A cDNA corresponding to 1-Cys peroxiredoxin, an evolutionarily conserved thiol-specific antioxidant enzyme, was isolated from buckwheat (Fagopyrum esculentum Moench), a dicotyledonous plant species belonging to the Polygonaceae family. The cDNA, which we have designated as FePer1, contains a major open reading frame capable of encoding a polypeptide of 219 residues with a predicted molecular mass of 24.3kDa. The deduced primary structure of FePer1 polypeptide shows a high level (about 70%) of sequence homology to other recently identified plant 1-Cys peroxiredoxins. FePer1 also exhibits a significant level of sequence similarity to non-plant 1-Cys peroxiredoxins, sharing 52 and 42% identities with mammalian and fungal 1-Cys peroxiredoxins, respectively. As for all 1-Cys peroxiredoxins identified from various organisms, the amino acid sequence proposed to constitute the active site of the enzyme is highly conserved in FePer1 polypeptide. The gene corresponding to FePer1 cDNA is a single-copy gene in the buckwheat genome. Its expression is regulated in a seed-specific and temporal manner during seed development. FePer1 gene is induced transiently for a short period immediately after seed imbibition.