Flowering Time Flower Meristem Identity Flower Organ Identity Fruit Development FT APETALA1, LEAFY, CAULIFLOWER, (TERMINAL FLOWER) A, B, C FRUITFULL, SHATTERPROOF INDEHISCENT

B ACCA B carpel petal stamen sepal

normal flower

sepal petal stamen carpel B B ACCA What gene prevents the B gene from being active in the center of flowers?

In SUPERMAN mutants (SUP), the B activity expands into the center of the flower and converts the two carpels into two stamens. ACCA BB stamen sepal petal stamen

Superman mutant

The SUPERMAN gene normally functions to prevent B gene activity in the center of flowers ACCA BB stamen sepal petal stamen

normal BC mutant ?? sepal petal stamen carpel B B ACCA AAAA

normal BC mutant sepal petal stamen carpel B B ACCA AAAA sepal *

BC double mutant all organs are sepals

sepal petal stamen carpel B B ACCA What happens if the A, B and C genes are all inactivated in the ABC triple mutant?

normal ABC mutant ?? sepal petal stamen carpel B B ACCA

ABC mutant leaf * normal sepal petal stamen carpel B B ACCA

ABC triple mutant all organs are leaves

Goethe believed that floral organs are derived from leaves Goethe, 1790

The C gene is active in cells that will form stamens and carpels petal sepal carpel leaf sepal stamen

What would happen if the C gene was mis-expressed in cells that would normally form sepals? petal sepal carpel leaf sepal stamen

B normal stamen carpel sepal B ACCA petal

Regulatory region stamens and carpels C GENE Coding Region sepals Add sepal regulatory region: Remove regulatory region:

Flowering Time Flower Meristem Identity Flower Organ Identity Fruit Development FT APETALA1, LEAFY, CAULIFLOWER, (TERMINAL FLOWER) A, B, C FRUITFULL, SHATTERPROOF INDEHISCENT