FIGURE 2.

Model depicting the putative evolution of different higher plant fructosyl transferases. Likely, an ancestral VI duplicated in two VI types (I and II) in a non-fructan-accumulating plant, probably before the separation of monocots and dicots. Within the basal eudicots, a type I VI was recruited to create a preliminary FT (a 6-SST/6-SFT) in Pachysandra terminalis, a recent evolutionary event. During older evolutionary events, certain monocot and dicot type II VIs evolved into preliminary 1-SSTs and 6-SST/6-SFTs that later specialized into genuine, more specific 1-SSTs and 6-SFTs. Likely, 1-FFTs (dicots) and 6G-FFTs (monocots) evolved later, based on (preliminary) 1-SST precursors. See text for more details.