Chapter 8 Use of Transgenic Plants to Uncover Strategies for Maintenance of Redox Homeostasis During Photosynthesis

Abstract Plant cells encounter a spectacular variation in the supply and consumption of redox components, due to changes in photosynthesis caused by the environment. To prevent these huge fluxes from causing catastrophic oxidative damage, there is an extensive network of compensatory, buffering mechanisms. These must be integrated with signaling cascades in a greater redox network, to ensure that short-term responses are adequate and that, if buffering capacity is exceeded, there is a response at the transcript level. Transgenic approaches have been fundamental in identifying the interconnections between redox fluxes, buffering, and signaling networks. In this review we discuss how this has shaped current understanding, and how transgenics might be used in the future to unravel the complex network required for energy metabolism, redox homeostasis, autotrophic growth and development under changing conditions. There are obvious problems associated with describing a highly interconnected network in the linear format of a written review, but we attempt this by first describing how redox poise is maintained in electron transport chains, move on to buffering pathways throughout the cell, and finally describe the mechanisms that detect signals, leading to interpretation of these changes at the level of altered transcription.