale. Concerning refermentation methods, traditional Martinotti (MB – 30 days length), extended Martinotti (ML) with 4 months of aging on lees and Classic method (CL) with 11 months of aging on lees were compared; in a second trial, skin contact (MM), enzyme addition on must also subjected to maceration (ME), and enzyme addition on base wine (VE) were evaluated. All experimental trials were performed in triplicate. Basic chemical composition, varietal (terpenes and C13-norisoprenoids in free and bound form) and non-varietal aroma compounds were evaluated by LLE-GCMS analysis; finally, sensory analysis was also performed, by descriptive testing.

Pratiquement tout le territoire d’Istrie possède les bonnes conditions naturelles pour la viticulture, laquelle dans ce lieu a une tradition millénaire. La viticulture était et reste toujours la plus importante branche de production agraire et d’économie. Les sites viticoles en Istrie sont caractérisés par des diverses conditions naturelles.