Involved in the synthesis of the hemicellulose glucuronoxylan, a major component of secondary cell walls. Probably involved in the synthesis of the glycosyl sequence at the glucuronoxylan reducing end. Expressed in developing interfascicular fibers and xylem cells in stems and developing secondary xylem in roots. Dwarf phenotype. Strong reduction of secondary wall thickness, collapsed xylem vessels and reduced xylan content in cell wall. Belongs to the glycosyltransferase 47 family.