Plants ectopically expressing the iron-binding protein, ferritin, are tolerant to oxidative damage and pathogens

Transgenic tobacco plants that synthesize alfalfa ferritin in vegetative ti ssues-either in its processed form in chloroplasts or in the cytoplasmic no nprocessed form-retained photosynthetic function upon free radical toxicity generated by iron excess or paraquat treatment. Progeny of transgenic plan ts accumulating ferritin in their leaves exhibited tolerance to necrotic da mage caused by viral (tobacco necrosis virus) and fungal (Alternaria altern ata, Botrytis cinerea) infections. These transformants exhibited normal pho tosynthetic function and chlorophyll content under greenhouse conditions. W e propose that by sequestering intracellular iron involved in generation of the very reactive hydroxyl radicals through a Fenton reaction, ferritin pr otects plant cells from oxidative damage induced by a wide range of stresse s.