Methyl jasmonate effect on Tempranillo (Vitis vinifera L.) grape phenolic content: A 2-year study

Resumen

There has been a great concern in recent years about the impact of climate change on viticulture. In particular, climate change is known to accelerate vine phenology and grape ripening, decoupling sugar-phenolic accumulation. The application of elicitor compounds could be an interesting strategy in order to face this problem. Elicitors are molecules able to trigger plant defense mechanisms, including the synthesis of phenolic compounds. Recent studies have shown that field applications of methyl jasmonate (MeJ) could increase grape phenolic content. Therefore, the aim of this work was to analyse the impact on grape phenolic composition of MeJ foliar application to Tempranillo grapevines over two consecutive vintages. The vineyard was located in Rioja Baja, which is the warmest and driest subarea of Rioja wine region. Grape phenolic composition was determined by HPLC. A two-way ANOVA evaluating treatment and vintage effect was applied. The study showed that stilbenes were greatly affected by the treatment. Moreover, total anthocyanins (i.e., non acylated type) were affected by both treatment and vintage while flavanols, flavonols and gallic acid were only affected by the vintage. Neither the treatment nor vintage influenced hydroxycinnamic acids. Based on these results, it could be concluded that MeJ exerted a greater effect on stilbenes and anthocyanins than on the rest of phenolic compounds. Increasing grape phenolic content might be of great interest in viticulture, especially in those areas in which it is difficult to achieve a proper balance between sugar accumulation and phenolic maturity.