Class III peroxidase: An essential enzyme for enhancing plant physiological and developmental process by maintaining the ROS level: A review

Since plants are sessile organisms, they are inevitably exposed to various environmental stresses, and the accumulation of reactive oxygen species (ROS) could affect the growth and development of plants. ROS play either positive or negative roles in various plant life activities as a two-edge sword. Class III peroxidase (CIII PRX) is a highly conserved antioxidant enzyme family specifically identified in plants, which is involved in maintaining ROS homeostasis in the cell and plays multiple functions in plant growth metabolism and stress response. In this review, the classification and structure of CIII PRXs are represented, and the roles of CIII PRXs in physiological and developmental processes such as plant growth, cell wall modification, loosening and stiffening, and lignin biosynthesis are described in detail. The molecular mechanisms of CIII PRXs in response to abiotic stress such as salt and drought, and biological stress such as pathogens invasion are introduced, with emphasis on the research results of PRX related genes in signal transduction. Furthermore, we summarize the difficulty in exploring the function of individual CIII PRX gene due to functional redundancy and promising technique that may break this research bottleneck.