Mapping the N-linked glycosites of rice (Oryza sativa L.) germinating embryos

PLoS One. 2017 Mar 22;12(3):e0173853. doi: 10.1371/journal.pone.0173853. eCollection 2017.

Abstract

Germination is a key event in the angiosperm life cycle. N-glycosylation of proteins is one of the most common post-translational modifications, and has been recognized to be an important regulator of the proteome of the germinating embryo. Here, we report the first N-linked glycosites mapping of rice embryos during germination by using a hydrophilic interaction chromatography (HILIC) glycopeptides enrichment strategy associated with high accuracy mass spectrometry identification. A total of 242 glycosites from 191 unique proteins was discovered. Inspection of the motifs and sequence structures involved suggested that all the glycosites were concentrated within [NxS/T] motif, while 82.3% of them were in a coil structure. N-glycosylation preferentially occurred on proteins with glycoside hydrolase activities, which were significantly enriched in the starch and sucrose metabolism pathway, suggesting that N-glycosylation is involved in embryo germination by regulating carbohydrate metabolism. Notably, protein-protein interaction analysis revealed a network with several Brassinosteroids signaling proteins, including XIAO and other BR-responsive proteins, implying that glycosylation-mediated Brassinosteroids signaling may be a key mechanism regulating rice embryo germination. In summary, this study expanded our knowledge of protein glycosylation in rice, and provided novel insight into the PTM regulation in rice seed germination.

MeSH terms

  • Amino Acid Sequence
  • Brassinosteroids / chemistry
  • Brassinosteroids / metabolism
  • Carbohydrate Metabolism
  • Cell Wall / metabolism
  • Endoplasmic Reticulum / metabolism
  • Germination
  • Glycoproteins / chemistry*
  • Glycoproteins / genetics
  • Glycoproteins / metabolism*
  • Glycosylation
  • Metabolic Networks and Pathways
  • Oryza / genetics
  • Oryza / growth & development*
  • Oryza / metabolism*
  • Peptide Mapping
  • Plant Proteins / chemistry*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Protein Interaction Domains and Motifs
  • Protein Processing, Post-Translational
  • Signal Transduction
  • Starch / metabolism
  • Sucrose / metabolism

Substances

  • Brassinosteroids
  • Glycoproteins
  • Plant Proteins
  • Sucrose
  • Starch

Grants and funding

This work was supported by Agricultural Sciences and Technologies Innovation Program of Chinese Academy of Agricultural Sciences (CAAS) to Rice Reproductive Developmental Biology Group, Chinese High-yielding Transgenic Program (No. 2016ZX08001-004) and National Natural Science Foundation of China (grant number: 31401366 and 31371605). Jingjie PTM-Biolabs provided support in the form of salaries for authors [SZ and JZhu], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.