Hydrogen Peroxide: Its Role in Plant Biology and Crosstalk with Signalling Networks

Abstract

Hydrogen peroxide (H₂O₂) is steadily gaining more attention in the field of molecular biology research. It is a major REDOX (reduction⁻oxidation reaction) metabolite and at high concentrations induces oxidative damage to biomolecules, which can culminate in cell death. However, at concentrations in the low nanomolar range, H₂O₂ acts as a signalling molecule and in many aspects, resembles phytohormones. Though its signalling network in plants is much less well characterized than are those of its counterparts in yeast or mammals, accumulating evidence indicates that the role of H₂O₂-mediated signalling in plant cells is possibly even more indispensable. In this review, we summarize hydrogen peroxide metabolism in plants, the sources and sinks of this compound and its transport via peroxiporins. We outline H₂O₂ perception, its direct and indirect effects and known targets in the transcriptional machinery. We focus on the role of H₂O₂ in plant growth and development and discuss the crosstalk between it and phytohormones. In addition to a literature review, we performed a meta-analysis of available transcriptomics data which provided further evidence for crosstalk between H₂O₂ and light, nutrient signalling, temperature stress, drought stress and hormonal pathways.

Keywords: H2O2; growth and development; plant hormone; signalling; stress.

Figure 1

Key enzymes of hydrogen peroxide metabolism in plants. The list shows enzymes that directly catalyse hydrogen peroxide production or degradation in Arabidopsis, including the numbers of different isozymes, a comparison of relative gene expression profiles in seedlings, roots and shoots and the figure indicates subcellular localization. Colour coding: anabolic processes (green), catabolic processes (red), based on UniProt [16], SUBA 3.0 [17] and average gene expression profiles in 45, 24 and 7 NGS experiments for seedlings, leaf and root respectively (ThaleMine [18]).

Figure 2

Hydrogen peroxide-mediated processes in plant growth and development. This figure summarizes our present-day knowledge about the role of H₂O₂ in the life of plants as described, with references, in Section 5. ABA—abscisic acid, AUX—auxin, BR—brassinosteroids, ET—ethylene, GA—gibberellins, SA—salicylic acid, JA—jasmonic acid, AOX—amine oxidases, PRX—peroxidases, RBOH—NADPH oxidases, PCD—programmed cell death. The water droplet shape indicates flooding and absence of water, for hypoxia and drought, respectively.