title: Kaolin exogenous application boosts antioxidant capacity and phenolic content in berries and leaves of grapevine under summer stress.
abstract: Heat waves, high light intensities and water deficit are becoming important threats in many important viticultural areas worldwide, so the implementation of efficient and cost-effective mitigation strategies is crucial for the production of premium wines while maintaining productivity. In this context, the foliar application of kaolin, a chemically inert mineral with excellent reflective properties, is being developed and experimented as a strategy to reduce the impact of heat and drought in Douro vineyards (Northern Portugal), already revealing promising results. In the present study we investigated if an improved antioxidant capacity is part of the beneficial effects of kaolin, by studying changes in the enzymatic and nonenzymatic antioxidant system in leaves and berries (cv Touriga Nacional). Results showed that mature grape berries contained higher amounts of total phenols (40%), flavonoids (24%), anthocyanins (32%) and vitamin C (12%) than fruits from control vines, and important changes were also measured in leaves. In parallel, kaolin application improved the antioxidant capacity in berries, which was correlated with the observed increased content in secondary metabolites. Kaolin application also regulated secondary metabolism at the transcriptional level through the increase in the transcript abundance of genes encoding phenylalanine ammonia lyase and chalcone synthase.
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Apt. 1013, 5000-801 Vila Real, Portugal. Electronic address: liatdinis@utad.pt.
authors.forename: L-T
authors.initials: LT
authors.lastname: Dinis
authors.affiliation: School of Agriculture Sciences Veterinary ECAV, University of Trás-os-Montes Alto Douro, Apt. 1013, 5001-801 Vila Real, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Bernardo
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Apt. 1013, 5000-801 Vila Real, Portugal; Grupo de Investigação em Biologia Vegetal Aplicada e Inovação Agroalimentar (AgroBioPlant), Departamento de Biologia, Universidade do Minho, 4710-057 Braga, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Conde
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Apt. 1013, 5000-801 Vila Real, Portugal; Grupo de Investigação em Biologia Vegetal Aplicada e Inovação Agroalimentar (AgroBioPlant), Departamento de Biologia, Universidade do Minho, 4710-057 Braga, Portugal.
authors.forename: D
authors.initials: D
authors.lastname: Pimentel
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Apt. 1013, 5000-801 Vila Real, Portugal.
authors.forename: H
authors.initials: H
authors.lastname: Ferreira
authors.affiliation: Life Sciences and Environment School, University of Trás-os-Montes and Alto Douro, Apt. 1013, 5001-801 Vila Real, Portugal; Laboratory Animal Science, Institute for Molecular and Cell Biology, University of Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Félix
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Apt. 1013, 5000-801 Vila Real, Portugal; Grupo de Investigação em Biologia Vegetal Aplicada e Inovação Agroalimentar (AgroBioPlant), Departamento de Biologia, Universidade do Minho, 4710-057 Braga, Portugal; Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: H
authors.initials: H
authors.lastname: Gerós
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Apt. 1013, 5000-801 Vila Real, Portugal.
authors.forename: C M
authors.initials: CM
authors.lastname: Correia
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Apt. 1013, 5000-801 Vila Real, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Moutinho-Pereira
mesh_terms: D000872:Anthocyanins / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000187:drug effects; D005419:Flavonoids / Q000378:metabolism; D005638:Fruit / Q000187:drug effects / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007616:Kaolin / Q000494:pharmacology*; D010636:Phenols / Q000378:metabolism*; D010936:Plant Extracts / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011891:Rain; D017382:Reactive Oxygen Species / Q000378:metabolism; D012621:Seasons; D013312:Stress, Physiological / Q000187:drug effects*; D013696:Temperature; D014158:Transcription, Genetic / Q000187:drug effects; D027843:Vitis / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D007616:Kaolin; D001205:Ascorbic Acid
keywords: Antioxidants; Oxidative stress; ROS; Scavenging systems; Vitis vinifera