Increased tolerance to abiotic stresses in tobacco plants expressing a barley cell wall peroxidase

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 (H ₂O ₂), in higher plants. H ₂O ₂ 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 H ₂O ₂ as oxidant, are capable of depleting H ₂O ₂ 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.