Dynamic proteomic changes in soft wheat seeds during accelerated ageing

Abstract

Previous research demonstrated that soft wheat cultivars have better post-harvest storage tolerance than harder cultivars during accelerated ageing. To better understand this phenomenon, a tandem mass tag-based quantitative proteomic analysis of soft wheat seeds was performed at different storage times during accelerated ageing (germination ratios of 97%, 45%, 28%, and 6%). A total of 1,010 proteins were differentially regulated, of which 519 and 491 were up- and downregulated, respectively. Most of the differentially expressed proteins were predicted to be involved in nutrient reservoir, enzyme activity and regulation, energy and metabolism, and response to stimulus functions, consistent with processes occurring in hard wheat during artificial ageing. Notably, defense-associated proteins including wheatwin-2, pathogenesis-related proteins protecting against fungal invasion, and glutathione S-transferase and glutathione synthetase participating in reactive oxygen species (ROS) detoxification, were upregulated compared to levels in hard wheat during accelerated ageing. These upregulated proteins might be responsible for the superior post-harvest storage-tolerance of soft wheat cultivars during accelerated ageing compared with hard wheat. Although accelerated ageing could not fully mimic natural ageing, our findings provided novel dynamic proteomic insight into soft wheat seeds during seed deterioration.

Keywords: Accelerated ageing; Post-harvest storage-tolerance; Proteomics; Soft wheat seeds.

Figure 1. CO₂ concentration and germination rates of wheat seeds during artificial ageing.

Figure 2. Functional-enrichment-based clustering of DEPs (GO analysis).

(A) Biological process, (B) cellular component and (C) molecular function. Each category of DEPs includes both up- and down-regulated proteins. YM45/97 represents proteins displaying significant changes in Gr45% compared with Gr97%; YM28/97 represents proteins displaying significant changes in Gr28% compared with Gr97%; YM6/97 means proteins displaying significant changes in Gr6% compared with Gr97%.

Figure 3. Functional-enrichment-based clustering of DEPs.

(A) Protein domain and (B) KEGG pathway. Each category includes both up- and down-regulated DEPs. YM45/97 represents proteins displaying significant changes in Gr45% compared with Gr97%; YM28/97 represents proteins displaying significant changes in Gr28% compared with Gr97%; YM6/97 represents proteins displaying significant changes in Gr6% compared with Gr97%.