Fig. 11

Hypothetical structures that may be synthesized by poplar GAUT12.1. Depiction of four possible structures that could be synthesized by GAUT12 based on available published data on the chemistry and biochemistry of cell walls and cell wall fractions from GAUT12 mutants and transgenics versus their respective controls. The rectangles depict glycan domains of xylan, the xylan reducing end sequence (XRGalAX), homogalacturonan (HG), arabinogalactan (AG), rhamnogalacturonan I (RG-I), and the two unique xylan regions (Xylan-1, Xylan-2) of the plant proteoglycan Arabinoxylan Pectin Arabinogalactan Protein 1 (APAP1). The oval depicts the arabinogalactan protein (AGP) core of APAP1. The question marks (?) depict hypothetical covalent linkages. Hypothesized function of GAUT12 in structures shown: structure 1—insertion of GalA into the xylan reducing end sequence; structure 2—synthesis of HG covalently connected directly or indirectly to xylan/xylan reducing end sequence; structure 3—synthesis of HG domain in APAP1; structure 4—synthesis of HG associated with xylan synthesis but not covalently bound to the xylan polymer. Strength of supportive published data and data from this work: + mild agreement, ++ strong agreement, − mild disagreement; −− strong disagreement