N-Glycosylation profiling in rice

As a ubiquitous and essential posttranslational modification occurred in both plants and animals, protein N-linked glycosylation regulates various important biological processes. Unlike the well studied animal N-glycoproteomes, the landscape of rice N-glycoproteome remains largely unexplored. Here, by developing of a chemical glycoproteomics strategy based on metabolic glycan labeling (MGL) for labeling and enrichment of N-glycoproteins in rice, we report a comprehensive rice N-glycoproteome profiling. In rice seedlings metabolically labeled with N-azidoacetylgalactosamine (GalNAz), followed by conjugation with affinity probes via click chemistry, we identify a total of 426 N-glycosylation sites and 680 N-glycosylated proteins, which are involved in various important biological and pathological processes. In particular, various components of the ER-associated protein degradation (ERAD) machinery are N-glycosylated, which N-glycans play crucial roles for the proper function of ERAD. In addition to providing an invaluable resource for studying the biological function of N-glycosylation in rice, this work demonstrates the versatility of MGL in glycoproteomic proofing for various crop species.