Required for pollen tube (PT) growth and integrity by affecting the stability of the pollen-specific ANX1 and ANX2 proteins. Involved in protein N-glycosylation in the endoplasmic reticulum (ER), especially in the female gametophyte. Mediates PT reception in synergids through protein glycosylation. Protein modification; protein glycosylation. In ovules, mostly observed in the female gametophyte (FG) including the synergids, which showed a ring shaped localization around their nuclei, and throughout the pollen tube (PT). Pollen tube (PT) overgrowth inside the female gametophyte (FG) without PT rupture. Premature burst immediately after PT germination. Dwarf plants accumulating anthocyanins and dying prematurely in RNAi conditions. Impaired accumulation of ANX1 and ANX2 proteins. Belongs to the glycosyltransferase group 1 family. Glycosyltransferase 33 subfamily.