Integration of quantitative proteomics, redox metabolomics and proteogenomics to identify sources of seed dormancy control and pre-harvest sprouting resistance in wheat.

In this work we analyzed dormancy-imposing processes in aleurone and embryo tissue-specific proteomes and redox metabolomes using redox proteomics, fluorescent labeling and 2-DE, comparative iTRAQ-based quantitation and redox metabolite measurements. iTRAQ-based approach resulted in over 6400 high confidence protein identifications, of which 62 and 115 showed significant differential expression in dormant phenotypes, and 368 and 1034 were dormancy genotype-specific in embryo and aleurone, respectively. In dormant embryos, significant alterations were found for protein translation, folding, transport and degradation, DNA-repair, and mRNA surveillance, oxidative and nitrosative stress response. Potentially critical for imposing dormancy and after-ripening regulation, changes were found in cell cycle control, epigenetic regulation of gene expression, arrest of development and growth. Proteins responsible for natural defences against pathogens were up-regulated in dormant aleurone. Corresponding genes on chromosome arms where QTL for sprouting tolerance had been previously identified were further analysed to compare their location in the QTL region. The level of total glutathione was significantly higher in dormant embryo tissues, and the capacity for GSSG disulfide regeneration decreased dramatically upon after-ripening. In dormant embryo the concentration of total and reduced ascorbate increased 2-3 fold during after-ripening indicating high capacity for ascorbate regeneration.