1. defined concept of homologous organs
Richard Owen, 1843
defined concept of homologous organs
Homeotic transformations of organs in plants…
“Metamorphosis of Plants”
Published by Johan Goethe, 1790

2. Wild type.                APETALA1:    PISTILLATA :   AGAMOUS:                                  "A" class           "B" class          "C" class

3. Wild type.                APETALA1:    PISTILLATA :   AGAMOUS:                                  "A" class           "B" class          "C" class

4. AP1 mRNA
AG1 mRNA
AP1 in AG1 mutant

6. ~550 MYA

7. plena
Shp1/2
Plena
clade Ag
Far AG
clade

10. Central zone
adaxial
abaxial
apical
basal
phyllotaxy

12. Abaxial
domain
Adaxial
domain

13. adaxial
abaxial
Lateral primordia formation/polarity:
abaxial identity:
crabsclaw, YABBY, KANADI - arabidopsis
adaxial identity:
phantastica - Antirrhinum
roughsheath - maize
phabulosa - arabidopsis

14. Wild type Phb McConnell and Barton. 1998. Development 125:2935
1. Ad/ab polarity is needed for lateral expansion
2. Adaxial cells determine initiation of the axial meristem
Wild type
Phb

16. Wild Type
phabulosa

18. Dominant Phabulosa/Phavulota mutations
HomeoBox-
Zipper
DNA binding
domain
START
Sterol
binding
domain

19. WT
Phb

21. Triple knockout phenotype:
Emery et al Current Biology, Vol. 13, 1768–1774,
Dominant Phb phenotype

22. Abaxial domain Adaxial domain
Boundary required for Later growth of leaf blade
Abaxial
domain
Adaxial
domain

23. Abaxial determinants:
Development 126, (1999)
Members of the YABBYgene family specify abaxial cell fate in Arabidopsis
Kellee R. Siegfried1,*, Yuval Eshed1, Stuart F. Baum1, Denichiro Otsuga2, Gary N. Drews2
and John L. Bowman1,‡
KANADI regulates organ polarity
in Arabidopsis
Randall A. Kerstetter, Krista Bollman, R. Alexandra Taylor,
Kirsten Bomblies & R. Scott Poethig
2001 Nature 411:706-8

29. Dominant Phabulosa/Phavulota mutations
HomeoBox-
Zipper
DNA binding
domain
START
Sterol
binding
domain

30. Carrington and Ambros 2003, Science 301:337

33. PTGS pathway in eukaryotes
Carpel Factory (DCL1)
Adapted from Williams and Rubin 2001, PNAS

34. Jacobsen et al. 1998. Development 126:5231

35. AGO is a component of the RISC RNA induced silencing complex
Kidner and Martienssen, Nature Mar 4;428(6978):81-4
Argonaut
phenotypes
AGO is a component of the RISC RNA induced silencing complex

36. miR165 WT
PHB WT
miR165
ago
PHB
ago

37. Abaxial domain Adaxial domain
Boundary required for Later growth of leaf blade
Abaxial
domain
Adaxial
domain

38. Asymmetric expression of YAB3 requires
KANADI function

39. PHABULOSA expression in the radialized
(adaxialized) KANADI triple mutant

40. In tomato, YABBY is restricted to cytoplasmic dense cells at the margins of the ad/ab boundary

43. Emery et al. 2003. Current Biology, Vol. 13, 1768–1774,

44. Bohmert et al EMBO J 17:

45. Meristem initiation/maintenance:
Knotted -maize
shoot apical meristemless -arabidopsis
Meristem size:
clavata1
clavata2
clavata3
Lateral organ polarity:
Abaxial genes:
crabsclaw, YABBY
Kanadi
Adaxial genes:
phabulosa
Phavoluta
Revoluta
Organ number and polarity:
Carpel Factory
Argonaute

46. Dominant Phabulosa/Phavulota mutations
HomeoBox-
Zipper
DNA binding
domain
START
Sterol
binding
domain

48. Bohmert et al EMBO J 17:

49. adaxial
abaxial
Lateral primordia formation/polarity:
abaxial identity:
crabsclaw, YABBY, KANADI - arabidopsis
adaxial identity:
phantastica - Antirrhinum
roughsheath - maize
phabulosa - arabidopsis

50. Carrington and Ambros 2003, Science 301:337

52. Wild type.                APETALA1:    PISTILLATA :   AGAMOUS:                                  "A" class           "B" class          "C" class

53. AP1 mRNA
AG1 mRNA
AP1 in AG1 mutant

54. Dominant Phabulosa/Phavulota mutations
HomeoBox-
Zipper
DNA binding
domain
START
Sterol
binding
domain

55. Phv
Adaxial
domain
Domain boundary
Required for lateral
growth

56. WT
clv3
clv3
Fletcher et al Science 283:

59. KANADI expression in the abaxial domain

60. Development 126, (1999)
Members of the YABBYgene family specify abaxial cell fate in Arabidopsis
Kellee R. Siegfried1,*, Yuval Eshed1, Stuart F. Baum1, Denichiro Otsuga2, Gary N. Drews2
and John L. Bowman1,‡

61. Development 126, (1999)
Members of the YABBYgene family specify abaxial cell fate in Arabidopsis
Kellee R. Siegfried1,*, Yuval Eshed1, Stuart F. Baum1, Denichiro Otsuga2, Gary N. Drews2
and John L. Bowman1,‡

62. Current Biology 2001, 11:1251–1260
Establishment of polarity in lateral organs of plants
Yuval Eshed*, Stuart F. Baum, John V. Perea and John L. Bowman