Week 13 L4: Plant Reproduction - ABCE Model

Question 1

What combination of genes make a sepal?

Answer 1

A

Question 2

What combination of genes makes a petal?

Answer 2

A+B

Question 3

What does genes B+C make?

Answer 3

stamen

Question 4

What does gene C make?

Answer 4

Carpel

Question 5

Where are the genes encoding key TF found?

Answer 5

floral meristem

Question 6

What encodes the TF needed for specificity of floral organs?

Answer 6

ABC (+E model)

Question 7

What are the MADS box genes?

Answer 7

once activated by TF (encoded by ABCE genes) it creates a specific plant organ

Question 8

What is the arrangement of MADS box genes and CArG for floral development?

Answer 8

The MADS box genes encode TF factors which bind to DNA at a specific transcription activation site.

Depending on the combination of MADS TF to a specific CArG will initiate a specific transcription to a plant organ

Question 9

What gene is needed in each quartet model for organ formation?

Answer 9

E genes (sepalata genes) 
SEP

Question 10

What is CArG?

Answer 10

The DNA motif bound by MADS box proteins

Question 11

What does the quartet model only apply to?

Answer 11

highly derived eudicots like arabidopsis

Question 12

What creates variation in plants flower formation?

Answer 12

Differences in MADS box genes and where they are expressed may explain in part of how flowers evolved and diversified.

Question 13

How do MADs box genes interact with one another?

Answer 13

via MADs box proteins

Question 14

What binds to MADs box genes in plants?

Answer 14

The genes which contain this motif are called the MADS-box gene family. … The MADS domain binds to DNA sequences of high similarity to the motif CC[A/T]6GG termed the CArG-box.

Question 15

What do the MADs box genes create?

Answer 15

TF

AP1, AP3, PI, AG & SEP

Question 16

What do the MADs box proteins bind to?

Answer 16

CArG-box of TARGET dna

Question 17

What part of the MADs box TF bind to the CArG-box motif?

Answer 17

MADs domain on the protein

DNA binding CArG box

Question 18

What is the quartet model?

Answer 18

A combination of 4 MADs box genes biding to CArG seq

Question 19

What combination of quartet model TF interact to make carpels?

Answer 19

AG (C) + sep

Question 20

What CArG does the AG/SEP TF interact with?

Answer 20

CArG1

Question 21

What combination of quartet model TF makes a stamen?

Answer 21

SEP/AG

PI/AP3

Question 22

What CArG gene does PI/AP3 bind to?

Answer 22

CArG2

Question 23

What combination of TF makes a petal?

Answer 23

AP1/SEP

PI/AP3

Question 24

What CArG gene does AP1/SEP bind to?

Answer 24

CArG3

Question 25

What combination of TF makes a sepal?

Answer 25

AP1 and SEP

Question 26

What are the 3 different combinations of TF pairs?

Answer 26

AG/SEP - CARG1 PI/AP3 - CARG2 AP1/SEP - CARG3

Question 27

How many MADs do proteins to MADs box gens have?

Answer 27

some have nearly 100 diff MADS proteins

Question 28

What plant types have the ABCE model?

Answer 28

gymnosperms and angiosperms

Question 29

What is a basal angiosperm?

Answer 29

sporophyte dominant | enclosed gametophyte

Question 30

What is the most basal angiosperm?

Answer 30

amborella

Question 31

Is a amborella have both male and female plants?

Answer 31

YES

Question 32

What is a special feature of a female amborella?

Answer 32

it has a staminode | and tepal

Question 33

What is a staminode?

Answer 33

it looks like a stamen but is actually not It's a female flower. Thus it can attract pollinators as the stamen produces pollen. It tricks the insect to giving the plant pollen by what is on it bod

Question 34

What is a tepal?

Answer 34

not quite a petal not quite a sepal

Question 35

What kind of structure is the tepal?

Answer 35

Sterile | perianth structure

Question 36

What is a perianth structure?

Answer 36

non-reproductive (accessory, sterile) part of the flower, consisting of floral leaves surrounding the androecium and gynoecium. It is differentiated into outer and inner whorls.

Question 37

What does sterile mean?

Answer 37

unable to produce viable offspring

Question 38

What can change in the ABC model to produce petal-like sepals in the basal eudicot - clematis integrifolia?

Answer 38

limiting the location of B gene expression can result in plants with no true petals. The model predicts that the B gene would be reduced so that it never overlaps with A Resulting in 2 whorls with sepals due to B gene under-expression.

Question 39

What would A with no B result in?

Answer 39

two whorls with sepals

Question 40

What would the over-expression of B gene result in?

Answer 40

Many petals

Question 41

What is a feature of the Clematis integrifolia species?

Answer 41

petal-like sepals | NO trie petals

Question 42

What is a feature of C. chiisanensis?

Answer 42

``` separate whorls of pateloid sepals and true petals. over-expression of B class genes ```

Question 43

How do we know that the b class gene is overepressed in Clc clematis?

Answer 43

The APIII IN Clc is highly expressed on assay and the AP3 is absent in the Cli plant

Question 44

What ABC model does a tulip have?

Answer 44

Over expression of B gene forming tepals

Question 45

What is the feature of tulips and their gene expression?

Answer 45

A genes are only expressed with B genes, resulting in 2 whorls of petal-like organs

Question 46

What whorls are B gnes expressed in in tulips?

Answer 46

outer and inner tepal (whorls 1&2) as wells as the stamen (whorl 3

Question 47

What is the 'Fading borders' model?

Answer 47

In contrast, in the fading borders model, the borders between A, B, and C functions are blurred to produce a gradual transition of organ identity programs across the floral meristem. Hence, floral organs are influenced by “ABc,” “aBC,” and “abC” activities, where lowercase font indicates lower functional influence.

Question 48

What is the blurred boundaries of the genes in the ABC model known as?

Answer 48

fading borders model

Question 49

What would A(faded)Bc create?

Answer 49

sepaloid tepal

Question 50

What does the ABCE model only apply to?

Answer 50

highly derived eudicots like arabidopsis

Question 51

What are the MADs box gene expression in the gymnosperm (conifer) between male and female cones?

Answer 51

F : C | M : B+C

Question 52

How is the presence of a common ancestor thought by the gymnosperm and angiosperm? EVO

Answer 52

the cone and flowers respectively are both formed by the interaction of B and C function genes, implying presence in common ancestor

Question 53

What is the 'out of female' hypothesis? EVO

Answer 53

B function genes became expressed to generate stamen-like structures from carpel-like organs (male derived form female) - not clear

Question 54

What are the A and E genes called/function? EVO

Answer 54

act as meristem identifiers - make the reproductive structure more recognisable as a "flower" to us

Question 55

What type fo plant only truly differentiate petals and sepals?

Answer 55

only higher eudicots e.g. arabidopsis

Question 56

What level of plant shows varying degrees of differentiation and what structures do they create?

Answer 56

lower eudicots monocots basal angiosperm Differentiation of petaloid and sepaloid organs from leaf-like structures

Question 57

what are the petal-like structures in grasses?

Answer 57

lodicule

Question 58

What is an example of a grass?

Answer 58

rice flowers

Question 59

How does grass pollinate?

Answer 59

wind

Question 60

What is the importance of lodicule swelling in rice?

Answer 60

Important in agronomics | potential for outcrossing

Question 61

What is the effects in pollen exchange due to loss of lodicule swelling?

Answer 61

fewer pollen grains exchange since florets do not open.