Specific profile of Tempranillo grapevines related to Esca-leaf symptoms and climate conditions

Esca is a destructive fungal disease affecting grapevines worldwide. In the Esca complex, grapevine leaf stripe disease (GLSD) designates specifically the disease that causes the typical leaf symptoms on infected vines. Understanding foliage alterations produced by GLSD may help to identify potential markers of tolerance to this disease. In this work, changes related to physiological parameters, photosynthetic pigments and phenolic compounds were evaluated. Moreover, the expression of 10 genes was tracked determined by quantitative reverse transcription-PCR. For this, symptomatic and asymptomatic vines from three different Tempranillo vineyards were evaluated. Vineyards differed in climate classification and water resources. Botryosphaeriaceae species and Esca causal agents (Phaeomoniella chlamydospora, Phaeoacremonium spp. and Fomitiporia mediterranea) were isolated and identified from symptomatic vines. Under water restriction, a significant decrease on the physiological activity of symptomatic vines was observed. Also, symptomatic leaves showed lower content on chlorophylls and carotenoids and some alterations on their phenolic profiles. GLSD symptoms induced the expression of defense-related genes, especially PR6, STS and Chit 1b. This research provides valuable information regarding physiological, chemical and molecular changes in Esca affected leaves of Tempranillo grown in vineyards related to the climate conditions.