Strategies to maintain redox homeostasis during photosynthesis under changing conditions

Abstract

Plants perform photosynthesis and assimilatory processes in a continuously changing environment. Energy production in the various cell compartments and energy consumption in endergonic processes have to be well adjusted to the varying conditions. In addition, dissipatory pathways are required to avoid any detrimental effects caused by over-reduction. A large number of short-term and long-term mechanisms interact with each other in a flexible way, depending on intensity and the type of impact. Therefore, all levels of regulation are involved, starting from energy absorption and electron flow events through to post-transcriptional control. The simultaneous presence of strong oxidants and strong reductants during oxygenic photosynthesis is the basis for regulation. However, redox-dependent control also interacts with other signal transduction pathways in order to adapt metabolic processes and redox-control to the developmental state. Examples are given here for short-term and long-term control following changes of light intensity and photoperiod, focusing on the dynamic nature of the plant regulatory systems. An integrating network of all these mechanisms exists at all levels of control. Cellular homeostasis will be maintained as long as the mechanisms for acclimation are present in sufficiently high capacities. If an impact is too rapid, and acclimation on the level of gene expression cannot occur, cellular damage and cell death are initiated.

Redox potential (Eh) and pH as drivers of soil/plant/microorganism systems: a transdisciplinary overview pointing to integrative opportunities for agronomy

“…Severe protein oxidation is costly to the cell since oxidatively-damaged proteins need to be degraded by specific proteases (Sweetlove et al 2009). Conversely, dissipatory pathways are required to avoid any detrimental effects caused by over-reduction of the cellular redox state (Scheibe et al 2005).…”

“…The simultaneous presence of strong oxidants and strong reductants during oxygenic photosynthesis is the basis for regulation (Scheibe et al 2005). Glutathione, glutaredoxins and ascorbate are involved in a large variety of cellular processes and play a crucial role in response to oxidative stress and control of reactive oxygen species (ROS) Mullineaux and Rausch 2005;Noctor and Foyer 1998;Sanchez-Fernandez et al 1997;Xing et al 2006).…”

“…Shortterm and long-term mechanisms interact with each other in a flexible way, depending on intensity and the type of impact (Scheibe et al 2005). Cellular homeostasis will be maintained as long as the mechanisms for acclimation are present in sufficiently high capacities.…”

“…Cellular homeostasis will be maintained as long as the mechanisms for acclimation are present in sufficiently high capacities. If an impact is too rapid, and acclimation at the level of gene expression cannot occur, cellular damage and cell death are initiated (Scheibe et al 2005).…”

“…For instance, understanding the structure and the function of cell compartmentalization for Eh and pH was crucial to understanding fundamental processes in cell physiology (Hansen et al 2006;Scheibe et al 2005). At another scale, Hinsinger et al (2009) consider that it is urgent to improve the methodology for describing the physical architecture of the rhizosphere on a micro-scale and to express these findings to interpret the data in respect of their functional relevance.…”