Résumé
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•Microvines guaiacol applications affect positively glycosylated aroma precursors.•The highest aroma impact after guaiacol application takes place at grape ripening stages.•Geraniol aglycone increment was 50 higher in treated Microvine fruits than control.•Guaiacol could be used as an elicitor to enhance the varietal aroma differentiation.
Previous field-grown experiments were carried out to study the effect of guaiacol spraying on the accumulation of aromatic compounds in grapevine fruits and their wines. It was shown that such treatments increase guaiacol glycoconjugates in leaves, shoots and fruits of Monastrell variety (Vitis vinifera), where there was a release of aglycone compounds during wine processing, modulating the final wine aromatic profile, not only in terms of guaiacol. However, it remains unstudied the effect on the glycosylated grape aroma precursors pool and the time of their maximum expression. Nowadays, it is possible to use a model vine known as Microvine (DRCF-Dwarf Rapid Cycling and Continuous Flowering) to perform original physiological studies on fruit development in controlled environments. Therefore, the aim of this work was to use the Microvine model to study the effect of guaiacol sprays in such fraction when applied at several fruit developmental stages. The applications were carried out from phenological stage BBCH 71 (fruit set: young fruits begin to swell, remains of flowers lost) to BBCH 85 (softening of berries), to reveal stage-specific responses of the accumulation of glycosylated aroma precursors at BBCH 89 (berries ripe for harvest). Here, it is showed that guaiacol is an elicitor of the accumulation of glycosylated aromatic compounds in the fruit, with a higher efficiency when applied during ripening stages. Especially significant was the geraniol accumulation increment which was fiftyfold higher than in control ones.