This study aimed to explore the prospects for enhancing abiotic stress tolerance through expression of a cell wall-targeted peroxidase in transgenic plants. Abiotic stresses result in the production of several Reactive Oxygen Species (ROS), including hydrogen peroxide (H2O2), in higher plants. H2O2 is highly diffusible and has a stress signalling role, but is also the source, through Fenton reactions, of highly destructive hydroxyl free radicals. Type III peroxidases, a family of heme-containing proteins which oxidise a range of substrates using H2O2 as oxidant, are capable of depleting H2O2 levels in several cellular compartments and specific peroxidases have been linked to stress defences. In the present study, we demonstrate expression of a pathogen-induced apoplastic barley peroxidase in transgenic tobacco plants and show that it confers improved tolerance to several abiotic stresses, including high and low temperatures, salinity, metal ion and osmotic stress
