Fig. 8

Models of strigolactone signalling evolution. Three models of land plant evolution, showing the likely origins of different protein families involved in SL/KL synthesis and signalling. a Traditional view [37]. b ‘Hornworts-basal’ model [38]. c ‘Monophyletic bryophytes’ [44]. Depending on the scheme of evolution, the likely origin(s) of SL perception vary considerably. Curved lines represent the innovations (duplications, sub/neo-functionalization) in the DDK and SMXL lineages implied by each scenario. Hor = hornworts, Liv = liverworts, Mos = mosses, Lyc = lycophytes, Mon = monilophytes, Gym = gymnosperms, Ang = angiosperms