Genetic_inheritance_of_flower_colour.ppt

genetic inheritance in flower color

1. WELCOME. . . .

2. GENETIC INHERITANCE
IN FLOWER COLOUR

3. INTRODUCTION
Introducing desired foreign genes or changing
endogenous gene expression by genetic
engineering.
petunia, roses, chrysanthemum and carnation
use of genetic transformation techniques.
focused on altering flower colour

4. MAJORBIOTECHNOLOGY COMPANIES
The major world players are
1.Florigene
2.CalgenePacific
3.DNA Plant Technology
4.Japan breweries

5. FLORIGENE
•First company to obtain an alteration of colourby genetic
engineering.
•Transformed the pink chrysanthemum variety
'moneymaker' into a white flower, by blocking the
chalconesynthasegene responsible for pigment
synthesis.
•The company’s research activity remains focussed
on colourmodification using genes of the
anthocyaninbiosynthesis pathway.

6. The “blue rose” program remains high on the
company’s list of objectives.
Through manipulation of the anthocyanin
biosynthetic pathway present in most flowers that
Florigene has created new varieties of carnation.
More recently Florigene and Suntory have
developed a novel coloured rose which is
scheduled for marketing in 2-3 years.

7. CALGENEPACIFIC(CP)
Identification, isolation and transferring of genes responsible for
colors are the main focus of research at CP.
Isolated the key genes responsible for the coloursblue and red.
Main research project is the development of blue flowers,
particularly a blue rose.
The freesia has blue varieties.
CP expects that blue flowers would command a market share
close to that of red if they were freely available.
Blue transgenic petunia
Blue carnations and chrysanthemum
Blue rose

8. DNA PLANTTECHNOLOGY(DNAP)
Developed a transgenic chrysanthemum with altered
flower colour.
The first to report the development of a transgenic
rose.
Friable embryogenic tissues of rose have been
transformed and reproduced into flowering plants.
Although the transferred marker genes are of no direct
commercial interest, the procedure facilitates the
introduction of desirable genes, especially those
controlling flower colour, into commercial cultivars of
rose.

9. JAPANBREWERIES
In Japan, three large breweries, Kirin, Sapporo and
Suntory
Focus in particular on ornamental crops.
Suntory and Calgene Pacific have set up a joint
venture named International Flower Development
(IFD).
IFD has applied for world patent on several techniques
to control flower colour in plants.

10. GENITICAL REASONS FOR INHERITANCE OF
FLOWER COLOUR

11. INCOMPLETEDOMINANCE
In incomplete dominancethe heterozygote exhibits a
phenotype that is intermediate between the
corresponding homozygotes
Example:
Flower color in the four o’clock plant
Two alleles
C
R
= wild-type allele for red flower color
C
W
= allele for white flower color

12. 1:2:1 phenotypic
ratio NOT the 3:1
ratio observed in
simple Mendelian
inheritance
In this case, 50% of
the C
R
protein is not
sufficient to produce
the red phenotype

13. The heterozygote exhibits a phenotype that includes
both traits expressed by the homozygotes
Example: PP = purple flowers, pp = white flowers, Pp =
both purple and white flowers on the same plant
CODOMINANCE

14. Environmental conditions
may have a great impact
on the phenotype of the
individual
Example 1
Snapdragon flower color
vs. Temperature and
degree of sunlight
ENVIRONMENT

15. FLOWERCOLOURMODIFICATION
Anthocyaninsare the most prevalent class of pigment
compounds in plants and in flowers these are deposited in the
large vacuoles of petal epidermal cells where most flower
colouris localised.
Anthocyaninsare relatively simple, water soluble, structures
with the hydroxylation pattern of the B ring at positions 3’, 4’
and 5’ being a key colourdeterminant.
Further modifications to the molecule are common and
beyond imparting small changes to max lend stability to
molecular complexes involving anthocyaninmolecules,
copigmentmolecules (typically flavonols, a product of the
same pathway) and in notable cases metal ions.

16. Such complexes are further influenced by petal
epidermal vacuolar pH. All of these components
impact directly on the observed colour.
A key branch point of the anthocyanin biosynthetic
pathway is centred around the intermediate DHK
(dihydrokaempferol). The enzymes FLS (flavonol
synthase), F3’H (flavonoid 3’ hydroxylase), F3’5’H
(flavonoid 3’5’ hydroxylase) and DFR
(dihydroflavonol reductase) all utilise this substrate
suggesting that this region of the pathway is a key
determinant of anthocyanin biosynthesis and thus
flower colour.

17. Florigene R&D has cloned and protected nearly
all genes in the anthocyanin/flavonoid pathway
from petunia and numerous homologues from a
diverse number of species in close collaboration
with Suntory Research in Japan. These genes are
the centrepoint of Florigene Intellectual
Property and our capability in the manipulation of
anthocyanin-based flower colour modification.

18. GENETICINHERITANCEOFFLOWER
COLORINCARNATION

19. GENETICMODIFICATION OFFLOWER
COLORINCARNATION
Flower colour is generally the result of the relative
concentration and type of twopigment types -
carotenoids and flavonoids.
Carotenoidsare responsible for yellow through
orange colours
Anthocyaninsare flavonoid based coloured
pigments.
There are three groups of anthocyanins, the
delphinidinsthat generally produce blue flower
colour, cyanidinsthat produce red or pink flower
colour, and pelargonidinsthat produce orange or
brick red flower colour.

20. THERELEVANTBIOCHEMICALPATHWAYISSHOWNINTHE
FIGUREBELOW.

21. Carnations lack the part of the anthocyanin
biosynthetic pathway that is responsible for the
production of delphinidin, as they lack a gene
encoding the enzyme flavonoid 3’5’ hydroxylase
(F3”5’H in the diagram) that converts
dihydrokaempferol (DHK) to dihydroquercetin (DHQ)
and then to dihydromyricetin (DHM).
In the genetically modified carnations commercialized
by Florigene a gene encoding flavonoid 3’5’
hydroxylase has been isolated from other plant
species and transferred to carnation.

22. Delphinidin is thus produced as a result of the combined
expression of the introduced genes together with
endogenous genes in the anthocyanin biosynthetic
pathway.
The production of delphinidin results in a change in
flower colour.

23. GENETICINHERITANCEOFFLOWER
COLORINMARIGOLD

24. good source of carotenoids
different levels of pigmentation caused by lutein.
the expression of several genes in the carotenoid
biosynthetic pathway:
1.phytoene synthase (Psy),
2.phytoene desaturase (Pds),
3.lycopene β-cyclase (Lcy-b) and
4.lycopene ε-cyclase (Lcy-e).
cDNA insertsfrom isolated clones were 1376–1916bp
long.

25. Northern blot analyses of three
varieties of marigold showed that
most gene transcripts were
expressed during flower
development.

26. GENETIC
INHERITANCEOF
FLOWERCOLORIN
ROSE

27. One gene involved in flower colour, is the
dihydroflavonol reductase (DFR) gene.
The DFR gene makes the enzyme dihydroflavonol
reductase (DFR) which turns on the manufacturing
process in the plant that produces pigment that in
turn colours flowers.

28. In roses the DFR gene is very good at
producing red pigment and hence the range of
red color commonly seen rose colours.
However, the rose DFR gene is particularly bad
at producing blue pigment, hence the difficulty
in breeding a blue rose.
The first critical step in producing a blue rose
was to stop the rose DFR gene making red
pigment.

29. PREVENTING REDPIGMENT
CSIRO first developed gene silencing, or hairpin
RNAi, in 1997.
Gene silencing uses a natural mechanism that
degrades RNA –the courier that delivers the
gene’s instructions to make proteins, like the
enzyme DFR

31. OPENINGTHEBLUEDOOR
In roses the pathway to producing red pigment is open,
but the blue pathway is closed.
Florigeneand Suntory inserted a gene commonly called a
delphinidingene from pansy that opened the door to the
production of blue pigment in the rose flowers.

32. IMPORTING THEBLUECOLOUR
Final task was to find a DFR gene good at
producing blue and placing it in the rose.
Florigene and Suntory decided to replace the
rose DFR gene with a DFR gene from an iris,
which is excellent at producing blue pigment.
The iris DFR gene was inserted into the rose
and subsequently a rose with a blue flower was
produced.

33. DRPETERWATERHOUSE, LEADEROFTHECSIRO
TEAMWHODISCOVEREDTHEGENESILENCING
TECHNOLOGY USEDTODEVELOPTHEBLUEROSE.

34. GENETICINHERITANCEOF
FLOWERCOLORIN
CHRYSANTHEMUM

35. For flower color modificationthe
chrysanthemum was transformed by the
genes coding chalcone synthase (chs)in
sense and antisense orientation, with
the aim of affecting floral pigmentation,
thereby producing new flower colors

36. Chimeric chalcone synthase (CHS) constructs were prepared in
both anti-sense and sense orientations, and introduced into the
chrysanthemum cultivar Moneymaker, along with a T-DNA vector
lacking a CHS construct.
For both the anti-sense and sense constructs, the majority of the
plants produced pink flowers typical of Moneymaker itself.
Of 133 sense and 83 anti-sense transgenic individuals 3 of each
set produced fully white or very pale pink flowers.
No white-flowering transgenic plants were obtained in control
transformations.
The white flowers were found to accumulate higher levels of
chalcone synthase precursors and to have reduced levels of
chalcone synthase message.

37. Rare multicoloured chrysanthemum stuns horticulturalists
A rare multicoloured chrysanthemum has stunned the horticultural
world after it burst into bloom at odds of thousands to one –exactly half
pink and half yellow.

38. GENETICINHERITANCEOF
FLOWERCOLORINGERBERA

40. The flower colour of Gerbera, an
important ornamental cut flower, is
derived from carotenoids and
flavonoids.
The material for the investigation
of phenotypic segregation and
segregation of flavonoids after
chromatographic analysis came
from 408 progenies of controlled
crosses
Phenotypic segregation analysis
showed acyanic genotypes to be
homozygous recessive and
recessive epistatic over cyanic
genotypes, respectively.

41. This was confirmed by the existence of two loci
controlling steps in biosynthesis (fht, dfror ans)
showing recessive mutants and complementary gene
action after crosses.
Flavoneformation is effected by one dominant allele
(fns+);dominant and recessive genotypes are now
available.

42. Regarding anthocyanidin
inheritance, an unusual epistasis
of 4′-hydroxylation
(pelargonidin formation) over
3′,4′-hydroxylation (cyanidin
formation)was observed.
Final proof of the postulated
gene actions will come from
enzymological and molecular
biological investigations of the
chemogenetically defined
Gerberagenotypes now
available.

43. Genetic inheritance of flower color
in petunia

44. The inheritance of specific flower colors in Petunia
hybrida Vilm can be explained through the combined
inheritance of anthocyanin pigmentation and pH.
The inheritance of anthocyanin pigmentation is
controlled by multiple independent genes {Hf and Mf)
that follow simple Mendelian genetics.
The inheritance of pH is more complex, being
controlled by two independent codominant genes (Ph1
and Ph2).

45. Linkage of the various pH and anthocyanin genes
prevents the expression of all of the potential gene
combinations.
Flower color in Petunia hybrida Vilm has been
studied for a long time (Hooker 1837).
One of the first major genetic studies identified was
nine genes that were involved in the inheritance of
flower color (Paris and Haney 1958).

46. Cultivars that contained cyanidinhad flowers that
were red through lavender. Similarly, those cultivars
that contained peonidinhad flowers that were red
through purple.
Two plants with the same genotype for
flavonoid pigments might not have the same
flower color
The aromatic rings of the various anthocyanins and
copigments stack on top of one another.
Differences in color are the result of changes in the
physical interaction or hydrogen bonding
between the stacked rings.

47. INHERITANCE OF FLOWER COLOR
The red-flowered parent (RHS 45A) contained
cyanidin(92%) and pelargonidin(8%), while the
violet-flowered (RHS 89C) parent contained
malvidin(77.3%) and petunidin(22.7%).
Both parents were inbred and were homozygous for
flower color genes.
Since the red parent did not contain either
delphinidin, petunidin, or malvidin, it was recessive
for hydroxylation at the 5' position.
This gene is denoted as Hf.

48. The red parent was also recessive for methylation,
since it did not contain peonidin.
This gene is denoted as Mf. The genotype of the
red parent must have been hfhfmfmf.
The violet parent, since it contained malvidinand
petunidin, was dominant for both 5'-hydroxylation
and methylation.
The genotype of the violet parent must have been
HfHfMfMf.
As expected of a heterozygote (HfhfMfmf), the F,
hybrid contained both 5'-hydroxylated and
methylatedanthocyanins.
The F, hybrid contained malvidin(95%) and
peonidin(4.8%).

49. INHERITANCE OF PH
The red parent (hfhfmfmf) had a pH of 5.5 with a
standard deviation of 0.2.
The violet parent (HfHfMfMf) had a pH of 6.2 with a
standard deviation of 0.1.
The F, hybrid population had a mean pH of 6.1,
which was slightly more acidic than the violet
parent.
The color of the F, hybrid was not violet (RHS 89C)
as expected from its genotype and anthocyanin
composition; it was purple (RHS 80A).