植物激素作用机理专题开花抗倒伏

赤霉素的生物合成及作用机制赤霉素生物合成赤霉素的信号传导赤霉素与开花素赤霉素与抗倒伏开花素（florigen）的定义Florigen

is

the

flower

hormone

thatregulates

flowering

and

has

the

samenature

in

different

plants1936

Chailakhyan开花素存在的实验证据VOL

309

9

SEPTEMBER

2005Leaf-specific

heat

shock

activation

of

gene

expression.GUS

staining

in

whole

plants

(A

to

C)

and

shoot

apex

(D

toF)

of

Hsp:GUS

plants

grown

under

short-day

conditions.Integration

of

signals

to

generate

aflower.

Appropriate

day

length

allows

theaccumulation

of

the

transcription

factorCO

that

controls

expression

of

FT

in

theleaf.

(Inset)

FT

transcript

moves

throughthe

phloem

to

the

shoot

apex

where

theFT

protein

is

produced

and

interactswiththe

transcription

factor

FD.

The

complexthen

activates

key

genes

such

as

AP1

tostart

flower

development.

LEAFY

(LFY)

isa

transcription

factor

required

for

AP1expression

in

wild-type

plants.

LFYexpression

isup-regulated

by

FT

in

theshoot

apex.446,

956-957

(26

April

2007）Elusive

flowering

signal

pruned

of

mystery

at

lastHeidi

Ledfordnature

newsLast

week,

two

papers

in

Science

reported

thediscovery

of

florigen,

a

long-sought

compound

withthe

power

to

make

flowers

bloom.

But

if

thecelebration

of

its

discovery

seems

a

little

muted,

it

isbecause

many

researchers

have

heard

this

claimbefore.

And

this

time,

the

reports

come

as

an

oldone

is

retracted

amid

charges

of

data

manipulation.The

discovery

of

florigen

was

heralded

in

2005,when

another

Science

paper1

claimed

that

it

was

the

RNA

produced

by

a

gene

called

FLOWERINGLOCUS

T,

or

FT.

But

now

the

authors

of

that

paperhave

retracted

their

findings,

and

in

its

stead

cometwo

papers

that

say

florigen

is

not

FT

RNA,

but

theprotein

produced

by

the

FT

gene……The

Coincidence

Model

of

PhotoperiodismHd1

=

Heading-date1,

rice

ortholog

of

COHd3a

=

Heading-date

3a,

rice

ortholog

of

FTH

d1

RepresseractivityThe

nature

of

floral

signals

inArabidopsis.

II.

Roles

for

FLOWERINGLOCUS

T

(FT)

and

gibberellinTamotsu

Hisamatsu

*

and

Rod

W.

KingJournal

of

Experimental

Botany

2008

59(14):3821-3829;REVIEW-ARTICLEGibberellin

as

a

factor

in

floral

regulatory

networksEffie

Mutasa-Göttgens1

and

Peter

Hedden2,*1Broom's

Barn

Research

Centre,

Rothamsted

Research

Department

of

Applied

CropScience,

Higham,

Bury

St

Edmunds,

Suffolk

IP28

6NP,

UK2Rothamsted

Research,

Harpenden,

Herts

AL5

2JQ,

UKJournal

of

Experimental

Botany

2009，Volume

59,

Number

14

Pp.

3821-3829Gibberellins(GAs)

function

not

only

to

promote

the

growth

of

plant

organs,

but

also

to

induce

phase

transitions

duringdevelopment.

Their

involvement

in

flower

initiationin

long-day

(LD)

and

biennial

plants

is

well

establishedand

there

is

growing

insight

into

the

mechanisms

by

which

floral

induction

is

achieved.

The

extent

to

which

GAs

mediate

the

photoperiodicstimulus

to

flowering

in

LD

plants

is,

with

a

few

exceptions,

less

clear.

Despite

evidence

for

photoperiod-enhanced

GAbiosynthesis

in

leaves

of

many

LD

plants,

through

up-regulation

of

GA

20-oxidase

gene

expression,

a

function

for

GAs

astransmitted

signalsfrom

leaves

to

apices

in

response

to

LD

has

been

demonstrated

only

in

Lolium

species.

In

Arabidopsisthaliana,

as

one

of

four

quantitative

floral

pathways,

GA

signalling

has

a

relatively

minor

influence

on

flowering

time

in

LD,

while

in

SD,

in

the

absence

of

the

photoperiod

flowering

pathway,

the

GA

pathway

assumes

a

major

role

and

becomesobligatory.Gibberellins

promote

flowering

in

Arabidopsis

through

the

activation

of

genesencodingthe

floral

integratorsSUPPRESSOR

OF

OVEREXPRESSION

OF

CONSTANS

1

(SOC1),

LEAFY

(LFY),

and

FLOWERING

LOCUS

T

(FT)

in

theinflorescence

and

floral

meristems,

and

in

leaves,

respectively.

Although

GA

signallingis

not

required

for

floral

organspecification,

it

is

essential

for

the

normal

growth

and

development

of

these

organs.

The

sites

of

GA

production

and

actionwithin

flowers,

and

the

signalling

pathways

involved

are

beginning

to

be

revealed.Summary

of

findings

here

and

in

the

companionpaper

of

positive

effects

(arrows)

on

flowering

andCO/FT

for

two

commonly

used

LD

photoresponses.This

schematic

incorporates

effects

on

FT

and

flowering

of:mutants;

gene

silencing;

change

in

light

intensity;

and

a

block

tophotosynthesis.Predominantly,inLD,

photosyntheticsucroseamplifies

CO/FT

expression

(see

companion

paper)

whilephytochrome

acts

directly

and

also

via

GA,

which

plays

apermissive

and,

often,

non-limitingrole.

There

is

alsoa

direct

butlesser

LD-mediated

increase

in

GA

supply

via

the

petioleresponse

to

FR-rich

light.

A

dashed

arrow

indicates

a

potentialstep

of

regulation,

and

weaker

responses

are

indicated

by

thinner

arrows.The

electronics

symbol

for

a

speaker

is

used

toshow

sucrose

amplification

of

CO/FT

expression.赤霉素作为开花素应满足的条件applied

GAs

replace

the

need

for

LDinduction,florigenic

GAs

increase

in

leavessoon

after

LD

induction,these

GAs

move

to

the

shoot

apexbythe

time

of

floral

evocation,

andthe

concentration

of

GA

at

the

apex

issufficient

to

cause

flowering.MoreCriteriaExogenous

application

causes

theresponse;Endogenous

levels

should

be

related

tothe

response

(i.e.,

increase

before

theresponse

occurs).Lowering

endogenous

levels

preventsthe

response;Lowering

endogenous

levels

followed

byexogenous

application

restores

theresponse;Floral

homeotic

genesaretargets

of

gibberellin

signalinginflowerdevelopmentPANS

May

18,

2004

vol.

101

no.

20

7827-7832Phenotypesof

mutantplants.

(A-F)Flowers

of

ga1-3(A),

ga1-3

rgl1-1(B),

ga1-3

rga-t2

(C),

ga1-3rgl1-1

rga-t2

(D),ga1-3

rgl2-1

rga-t2

(E),

and

ga1-3rgl1-1

rgl2-1

rga-t2

(F).

(G-I)Inflorescenceapices

of

ga1-3(G),

ga1-3

rga-t2(H),

and

ga1-3rgl1-1

rgl2-1

rga-t2

(I)./content/101/20/7827.fullExpression

of

floral

homeotic

genes.

(A)Expression

of

AP1,

AP3,

PI,

and

AG

ininflorescence

apices

of

ga1-3

mutants

mock-treated

with

0.1%

ethanol

(M),

or

treated

with

100μM

GA

(GA).

Expression

analyses

were

done

after2

h

of

treatment.In

situ

localizationof

AP3

expression

in

WT

plants

(A–C)

and

ga1-3

mutants

(D–F).

(A

and

D)

An

inflorescence

apex

with

stage-2

and

stage-4

flowers.

(BandE)

A

stage-8

flower.

(C

and

F)

A

stage-10

flower.(Bars

=

100

μm.)In

situ

localization

of

AG

expression

in

WT

plants

(A–D)and

ga1-3

mutants

(E–H).

(A

and

E)

An

inflorescenceapex

with

a

stage-4

flower.

(B

andF)

A

stage-6

flower.(C

and

G)

A

stage-9

flower.

(D

and

H)

A

stage-12

flower.(Bars

=

100

μm.)/content/101/20/7827.fullGA4

Is

the

Active

Gibberellin

intheRegulation

of

LEAFY

Transcriptionand

Arabidopsis

Floral

InitiationThe

Plant

Cell

18:2172-2181

(2006)GA4

applied

to

ga1-3shows

an

FT-independenteffectonfloweringinSDandapermissiveeffectinvolving

FTexpression

inLD.

A

10

µl

drop

of

GA4

[1

mM

in

20%

ethanol:water(v:v)]

was

applied

to

each

of

three

leaves

onconsecutive

days

either

in

SD

or

at

the

start

of

a

far-red-rich

LD

(LD-FR).

Plants

of

ga1-3

flowered,

bolted,and

leaves

grew

(A).

Its

FT

expression

increased

mostafter

GA

treatment

in

LD

(B),

and

(C)

shows

the

effect

of

GA4

on

FT

expression

in

Columbia.

Prior

totreatment,

the

plants

of

ga1-3

had

been

grown

in

SD

for12

weeks

and

those

of

Columbia

for

5

weeks.

The

lowintensity

FR-rich

LD

exposure

was

for

2

d.

GA4

wasapplied

8

h

after

starting

the

day,

and

leaf

blades

wereharvested

19.5

h

later

for

assays

of

FT

expression(leaves

harvested

at

16

h

showed

similar

increases;

notshown).

There

was

no

effect

of

solvent

application

onflowering

or

gene

expression

(not

shown).

All

FTexpression

was

normalized

to

the

value

in

SD

withoutGA

application.

The

means

and

SE

were

based

onthree

replicates

for

FT

assays

and

10

replicates

forflowering

time. Real-time

RT-PCR

analysis

of

LFYexpression

in

excised

shoot

apicesduring

growth

in

short

days.

Estimatedtime

of

flower

induction

is

marked

byshaded

area.

Values

are

expressedrelative

to

18S

rRNA.

Inset:semiquantitative

RT-PCR

analysis

of

AP1and

AP3

expression

in

excised

shootapices

during

growth

in

short

days.

The18S

rRNA

was

amplified

as

an

internalcontrol.

AP1

can

be

detected

from

day

42and

AP3

from

day

49.

Numbers

indicatedays

after

sowing.Gas

chromatography–massspectrometry

(GC-MS)

quantifications

of

the

levels

of

GA1,

GA4,

and

GA5

inexcised

shoot

apices

during

growth

inshort

days.

Microdissected

shoot

apicesfrom

20

to

30

plants

were

pooled

for

eachtime

point.

Values

are

expressed

as

means±

SE

of

the

mean

(n

=

3).Effect

of

LD

on

expression

of

two

GA

20-oxidasegenes

in

the

leaf

blade,

petiole,

and

shoot

tip

ofArabidopsis.

Gene

expression

was

analysed

for

plants

ofColumbia

held

in

SD

(filled

circle)

or

shifted

to

LD

(opencircle).

The

values

of

the

second

SD

cycle

are

those

of

thefirst

day

as

previouslyvery

little

difference

across

days

wasfound

(Hisamatsu

et

al.,

2005).

The

shaded

areas

show

whenthe

‘overnight’

16

h

light

or

dark

treatments

wereimposed.

There

was

no

detectable

expression

of

GA

20-OXIDASE2

in

the

leaf

blade.

All

values

are

means

±SE(n=3).

Error

bars

when

not

evident

were

smaller

than

thesymbol.Dose–Response

Curves

for

the

Activation

of

LFY:GUS

Expressionby

Different

GAs.Three-day-old

seedlings

grown

in

half-strength

Murashige

and

Skoog

mediumsupplemented

with

0.5%

sucrose

were

treated

with

different

concentrations

ofGA1,

GA3,

GA4,

GA5,

GA6,

and

GA8

for

3

d

and

then

assayed

for

GUS

activity.Values

are

shown

as

means

±

2

x

SE

of

the

mean

(n

=

24).

MUG,

4-methylumbelliferyl

ß-D-glucuronide毒麦（野麦）Lolium

temulentumDiurnal

changes

in

the

content

of

five

GAs

in

the

leaf

blade

of

L.temulentum.

Plants

were

grown

in

SD

(

,

solid

line)

or

exposed

to

asingle

florally

inductive

LD

(

,

broken

line).

The

white

boxes

on

the

timescale

indicate

the

daily

8-h

natural

light

period,

the

hatched

box

indicatesthe

16-h

LD

extension

with

incandescent

lamps,

and

the

black

boxesindicate

the

SD

dark

periods.

GA

content

is

expressed

as

ng

g–1

dryweight

(dw).

The

LSD

(0.05)

is

for

the

three

replicate

extractions

for

all

11times

of

sampling

for

any

one

GA.

The

classes

of

enzyme

responsible

forthese

three

biosynthetic

conversions

are

indicated

near

the

arrows.Expression

of

LtGA2ox1

by

In-Situ

Hybridization

forStem

Cross-Sections

Taken

1.0

mm

Below

the

Shoot

Apex

of

Vegetative

Plants

of

L.

temulentum.Near-to-adjacent

sections

were

hybridized

together

withantisense

riboprobe

(A)

or

with

sense

probe

(C).

In

(B),the

boxed

area

in

(A)

is

shown

at

a

4.5x

magnificationbut

from

an

adjacent

section

from

a

separatehybridization

with

the

antisense

probe.

The

scale

barsare

150

µm.Effect

of

the

DOSE

of

Leaf

Applied

GA1(•)

or

GA5

(25

µg

per

plant)

onExpression

of

LtGA2ox1

in

the

Top

3.5mm

of

the

ShootTip

of

L.

temulentum.Plants

were

maintained

under

8

h

SD

andharvests

were

3

d

after

GA

treatment.Flowering

and

stem

elongation

are

shown

forthe

same

experiment.

Without

GA

application,the

plants

continued

to

grow

vegetatively.Valuesare

means

±

S.E.

(n

=

3

for

(A)

and

14for

(B)

and

(C)).Metabolism

of

Radiolabelled

GAs

asShown

byC-18

Reversed

PhaseHPLC

of

Methanolic

ExtractsofIsolated

Shoot

Tips

of

L.temulentum

Harvested

6

h

afterIncubation

on

Agar

Containing[14C]labelled

GA.HPLC

fractions

of

1

mL

were

collectedevery

minute

and

counted

in

a

liquidscintillation

spectrometer.

The

namedpeaks

relate

to

elution

times

for

standards.The

values

on

the

histograms

are

averages

of

at

least

three

separateextractions

and

HPLC

runs. OsGA3ox1

also

has

2,3–desaturaseactivity,

converting

GA20

to

GA5, as

well

as

a

2-oxidase

activityconverting

GA1

to

GA8, and

it

could

potentially

be

responsiblefor

synthesis

of

GA3

from

GA5/GA6.OsGA3ox1的神奇活性OOCOHOOCOHOOCOHCOOHGA6COOHGA5OOHOOCCOOHGA3HOOOCOHCOOHGA1OOCOHCOOHGA8HOHOCOOHGA3ox1GA20GA2ox1GA3ox1GA2ox2

HOOsGA2ox1屏障OsGA3ox2OsGA2ox1屏障E

through

G,

Serial

cross

sections

around

thevegetative

shoot

apex.

sam,

Shoot

apicalmeristem;

lp1

through

3,

leaf

primordium

1through

3;OsGA2ox1屏障B,

Median

longitudinal

section

of

the

vegetative

shoot

apex

athigher

magnification

than

(A).Lines

1,2,and

3

indicate

the

approximate

planes

ofbisectionshown

in

E,F,and

G.C,Median

longitudinal

section

of

the

inflorescencemeristem.

D,

Median

longitudinal

section

of

the

floral

meristem

at

the

primary

rachisbranch

stage.

Arrow

indicates

the

lateral

meristem.多年生黑麦草Expression

of

GADeactivation

Genesin

Shoot

Tipsof

L.temulentum

forPlants

Held

in

SD,Exposed

to

a

Single

LD,

orTreatedwithGA1

inSD.LtGA2ox1

expression.Putative

16,17-epoxidase

expression.LtGA2ox5

expression.Stem

segments

wereharvested

after

3

dandwere

ca.

0.8

mm

thick.Their

position

is

plottedas

mm

below

the

shootapex

and

is

also

showndiagrammatically

in

thefigure.

Values

are

means±

S.E.

(n

=

3).GA

2-oxidase

Genes

Are

Expressed

at

the

Base

of

the

SAM

and

AreResponsive

to

KNOX

and

CK

(A

and

B)

GUS

staining

of

AtGA2ox2::GUS(A)

and

AtGA2ox4::GUS

(B)

plants,

bars

=0.5

mm.(C)

Longitudinal

section

of

AtGA2ox4::GUS

plants,

bar

=

50

m.(D)

Quantitative

RT-PCR

analysis

of

AtGA2ox2

and

AtGA2ox4

expression

in

Ler

and

STMGR

10-day-old

plants

2hr

after

10

M

DEX

spray

(+DEX

2h)

or

after

10

days

on

MS

+1

M

DEX

(+DEX).Model

Depicting

Interactions

between

KNOX

Proteins,

GA,

and

CK

in

theShoot

ApexKNOX

proteins

are

expressed

intheSAM(purple),where

theyactivate

CKbiosynthesis

andrepress

GA

20-oxidase

gene

expression

and

hence

GA

biosynthesis

(GA20ox,

gray),thuspromoting

meristem

activity.CK

also

activates

GA2ox

(blue)

expression,

possibly

stimulatingGA

deactivation.

These

interactions

mayconfine

activeGA

tothe

leaf

(green).

KNOX

proteins

mayalso

activate

GA2ox

in

a

CK-independent

manner

(dashed

arrow).OOCOHOOCCOOHGA6COOHGA5OOOCOHCOOHGA3HOOOCOHCOOHGA1OOCOHCOOHGA8HOHOHOCOOHOHOOC3epi-2,2-dimethylGA1OHOHIMPLICATIONS

OF

GA

STRUCTUREFOR

FLORIGENICITYGA

speciesminimal

effective

dosesug

/

plant2,2-dimethyl

GA40.005GA320.1GA35GA125GA4inactiveGA32Applied

GAs

(25

µg

perplant)Can

Replace

theNeed

for

LD

in

theInduction

of

FloweringandEnhance

Stem

Elongationof

Vernalized

Plants

ofLolium

perenne（黑麦）Held

in

SD.GA4

became

active

whenapplied

simultaneously

with

TNE

(25

µg

per

plant),

whichwould

inhibit

2-oxidation.

Forcomparative

purposes,

theresponse

to

2

LD

is

also

shown.Floral

Scores

of

2

or

moreindicate

a

floral

apex.

Valuesare

means

±

S.E.

(n

=

14).More

evidencesA

growth

retardant,

16,17-dihydro

GA5,which

has

a

C2,3

double

bond,

induce

anequivalent

flowering

response

as

GA5.(EvansLT,

et

al,Duncan

KA.

1994.

The

differential

effects

of

C-16,17-dihydro

gibberellinsand

related

compounds

on

stemelongation

and

flowering

in

Lolium

temulentum.

Planta193:107–14)GA4

was

florigenic

for

floral

evocation

of

L.perenne（多年生黑麦草）if

applied

along

withTNE,

a

2-oxidase

inhibitor,

whereas

GA4

orTNE

alone

were

inactive.(C.

MacMillan,

unpublisheddata)UP促进广沾63S穗颈节伸长的效果CK1CK2TGA5复合剂促进培矮64S穗发育CKT<0.0001ppm4:56:34

上午清水对照空白对照1X10-5ppm1X10-4ppm1X10-3ppm1X10-2ppm不同浓度MMGA4对水稻（秋田小町）穗分化的促进作用（北京，2015.10）赤霉素的生物合成及作用机制赤霉素生物合成赤霉素的信号传导赤霉素与开花素赤霉素与抗倒伏CPS,

ent-copalyl

diphosphate

synthase;

KS,

ent-Kaurene

synthase;

KO,

ent-Kaurene

19-oxidase;

KAO,

ent-Kaurenoic

acid

oxidase;

GA7ox,

GA12-aldehyde

7-oxidase;

GA20ox,

GA

20-oxidase;

GA3ox,

GA

3-hydroxylase;

GA2ox,

GA

2-oxidase.CH2OPP

COOHCOOHCOOHCH2OHOOCHOCOOHOCHOOCOOHOCHOHOOHOCOOHOCHOHOCH2OPP贝壳杉烯GA8COOHCOOHOHCOOHGA15GA53GA34GGPPIPPOCOOHOCOCOOHOCOHGA20GA9GA12早期C13非羟化途径早期C13非羟化途径COOH3－磷酸甘油醛贝壳杉烯酸GA1COOHGA4OHO植物生长延缓剂的种类羟化酶抑制剂环化酶抑制剂丙酮酸加氧酶抑制剂植物生长延缓剂的种类Onium

compoundsCompounds

with

anN-containing

heterocycleAncymidolPaclobutrazolInabenfideTetcyclacisFlurprimidolUniconazoleTriazol

blocks

cytochromeP450-dependent

monooxygenasesStructural

Mimics

of2-oxoglutaric

acidProhexadione-calciumTrinexapacethylDaminozide2-Oxoglutaric

acid16,17-Dihydro-GAs水稻抗倒伏剂抑制基部节间伸长59传统抗倒伏剂的应用缺陷营养生长与生殖生长的时间重合传统抗倒伏剂的双重抑制作用传统抗倒伏剂应用上的矛盾烯效唑施用时期对水稻产量和穗粒数的影响产量（对照比%）穗粒数（对照比%）80701101009041223115

8烯效唑处理日期（DBH）传统抗倒伏剂有不可克服的缺陷CH2OPPCOOHCOOHCOOHCH2OHOOCHOCOOHOCHOOCOOHOCHOHOOHOCOOHOCHOHOCH2OPP贝壳杉烯GA8COOHCOOHOHCOOHGA15GA53GA34GGPPIPPOOCCOOHOCGA20COOHGA9OHOGA12早期C13非羟化途径早期C13非羟化途径COOH丙酮酸3－磷酸甘油醛贝壳杉烯酸GA1COOHGA4OHO62日本的水稻倒伏抑制剂上位节间63VIVIFUL的应用时期指南64完美化学调控的第一个目标抑制基部节间，同时促进生殖生长65水稻的理想株型Sketches

of

different

plant

types

of

rice.Left,

tall

conven