Modification on grape phenolic and aromatic composition due to different leafroll virus infections

Abstract

Viral diseases are reported to cause several detrimental effects on grapevine. Among them, leafroll, due to single or mixed infection of GLRaV1 and GLRaV3, and rugose wood, associated to GVA, are considered the most widespread and dangerous. The scarce literature available indicates the grape phenolic compounds are involved in the vine/virus interaction with possible important implications on red wine quality. In recent time also the grape aromatic compounds are regarded with great interest for their qualitative contribution to the evolution of red wine during aging. In order to investigate the alterations in berry phenolic and aromatic composition due to these viruses, in 2008 the healthy and theinfected (GLRaV1+GVA or GLRaV3+GVA) descendants of two clones of ‘Nebbiolo’ (Vitis vinifera L.) were compared ina vineyard of north-west Italy. Despite GLRaV1 and GLRaV3 are both casual agents of leafroll the quantitative and qualitative response of the vines changed depending on the specific virus. GLRaV1+GVA infection basically reduced yield and berry phenols. In addition the profile of berry anthocyanins was modified in favour of less stable di- substituted anthocyanins. GLRaV3+GVA infection mainly penalized grape soluble solids but increased the amount of bound aromatic compounds. Further investigations are needed, nevertheless the results confirmed leafroll viruses may negatively affect the vine behaviors thus potentially influencing the quality of the wines.