In-depth proteomic analysis of Glycine max seeds during controlled deterioration treatment reveals a shift in seed metabolism

Abstract

Seed aging is one of the major events, affecting the overall quality of agricultural seeds. To analyze the effect of seed aging, soybean seeds were exposed to controlled deterioration treatment (CDT) for 3 and 7days, followed by their physiological, biochemical, and proteomic analyses. Seed proteins were subjected to protamine sulfate precipitation for the enrichment of low-abundance proteins and utilized for proteome analysis. A total of 14 differential proteins were identified on 2-DE, whereas label-free quantification resulted in the identification of 1626 non-redundant proteins. Of these identified proteins, 146 showed significant changes in protein abundance, where 5 and 141 had increased and decreased abundances, respectively while 352 proteins were completely degraded during CDT. Gene ontology and KEGG analyses suggested the association of differential proteins with primary metabolism, ROS detoxification, translation elongation and initiation, protein folding, and proteolysis, where most, if not all, had decreased abundance during CDT. Western blotting confirmed reduced level of antioxidant enzymes (DHAR, APx1, MDAR, and SOD) upon CDT. This in-depth integrated study reveals a major downshift in seed metabolism upon CDT. Reported data here serve as a resource for its exploitation to metabolic engineering of seeds for multiple purposes, including increased seed viability, vigor, and quality.

Biological significance: Controlled deterioration treatment (CDT) is one of the major events that negatively affects the quality and nutrient composition of agricultural seeds. However, the molecular mechanism of CDT is largely unknown. A combination of gel-based and gel-free proteomic approach was utilized to investigate the effects of CDT in soybean seeds. Moreover, we utilized protamine sulfate precipitation method for enrichment of low-abundance proteins, which are generally masked due to the presence of high-abundance seed storage proteins. Reported data here serve as resource for its exploitation to metabolic engineering of seeds for multiple purposes, including increased seed viability, vigor, and quality.

Keywords: Abundant protein depletion; Controlled deterioration treatment; Low-abundance proteins; Metabolic engineering; Quantitative proteomics; Soybean.