Torres and Berlanga propose in a recent Spotlight article published in Molecular Plant that hydrogen peroxide forms, together with the calcium ion, several loops/circuits that amplify the regulatory signals, allowing the generation of a magnified response to stress situations.
Plants produce hydrogen peroxide (H2O2) not to kill microbes or cells but to act as a signal that activates and amplifies responses to pathogen attack or various environmental stresses. To do this, plant cells have some enzymes in the plasma membrane, NADPH oxidases, which produce this hydrogen peroxide that oxidizes some amino acids of proteins, modifying their activity. Thus, a few minutes after the attack or stress situation, H2O2 is produced, which acts as a signaling molecule and interacts with other plant signals such as calcium ion (Ca2+) or phosphorylation that also modify the activity of regulatory proteins, to generate the appropriate response.
The authors comment on an investigation carried out by Wang
Figure 1. Various amplification circuits increase H2O2 production and Ca2+ signaling in response to ABA (from -Torres and Berlanga. 2023. Molecular Plant, 16, 968970
Original Paper:
Torres, M.-Á., Berlanga, D.J. 2023. OsDMI3, a Ca2+/calmodulin kinase, integrates and amplifies H2O2 and Ca2+ signaling in ABA-mediated responses. Molecular Plant 16, 968–970. DOI: 10.1016/j.molp.2023.05.002