Peroxidase 12 (POX12)

Peroxidase 12 (POX12) is a secreted class III peroxidase from maize (Zea mays) that plays a critical role in the plant's innate immune system. It is primarily located in the apoplast, where it catalyzes the production of reactive oxygen species (ROS), such as hydrogen peroxide, during the early stages of pathogen infection. This process, known as the oxidative burst, is essential for strengthening the plant cell wall through the oxidative cross-linking of polymers like lignin. Reinforcement of the cell wall provides a physical barrier that restricts the penetration and spread of pathogens. POX12 is a specific target of the fungal effector protein Pep1, which is secreted by the corn smut fungus Ustilago maydis. Pep1 directly binds to and inhibits the enzymatic activity of POX12, effectively suppressing the host's oxidative burst. This inhibition allows the fungus to evade the plant's early immune defenses and establish a successful biotrophic infection. While not a target for human pharmaceuticals, POX12 is a significant target in agricultural biotechnology for developing crops with enhanced resistance to fungal diseases. Research into POX12 also provides insights into the conserved mechanisms of plant-pathogen co-evolution.

Other names

ZmPOX12Maize peroxidase 12Class III peroxidase 12POX12

Pep1 acts as a biological inhibitor that binds to the apoplastic peroxidase POX12, blocking its enzymatic activity and thereby suppressing the production of reactive oxygen species (ROS) and the subsequent oxidative burst.