Shown are GT family and subfamily assignments. Where only one candidate exists or a transcript is present >10-fold than other members of a GT family, the gene name is given in brackets. Xylan, RGI, XG and AG have diverse backbone substitution/branch patterns and the types of linkages are shown. For type II AG(P), the recently identified Arabidopsis xylosyl-terminal branch is included [50]. For xylan, the recently determined primary wall structure is shown [51]. The HM shown, as an example, is galactoglucomannan. Heteromannan (HM), rhamnogalacturanan I and II (RGI, RGII), type I and II arabinogalactan (AG), xylogalacturanan (XGA), xyloglucan (XG).