The dormancy‐related peroxiredoxin anti‐oxidant, PER1, is localized to the nucleus of barley embryo and aleurone cells

Abstract

Summary: Protection against desiccation‐induced injury, including damage by reactive oxygen species (ROS), is a necessary component of the genetic programmes active during late seed development. Likewise, protection against ROS respiration 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 Per1 in barley (Hordeum vulgare L.) has been proposed to play a protective role in embryo and aleurone cells against free‐radical damage during late seed development and early imbibition. PER1 represents a subgroup of the peroxiredoxin 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 patterns as well as localization at the tissue, cellular and subcellular level. While previous studies have shown the Per1 transcript to be dormancy‐related, we show here that the protein level is maintained in imbibed dormant seeds, 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, in mature imbibed dormant seeds, cytosolic levels are comparable to that of the nucleus. A putative nuclear localization signal (NLS) of bipartite nature was identified in the C‐terminal end of the PER1 sequence. Protective roles for PER1 in seeds are discussed.