Electrical stimulation: An abiotic stress generator for enhancing anthocyanin and resveratrol accumulation in grape berry

Plants are known to utilize electrical signals under several physiological conditions and electrical stimulation from the outside induces physiological changes in plants. In this study, to improve grape berry composition in field-grown grapevines, electrical stimulation of grapevine using solar panels was undertaken as an abiotic stress generator in 2015 and 2016 growing seasons. Electrical stimulation had a notable effect on grapevine growth and development as well as photosynthetic performance. Berry weight and tartaric acid and total phenolic contents in berries of grapevines exposed to electrical stimulation were similar among the grapevines tested. Brix in berries of grapevines exposed to electrical stimulation and electrode-treated grapevines was higher than that in control grapevines in both years. Electrical stimulation increased anthocyanin and resveratrol contents in berries of grapevines in both years relative to those of control grapevines and electrode-treated grapevines. The alteration of Brix and anthocyanin and resveratrol contents in berries was supported by the results of microarray analysis demonstrating the transcriptional upregulation of genes related to sucrose metabolism, phenylpropanoid biosynthesis, flavonoid biosynthesis, stilbenoid biosynthesis, and anthocyanin biosynthesis in grape cells exposed to electrical stimulation. Taken together, the results suggested that electrical stimulation of grapevine enhanced anthocyanin and resveratrol biosynthesis by activating their biosynthetic pathways.