Iron triggers a rapid induction of ascorbate peroxidase gene expression in Brassica napus

In plants, only ferritin gene expression has been reported to be iron-dependent, Here it is demonstrated that an iron overload of Brassica napus seedlings causes a large and rapid accumulation of ascorbate peroxidase transcripts, a plant-specific hydrogen peroxide-scavenging enzyme. This result documents a novel link between iron metabolism and oxidative stress, The ascorbate peroxidase mRNA abundance was not modified by reducing agents like N-acetyl cysteine, glutathione and ascorbate or by pro-oxidants such as hydrogen peroxide or diamide, Furthermore, the iron-induced ascorbate peroxidase mRNA accumulation was not antagonized by N-acetyl cysteine, Abscisic acid had no effect on the ascorbate peroxidase gene expression, Taken together these results suggest that iron-mediated expression of ascorbate peroxidase gene occurs through a signal transduction pathway apparently different from those already described for plant genes responsive to oxidative stress. (C) 1997 Federation of European Biochemical Societies.