Dissecting Long-Term Adjustments of Photoprotective and Photo-Oxidative Stress Acclimation Occurring in Dynamic Light Environments

Abstract

Changes in light intensity directly affect the performance of the photosynthetic apparatus. Light energy absorbed in excess of cells’ needs leads to production of reactive oxygen species and photo-oxidative damage. Excess light in both constant and dynamic environments induces photoprotective acclimation in plants. Distinct sets of signals and regulatory mechanisms are involved in acclimatory adjustment of photoprotection and photosynthesis under constant and dynamic (fluctuating) light conditions. We are still far away from drawing a comprehensive picture of acclimatory signal transduction pathways, particularly in dynamic environments. In this perspective article, we propose the use of Arabidopsis plants that produce H2O2 in chloroplasts (GO plants) under atmospheric CO2 levels as a tool to study the mechanisms of long-term acclimation to photo-oxidative stress. In our opinion there are new avenues to future investigations on acclimatory adjustments and signal transduction occurring in plants under dynamic light environments.

No Time to Waste: Transcriptome Study Reveals that Drought Tolerance in Barley May Be Attributed to Stressed-Like Expression Patterns that Exist before the Occurrence of Stress

“…All this data suggest that root plastids form relatively large antenna complexes per reaction center, what is consistent with the enhanced grana formation and a high carotenoids accumulation that is responsible for thermal dissipation of energy (Kobayashi et al, 2013 ). Thus, the energy dissipation mechanisms that are highly active in root plastids may be responsible also for their anti-oxidative role during drought stress, by the analogy to the photoprotective function of these mechanisms in leaf chloroplasts (Matsubara et al, 2016 ). The specific function of several DEGs from presented study that may contribute to this process is discussed later.…”

Photosynthetic Acclimation to Fluctuating Irradiance in Plants

“…In the first seconds after an increase in irradiance, faster linear electron transport increases the concentrations of plastoquinol and reduced thioredoxin, Calvin Bassham Benson (CBB) cycle metabolites and glutathione (Choudhury et al, 2018b), which may participate in retrograde signaling. During these first seconds, singlet oxygen ( 1 O 2 ) is produced in the photosystem II reaction center and, although it is unlikely to diffuse out of the cytosol, it can reduce β-carotene to β-cyclocitral, which may trigger changes in nuclear gene expression (Matsubara et al, 2016). Within minutes, hydrogen peroxide (H 2 O 2 ) levels increase due to the activity of superoxide dismutase (Mubarakshina et al, 2010;Choudhury et al, 2018a); H 2 O 2 can then diffuse into the cytosol and interact with several nuclear gene expression mediators (Pfalz et al, 2012).…”

Fluctuating Light Interacts with Time of Day and Leaf Development Stage to Reprogram Gene Expression

“…As a result, the mutants develop small rosettes with patchy pale-green leaves under photorespiratory LL conditions and bleach under HL. Yet, this pale-green phenotype disappears when the mutants are grown under FL (Matsubara et al, 2016), suggesting an interplay between FL acclimation and H 2 O 2 scavenging and/or signaling. Reinforcement of H 2 O 2 detoxification under FL, as indicated by the up-regulation of GPX7 and CAT2 ( Fig.…”