Quantitative N‑Glycomic and N‑Glycoproteomic Profiling of Peach [Prunus persica (L.) Batsch] during Fruit Ripening

Being
part of the human diet, peach is an important fruit
consumed
worldwide. In the present study, a systematic first insight into the
N-glycosylation of peach fruit during ripening was provided. First,
N-glycome by reactive matrix-assisted laser desorption ionization
time-of-flight (MALDI-TOF) mass spectrometry indicated that 6 of 24
N-glycans of peach were differentially expressed. Second, a comparative
N-glycoproteome was characterized via18O-tagged N-glycosylation site labeling followed by nano-liquid chromatography-electrospray
ionization-tandem mass spectrometry (nLC-ESI-MS/MS). Totally 1464
N-glycosites on 881 N-glycoproteins were identified, among which 291
N-glycosites on 237 N-glycoproteins were expressed differentially
with a fold change value of 1.5 or 0.67. The enrichment analysis of
GO and KEGG revealed that four pathways including other glycan degradation,
phenylpropanoid biosynthesis, amino sugar and nucleotide sugar metabolism,
and protein processing in endoplasmic reticulum were mainly enriched,
in which several important N-glycoproteins with dynamic change during
fruit ripening were further screened out. Our findings on a large
scale for N-glycosylation analysis of peach fruit during ripening
may provide new molecular insights for comprehending N-glycoprotein
functions, which should be of great interest to both glycobiologists
and analytical chemists.