A multidisciplinary study on the effects of phloem-limited viruses on the agronomical performance and berry quality of Vitis vinifera cv. Nebbiolo.

Viral infections are known to have a detrimental effect on grapevine yield and performance, but there is still a lack of knowledge about their effect on the quality and safety of end products. Vines of Vitis vinifera cv. Nebbiolo clone 308, affected simultaneously by Grapevine leafroll-associated virus 1 (GLRaV-1), Grapevine virus A (GVA), and Rupestris stem pitting associated virus (RSPaV), were subjected to integrated analyses of agronomical performance, grape berry characteristics, instrumental texture profile, and proteome profiling. The comparison of performance and grape quality of healthy and infected vines cultivated in a commercial vineyard revealed similar shoot fertility, number of clusters, total yield, with significant differences in titratable acidity, and resveratrol content. Also some texture parameters such as cohesiveness and resilience were altered in berries of infected plants. The proteomic analysis of skin and pulp visualized about 400 spots. The ANOVA analysis on 2D gels revealed significant differences among healthy and virus-infected grape berries for 12 pulp spots and 7 skin spots. Virus infection mainly influenced proteins involved in the response to oxidative stress in the berry skin, and proteins involved in cell structure metabolism in the pulp.