capes2012 6 auxines dao

7/28/2019 CAPES2012 6 Auxines Dao

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Leshormonesdecroissance:auxines

Auxine naturel

Auxinessynthtiques

er c e s ec


2/42

Rlephysiologiquedesauxines

Contrledeladominanceapicale

+Auxine auxine


3/42

Effetsdauxinessurlapex(coloptile),racineet(fruit)


4/42

Lerledesauxinesdanslenracinementest

connudans

1930s

Impossibled'aff icher l'image.Votreordinateur manquepeut-tredemmoirepour ouvrir l'imageou l'imageestendommage.Redmarrezl'ordinateur,puisouvreznouveau lef ichier.Si lex rougeesttoujoursaff ich,vous devrezpeut-tresupprimer l'imageavantdelarinsrer.

Impossibled'aff icher l'image.Votreordinateur manquepeut-tredemmoirepour ouvrir l'imageou l'imageestendommage.Redmarrezl'ordinateur,puisouvreznouveau lef ichier.Si lex rougeesttoujoursaff ich,vousdevrezpeut-tresupprimer l'imageavantdelarinsrer.

Adventitiousrootsare

stemstreated

with

auxin

Amorerecentexperimentinwhich

radishroots

were

dipped

into

auxin

andinitiatedlateralrootsata

frequencyproportionaltoauxin

concentration. M


5/42

Letransportpolairdesauxinesestconnudans

1930s

Asegmentcutfroma

Whenthesegmentis

inverted,it

is

unable

to

coleoptilecanmove

auxinfromtiptobase.

totip.

Thisexperiment,

carried

out

by

The

u er

a ar

block

was

H.G.Vander Weij revealedthat

auxinintheshootistranslocated

fromtiptobase.

loadedwithauxin,whichthe

segmenttranslocatedtothe

lowerblock.


6/42

Fonctionphysiologiquedesauxines


7/42

Lasynthse,letransportetlasignalisationdes

auxines

Catabolism Conjugation

Synthesis IAA Transport Perception

(receptor)

TFactivation/

inactivation

Target

genes

Biological

Functions

Les effets des auxines dpendent de leur synthse, transport,perception, signalisation et contrle de lexpression de gnes.


8/42

Auxinresponsepathway feedback

regulation


Synthesis IAA Transport Perception

(receptor)

TFactivation/

inactivation

Target

genes

Biological

Functions

Les voies designalisationsont contrles

extensivement pardesrgulations feedbackpositives

etnegatives.


9/42

LabiosynthsedIAA

ChezAgrobacteriumtumfaciens

TAMIPA

IAAId

dgradation


10/42

Lhomostasiedauxinesestcontrlaussiparla

conjugaisonet

la

dgradation

IAA

GH3 genes

are auxin-Arabidopsis

Riz

(GH3 genes)induced

GH3.13

surexpressionWildtype

GH3.13Wildt e

surexpression dune enzyme de conjugaison

surexpression

GH3 rduit le niveau dauxine.


11/42


Synthesis IAA

maintenuepar

la

synthse,

le

catabolisme,laconjugaisonetle

trans ort.

Transport


12/42

letranopsrtlonguedistancesviale

phlome.

transporteurs

protiques.

.


13/42

Lemouvementdauxineaucotombrag

IAAaccumulatesonthe

shadedsideof

phototropically

Increasedauxinpromotes

cellelongationontheshaded

side causin bendin toward

DR5::GUS

oleraceahypocotyls. thelight.

CelllengthAuxininduced

transcriptionoftheDR5

Auxin

p omo e se eva e on

thedarksideofthis

phototropically

stimulatedArabidopsis

concen ra onhypocotyl.


14/42

PlusieursmutantsdArabidopsis onttidentifis

ayantdes

rsponses

gravitropiques

anormales

pin2

WT

pin2WT Anal sis of these mutants has identifiedseveral types of auxin transport proteins, aswell as proteins that regulate their activity anddistribution.


15/42

Lemouvementdesauxinesviades

transporteursprotiques

defflux

et

dinflux

LesPIN:mouvement

directionneldauxines

vers

ABCB

ext r eur e ace u e.

ABCB

Celltocell

polar

auxin

transport

Lestransporteurs

dinflux

contribuentau

mouvement

Lestransporters B B

contribuent autransport

dauxine dans de

ABCB

cytoplasme.ren es rec ons


16/42

AUX1 importelauxinedanslacellule

AUX1/LAX

Carrier

mediated

auxin

uptake

Plusieurs gnes desprotines like-AUX1; Auxinuptakeis

mutants.


17/42

LesABCB sontimportantespourletransport

aux ne

PGP

abcb1abcb191abcb19

2 abcb19

2

abcb1WT

ABCB

WT abcb191

Lossoffunctionofsome ABCB

genes causesdiverse

phenotypes

Arabidopsisencodes21ABCB

proteins,manyofwhichare

necessar for ro er auxinincludingdwarfismandaltered

tropisms.

transport.


18/42

Lesprotines PIN nommes selon le

phnotype dupin

formedmutant

pin-formed, which has amutation in the PIN1 gene,makes some abnormal leavesand then a bare inflorescence.


19/42

LesPIN auxinsontparunelargefamilledegnesavec

desprofiles

dexpression

spcificques

PIN


20/42

LesprotinesPINsoriententdefaonasymmetrique

ans

esce u es

PIN1localizesto

thelower surface

ofroot

cortex

cells

Root

Base

forauxin

flow

from

shootapextoroot

apex.

Root

Apex


21/42

LesdiffrentesPINsoriententdiffremment

PIN2 localizestothelower

surface of root cortex cells andtheuppersurfaceofepidermal

cells.

PIN2isfunctions

pr mar y n e

redistributionof

auxinduringroot

gravitropism


22/42

LadistributiondesPINcontribuentla


23/42

LtatdephosphorylationdesPINsaffecteleurdistribution

pro e nsarep osp ory a e y

theproteinkinasePINOID(PID)and

dephosphorylatedby

the

protein

PPPP

.

P P

Control Staurosporine

treated

Staurosporineinhibitsprotein

kinases


24/42

Leseffetsdesauxinessontmedisparaumoins2types

ofrcepteurs

Perception

(receptor)ABP1

IAA

Perception

(receptor)SCFTIR1


25/42

AUXINBINDINGProtein1est ncessaire pourla

divisionet

lexpansion cellulaire

WildtypeEtOH

induced

LossoffunctionofABP1is

embryo

lethal.

ABP1

antisense Plantswereproducedthat

carryaninducibleantisense

ABP1 gene.They

were

grown

for12daysinnoninductive

conditions.

Atday12,ABP1 wassilenced

andplant

growth

was

severely

restricted.


26/42

LereceptorTIR1estuncomposantducomplexe

SCFTIR1dela

SCF

ubiquitin

ligase

FboxTIR1

auxinreceptor

SKP1

FboxTIR1

protein

SCFcomplex

CUL1

SCFubiquitinligasecomplex

(NamedforSKP1,CUL1andFbox

proteins)


27/42

LescomplexesUbiquitin ligase(E3)

ubiquitinylent lesprotines cibles

Ubiquitine

The F-box protein

ciblecible

recognizes and bindsto the target protein.The complex then

SKP1

rans ers u qu nproteins to the target.

CUL1


28/42

TIR1ncessite lafixationdauxine pour

tre activ

TargetAuxin


29/42

cibleAuxineQuesontlesciblesde

laprotolyse mdie

SCFTIR1?

I II III IV

Lesprotines Aux/IAAetpourleur dgradation


30/42

LademieviedesprotinesAux/IAAesttrscourte

PSIAA6


31/42

Lesprotines Aux/IAArpriment lactivit desfacteurs de

transcriptionappels

Auxin Response

Factors

(ARFs)

III IVDNAbinding

domain

Activation/

repression

domain

an ux pro e ns ave

sequencesimilarityintheirC

terminalregionsthroughwhich

I II IVAux/IAA

III

.

ARFhomodimer


32/42

R ressiondes nes

parIAA/Aux

en

absence

dauxine

Ds rpressiondela

transcription

des

gnes

ARF:FTactivateur

Aux/IAA:rpresseur

Auxineinduitladgradation

desAux/IAA

via

ubqitination.

LadgradationdesIAA/AuxparlAuxinencessitedelaprotineTIRquifonctionnedansE3


33/42

g / p p q


34/42

Rsum


35/42

Commentlesauxines peuventaffecterdenombre

processusdu

dveloppement

de

la

plante?

Perception

(receptor)

Target

genes

Auxin

induced

gene

productsAux/IAAproteins

GH3(auxinconjugation)

Jasmonicacidsynthesis

CKX(cytokinindegradation)

Transcriptionfactors Biological

FunctionsAuxinrepressedgeneproducts

Cellwallproteins

ARRs(Cytokininsignaling)

Transcriptionfactors


36/42

Dfautdanslasynthse,letransportoulasignalisation

causeun

phnotype

identique,

sans

racine

pin1,3,4,7Wildtype yucca1,4,10,11

yucca1,4,10,11,

mp and

pin1,3,4,7mutantsareallrootless


37/42

Inthecurrentmodelforauxin

inducedcellwallelongation,

auxinstimulates

a

lasma

H+ H+

AuxinH+

membraneboundproton

pump,whichacidifiesthecell

wall.H+

H+

Length

Cellwallacidificationis

sufficientto

induce

cell

Time

elongation.


38/42

Lauxinefonctionnecommeunmorphognedanslapex

racinaire

Auxinamount

Cellsatthequiescent

center ex erience

Cellsexperiencinga

lowauxinlevel

thehighestauxin

concentrationsand

remainquiescent.

elongateand

differentiate

Quiescent

Cellsnearthetip

experience

intermediate

auxin

centerlevelsanddivide

frequently


39/42

Lauxinefonctioneaussicommeundclencheurpour

initierdes

vnements

de

dveloppement

Alocalizedauxinmaximum(orminimum)canbesufficientto

n a ea

eve opmen a

even .

ere

ere

n ca es

ce s

triggeredtodifferentiatebyelevatedauxinlevels.


40/42

., ,

The inflorescence meristem of theArabidopsispin1 mutant does not make flowers. Applicationof a spot of auxin (red) triggers organogenesis.

La synthse enforce de lauxine dans une seule cellule


41/42

Lasynthseenforcedel auxinedansuneseulecellule

latrale

Theexperimental

increase

of

auxin

synthesisinonecellissufficientto

triggeralateralrootformation.

Singlecell

biosynthesis

(monitoredby

DR5::GUS .


42/42

Ungradientdauxineformdurantladiffrentiation

cellulairepour

la

formation

de

bois

Cambial

ZonePhloem Tracheids

(xylem)

capes2012 6 auxines dao

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