title: Differential phenolic production in leaves of Vitis vinifera cv. Alvarinho affected with esca disease.
abstract: Esca is a destructive disease of complex etiology affecting grapevines worldwide. A major constraint to the study and control of esca is that the disease is not diagnosed until external leaf and/or fruit symptoms are visible; however external symptoms usually appear several years after infection onset. We studied the phenolic content of V. vinifera cv. Alvarinho leaves using high performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS)/LC-MS. Leaves from affected cordons with and without visible symptoms (diseased and apparently healthy leaves, respectively) and leaves from asymptomatic cordons (healthy leaves) were analyzed. Application of principal components analysis (PCA) to HPLC data showed a clear separation between diseased, apparently healthy, and healthy leaves, with the apparently healthy leaves clustered in a medial position. Several compounds were highly correlated with diseased leaves indicating a differential phenolic production due to esca disease in V. vinifera cv. Alvarinho leaves. Total phenolic production was shown to significantly increase in diseased leaves, compared to healthy leaves, with apparently healthy leaves containing a medial amount. Trans-caffeoyltartaric acid, trans-coumaroyl-tartaric acid, quercetin-3-O-glucoside, quercetin-3-O-galactoside, kaempferol-3-glucoside and myricetin were identified among the compounds associated with disease and their content shown to change similarly to total phenolic production. This study shows that it is possible to discriminate between diseased, healthy and apparently healthy leaves by applying PCA to HPLC data.
authors.affiliation: Universidade do Minho, Departamento de Biologia, CITAB - Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas, Campus de Gualtar, 4710-057 Braga, Portugal. Electronic address: mrmlima@ucdavis.edu.
authors.forename: Marta R M
authors.initials: MRM
authors.lastname: Lima
authors.affiliation: Universidade do Minho, Departamento de Biologia, CITAB - Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Mafalda L
authors.initials: ML
authors.lastname: Felgueiras
authors.affiliation: Universidade do Minho, Departamento de Biologia, CITAB - Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Cunha
authors.affiliation: Divisão de Protecção e Controlo Fitossanitário, Laboratório de Protecção das Culturas, Estrada Exterior da Circunvalação nº11846, 4460-281 Senhora da Hora, Portugal.
authors.forename: Gisela
authors.initials: G
authors.lastname: Chicau
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, CEBAS (CSIC), Campus Universitario de Espinardo. Murcia. E-30100, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Ferreres
authors.affiliation: Universidade do Minho, Departamento de Biologia, CITAB - Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Alberto C P
authors.initials: ACP
authors.lastname: Dias
mesh_terms: D018533:Biomass; D002851:Chromatography, High Pressure Liquid; D010636:Phenols / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism* / Q000382:microbiology*; D025341:Principal Component Analysis; D053719:Tandem Mass Spectrometry; D027843:Vitis / Q000378:metabolism* / Q000382:microbiology*
chemical_list: D010636:Phenols
keywords: Esca; Flavonoids; Grapevine; High performance liquid chromatography (HPLC); Hydroxycinnamoyl tartaric acids; Principal components analysis (PCA); Vitis vinifera