Involved in the synthesis of the hemicellulose glucuronoxylan, a major component of secondary cell walls. Probably involved in the elongation of glucuronoxylan xylosyl backbone, especially in the formation of GlcUA side chain of xylans. Limited to xylem cells. Expressed in the root tip, xylem cells of roots, and in the vasculature of roots, cotyledons and leaves. In flowers, restricted to anthers. Moderate IRX phenotype. Slight reduction of secondary wall thickness and xylan content in cell wall (PubMed:15980264, PubMed:18980662). Specific loss of the GlcUA side chain in xylans. Slightly short inflorescence and reduced fertility (PubMed:18980649). Belongs to the glycosyltransferase 47 family.