Seed storage proteins (SSPs) are stored in protein storage vacuoles (PSVs) within plant endosperm cells. In rice, glutelins undergo post-Golgi trafficking via dense vesicles (DVs) to protein body II (PBII). Phosphatidylinositol 3-phosphate (PI3P) regulates endosomal, autophagic, and vacuolar trafficking, yet its role in glutelin transport remains unclear. Here, we characterized the glutelin precursor accumulation14 (gpa14) mutant, which exhibits over-accumulation of 57-kDa glutelin precursors an