A peroxiredoxin antioxidant is encoded by a dormancy-related gene, Per1, expressed during late development in the aleurone and embryo of barley grains.
Antioxidants can remove damaging reactive oxygen species produced as by-products of desiccation and respiration during late embryogenesis, imbibition of dormant seeds and germination. We have expressed a protein, PER1, encoded by the Balem (barley aleurone and embryo) transcript previously called B15C, and show it to reduce oxidative damage in vitro. PER1 shares high similarity to a novel group of thiol-requiring antioxidants, named peroxiredoxins, and represents a subgroup with only one conserved cysteine residue (1-Cys). PER1 is the first antioxidant belonging to the 1-Cys subgroup shown to be functionally active, and the first peroxiredoxin of any kind to be functionally described in plants. The steady state level of the transcript, Per1, homologous to a dormancy-related transcript (pBS128) from bromegrass (Bromus secalinus), increases considerably in imbibed embryos from dormant barley (Hordeum vulgare L.) grains. Our investigations also indicate that Per1 transcript levels are dormancy-related in the aleurone layer of whole grains. In contrast to most seed-expressed antioxidants Per1 disappears in germinating embryos, and in the mature aleurone the transcript is down-regulated by the germinating embryo or by gibberellic acid (GA). Our data show that the barley seed peroxiredoxin is encoded by a single Per1 gene. Possible roles of the PER1 peroxiredoxin in barley grains during desiccation, dormancy and imbibition are discussed.
Stacy
R A
RA
Division of General Genetics, University of Oslo, Norway.
Munthe
E
E
Steinum
T
T
Sharma
B
B
Aalen
R B
RB
D000975:Antioxidants; D004249:DNA Damage; D015536:Down-Regulation; D005609:Free Radicals; D018628:Gene Dosage; D015870:Gene Expression; D017343:Genes, Plant; D005875:Gibberellins / Q000494:pharmacology; D001467:Hordeum / Q000187:drug effects / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D008954:Models, Biological; D008969:Molecular Sequence Data; D010544:Peroxidases; D054464:Peroxiredoxins; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D018749:RNA, Plant / Q000032:analysis; D012639:Seeds / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D014018:Tissue Distribution
D000975:Antioxidants; D005609:Free Radicals; D005875:Gibberellins; C102157:PER1 protein, Hordeum vulgare; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C007842:gibberellic acid; D010544:Peroxidases; D054464:Peroxiredoxins