TMT-based proteomic analysis of the causes of reduced seed viability in Allium mongolicum under accelerated aging

Abstract

Background: Seeds are the most basic production material in agricultural production and occupy an important position in the whole process of agricultural production. However, aging begins to occur after seed harvested, serious aging will affect the conservation of germplasm resources. Seed propagation is the most commonly used method in the production of A.mongolicumseeds, but with the prolongation of storage time, A.mongolicum seeds undergo different degrees of aging. Therefore, we used an integrated approach of Tandem Mass Tag(TMT) labeling in conjunction with liquid chromatographytandem mass spectrometry (LC-MS/MS) to capture the differential protein expression profiles of A.mongolicumseeds under unaged (CK), lightly aged (T1), and severely aged (T4) treatments to provide evidence of protein expression levels for revealing the aging mechanism study of A.mongolicumseeds. Results: A total of 4336 proteins were identified in this study, of which 4318 total proteins could be quantified. There were 291 diferentially expressed proteins (DEPs) identifed after accelerated aging treatments. Compared with CK, 36 DEPs (16 up-regulated and 20 down-regulated) were found in T1; and 139 DEPs (64 up-regulated and 75 down-regulated) in T4. Compared with T1, 116 DEPs (51 up-regulated and 65 down-regulated) were found in T4. A number of candidate proteins associated with seed aging were screened, for example, ATP-dependent RNA helicase-like protein DB10(Unigene0060546)、β-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)、glutathione S-transferase U17-like(Unigene0051938). Conclusions: This study was the first to determine the proteome of A.mongolicum seeds, these data provided references for further study of seed aging mechanism of A.mongolicum. The results showed that the related proteins were significantly enriched in glutathione metabolism and other pathways after accelerated aging. In addition, among the candidate proteins, PAP2 is down-regulated after aging, which was speculated to be the main reason for limiting radicle growth.