Glutathione-mediated plant response to high-temperature

Abstract

In the context of the climate change, global rise of temperature as well as intense heat waves affect plant development and productivity. Among the molecular perturbations that high temperature induces in living cells is the accumulation of reactive oxygen species (ROS), which can damage macromolecules of the cell and perturb the cellular redox state. To cope with deleterious effects of ROS, plant, as other organisms, have developed strategies to scavenge ROS and to regulate their redox state. Among those, glutathione plays a major role in maintaining the cellular redox state and the function of key antioxidant enzymes like peroxidases. Here, we investigated the contribution of the redox systems in plant adaptation to high temperature. We studied two different high temperature regimes: a rise of ambient temperature to 27C inducing a plant developmental adaptation program called thermomorphogenesis, and a 37C treatment mimicking intense heat wave and affecting plant viability. Using the genetically encoded redox marker roGFP, we show that high temperature regimes lead to cytoplasm and nuclear oxidation and impact profoundly the glutathione pool rather than the glutathione redox state. Moreover, plant can restore the pool within a few hours, which likely contribute to plant adaptation to high temperature. However, conditional glutathione deficient mutants fail to adapt to intense heat waves or to induce thermomorphogenesis, suggesting that glutathione is involved in both heat adaptation mechanisms. We also evaluate by RNAseq analyses, how plant change its genome expression signature upon heat stress and identified a marked genome expression deviation in the glutathione deficient mutant which might contribute to their sensitivity to high temperature. Thus, we define glutathione as a major actor in the adaptation of plant to contrasting high temperature regimes.

Chloroplasts lacking class I glutaredoxins are functional but show a delayed recovery of protein cysteinyl redox state after oxidative challenge

“…Regarding mutants lacking all class I GRX of one compartment, double null mutants of A. thaliana lacking cytosolic GRXC1 and GRXC2 were originally described to be lethal (Riondet et al, 2012) but have recently been reported to be viable and with a WT-like phenotype (Schlößer et al, 2023). In the secretory pathway, which lacks a GR and thus possesses a less reducing E GSH , double mutants of GRXC3/GRXC4 grow normally (Schlößer et al, 2023) but showed decreased hypocotyl length compared to WT when grown in elevated temperature (Dard et al, 2022). Regarding plastid-targeted class I GRX, no null mutants were described yet.…”