The transition from vegetative growth to flowering is an important change in the life cycle of a plant. Tight control over this switch ensures reproductive success. In the model plant Arabidopsis thaliana (Arabidopsis), endogenous and environmental signals acting on the shoot apical meristem cause acquisition of inflorescence meristem fate. This results in new patterns of aerial development, seen as the transition from making leaves to the production of flowers. This process depends on two THREE-AMINO-ACID-LOOP-EXTENSION homeodomain transcription factors called PENNYWISE and POUND-FOOLISH. These factors maintain meristem activity essential for flowering by repressing a set of lateral organ boundary genes comprising BLADE-ON-PETIOLE1/2 and its downstream effectors: ARABIDOPSIS THALIANA HOMEOBOX GENE1 and KNOTTED1-LIKE FROM ARABIDOPSIS THALIANA6. Misexpression of this module in pny pnf apices blocks meristem competence to flower but the mechanism is unclear.

My thesis sheds light on regulatory interactions that define this module and block meristem competence to flower.