title: Plant responses to stresses: Role of ascorbate peroxidase in the antioxidant protection.
abstract: When plants are exposed to stressful environmental conditions, the production of Reactive Oxygen Species (ROS) increases and can cause significant damage to the cells. Antioxidant defenses, which can detoxify ROS, are present in plants. A major hydrogen peroxide detoxifying system in plant cells is the ascorbate-glutathione cycle, in which, ascorbate peroxidase (APX) enzymes play a key role catalyzing the conversion of H(2)O(2) into H(2)O, using ascorbate as a specific electron donor. Different APX isoforms are present in distinct subcellular compartments, such as chloroplasts, mitochondria, peroxisome, and cytosol. The expression of APX genes is regulated in response to biotic and abiotic stresses as well as during plant development. The APX responses are directly involved in the protection of plant cells against adverse environmental conditions. Furthermore, mutant plants APX genes showed alterations in growth, physiology and antioxidant metabolism revealing those enzymes involvement in the normal plant development.
authors: Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors: Andréia
authors: A
authors: Caverzan
authors: Gisele
authors: G
authors: Passaia
authors: Silvia Barcellos
authors: SB
authors: Rosa
authors: Carolina Werner
authors: CW
authors: Ribeiro
authors: Fernanda
authors: F
authors: Lazzarotto
authors: Márcia
authors: M
authors: Margis-Pinheiro
keywords: abiotic stress; antioxidant system; ascorbate peroxidase; mutant plants; reactive oxygen species