Xylan is a linear polymer of ?-(1,4)-linked xylose residues substituted with, glucuronic acid (GlcA), and/or arabinose residues. In rice GT 43 family glycotransferases OsGT43A (LOC_Os05g03174), OsGT43E (LOC_Os05g48600), OsGT43H (LOC_Os04g01280), and OsGT43J (LOC_Os06g47340)are predicted or reported to facilitate the polymerization of ?-(1,4)-linked xylose residues to form the xylan backbone. In rice XAX1( LOC_Os02g22380) a glycosyltransferase belonging to the grass-specific subfamily of family G61 mediates the substitution of xylan residues by arabinopyranosyl residues (arabinosylation of the xylan).
