Proteomic Analysis of the Effect of Accelerated Ageing on Allium mongolicum Seeds

Seed propagation is the most commonly used method for producing Allium mongolicum seeds. However, as storage time increases, the seeds may suffer from ageing to varying degrees. This study aims to investigate the proteome expression of A. mongolicum seeds with different levels of vigor. The findings of this study will provide evidence of protein expression levels that reveal the mechanism behind the ageing of A. mongolicum seeds. An integrated approach of tandem mass tag (TMT) labeling in conjunction with liquid chromatography-mass spectrometry (LC-MS/MS) was used to capture the differential protein expression profiles of A. mongolicum seeds under unaged (Control), lightly aged (LA) and severely aged (SA). In total, 4336 proteins were identified, of which 4318 were quantifiable. After accelerated ageing, 291 differentially expressed proteins (DEPs) were identified. Compared with Control, 36 DEPs (16 up-regulated and 20 down-regulated) were found in LA; and 139 DEPs (64 up-regulated and 75 down-regulated) in SA. Compared with LA, 116 DEPs (51 up-regulated and 65 down-regulated) were found in SA. A number of candidate proteins associated with seed ageing were screened, including ATP-dependent RNA helicase-like protein DB10 (Unigene0060546), beta-D-glucan exohydolase (Unigene0008772), Histone H1.2 partial (Unigene0049278), defensin Ec-AMP-D2 (Unigene0042879), NAD(P)H dehydrogenase (quinone) FQR1 (Unigene0047137), glutathione S-transferase (Unigene0000863), oleosin S1-2 (Unigene0011542), probable inactive purple acid phosphatase 2 (Unigene0010352), glutathione S-transferase U8-like (Unigene0006910), and glutathione S-transferase U17-like (Unigene0051938). Additionally, this study was the first to determine the proteome of A. mongolicum seeds. These data provided references for further study of seed ageing mechanism of A. mongolicum.