• New Study Reveals How Plants Sense H2O2 to Regulate Immunity

    TIME: 18 Oct 2022
    Hydrogen peroxide (H2O2) is a ubiquitous molecule in all aerobic organisms. At high concentrations, H2O2 causes oxidative stress, whereas at low concentrations, H2O2 serves as an important secondary signal to regulate numerous biological processes including, but not limited to, plant-microbe interactions, abiotic stress tolerance, pollen tube growth, root hair formation, leaf cell expansion and casparian strip formation. However, the endogenous H2O2 concentrations are too low to efficiently oxidize most target proteins, and it remains to be shown how plants sense endogenous H2O2 to regulate biological processes.
     
    In a recent study published on Nature Plants (DOI:10.1038/s41477-022-01252-5), research group of Prof. ZHOU Jian-Min from the Institute of Genetics and Developmental Biology (IGDB), Chinese Academy of Sciences and their collaborators illustrate a redox relay, with peroxiredoxin B (PRXIIB) as a sensor for H2O2 and ABA insensitive 2 (ABI2) as a target protein, that mediate ROS signaling during plant immunity.  
     
    The production of H2O2 is a hallmark of plant immune system and plays a critical role in plant immunity, such as stomatal closure to limit pathogen entry. To investigate mechanisms by which H2O2 regulates plant stomatal immunity, the research group performed mass-spectrometry-based analysis termed SulfenQ, and showed that type II PRXIIB was directly oxidized at its peroxidatic cysteine by H2O2 generated upon immune activation.
     
    Furthermore, they showed that PRXIIB form disulfide-conjugates with ABI2, subsequently transducing H2O2 signal to ABI2. This oxidation dramatically sensitizes H2O2-mediated inhibition of the ABI2 phosphatase activity and is required for stomatal immunity in plants.
     
    This study establishes the link between endogenous H2O2 sensing and biological functions, and the mechanisms described in this study may serve as a paradigm for similar researches in plant stress acclimation and development in the future.
     
    Contact:
    Dr. ZHOU Jian-Min
    Institute of Genetics and Developmental Biology, Chinese Academy of Sciences

    Email: jmzhou@genetics.ac.cn