Download Control of bolting and flowering in sugar beet Early flowering in

Control of bolting and flowering in
sugar beet
Pierdomenico Perata
Antonietta Santaniello
Early flowering in sugar beet
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Early flowering in sugar beet
Troubles:
Lower yield
Difficult harvest
Increases seed dispersal (“wild beet”)
The physiology of flowering
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Photoperiodic control of flowering
Pharbitis, short
day plant
Arabidopsis, long
day plant
Beta vulgaris, long
day plant
Vernalisation
cauliflower plant
grown 5 years in a
heated greenhouse
Vernalised
cauliflower plant
=
flowering
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Vernalisation in sugar beet
Sugar beet plants require vernalisation
Temperature:
8°C
Lenght:
~ 70 gg
Early flowering
Spring sowing (4-6 leaves stage)
Fall sowing
Temperature:
3-5°C
Lenght:
few days
Low temperatures in southern Italy
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Molecular
biology of
flowering
Molecular
biology of
flowering
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Transition from vegetative to flowering meristem
Transition from vegetative to flowering meristem
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Flower and
inflorescence
identity: “terminal
flower” gene
tfl mutant
Mutations in CAL and
AP1 results in a strong
inflorescence phenoype
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The ABC model
AP1
The ABC model
Positive interaction between
genes coding for the same
function.
A genes and C genes compete
and the expression of one class
excludes the expression of the
other class
AP3
PI
AG
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The ABC model
Vernalisation
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Physiology and genetics of flowering in sugar
beet
VERNALISATION
LONG DAY
GIBBERELLINS?
B Gene
BOLTING
FLOWERING
Early flowering in sugar beet
induction
Gibberellis
“bolting”
Flower differentiation
Flowering
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Hormonal modulation of flowering
Gibberellins
Hormonal modulation of flowering
Gibberellins
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Gibberellins and flowering
vernalisation
Long day
gibberellins
Gibberellins and flowering
vernalisation
Long day
gibberellins
bolting and flowering are distinct processes
(bolting without flowering is possible)
GA 3 induces bolting
(without vernalisation and long day conditions
GA 3 cannot induce flowering
(unless vernalisation and long day conditions
occur)
(Margara, 1960)
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Gibberellins and flowering
in some carrot CV GA 3 induces
flowering (replacing
vernalisation)
in Lolium temulentum:
GA 5 → flowering induction
GA 1+GA 4 → differentiation
(King et al., 2001)
In Vitis vinifera
gibberellins inhibit
flowering
Gibberellins and flowering in sugar beet
VERNALISATION
FLOWERING
GA1
GA8
GA5
Data: SORCE & LORENZI, UniPISA
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Fitoregolatori e prefioritura
VERNALISATION
FLOWERING
GA1
GA5
INHIBITION OF
GA SYNTHESIS
O
HO
H
OH
CO
2β-idrossilasi
H
PACLOBUTRAZOLE
BIOLOGICALLY
ACTIVE GAs
COOH
GA29
O
O
O
H
CO
OH
3 β-idrossilasi
HO
H
H
OH
CO
OH
CO
HO
H
HO
H
H
GA20
REGALIS
COOH
COOH
COOH
GA8
GA1
O
O
2,3-desaturasi
H
H
OH
CO
OH
CO
HO
H
H
COOH
COOH
GA5
GA3
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CONCLUSION:
Selection of CV with lower tendency to
early flowering
Identification of genes responsible for
the vernalisation response
Center for Research
on Crop Physiology
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