Roles of Plant Peroxidases in Cell Wall Formation and Modification

Class III peroxidases (plant peroxidases) exist as large multigene families in higher plants, and most of them are localized in the cell wall. It has been reported that they are involved in lignification, cell elongation, stress defense, phytohormonal regulation, suberization and structural protein formation. However, the underlying mechanisms and the presentation of their functions are not fully understood. Plant peroxidases can function as catalytic enzymes that oxidize phenolic compounds while consuming hydrogen peroxide and/or as generators of reactive oxygen species. Moreover, biochemical approaches to characterize plant peroxidases have revealed the catalytic property of plant peroxidases responsible for lignin biosynthesis. In conclusion, not only spatiotemporal regulation of gene expression and protein distribution, but also differentiated oxidation properties of each plant peroxidase, define the function in the cell wall.