Peroxidases have more functions than a Swiss army knife

Abstract

Plant peroxidases (class III peroxidases) are present in all land plants. They are members of a large multigenic family. Probably due to this high number of isoforms, and to a very heterogeneous regulation of their expression, plant peroxidases are involved in a broad range of physiological processes all along the plant life cycle. Due to two possible catalytic cycles, peroxidative and hydroxylic, peroxidases can generate reactive oxygen species (ROS) ( • OH, HOO• ), polymerise cell wall compounds, and regulate H 2 O 2 levels. By modulating their activity and expression following internal and external stimuli, peroxidases are prevalent at every stage of plant growth, including the demands that the plant meets in stressful conditions. These multifunctional enzymes can build a rigid wall or produce ROS to make it more flexible; they can prevent biological and chemical attacks by raising physical barriers or by counterattacking with a large production of ROS; they can be involved in a more peaceful symbiosis. They are finally present from the first hours of a plant's life until its last moments. Although some functions look paradoxical, the whole process is probably regulated by a fine-tuning that has yet to be elucidated. This review will discuss the factors that can influence this delicate balance.Keywords Evolution . ROS . (abiotic and biotic) stress . Cell wall loosening and cross-linking . Senescence . Fruit ripening . Symbiosis Multigenic family, evolution and homologyHeme peroxidases specific to plants belong to a superfamily that contains three different classes of peroxidases Communicated by P. Kumar

Changes in the root proteome of Triticosecale grains germinating under osmotic stress

“…They are involved, among other processes, in the regulation of reactive oxygen species (ROS), which are formed in excess as a result of osmotic stress (Xiong and Zhu 2002;Passardi et al 2005;Koussevitzky et al 2008). Our experiment showed various levels of the peroxidase family of proteins.…”

An anionic class III peroxidase from zucchini may regulate hypocotyl elongation through its auxin oxidase activity

“…For example, the Arabidopsis thaliana genome contains 73 diVerent genes encoding class III peroxidases . This high number of isoforms probably explains the description of a plethora of physiological functions (Passardi et al 2005) such as, the formation of lignin in the secondary cell walls (Gabaldon et al 2006;Sasaki et al 2006), isodityrosine cross-linking between extensin molecules during normal growth (Iiyama et al 1994), and auxin catabolism in vitro and in vivo (Lagrimini 1996). The diversity of processes catalyzed by peroxidases as well as the great number of their isoforms suggests the possibility for a functional specialization of each isoform.…”

PeroxiBase: A class III plant peroxidase database

“…Genes encoding this enzyme family are particularly numerous in Angiosperms. The high number of isoenzymes and their remarkable catalytic versatility allow them to be involved in a broad range of physiological and developmental processes all along the plant life cycle (Passardi et al, 2005). Plant peroxidases have been shown to be involved in the cross-linking of cell wall constituents, lignin polymerization, the catabolism of auxin -a hormone having a critical role in plant growth and development -and the formation of reactive oxygen species (superoxide, hydroxyl radical).…”