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Climate Change & Redox Signaling

Team CCARS / Graham Noctor


Key objective : Unravelling the complexity of redox interactions in the control of plant stress responses at the metabolic and gene expression levels


Redox signaling and climate change

Recent years have witnessed an explosion of interest on reactive oxygen species (ROS) and related redox processes as regulators of numerous processes in plants. Antioxidant and redox factors play roles in modulating plant function in response to environmentally-induced changes in their status: they are therefore key targets for evaluating how plants will be affected by ongoing climate changes.

One focus of the team is on the function of the NADPH-dependent ascorbate-glutathione pathway in H2O2 metabolism and associated signaling. We have reported new information on the function of specific enzymes involved in this pathway and have published an integrated model able to quantitatively analyze this pathway within the integrated cellular network.


We have also reported that pathogenesis-related responses can be strongly activated by growing plants at high CO2, and that such effects are dependent on redox factors. The observations raise questions about interactions between primary metabolic pathways, redox, and biotic stress resistance within the context of ongoing increases in atmospheric CO2. Such questions will be analyzed within the context of the French ANR project “HIPATH” (2018-2022), which involves four IPS2 teams and is coordinated by the CCARS team.

Another focused topic in the team aims at understanding thioredoxin (TRX) related functions. These thiol-disulfide proteins are key redox actors in plants, modulating the activity of their target enzymes or providing reducing power for antioxidant systems in response to environmental cues. Plants TRXs correspond to a multigene family and are found in most subcellular compartments. Chloroplast TRX isoforms can have specific functions in carbon primary metabolism (regulation of Calvin-Benson cycle, chlorophyll biosynthesis, starch metabolism, …) and recent findings have extended their roles to  photosynthesis-unrelated functions. In Arabidopsis, we have recently shown new roles for Trxs y, a sub-class of plastidial TRXs, in seed physiology linked to hormonal signaling and in leaves linked with regulation of monodehydroascorbate reductase in the context of drought stress tolerance. Ongoing projects focus on the importance of redox proteins in heat stress tolerance in relationship with brassinosteroids (a class of hormones) in the model plant Arabidopsis and as molecular markers in wheat.


Interaction between metabolism and epigenetics in plant adaptation to climate change

Chromatin modifications require primary metabolites as substrates or cofactors. It remains largely unclear how epigenetics and metabolism are coordinated in plants under varying growth conditions.  We proposed models of interaction between epigenetics and metabolism to regulate plant growth and adaptation to environmental variation in two perspective reviews. We have been focusing research on the function of histone acetylation and methylation enzymes in epigenetic regulation of gene expression in responding to metabolic variation under changing growth conditions. In particular, we are interested in regulation of chromatin modifiers by cellular redox states and energetic levels in plants.