PROTEOMIC ANALYSIS INDICATES ACTIVATION OF REACTIVE OXYGEN SPECIES SIGNALING DURING SEED GERMINATION AND SEEDLINGS GROWTH IN HORDEUM VULGARE (BARLEY)

Seed germination occur as a result of cross-talk between embryo and embryo-surrounding tissues, however, the underlying mechanisms, especially during initial germination stage, are still not fully understood. Here, we utilized a gel based proteomics approach to investigate the changes in proteome during seed germination and early stages of seedlings growth. Proteins from different stages of germination and growing seedlings were isolated using Tris-Mg/NP-40 buffer and resolved using high-resolution two-dimensional gel electrophoresis. A total of 63 differentially modulated spots were identified in 2 to 4 days germinated seeds compared to that of 1 day germinated seeds. Among those proteins, 21 and 42 proteins showed increased and decreased abundances respectively. Gene ontology analysis revealed that proteins involved in methionine metabolism, amino acid biosynthesis, energy metabolism, and defense response were up regulated; while more than half of down regulated proteins were associated with the metabolic processes, and cell division. H 2 O 2 concentration was more than two fold higher in 4 days germinating seeds in comparison with the 1 day germinating seeds, suggesting the involvement of ROS signaling during seed germination. Taken together, these results enriched our knowledge of the biological process in seed germination and seedlings growth in barley. Keywords : Barley; Proteomics; Seed germination; Reactive oxygen species; Hydrogen peroxide