title: Dissecting the integrative antioxidant and redox systems in plant mitochondria. Effect of stress and S-nitrosylation.
abstract: Mitochondrial respiration provides the energy needed to drive metabolic and transport processes in cells. Mitochondria are a significant site of reactive oxygen species (ROS) production in plant cells, and redox-system components obey fine regulation mechanisms that are essential in protecting the mitochondrial integrity. In addition to ROS, there are compelling indications that nitric oxide can be generated in this organelle by both reductive and oxidative pathways. ROS and reactive nitrogen species play a key role in signaling but they can also be deleterious via oxidation of macromolecules. The high production of ROS obligates mitochondria to be provided with a set of ROS scavenging mechanisms. The first line of mitochondrial antioxidants is composed of superoxide dismutase and the enzymes of the ascorbate-glutathione cycle, which are not only able to scavenge ROS but also to repair cell damage and possibly serve as redox sensors. The dithiol-disulfide exchanges form independent signaling nodes and act as antioxidant defense mechanisms as well as sensor proteins modulating redox signaling during development and stress adaptation. The presence of thioredoxin (Trx), peroxiredoxin (Prx) and sulfiredoxin (Srx) in the mitochondria has been recently reported. Cumulative results obtained from studies in salt stress models have demonstrated that these redox proteins play a significant role in the establishment of salt tolerance. The Trx/Prx/Srx system may be subjected to a fine regulated mechanism involving post-translational modifications, among which S-glutathionylation and S-nitrosylation seem to exhibit a critical role that is just beginning to be understood. This review summarizes our current knowledge in antioxidative systems in plant mitochondria, their interrelationships, mechanisms of compensation and some unresolved questions, with special focus on their response to abiotic stress.
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Lázaro
authors.affiliation: Department of Stress Biology and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas Murcia, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Jiménez
authors.affiliation: Department of Stress Biology and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas Murcia, Spain.
authors.forename: Daymi
authors.initials: D
authors.lastname: Camejo
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Iglesias-Baena
authors.affiliation: Department of Stress Biology and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas Murcia, Spain.
authors.forename: María Del Carmen
authors.initials: Mdel C
authors.lastname: Martí
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Lázaro-Payo
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Barranco-Medina
authors.affiliation: Department of Stress Biology and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas Murcia, Spain.
authors.forename: Francisca
authors.initials: F
authors.lastname: Sevilla
keywords: S-nitrosylation; abiotic stress; ascorbate-glutathione cycle; mitochondria; peroxiredoxin; signaling; sulfiredoxin; thioredoxin