The dormancy-related peroxiredoxin anti-oxidant, PER1, is localized to thenucleus of barley embryo and aleurone cells

Protection against desiccation-induced injury, including damage by reactive oxygen species (ROS), is a necessary component of the genetic programmes a ctive during late seed development. Likewise, protection against ROS respir ation by products is required during seed imbibition and germination. Late embryogenesis abundant (LEA) proteins are proposed to protect seed tissues against desiccation-induced damage. Specifically, the atypical Lea gene Per 1 in barley (Hordeum vulgare L.) has been proposed to play a protective rol e in embryo and aleurone cells against free-radical damage during late seed development and early imbibition. PER1 represents a subgroup of the peroxi redoxin family of thiol-requiring anti-oxidants with one conserved cysteine residue (1-Cys), and displays in vitro anti-oxidant activity. In this work , we use antiserum generated against PER1 to study protein accumulation pat terns as well as localization at the tissue, cellular and subcellular level . White previous studies have shown the Per1 transcript to be dormancy-rela ted, we show here that the protein level is maintained in imbibed dormant s eeds, but not in non-dormant seeds. Our data identify the location of this seed-specific peroxiredoxin as the nucleus of immature embryos and aleurone layers. Highest levels of protein are detected in nucleoli. In contrast, i n mature imbibed dormant seeds, cytosolic levels are comparable to that of the nucleus. A putative nuclear localization signal (NLS) of bipartite natu re was identified in the C-terminal end of the PER1 sequence. Protective ro les for PER1 in seeds are discussed.