ROS Regulation During Abiotic Stress Responses in Crop Plants

Abstract

Abiotic stresses such as drought, cold, salt and heat cause reduction of plant growth and loss of crop yield worldwide. Reactive oxygen species (ROS) including hydrogen peroxide (H2O2), superoxide anions (O2•-), hydroxyl radical (OH•) and singlet oxygen (1O2) are by-products of physiological metabolisms, and are precisely controlled by enzymatic and non-enzymatic antioxidant defense systems. ROS are significantly accumulated under abiotic stress conditions, which cause oxidative damage and eventually resulting in cell death. Recently, ROS have been also recognized as key players in the complex signaling network of plants stress responses. The involvement of ROS in signal transduction implies that there must be coordinated function of regulation networks to maintain ROS at non-toxic levels in a delicate balancing act between ROS production, involving ROS generating enzymes and the unavoidable production of ROS during basic cellular metabolism, and ROS-scavenging pathways. Increasing evidence showed that ROS play crucial roles in abiotic stress responses of crop plants for the activation of stress-response and defense pathways. More importantly, manipulating ROS levels provides an opportunity to enhance stress tolerances of crop plants under a variety of unfavorable environmental conditions. This review presents an overview of current knowledge about homeostasis regulation of ROS in crop plants. In particular, we summarize the essential proteins that are involved in abiotic stress tolerance of crop plants through ROS regulation. Finally, the challenges toward the improvement of abiotic stress tolerance through ROS regulation in crops are discussed.

Leaf Development Monitoring and Early Detection of Water Deficiency by Low Field Nuclear Magnetic Resonance Relaxation in Nicotiana tabacum Plants

“…LWW 3 measured in leaves of leaf rank 4 (Figure 5f) was around 360 g·m −1 and did not change between the two stages in control plants. At 42 DAS, water stress or the addition of the TIMAC SL28 had no effect on the amount of water in old leaves expressed in LWW 3 . At the second stage (57 DAS), the LWW 3 increased significantly up to 430 g·m 2 in leaves of the water stressed plants, this increase was not observed in plants treated with the TIMAC SL28.…”

“…Drought stress can also have a negative impact on plants at other levels, including limiting growth [2], and creating oxidative stress [3]. Water stress thus negatively affects the quantity and quality of the yield of most crops.…”

Free Radicals and Antioxidant System in Seed Biology

“…Cellular antioxidant mechanisms control ROS concentrations, rather than to eliminate them completely, suggesting that some ROS may act as signaling molecules [5,[34][35][36][37]46]. Although ROS have been considered as detrimental to seeds, advances in plant physiology evaluated them as messengers of various signal transduction pathways in plants.…”

“…Although ROS have been considered as detrimental to seeds, advances in plant physiology evaluated them as messengers of various signal transduction pathways in plants. ROS are suggested as being beneicial for seed germination, seedling growth, protection against pathogens and controlling the cell redox status [28][29][30][31][32][33][34][35][36][37][38][39][40]. H 2 O 2 is shown to be involved in the tolerance to various abiotic stresses acting as a secondary messenger [71], in cellular defense mechanisms against pathogens [72].…”

“…ROS are also proved to act as a positive signal in seed dormancy release [30][31][32][33]. The dual function of ROS in plants depends on the levels of antioxidant compounds, and enzyme activities release [34][35][36][37][38]. By this way, plants can eliminate potentially harmful ROS that is produced under stress conditions, or control ROS concentrations in order to regulate various signaling pathways [34][35][36][37][38].…”