Rootstocks are among the main factors that influence grape development as well as fruit and wine composition. In this work, rootstock/scion interactions were studied using transcriptomic and metabolic approaches on leaves of the “Gaglioppo” variety, grafted onto 13 different rootstocks growing in the same vineyard. The whole leaf transcriptome of “Gaglioppo” grafted onto five selected rootstocks showed high variability in gene expression. In particular, significant modulation of transcripts linked to primary and secondary metabolism was observed. Interestingly, genes and metabolites involved in defense responses (e.g., stilbenes and defense genes) were strongly activated particularly in the GAG-41B combination, characterized in addition by the down-regulation of abscisic acid (ABA) metabolism. On the contrary, the leaves of “Gaglioppo” grafted onto 1103 Paulsen showed an opposite regulations of those transcripts and metabolites, together with the greater sensitivity to downy mildew in a preliminary in vitro assay. This study carried out an extensive transcriptomic analysis of rootstock effects on scion leaves, helping to unravel this complex interaction, and suggesting an interesting correlation among constitutive stilbenes, ABA compound, and disease susceptibility to a fungal pathogen.

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We report the results of an aging trial of Montepulciano d'Abruzzo D.O.C. wine in commercially available oak barrels that differed in the type of wood grain (extra fine and fine) and cooperage toasting conditions: medium (EVM), light (EVL), medium for a shorter time (CM), and, finally, a single short-time pretoasting stage at high temperature (ExpT). The chemical-physical composition, the volatile substances released by the wood, and the sensory characteristics of wines after 6 and 12 mo of aging were monitored. The differences observed were mainly in the concentration of volatile substances and the olfactory characteristics of the wines. The volatile compounds that could distinguish among the wines were the cis isomer of beta-methyl-gamma-octalactone, the ratio between cis and trans octalactone, vanillin, cyclotene, maltol, 5-methyl guaiacol, and the furfuryl compounds. The concentration of cis octalactone was influenced by the type of grain of the wood, while the cis/trans octalactones ratio varied depending on the toasting conditions used in the production of the barrels (the highest concentration was in EVL). In particular, the length of time (EVM compared with CM) and the temperature (EVM compared with EVL) of the toasting process influenced the concentration of vanillin, furfuryl alcohols, cis octalactone, and 5 methyl guaiacol. Among the olfactory descriptors, statistically significant differences were detected in the notes of caramel, toasty, spicy, green pepper, coconut, and wood.

Modifications in grape quality parameters induced by mixed infection with GFLV and GFkV, GLRaV-1 and GVA, and GLRaV-3 and GVA in three Nebbiolo clones were compared against healthy plants of the same clones in two experimental vineyards in Piemonte, northwest Italy. The aim of the study was to evaluate the effect of virus infection on the mechanical properties of the berry skin and the whole berry as assessed by texture analysis tests, and on the amount and quality of berry skin phenols. Differences were observed in grapevine vigour, yield and juice composition, depending on the viral status of the plants. The anthocyanin profile of the vines infected with GFV and GFkV and those infected with GLRaV-1 and GVA showed a lower percentage of the more stable tri-substituted malvidin-3-glucoside and a higher percentage of cyanidin and peonidin-3-glucosides. Texture analysis showed that the viruses may increase berry-skin thickness and reduce phenol extractability. These effects carry practical implications for wine quality.