Hydrogen Gas, ROS Metabolism, and Cell Signaling: Are Hydrogen Spin States Important?

Molecular hydrogen (H2) is now considered part of the suite of small molecules that can control cellular activity. As such, H2 has been suggested to be used in the therapy of diseases in humans and in plant science to enhance the growth and productivity of plants. Treatments of plants may involve the creation of hydrogen-rich water (HRW), which can then be applied to the foliage or roots systems of the plants. However, the molecular action of H2 remains elusive. It has been suggested that the presence of H2 may act as an antioxidant or on the antioxidant capacity of cells, perhaps through the scavenging of hydroxyl radicals. H2 may act through influencing heme oxygenase activity or through the interaction with reactive nitrogen species. However, controversy exists around all the mechanisms suggested. Here, the downstream mechanisms in which H2 may be involved are critically reviewed, with a particular emphasis on the H2 mitigation of stress responses. Hopefully, this review will provide insight that may inform future research in this area.

Section: Discussionmentioning

confidence: 97%

Downstream Signalling from Molecular Hydrogen

Hancock

Russell

2021

“…The presence of H 2 may alter antioxidant levels in cells [ 77 ] and so indirectly alter NO metabolism. However, there is also potential for a more direct interaction with H 2 and some nitrogen compounds [ 78 , 79 ]. Certainly, H 2 has been shown to have effects in plants [ 80 , 81 ] and has touted as a future treatment for plants [ 82 ].…”

Section: Interactions Of Nitric Oxide With Other Reactive Signalsmentioning

confidence: 99%

Nitric Oxide: Its Generation and Interactions with Other Reactive Signaling Compounds

Hancock

Neill

2019

Self Cite

Nitric oxide (NO) is an immensely important signaling molecule in animals and plants. It is involved in plant reproduction, development, key physiological responses such as stomatal closure, and cell death. One of the controversies of NO metabolism in plants is the identification of enzymatic sources. Although there is little doubt that nitrate reductase (NR) is involved, the identification of a nitric oxide synthase (NOS)-like enzyme remains elusive, and it is becoming increasingly clear that such a protein does not exist in higher plants, even though homologues have been found in algae. Downstream from its production, NO can have several potential actions, but none of these will be in isolation from other reactive signaling molecules which have similar chemistry to NO. Therefore, NO metabolism will take place in an environment containing reactive oxygen species (ROS), hydrogen sulfide (H2S), glutathione, other antioxidants and within a reducing redox state. Direct reactions with NO are likely to produce new signaling molecules such as peroxynitrite and nitrosothiols, and it is probable that chemical competitions will exist which will determine the ultimate end result of signaling responses. How NO is generated in plants cells and how NO fits into this complex cellular environment needs to be understood.

“…H 2 has been indicated to relieve abiotic stress in cells, thus improving responses to stress challenges in plants [73]. There are two spin states (para-and ortho-) of H 2 [77]. Some enzymes involved in ROS metabolism and signaling have been shown to be affected by magnetic fields.…”

Section: Heavy Metal Stressmentioning

confidence: 99%

“…Some enzymes involved in ROS metabolism and signaling have been shown to be affected by magnetic fields. The crosstalk between the magnetic field and H 2 was suggested to be a possible mechanism for changing cell functions [77]. Therefore, H 2 alleviates heavy metal toxicity mainly by decreasing ROS content and enhancing the activities of typical antioxidant enzymes.…”

Section: Heavy Metal Stressmentioning

confidence: 99%

Research Progress on the Functions of Gasotransmitters in Plant Responses to Abiotic Stresses

Yao

Yang

et al. 2019

Abiotic stress is one of the major threats affecting plant growth and production. The harm of abiotic stresses includes the disruption of cellular redox homeostasis, reactive oxygen species (ROS) production, and oxidative stress in the plant. Plants have different mechanisms to fight stress, and these mechanisms are responsible for maintaining the required homeostasis in plants. Recently, the study of gasotransmitters in plants has attracted much attention, especially for abiotic stress. In the present review, abiotic stressors were mostly found to induce gasotransmitter production in plants. Meanwhile, these gasotransmitters can enhance the activity of several antioxidant enzymes, alleviate the harmfulness of ROS, and enhance plant tolerance under various stress conditions. In addition, we introduced the interaction of gasotransmitters in plants under abiotic stress. With their promising applications in agriculture, gasotransmitters will be adopted in the near future.Plants 2019, 8, 605 2 of 23 unique and regulate specific biological functions. Gasotransmitters have long been of great interest in a wide range of fields. Over the past few decades, the roles of these signaling molecules have been extensively studied for their biological applications. Recently, the emissions of endogenous gasotransmitters in plants have been widely studied and analyzed, thereby providing information to facilitate our understanding of new gasotransmitter signaling pathways. Previous studies found that in response to abiotic stressors, plants usually produce these gasotransmitters [12][13][14]. In addition, there is now considerable evidence to show that gasotransmitters can play a pivotal role in enhancing plant tolerance [2,15,16]. Subsequently, biological gases from complex extra and intracellular pathways and gas mediators may regulate many processes in an antagonistic or synergistic way.In the present review, we introduce the production of gasotransmitters in plants under abiotic stress. Meanwhile, we focused on the recent advances in the roles of gasotransmitters under abiotic stresses and their interaction with other gasotransmitters.