title: Short-term UV-B radiation affects photosynthetic performance and antioxidant gene expression in highbush blueberry leaves.
abstract: The impact of increased artificial UV-B radiation on photosynthetic performance, antioxidant and SOD activities and molecular antioxidant metabolism responses in leaves of two highbush blueberry (Vaccinium corymbosum L. cv. Brigitta and Bluegold) genotypes was studied. Plants were grown in a solid substrate and exposed to 0, 0.07, 0.12 and 0.19 W m(-2) of biologically-effective UV-B irradiance for 0-72 h. Our findings show that net photosynthesis (Pn) decreased significantly in Bluegold, accompanied by a reduction in the effective quantum yield (ФPSII) and electron transport rate (ETR), especially at the highest UV-B irradiation. On the other hand, Brigitta showed a better photosynthetic performance, as well as a clear increment in the antioxidant activity response that could be associated with increased superoxide dismutase activity (SOD) in the early hours of induced UV-B stress in all treatments. At the molecular level, the expression of the three antioxidant genes evaluated in both genotypes had a similar tendency. However, ascorbate peroxidase (APX) expression was significantly increased (6-fold) in Bluegold compared to Brigitta. Thus, the reduction of Pn concomitant with a lower photochemical performance and a reduced response of antioxidant metabolism suggest that the Bluegold genotype is more sensitive to UV-B radiation, while Brigitta appears to tolerate better moderate UV-B irradiance in a short-term experiment.
authors.affiliation: Núcleo de Investigación en Producción Alimentaría (NIPA-UCT), Facultad de Recursos Naturales, Universidad Católica de Temuco, P.O. Box 56-D, Temuco, Chile; Escuela de Agronomía, Facultad de Recursos Naturales, Universidad Católica de Temuco, P.O. Box 56-D, Temuco, Chile. Electronic address: claudio.inostroza@uct.cl.
authors.forename: Claudio
authors.initials: C
authors.lastname: Inostroza-Blancheteau
authors.affiliation: Departamento de Ciencias Físicas, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, P.O. Box 54-D, Temuco, Chile; Center for Optics and Photonics, Universidad de Concepción, Casilla 4012, Concepción, Chile.
authors.forename: Patricio
authors.initials: P
authors.lastname: Acevedo
authors.affiliation: Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, P.O. Box 114-D, Santiago, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Loyola
authors.affiliation: Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, P.O. Box 114-D, Santiago, Chile.
authors.forename: Patricio
authors.initials: P
authors.lastname: Arce-Johnson
authors.affiliation: Departamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, P.O. Box 54-D, Temuco, Chile; Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, P.O. Box 54-D, Temuco, Chile.
authors.forename: Miren
authors.initials: M
authors.lastname: Alberdi
authors.affiliation: Departamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, P.O. Box 54-D, Temuco, Chile; Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, P.O. Box 54-D, Temuco, Chile.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Reyes-Díaz
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D029798:Blueberry Plants / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects*; D016166:Free Radical Scavengers / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D017343:Genes, Plant; D005838:Genotype; D010788:Photosynthesis / Q000235:genetics / Q000528:radiation effects*; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics* / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D045332:Photosystem II Protein Complex; D013482:Superoxide Dismutase
keywords: Antioxidant gene expression; Highbush blueberry; Photochemical parameters; Radical scavenging activity; UV-B radiation