Influence of the photoperiod on redox regulation and stress responses in Arabidopsis thaliana L. (Heynh.) plants under long- and short-day conditions

Abstract

Arabidopsis thaliana L. (Heynh.) plants were grown in low light (150 micromol photons m(-2) s(-1) and 20 degrees C) either in short days (7.5 h photoperiod) or long days (16 h photoperiod), and then transferred into high light and low temperature (350-800 micromol photons m(-2) s(-1) at 12 degrees C). Plants grown in short days responded with a rapid increase in NADP-malate dehydrogenase (EC 1.1.1.82) activation state. However, persisting overreduction revealed a new level of regulation of the malate valve. Activity measurements and Northern-blot analyses indicated that NADP-malate dehydrogenase transcript and protein levels increased within a few hours. Using macroarrays, additional changes in gene expression were identified. Transcript levels for several enzymes of glutathione metabolism and of some photosynthetic genes increased. The cellular glutathione level increased, but its redox state remained unchanged. A different situation was observed in plants grown in long-day conditions. Neither NADP-malate dehydrogenase nor glutathione content changed, but the expression of several antioxidative enzymes increased strongly. We conclude that the endogenous systems that measure day length interact with redox regulation, and override the interpretation of the signals, i.e. they redirect redox-mediated acclimation signals to allow for more efficient light usage and redox poising in short days to systems for the prevention of oxidative damages when grown under long-day conditions.

The Dynamics of Photosynthesis

“…When low lightgrown plants under a short-day photoperiod (7.5 h photoperiod) were transferred to high light, both the level of transcript and protein for NADP-malate-dehydrogenase increased (29). This was not observed when low light-grown plants under a long photoperiod (16 h) were switched to high light.…”

Glyphosate-induced oxidative stress in rice leaves revealed by proteomic approach

“…The up-regulation of MDH has also been reported in different plant species under several stresses [22] including herbicides [13]. It has been hypothesized that an alteration in the chloroplast redox state caused by abiotic stresses is responsible for the release of redox signals, which in turn activate the transcription of several nuclear-encoded genes, among them NADP-MDH [22]. In addition, recently it has been revealed that a glucose catabolism associated enzyme such as MDH was markedly increased in young poplar leaves following exposure to ozone, suggesting that glucose catabolism could partly be due to a need for energy and reducing power for detoxification and the repair of damage caused by oxidative molecules [7].…”

“…We identified an up-regulated MDH from both the herbicide-treated samples. The up-regulation of MDH has also been reported in different plant species under several stresses [22] including herbicides [13]. It has been hypothesized that an alteration in the chloroplast redox state caused by abiotic stresses is responsible for the release of redox signals, which in turn activate the transcription of several nuclear-encoded genes, among them NADP-MDH [22].…”

Signalling crosstalk in light stress and immune reactions in plants

“…These characteristics position RE in a regulatory network, which seems to functionally interconnect photoperiodic growth, amino acid homoeostasis and ROS signalling in Arabidopsis leaves [48,50,51]. Indeed, the photoperiod is emerging as a key environmental factor that modulates plant responses to organellar ROS signals [2,22,48,[52][53][54][55][56].…”