关键词: 紫荆, 种子休眠, 蛋白质组, 代谢通路

Abstract:

【Objective】This study investigated proteom-level changes between dormant and broken dormancy seeds of Cercis chinensis to get a better understanding of the intrinsic mechanisms underlying seed dormancy and germination.【Method】The mature seeds were soaked in hot water until they reached a constant weight, and then subjected to stratification treatment mixed with moisture sand in a 4 ℃ environment until dormancy was released and germination occurred. Label-free quantitative proteomics and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to perform proteome quantitative and qualitative analysis on dormant and dormancy-broken seeds after 45 days of cold stratification were performed based on, respectively. Bioinformatics analysis was also conducted to explore the expression and function mechanism of differentially expressed proteins (DEPs) between dormant and dormancy-broken seeds, and to discuss the proteins and its mechanisms related to the dormancy release.【Result】A total of 3 928 proteins were identified in this study, with 3 122 proteins were detected in dormant samples and 3 758 proteins were detected in dormancy-broken samples. After screening the proteins based on the standard of fold changes greater than 2.0 and P<0.05, we filtered 1 031 DEPs. Among these, 779 proteins were up-regulated and 252 proteins were down-regulated. The DEPs were annotated using GO annotation into three categories and 49 subcategories of biological processes, cellular components and molecular functions. The annotated DEPs were closely related to metabolic processes, enzyme catalytic activity, synthesis of cellular components, and stress response. In addition, the KEGG metabolic pathway annotation results showed that 1 012 DEPs were annotated, involving 264 pathways. The DEGs were mainly associated with carbon metabolism, polysaccharide decomposition, and protein processing. The significant enrichment results revealed seven pathways, mainly involving the hormone synthesis, secondary metabolite synthesis, and lipid metabolism. The highly abundant DEPs that may be linked to dormancy breaking are proteins related to β-glucosidase activity, ubiquinone, terpene quinone organisms related proteins, and glyoxylic acid cycle-related proteins. 【Conclusion】This study demonstrates that the dormancy release of C. chinensis seeds is a complex biological process that involves cell morphological changes, enzyme catalysis, polysaccharide decomposition and hormone signal transduction. The release of dormancy is regulated by the interaction of multiple metabolic pathways. Further research is needed to study the molecular mechanism of dormancy release using molecular biological methods such as transcriptomics and metabonomics.

Key words: Cercis chinensis, seed dormancy, proteome, metabolic pathway