Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Biotechnology & Applied Microbiology, Genetics & Heredity, Barley, Hordeum vulgare, Ubiquitin proteasome system (UPS), Biotic stress, Abiotic stress, UBIQUITIN LIGASE, NEGATIVE REGULATION, BIOCHEMICAL FUNCTION, PROTEIN FAMILY, CELL-DEATH, GENE, PROTEASOME, RESISTANCE, TOLERANCE, THALIANA, Amino Acid Sequence, Arabidopsis, Ascomycota, Droughts, Gene Expression Regulation, Plant, Genome, Plant, Hordeum, Host-Parasite Interactions, Oryza, Phylogeny, Plant Proteins, Seedlings, Sequence Alignment, Ubiquitin-Protein Ligases, 06 Biological Sciences, 08 Information and Computing Sciences, 11 Medical and Health Sciences, Bioinformatics, 31 Biological sciences, 32 Biomedical and clinical sciences

Abstract:

BACKGROUND: Controlled turnover of proteins as mediated by the ubiquitin proteasome system (UPS) is an important element in plant defense against environmental and pathogen stresses. E3 ligases play a central role in subjecting proteins to hydrolysis by the UPS. Recently, it has been demonstrated that a specific class of E3 ligases termed the U-box ligases are directly associated with the defense mechanisms against abiotic and biotic stresses in several plants. However, no studies on U-box E3 ligases have been performed in one of the important staple crops, barley. RESULTS: In this study, we identified 67 putative U-box E3 ligases from the barley genome and expressed sequence tags (ESTs). Similar to Arabidopsis and rice U-box E3 ligases, most of barley U-box E3 ligases possess evolutionary well-conserved domain organizations. Based on the domain compositions and arrangements, the barley U-box proteins were classified into eight different classes. Along with this new classification, we refined the previously reported classifications of U-box E3 ligase genes in Arabidopsis and rice. Furthermore, we investigated the expression profile of 67 U-box E3 ligase genes in response to drought stress and pathogen infection. We observed that many U-box E3 ligase genes were specifically up-and-down regulated by drought stress or by fungal infection, implying their possible roles of some U-box E3 ligase genes in the stress responses. CONCLUSION: This study reports the classification of U-box E3 ligases in barley and their expression profiles against drought stress and pathogen infection. Therefore, the classification and expression profiling of barley U-box genes can be used as a platform to functionally define the stress-related E3 ligases in barley.