Required for the biosynthesis of the tetrasaccharide primer sequence, beta-D-Xyl-(1,3)-alpha-l-Rha-(1,2)-alpha-D-GalA-(1,4)-D-Xyl, located at the reducing end of glucuronoxylan. Might catalyze the transfer of the reducing Xyl residue onto a protein acceptor in the endoplasmic reticulum, which is then transported to the Golgi where the subsequent additions of sugar residues take place. Glycan metabolism; pectin biosynthesis. Expressed in stems, leaves, flowers, siliques and roots. Detected in fibers and xylem cells undergoing secondary wall thickening. By light. Dwarf phenotype. Severe reduction in the mechanical strength of stems and collapsed vessels. Reduced fertility. The name gaolaozhuangren came from a group of small people in a modern Chinese novel. Belongs to the glycosyltransferase 8 family.