Fig. 5

Transgenic complementation experiments of Arabidopsis ino-1 by SlINO and AtINO expressed by P-AtINO, P-SlINO and the constitutive CaMV 35S promoter (all ovules at stage 4-I). ino-1 ovules (a) show the effect of loss of AtINO on outer integument growth. The inner integument is intact and where the outer integument should have grown to cover it, as in the wildtype (b), no integument was initiated on the gynobasal side (arrowhead). The SlINO protein, when expressed using P-AtINO (c), cannot complement ino-1 but leads to a small amount of misdirected growth (arrowhead) from the area where the outer integument should have arisen. This growth does not occur when P-SlINO is used to drive expression of SlINO (d) or AtINO (e). SlINO acts in a manner similar to other Arabidopsis YABBY genes when expressed using the constitutively active CaMV 35S promoter [64], promoting symmetrical growth of the outer integument (arrowhead) (f). This leads to a sup-like phenotype [5] in an ino-1 mutant background, showing that the SlINO protein is functional and can effect outer integument growth. i: inner integument; o: outer integument; WT: wildtype. Scale bar in a represents 50 μm in panels a-e and 250 μm in f