iTRAQ-based quantitative proteomic analysis of dark-germinated soybeans in response to salt stress.

Soybean germination under stressful conditions, especially salt stress, has been verified to be an effective way of accumulating gamma-aminobutyric acid (GABA) in dark-germinated soybeans. In this study, a combination of physiological characteristics and isobaric tags for relative and absolute quantitation (iTRAQ) in a proteomic-based approach was used to investigate the protein changes in dark-germinated soybeans under salt stress. A total of 201 differentially abundant proteins (DAPs) were identified and divided into 13 functional groups. Under salt stress, 20 metabolic pathways were significantly enriched in dark-germinated soybeans. GABA content and antioxidase activity were increased while the growth and development of soybeans were inhibited by the salt stress. Promoting the synthesis of ROS-scavenging enzymes, maintaining the protein metabolic balance and re-establishing cellular homeostasis were very important strategies for growth stimulation in response to salt stress. In summary, these results showed comprehensive proteome coverage of dark-germinated soybeans in response to salt treatment, and increased our understanding of the molecular processes involved in plant networks responding to stresses.