Sameera Karumannil, Taiba Saeed, Mohd Tanveer Alam Khan, Mohammad Yusuf, Sajeesh Kappachery, Mayank Anand Gururani2025-06-0320259781032647692http://136.232.12.194:4000/handle/123456789/1308Hydrogen Peroxide: Signaling Mechanisms and Crosstalk in Plant Development and Stress Responses Edited ByMohd Tanveer Alam Khan, Taiba Saeed, Aqeel Ahmad, Qazi Fariduddin, Mohammad YusufHydrogen peroxide (H2O2) serves as a signaling molecule in plant cells. It acts as a secondary messenger in various signal transduction pathways, mediating responses to stress. It can activate specific proteins, transcription factors, and enzymes involved in stress responses, such as mitogen-activated protein kinases (MAPKs) and calcium-dependent protein kinases. While H2O2 is a reactive oxygen species (ROS) and can cause cellular damage, plants have antioxidant systems to manage its levels. Enzymes like catalase, peroxidase, and superoxide dismutase help detoxify excess H2O2. H2O2 is involved in strengthening the cell wall. It can activate the cross-linking of cell wall components, contributing to cell wall reinforcement and enhanced resistance to pathogens. High levels of H2O2 can induce programmed cell death as a defense mechanism against invading pathogens. This helps contain the spread of infections within the plant. H2O2 can modulate the expression of stress-responsive genes. Transcription factors like WRKY, NAC, and MYB are often involved in the regulation of genes related to stress responses, and their activation can be influenced by H2O2. H2O2 can modify proteins through oxidation of cysteine residues, affecting their activity. Redox-sensitive proteins, including kinases and phosphatases, are involved in signaling cascades triggered by H2O2. Enzymes involved in the synthesis of secondary metabolites, such as phenolics and flavonoids, are often upregulated in response to stress-induced H2O2. These compounds contribute to the plant’s defense against stress. The expression of genes encoding ROS-scavenging enzymes is induced by H2O2. This includes enzymes like catalase, peroxidase, and glutathione peroxidase, which help mitigate oxidative stress. Understanding the physiological and molecular aspects of plant H2O2 metabolism during stress conditions is crucial for developing strategies to enhance stress tolerance in crops and improve agricultural productivity. Researchers continue to investigate the intricate network of signaling pathways and gene regulatory networks associated with H2O2 in plant stress responses.en-USHydrogen peroxideCrosstalkReactive oxygen speciesProgramed Cell DeathBook chapter