title: Physiology of pepper fruit and the metabolism of antioxidants: chloroplasts, mitochondria and peroxisomes.
abstract: OBJECTIVE
  Pepper (Capsicum annuum) contains high levels of antioxidants, such as vitamins A and C and flavonoids. However, information on the role of these beneficial compounds in the physiology of pepper fruit remains scarce. Recent studies have shown that antioxidants in ripe pepper fruit play a key role in responses to temperature changes, and the redox state at the time of harvest affects the nutritional value for human consumption. In this paper, the role of antioxidant metabolism of pepper fruit during ripening and in the response to low temperature is addressed, paying particular attention to ascorbate, NADPH and the superoxide dismutase enzymatic system. The participation of chloroplasts, mitochondria and peroxisomes in the ripening process is also investigated.
  Important changes occur at a subcellular level during ripening of pepper fruit. Chloroplasts turn into chromoplasts, with drastic conversion of their metabolism, and the role of the ascorbate-glutathione cycle is essential. In mitochondria from red fruits, higher ascorbate peroxidase (APX) and Mn-SOD activities are involved in avoiding the accumulation of reactive oxygen species in these organelles during ripening. Peroxisomes, whose antioxidant capacity at fruit ripening is substantially affected, display an atypical metabolic pattern during this physiological stage. In spite of these differences observed in the antioxidative metabolism of mitochondria and peroxisomes, proteomic analysis of these organelles, carried out by 2-D electrophoresis and MALDI-TOF/TOF and provided here for the first time, reveals no changes between the antioxidant metabolism from immature (green) and ripe (red) fruits.
  
  
  CONCLUSIONS
  Taken together, the results show that investigation of molecular and enzymatic antioxidants from cell compartments, especially chloroplasts, mitochondria and peroxisomes, is a useful tool to study the physiology of pepper fruit, particularly in the context of expanding their shelf-life after harvest and in maintaining their nutritional value.
authors.affiliation: Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain and josemanuel.palma@eez.csic.es.
authors.forename: José M
authors.initials: JM
authors.lastname: Palma
authors.affiliation: Group of Abiotic Stress, Production and Quality, Department of Biology of Stress and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura, CSIC, Campus Universitario Espinardo, 30100 Murcia, Spain.
authors.forename: Francisca
authors.initials: F
authors.lastname: Sevilla
authors.affiliation: Group of Abiotic Stress, Production and Quality, Department of Biology of Stress and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura, CSIC, Campus Universitario Espinardo, 30100 Murcia, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Jiménez
authors.affiliation: Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain and.
authors.forename: Luis A
authors.initials: LA
authors.lastname: del Río
authors.affiliation: Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain and.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Corpas
authors.affiliation: Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, Apartado 419, 18080 Granada, Spain and.
authors.forename: Paz
authors.initials: P
authors.lastname: Álvarez de Morales
authors.affiliation: Group of Abiotic Stress, Production and Quality, Department of Biology of Stress and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura, CSIC, Campus Universitario Espinardo, 30100 Murcia, Spain.
authors.forename: Daymi M
authors.initials: DM
authors.lastname: Camejo
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002212:Capsicum / Q000502:physiology*; D002736:Chloroplasts / Q000378:metabolism; D005638:Fruit / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism; D020675:Peroxisomes / Q000378:metabolism
chemical_list: D000975:Antioxidants
keywords: Antioxidants; Capsicum annuum; NADPH; ascorbate; chloroplasts; low temperature; mitochondria; pepper fruit; peroxisomes; proteomics; reactive oxygen and nitrogen species; ripening; superoxide dismutase