Comprehensive analysis of bamboo oligosaccharyltransferases reveals the potential role of PedDGL1-C-mediated PePRX2 glycosylation in shoot lignification

Protein glycosylation is a crucial post-translational modification in plants, playing vital roles in various physiological processes. Oligosaccharyltransferases (OSTs) are at the core of the N-glycosylation pathway, responsible for transferring oligosaccharide chains to target proteins. Despite the ecological and economic significance of bamboo as a class of fast-growing plants, the genomic organization and functional diversification of OST family remain poorly characterized in bamboo species. Through comprehensive phylogenomic analysis across 12 bamboo genomes, we identified 227 OST members and revealed that gene family expanded primarily through paleopolyploidization events, with functional conservation maintained under purifying selection. Our systematic investigation of 21 Phyllostachys edulis OST members demonstrated tissue-specific expression patterns during shoot fast growth stages, exhibiting spatiotemporal regulation correlated with culm lignification. Subcellular localization confirmed one OST (PedDGL1-C) targeted endoplasmic reticulum, consistent with its canonical role in N-glycosylation. Protein interaction assays (Y2H, LCA, BiFC and Co-IP) established physical association of PedDGL1-C with one lignification-related class III peroxidase PePRX2. Mass spectrometric analysis identified two conserved N-glycosylation sites (N102 and N216) on PePRX2. Glycosite mutation of N102A, N216A, and N102A/N216A showed reduced molecular weights while maintaining unchanged subcellular localization of PePRX2. Strikingly, N102 mutation not only disrupted PedDGL1-C-PePRX2 interaction but also caused significant attenuation of peroxidase activity, suggesting a mechanistic link between OST-mediated glycosylation and enzyme function. This study provides the first genome-wide characterization of OSTs in bamboo, demonstrating that PedDGL1-C orchestrates shoot growth through glycosylation-dependent regulation of PePRX2. Our findings advance understanding of post-translational regulatory networks underlying rapid bamboo growth and offer new insights into protein glycosylation mechanisms in monocots. • Phylogenomic analysis of 227 bamboo OST genes shows paleopolyploidization-driven expansion under purifying selection. • Moso bamboo OST genes are shoot-specific and spatiotemporally correlated with lignification. • ER-localized PedDGL1-C binds and glycosylates lignin-related peroxidase PePRX2 at two sites (N102 and N216). • PePRX2 N102A mutation disrupts the binding to PedDGL1-C and significantly reduces its enzyme activity.