AIM: In a recent study, it was determined that the mid-ripening period is the most suitable for the application of methyl jasmonate (MeJ), benzothiadiazole BTH and MeJ+BTH on Monastrell grapes, to favor maximum accumulation of phenolic compounds at the time of harvest. However, the increase in the anthocyanin content of grapes was not reflected in all the wines (Paladines-Quezada et al., 2021). For this reason, the aim of this work was to evaluate whether the application of two pre-harvest elicitors, MeJ and BTH on Monastrell grapes during two maturation stages, affects the composition and structure of their skin cell walls. METHODS: This study was conducted for two years (2016 and 2017) on Vitis vinifera L. cv Monastrell, located in Jumilla (southeast Spain). A foliar application was carried out with a water suspension of 2 elicitors: (MeJ) 10 mM; (BTH) 0.3 mM, and a mixture of both. The treatments were applied at different timings of ripening (at veraison and mid-ripening). For all treatments, a second application was performed 7 days after the first application. The composition of the berry skin cell wall was analyzed. RESULTS: MeJ and MeJ+BTH treatments applied at veraison had the greatest influence on the composition of the skin cell walls. They decreased the concentration of hemicellulose and pectic derivatives, and increased the concentration of lignin, proteins and phenols. On the other hand, BTH applied at veraison and mid-ripening was the only treatment that increased the concentration of cellulose in the skin cell walls. CONCLUSIONS: MeJ and MeJ+BTH treatments increased the concentration of the main components involved in cell wall strengthening. This fact can contribute to resistance to fungal attacks, but it can make it difficult to extract polyphenols from the skin during the maceration process.
Authors: Diego F., Paladines-Quezada – Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), Ctra. La Alberca s/n, 30150. Murcia-Spain,José I. FERNÁNDEZ-FERNÁNDEZ, IMIDA Juan D. MORENO-OLIVARES, IMIDA Juan A. BLEDA-SÁNCHEZ, IMIDA Rocío GIL-MUÑOZ, IMIDA
Keywords: methyl jasmonate, benzothiadiazole, veraison, mid-ripening