Seed 1-cysteine peroxiredoxin antioxidants are not involved in dormancy, but contribute to inhibition of germination during stress

• Published in: Plant physiology (Bethesda) Vol. 133; no. 3; pp. 1148 - 1157
• Main Authors: Haslekas, C, Viken, M.K, Grini, P.E, Nygaard, V, Nordgard, S.H, Meza, T.J, Aalen, R.B
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.11.2003; American Society of Plant Physiologists
• Subjects: Agronomy. Soil science and plant productions; Allium cepa; antioxidant activity; Antioxidants; Antiserum; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; AtPER1 protein; Barley; Biological and medical sciences; cell nucleus; Cell Nucleus - genetics; Cell Nucleus - metabolism; Complementary DNA; cultured cells; cysteine; cytoplasm; Cytoplasm - genetics; Cytoplasm - metabolism; Dormancy; Economic plant physiology; Embryo development. Germination; Environmental Stress and Adaptation; Escherichia coli - genetics; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; gene expression; Germination; Germination - drug effects; Germination - genetics; Germination and dormancy; green fluorescent protein; Green Fluorescent Proteins; Growth and development; Hordeum vulgare; Imbibition; Luminescent Proteins - genetics; Luminescent Proteins - metabolism; mannitol; Mannitol - pharmacology; Messenger RNA; molecular sequence data; nucleotide sequences; oxidative stress; Paraquat - pharmacology; peroxidases; peroxiredoxin; Phenotype; Plant physiology and development; plant proteins; Plants, Genetically Modified; protein content; Proteins; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; reporter genes; RNA interference; salt stress; seed dormancy; seed germination; Seeds - drug effects; Seeds - genetics; sodium chloride; Sodium Chloride - pharmacology; Transgenic plants; water stress; Oxidative stress; Monocotyledones; Seeds; Hordeum vulgare; Germination; Gene overexpression; Hydroperoxide; Oxidant; Antioxidant; Cereal crop; Arabidopsis thaliana; Dormancy; Regulation(control); Cruciferae; Gramineae; Dicotyledones; Angiospermae; Spermatophyta; Transgenic plant; Inhibition; Experimental plant; Osmotic pressure; Localization
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.103.025916

Peroxiredoxins (Prx) are thiol-dependent antioxidants containing one (1-cysteine [-Cys]) or two (2-Cys) conserved Cys residues that protect lipids, enzymes, and DNA against reactive oxygen species. In plants, the 1-Cys Prxs are highly expressed during late seed development, and the expression pattern is dormancy related in mature seeds. We have expressed the Arabidopsis 1-Cys Prx AtPER1 in Escherichia coli and show that this protein has antioxidant activity in vitro and protects E. coli in vivo against the toxic oxidant cumene hydroperoxide. Although some 1-Cys Prxs are targeted to the nucleus, a green fluorescent protein-AtPER1 fusion protein was also localized to the cytoplasm in an onion epidermis subcellular localization assay. It has been proposed that seed Prxs are involved in maintenance of dormancy and/or protect the embryo and aleurone layer surviving desiccation against damage caused by reactive oxygen species. These hypotheses were tested using transgenic Arabidopsis lines overexpressing the barley (Hordeum vulgare) 1-Cys PER1 protein and lines with reduced levels of AtPER1 due to antisensing or RNA interference. We found no correlation between Prx levels and the duration of the after-ripening period required before germination. Thus, Prxs are unlikely to contribute to maintenance of dormancy. RNA interference lines almost devoid of AtPER1 protein developed and germinated normally under standard growth room conditions. However, seeds from lines overexpressing PER1 were less inclined to germinate than wild-type seeds in the presence of NaCl, mannitol, and methyl viologen, suggesting that Prx can sense harsh environmental surroundings and play a part in the inhibition of germination under unfavorable conditions.