Oxidative Stress: Antagonistic Signaling for Acclimation or Cell Death?

Abstract

Severe environmental stress imposed on plant tissues induces changes in oxygen (O 2 ) metabolism that cause oxidative stress. Oxidative stress occurs when reactive oxygen species (ROS) are not rapidly scavenged and the rate of repair of damaged cell components fails to keep pace with the rate of damage. If this situation persists, irreversible damage results in a loss of physiological competence and eventual cell death. However, ROS production in leaves resulting from moderate environmental stresses, within the adaptive range of the plant, also has important local and systemic signaling roles. In these circumstances, ROS production induces defense mechanisms that protect the plant but do not result in oxidative stress. We shall illustrate ROS involvement in signaling in both of these situations by considering the role of chloroplasts in initiating cellular responses to environmental perturbations, choosing examples where this organelle interacts with specific signaling pathways.

Periodic root branching in Arabidopsis requires synthesis of an uncharacterized carotenoid derivative

“…S2 G and H). Also, if CPTA treatment resulted in substantial damage, the seedlings might not be expected to recover if CPTA were removed (33,34). Seedlings germinated on CPTA-containing growth medium were transferred to standard growth medium at 5 das and assayed for recovery.…”

Incompatibilidade de enxertia em Prunus

“…Este comportamento tem sido amplamente relacionado a diferentes formas de estresses em tecidos vegetais e resulta em dano oxidativo secundário, devido ao acúmulo de espécies reativas de oxigênio (ROS), como o peróxido de hidrogênio (H 2 O 2 ) (CARNEIRO et al, 2012;WANG et al, 2012). As ROS têm potencial de interagir com muitos componentes celulares e a sua alta concentração gera estresse oxidativo, podendo levar à morte celular, que, quando ocorre, se caracteriza por necrose dos tecidos (GAO et al, 2008;MULLINEAUX & BAKER, 2010;IAKIMOVA et al, 2013), sintoma comum na região de união de combinações incompatíveis.…”

Influence of plastids on light signalling and development

“…Thus, plastid-to-nucleus signalling broadly affects plant cells by optimizing chloroplast function and helping to coordinate extrachloroplastic processes with chloroplast function. Known plastid signals include hydrogen peroxide, 3 0 -phosphoadenosine 5 0 -phosphate, b-cyclocitral, methylerythritol cyclodiphosphate, thiols and particular proteins [2,3,9,13,15]. Nonetheless, our knowledge of plastid signals and plastid-to-nucleus signalling mechanisms is incomplete.…”

“…Plastidto-nucleus signalling affects numerous plastidic and extraplastidic processes, such as the biogenesis of chloroplasts and amyloplasts [3][4][5][6], the circadian rhythm [7,8], DNA replication [3], the transcription of genes that encode ribosomal RNA by RNA polymerase I [9], development [10] and the optimization of photosynthesis to various qualities of light [3]. Plastid-to-nucleus signalling also contributes to the response to wounding, biotic stress, abiotic stress and sugar [2,3,9,[11][12][13][14]. Thus, plastid-to-nucleus signalling broadly affects plant cells by optimizing chloroplast function and helping to coordinate extrachloroplastic processes with chloroplast function.…”

“…Extraplastidic signalling mechanisms, plastid-to-nucleus signalling mechanisms and the integration of these signalling mechanisms are major regulators of photosynthesis-associated nuclear genes (PhANGs) [1][2][3]. Plastidto-nucleus signalling affects numerous plastidic and extraplastidic processes, such as the biogenesis of chloroplasts and amyloplasts [3][4][5][6], the circadian rhythm [7,8], DNA replication [3], the transcription of genes that encode ribosomal RNA by RNA polymerase I [9], development [10] and the optimization of photosynthesis to various qualities of light [3].…”