Application of salicylic acid to cv. Muscat Hamburg grapes for quality improvement: Effects on typical volatile aroma compounds and anthocyanin composition of grapes and wines

Aromas and anthocyanins are important factors affecting grapes and wines quality. Monoterpenes are regarded as typical volatile aroma compounds in Muscat Hamburg grapes. In this study, we determined the effects of exogenous salicylic acid (SA) on anthocyanins and monoterpene components of Muscat Hamburg (Vitis vinifera) berries and wines. Berries were treated with aqueous solutions of SA (0.0, 50, 100 and 200 mg/L) at E-L 34 (berry color change stage) during 2018 and 2019 seasons. 50 mg/L salicylic acid (SA50) significantly increased the sum of anthocyanins contents in ripe berries, while 100 mg/L and 200 mg/L salicylic acid had the opposite effect. Additionally, SA50 significantly promoted the free or bound monoterpenes accumulation in mature grapes. The concentrations of geraniol, neral, geranic acid, nerol, nerol oxide, and phellandrene were higher in the wine produced from SA50 treatment grapes than in the wine produced from control groups. The SA50 treatments increased the transcription of some key genes related to monoterpene biosynthesis, namely, VviPNLinNer1, VviPNLinNer2, VviPNLNGl2, VviPNLNGl4, VviTer, and VviGT14, which accelerated the synthesis and accumulation of monoterpene components in grapes. Overall, these study findings can provide fundamental knowledge for future improvements to grape aromas and anthocyanins.

Automated summary

This study found that exogenous salicylic acid affected the anthocyanins and monoterpene compounds in Muscat Hamburg grapes. The treatment of 50 mg/L salicylic acid significantly increased the anthocyanins content and promoted the accumulation of free or bound monoterpenes in mature grapes. It also increased the concentration of monoterpene components in the wine and accelerated the synthesis and accumulation of monoterpene components in grapes by upregulating key genes related to monoterpene biosynthesis. These findings provide fundamental knowledge for future improvements to grape aromas and anthocyanins.