Harnessing Evolutionary Toxins for Signaling: Reactive Oxygen Species, Nitric Oxide and Hydrogen Sulfide in Plant Cell Regulation.

John T Hancock

doi:10.3389/fpls.2017.00189

Abstract

During the early periods of evolution, as well as in niche environments today, organisms have had to learn to tolerate the presence of many reactive compounds, such as reactive oxygen species, nitric oxide, and hydrogen sulfide. It is now known that such compounds are instrumental in the signaling processes in plant cells. There are enzymes which can make them, while downstream of their signaling pathways are coming to light. These include the production of cGMP, the activation of MAP kinases and transcription factors, and the modification of thiol groups on many proteins. However, organisms have also had to tolerate other reactive compounds such as ammonia, methane, and hydrogen gas, and these too are being found to have profound effects on signaling in cells. Before a holistic view of how such signaling works, the full effects and interactions of all such reactive compounds needs to be embraced. A full understanding will be beneficial to both agriculture and future therapeutic strategies.

Highlights

Reactive compounds such as those derived from oxygen, nitrogen, and sulfur are instrumental in cell signaling pathways (Mittler et al, 2011; Mur et al, 2013; García-Mata and Lamattina, 2013; Hancock and Whiteman, 2014)
Oxygen is a di-radical (Cheeseman and Slater, 1993) and undergoes redox reactions to yield a family of reactive compounds [the so called reactive oxygen species (ROS)], including the superoxide anion, hydrogen peroxide (H2O2) and the hydroxyl radical
Despite all this, cells still use ROS as signaling molecules (Mittler et al, 2011). It appears that the presence of oxygen in the atmosphere has had a profound influence in the evolution of aerobic organisms, as has been discussed by others (Lane, 2002; Dowling and Simmons, 2009; Metcalfe and Alonso-Alvarez, 2010)

Summary

INTRODUCTION

Reactive compounds such as those derived from oxygen, nitrogen, and sulfur are instrumental in cell signaling pathways (Mittler et al, 2011; Mur et al, 2013; García-Mata and Lamattina, 2013; Hancock and Whiteman, 2014). Despite all this, cells still use ROS as signaling molecules (Mittler et al, 2011) It appears that the presence of oxygen in the atmosphere has had a profound influence in the evolution of aerobic organisms, as has been discussed by others (Lane, 2002; Dowling and Simmons, 2009; Metcalfe and Alonso-Alvarez, 2010). The early atmosphere of the Earth’s history was rich in other noxious compounds, such as methane, ammonia, and hydrogen (Lane, 2002) Such compounds should be included in the suite of potential cell signaling molecules, giving a more holistic understanding of how all these compounds may be controlling cellular functions in plants

Roles of Reactive Signaling Compounds

Interactions of Reactive Signaling Compounds

CONCLUSION AND FUTURE DIRECTIONS

AUTHOR CONTRIBUTIONS