Comprehensive quantification of N-glycoproteome in Fusarium graminearum reveals intensive glycosylation changes against fungicide

• A robust system for N-glycoproteome quantification was established.
• 774 N-glycosylation sites in 406 proteins were identified in F. graminearum.
• N-glycoproteins were highly enriched in cell wall and membrane regions.
• The protein and glycosylation synthesis was heavily suppressed by fungicide.
• The protease and glycosyl-transferase activity were decreased upon fungicide.

Glycoproteomics is greatly developed in recent years and big data of N-glycoproteome in mammalian tissues and cells were already established. However, the glycoproteomic studies on plant, fungus and bacteria are far left behind. In this study, we comprehensively mapped and quantified the N-glycosylation of Fusarium graminearum by combining stable isotope dimethyl labeling, hydrophilic interaction chromatography (HILIC) and high-resolution mass spectrometry. The N-glycosylation changes in Fusarium graminearum after fungicide treatment were extensively studied. Altogether we identified 927 N-glycopeptides, corresponding to 406 proteins and 774 sites and the glycosylation level was found to be largely down-regulated upon fungicide treatment. With the help of advanced bioinformatics, it was found that the N-glycoproteome changes were highly enriched in cell wall, membrane and extracellular regions. Moreover, the fungal metabolism, protein and glycosylation synthesis, and protease and glycosyl-transferase activity were all closely related with the down-regulated proteins, indicates that fungicide may affect fungal development in these aspects. These results will be useful for future studies on fungal biology. The established system for N-glycoproteome quantification has comparative or better performance compared with previous strategies and will be helpful in N-glycoproteomics of fungus and other species.SignificanceWe developed a robust HILIC-based system for N-glycoproteome quantification in fungus and established the largest quantitative N-glycosylation dataset in fungus, showing the high performance of the new system. The identified N-glycoproteins were proved to be high confident due to the high percentage of proteins in extracellular region and plasma. The quantification results were also accuracy and reproducible in two replicates. By the help of advanced bioinformatic tools, the obtained data was systematically analyzed. It was found that the N-glycosylation level was largely changed in cell wall, membrane and extracellular regions. Moreover, the cell metabolism, protein synthesis, and protease activity were also greatly deceased after fungicide treatment.

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