External stimuli such as microbial infections, ultraviolet radiation, and chemical stressors can modulate the synthesis of polyphenols in the plants. Cv. ‘Refošk’ was used to show the influence of the GLRaV-1 and rugose wood (RW) on the polyphenols in grape. The infection shifted polyphenols from seeds to grape skins but had no impact on anthocyanins.