Flowering Time Flower Meristem Identity Flower Organ Identity Fruit Development FT APETALA1, LEAFY, CAULIFLOWER, (TERMINAL FLOWER) A, B, C, D FRUITFULL,
Dec 20, 2015
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Flowering Time
Flower Meristem Identity
Flower Organ Identity
Fruit Development
FT
APETALA1, LEAFY, CAULIFLOWER, (TERMINAL FLOWER)
A, B, C, D
FRUITFULL, SHATTERPROOFINDEHISCENT
B
A C C A
B
carp
el
pet
al
pet
al
stam
en
stam
en
sep
al
sep
al
1 12 23 34
normal flower
sep
al
sep
al
pet
al
pet
alst
amen
stam
en
carp
elBB
A C C A
What gene prevents the B gene from beingactive in the center of flowers?
In SUPERMAN mutants (SUP), the B activityexpands into the center of the flower and convertsthe two carpels into two stamens.
A C C A
B B
stam
en
stam
en
sep
al
sep
al
pet
al
pet
al
stam
en
Superman mutant
The SUPERMAN gene normally functions toprevent B gene activity in the center of flowers
A C C A
B B
stam
en
stam
en
sep
al
sep
al
pet
al
pet
al
stam
en
normal BC mutant ??se
pal
sep
al
pet
al
pet
alst
amen
stam
en
carp
el
BB
A C C A
A A A A
normal BC mutantse
pal
sep
al
pet
al
pet
alst
amen
stam
en
carp
el
BB
A C C A
A A A A
sep
al
sep
al
sep
al
sep
alse
pal
sep
al
*
BC double mutant
all organsare sepals
sep
al
sep
al
pet
al
pet
alst
amen
stam
en
carp
elBB
A C C A
What happens if the A, B and C genes are allinactivated in the ABC triple mutant?
normal ABC mutant ??se
pal
sep
al
pet
al
pet
alst
amen
stam
en
carp
el
BB
A C C A
ABC mutant
leaf
leaf
leaf
leaf
leaf
leaf*
normalse
pal
sep
al
pet
al
pet
alst
amen
stam
en
carp
el
BB
A C C A
“ABC” triple mutant
all organsare leaves
Goethe believed that floral organs are derived from leaves
Goethe, 1790
• 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.
• 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?
leaf petal?A+B
“D” mutant
all organsare sepals
A B
C D
D Activity is required forpetal, 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.
sep
al
stam
en
pet
al
carp
el
pet
al
stam
en
sep
al
B
A C C A
B
D D
normal D mutantse
pal
sep
al
pet
al
pet
alst
amen
stam
en
carp
el
BB
A C C A
A A A A
sep
al
sep
al
sep
al
sep
alse
pal
sep
al*
DD
• 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?
Regulatory regionPetals, stamens and carpels
D GENECoding Region
leavesAdd Leaf regulatory region:
Remove regulatory region:
leaf petalA+B+D
?
leaf petalA+B+D
A = sepals
A + B + D = petals
C + D = carpels
B + C + D = stamens
The ABCD genes act alone, or incombination, to specify the fourtypes of flower organs
The ABCD genes are sufficient to convert leaves into flower organs
The ABCD model is applicable to allflowering plants
The C gene is active in cells that will form stamens and carpels
petal
sepalcarpel
leaf
sepalstamen
What would happen if the C gene was mis-expressedin cells that would normally form sepals?
petal
sepalcarpel
leaf
sepalstamen
B
normal
stam
en
stam
en
carp
el
sep
al
sep
al
B
A C C A
pet
al
pet
al
Regulatory regionstamens and carpels
C GENECoding Region
sepalsAdd 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, D
FRUITFULL, SHATTERPROOFINDEHISCENT
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