Impact of foliar symptoms of "Esca proper" on proteins related to defense and oxidative stress of grape skins during ripening.

Esca is one of the major diseases affecting vineyards with direct impact on product yield; nevertheless, scientific studies concerning its impact on grape quality are scarce. As an attempt to better understand the mechanisms behind "Esca proper" development in grapes, this work focused on the identification of proteins whose expression is altered by the disease. 2-DEs were performed on protein extracts from grape skins at different stages of maturity for two consecutive vintages. Grapes were collected in 2009 and in 2010 from plants that did not present signs of infection by Esca proper since the 2004 vintage and from plants that presented cast leaf symptoms at least once since 2004. For the first time, 13 proteins were shown to be influenced by Esca proper during the ripening process. Extensive bioinformatics analysis allowed the grouping of proteins involved in (i) stress tolerance and defense response, (ii) oxidative phosphorylation, (iii) oxidation-reduction processes in mitochondria, and (iv) oxidation-reduction processes in chloroplasts. Of these 13 proteins, cysteine synthase is the only one implicated in a metabolic pathway of oenological interest. This study shows how foliar symptoms of Esca proper may impact stress-related pathways in grapes, which are characterized by modifications in the chain of oxidative phosphorylation and redox scavenging.