TMT Proteomics-Based Study of Proteins and Pathways Associated with β-Glucan Degradation in Barley Germination

Background: Zangqing '1127', a hull-less barley type recognized for its high β-glucan content, holds significant agricultural and nutritional potential. Nonetheless, the molecular mechanisms underlying the degradation of β-glucan during barley germination have yet to be thoroughly investigated. Objectives: This study sought to identify the key proteins and pathways involved in this process using quantitative proteomics. Methods: Seeds of Zangqing '1127' were collected at 0, 24, and 96 h post germination, and TMT-based quantitative proteomics was used to analyze changes in the proteome. To annotate the functions of differentially expressed proteins (DEPs), Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. Results: In total, 3230 unique proteins were identified, which included 610 DEPs during the germination phase. Enrichment analysis showed that these DEPs were primarily associated with key biological processes involved in β-glucan degradation, including cell wall modification, polysaccharide metabolism, and carbon metabolism. Five proteins exhibiting notably high expression levels were identified as potential regulatory candidates for this process. Conclusions: These results enhance our comprehension of the proteomic dynamics associated with β-glucan degradation during barley germination and suggest new candidate targets for functional studies. This study provides deeper insight into the molecular mechanisms governing β-glucan metabolism, with potential implications for agricultural improvement and the nutritional quality of barley.