Antioxidant and signaling functions of the plastoquinone pool in higher plants

Abstract

The review covers data representing the plastoquinone pool as the component integrated in plant antioxidant defense and plant signaling. The main goal of the review is to discuss the evidence describing the plastoquinone‐involved biochemical reactions, which are incorporated in maintaining the sustainability of higher plants to stress conditions. In this context, the analysis of the reactions of various redox forms of plastoquinone with oxygen species is presented. The review describes how these reactions can constitute both the antioxidant and signaling functions of the pool. Special attention is paid to the reaction of superoxide anion radicals with plastohydroquinone molecules, producing hydrogen peroxide as signal molecules. Attention is also given to the processes affecting the redox state of the plastoquinone pool because the redox state of the pool is of special importance for antioxidant defense and signaling.

Zinc Uptake, Photosynthetic Efficiency and Oxidative Stress in the Seagrass Cymodocea nodosa Exposed to ZnO Nanoparticles

“…A relationship between closed reaction centers ( q p ) and increased H 2 O 2 generation was noticed (Figure 9, Figure 10, Figure 11). The PQ pool is considered as the component integrated in plant antioxidant defense [55], which at a 12 h of exposure mediated the generation of chloroplastic H 2 O 2 [22], acting as a fast acclimation-signaling molecule [55,56].…”

“…Closed reaction centers ( q p ) indicate excess photon supply and associated ROS production [57,58,59]. This photosynthesis derived H 2 O 2 is moving throughout leaf veins, serving as a signaling molecule and triggering a stress-defense response [22,35,44,55,56,60,61]. Thus, this stress-defense response triggered a significant increase of the fraction of open PSII reaction centers ( q p ) (Figure 8) and a significant increase of Φ PSΙΙ (Figure 5a) and ETR (Figure 7a) observed after 24 h exposure of C. nodosa to 10 mg L −1 ZnO NPs; while at the same time, H 2 O 2 generation decreased to control levels (Figure 11e).…”

Oxygen and ROS in Photosynthesis

“…ROS are known to participate in retrograde signaling, acclimation to biotic or abiotic stresses, programmed cell death (PCD) and many other processes (for recent reviews, see [9][10][11][401][402][403][404][405][406][407]). Here, we aim to briefly summarize what is known (and what is not) about how chloroplast-derived ROS are sensed and how the signaling cascades are initiated.…”

Leaf Age-Dependent Effects of Foliar-Sprayed CuZn Nanoparticles on Photosynthetic Efficiency and ROS Generation in Arabidopsis thaliana

“…The intracellular ROS signaling pathways are initiated by the redox state of the PQ pool that regulates photosynthetic gene expression, comprising also a mechanism of plant acclimation [38,63,64]. The redox state of the PQ pool is of unique significance for antioxidant defense and signaling [65]. It has been shown recently that ROS generation is influenced also by the circadian system [66,67].…”