Reactive Oxygen Species: A Crosslink between Plant and Human Eukaryotic Cell Systems

Abstract

Reactive oxygen species (ROS) are important regulating factors that play a dual role in plant and human cells. As the first messenger response in organisms, ROS coordinate signals in growth, development, and metabolic activity pathways. They also can act as an alarm mechanism, triggering cellular responses to harmful stimuli. However, excess ROS cause oxidative stress-related damage and oxidize organic substances, leading to cellular malfunctions. This review summarizes the current research status and mechanisms of ROS in plant and human eukaryotic cells, highlighting the differences and similarities between the two and elucidating their interactions with other reactive substances and ROS. Based on the similar regulatory and metabolic ROS pathways in the two kingdoms, this review proposes future developments that can provide opportunities to develop novel strategies for treating human diseases or creating greater agricultural value.

Keywords: ROS scavenging; cellular response; oxidative stress; reactive oxygen species (ROS); regulatory factors.

Figure 1

External factors generate ROS directly/indirectly (e.g., heavy metals, UV) in plants, which then regulate functions via CDKs/MAPKs affecting transcription and the cell cycle, and control cell death via calcium, mitochondria, and chloroplasts, with ROS waves activating defense. (A) External environmental factors can generate ROS directly or indirectly, such as heavy metal ions, ultraviolet radiation, etc., which generate ROS through oxidation. Some pathogens can generate ROS by stimulating miRNAs, regulatory proteins, and phytohormones. (B,C) After ROS is produced, it mainly regulates plant-related functions through two pathways. The first pathway (B), as indicated by the black line, activates or inhibits the activity of CDK- and MAPK-related proteins due to the concentration of ROS, thus affecting the activity of downstream transcription factors and the expression of related genes, and ultimately controlling peroxidases, non-enzymatic antioxidants, and related events in the cell cycle progression. The second pathway (C), as indicated by the blue line, controls programmed cell death by affecting calcium pools, mitochondria, and chloroplasts. (D) Calcium ions are transported through calcium channels to activate RBOH and produce ROS in the extracellular space. ROS can freely enter and exit cells through water channel proteins. (E) ROS waves can be formed to transmit throughout the plant, activating PTI and SAR. “Parts of the figure were drawn by using pictures from Servier Medical Art. Servier Medical Art by Servier is licensed under a Creative Commons Attribution 3.0 Unported License (https://creativecommons.org/licenses/by/3.0/ (accessed on 20 October 2022))”.

Figure 2

ROS act as messengers to affect regulating pathways and control immunity, triggered by external factors. Meanwhile, mitochondrial issues cause ROS leakage, leading to diseases and apoptosis. (A) As indicated by the black line, certain signaling molecules promote ROS production via receptor activation of associated proteins, and subsequently control the function of relevant pathways by affecting downstream CDKs, MAPKs, and transcription factors. (B) Some external factors can also lead to ROS production. (C) As shown by the blue line, mitochondrial dysfunction can cause ROS leakage, resulting in the occurrence of diseases and tumors, and ultimately leading to cell apoptosis. (D) As indicated by the orange line, ROS can regulate immune function by controlling transcription factors. “Parts of the figure were drawn by using pictures from Servier Medical Art. Servier Medical Art by Servier is licensed under a Creative Commons Attribution 3.0 Unported License (https://creativecommons.org/licenses/by/3.0/ (accessed on 20 October 2022))”.

Figure 3

The similarities and differences in ROS functions between plant and human. The yellow and green sections on the left and right represent the unique ROS functions in plants and humans, respectively. The middle section represents the shared ROS functions between the two.