Quantitative proteomics analysis reveals the anthocyanin biosynthetic mechanism in barley

Anthocyanin biosynthesis is complex, and synthetic mechanisms have not been clarified in purple barley. Pro-teomic techniques and bioinformatics were used to analyse the differences in protein during the three stages (groups A, C, and E). A total of 4185 proteins were identified in three stages of highland barley samples with anthocyanin contents of 0 (group A), 0.17 (group C), and 0.53 mg/g (group E). DEPs associated with photo-synthesis, small molecule metabolic processes, generation of precursor metabolites and energy, and anthocyanin biosynthesis. KEGG pathway enrichment revealed that DEPs involved 474 significant metabolic pathways, mainly involved carbon metabolism, amino acid and secondary metabolite biosynthesis. In these significantly correlated anthocyanin synthesis pathways, six key proteins, P51106, M0Y9M3, A0A287WTB9, A0A287RU82, Q8LPD5, and A0A287P1Q6, were likely to participate in regulating anthocyanin synthesis. Proteins P51106 and M0Y9M3 were identified as dihydroflavonol 4-reductase and phenylalanine ammonia-lyase, which were key enzymes for anthocyanin synthesis. Proteins A0A287WTB9 and A0A287RU82 were identified to contain the functional domains of the transcription factors Myb and BHLH, involved in the regulation of anthocyanin syn-thesis. Q8LPD5 (Glutathione-S-transferase) and A0A287P1Q6 (alpha-1,3-glucosyltransferase) might be involved in anthocyanin transport and glycosidic bond modification, respectively. The PRM results were consistent with the TMT data.