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

4. B ACCA B carpel petal stamen sepal 1122334

5. normal flower

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

7. 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

8. Superman mutant

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

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

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

12. BC double mutant all organs are sepals

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

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

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

16. “ABC” triple mutant all organs are leaves

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

18. All flower organs are converted into leaves in the abc triple mutant. The ABC genes are necessary to convert leaves into each of the flower organs.

19. The A and B genes are necessary for petal development. What would happen if the A and B genes were mis-expressed in leaves? Are the A and B genes sufficient to convert normal leaves into petals?

20. leafpetal? A+B

21. “D” mutant all organs are sepals

22. AB CD

23. D Activity is required for petal, stamen and carpel development The D gene is expressed in cells that will form petals, stamens and carpels. The D gene is required for the activity of the B and C genes.

24. sepal stamen petal carpel petal stamen sepal B ACCA B DD

25. normal D mutant sepal petal stamen carpel B B ACCA AAAA sepal * DD

26. The A, B and D genes are necessary for petal development. What would happen if the A, B and D genes were mis-expressed in leaves? Are the A, B and D genes sufficient to convert normal leaves into petals?

27. Regulatory region Petals, stamens and carpels D GENE Coding Region leaves Add Leaf regulatory region: Remove regulatory region:

28. leafpetal A+B+D ?

29. leafpetal A+B+D

30. A = sepals A + B + D = petals C + D = carpels B + C + D = stamens

31. The ABCD genes act alone, or in combination, to specify the four types of flower organs The ABCD genes are sufficient to convert leaves into flower organs The ABCD model is applicable to all flowering plants

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

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

34. B normal stamen carpel sepal B ACCA petal

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

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