Proteome and lysine acetylome analysis reveals insights into the molecular mechanism of seed germination in wheat

Seed germination is the first stage in wheat growth and development, directly affecting grain yield and quality. As an important post-translation modification, lysine acetylation participates in diverse biological functions. However, little is known regarding the quantitative acetylproteome characterization during wheat seed germination. In this study, we generated the first comparative proteomes and lysine acetylomes during wheat seed germination. In total, 5,639 proteins and 1,301 acetylated sites on 722 proteins were identified at 0, 12 and 24 h after imbibitions. Several particularly preferred amino acids were found near acetylation sites, including K(ac)S, K(ac)T, K(ac)K, K(ac)R, K(ac)H, K(ac)F, K(ac)N, K(ac)*E, FK(ac) and K(ac)*D, in the embryos during seed germination. Among them, K(ac)H, K(ac)F, FK(ac) and K(ac)K were conserved in wheat. Biosynthetic process, transcriptional regulation, ribosome and proteasome pathway related proteins were significantly enriched in both differentially expressed proteins and differentially acetylated proteins through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. We also revealed that histone acetylation was differentially involved in epigenetic regulation during seed germination. Meanwhile, abscisic acid and stress related proteins were found with acetylation changes. In addition, we focused on 8 enzymes involved in carbohydrate metabolism, and found they were differentially acetylated during seed germination. Finally, a putative metabolic pathway was proposed to dissect the roles of protein acetylation during wheat seed germination. These results not only demonstrate that lysine acetylation may play key roles in seed germination of wheat but also reveal insights into the molecular mechanism of seed germination in this crop.