Physiologia Plantarum lecturee + IRT1 Fe + Phytosiderophores 3 PS PS GRAMINACEOUS Fe +-PS YS1...

Physiologia Plan

Mechanisms of iron hand their r

Dr. Jean‐FraDr. Jean FraCNRS‐INRA Mon

ntarum lecture:

homeostasis in plants pregulations

ancois Briatancois Briatntpellier, France

Jean-François BRIAT

@[email protected]

http://www.montpellier.inra.fr/ip p

Mechanisms of iron hand their rand their r

ibip/index.htmp

homeostasis in plants regulations regulations

IPNC Sacramento27 A 200927 August 2009

Iron is an essentia

26 +2Fe +3

Transition metal Fe2

Fe34th element on earthFe 355.85

Fe3

-Low iron availaibility in 1/3 of the cultivate-Diet for 2/3 of the world population is base

Abunda

p pless than 10% of the recommended daily ir

3 billi h b i i d fi i

As a co

3 billion human beings are iron deficientand retardation of mental and psych

Iron entrance in the fIron entrance in the fa major public

http:

al element for life

2+

3+

Ferrous iron, reduced

F i i idis d3+ Ferric iron, oxidised

d soils (calcaraceous)ed on plant food (100 g of cereal flour contain

ant… but

p gon supply)

(i d ibili f i f i

onsequence

t (increased susceptibility for infections homotor development and of growth)

food chain is linked to food chain is linked to health problem//www.who.int/nutrition/topics/ida/en/index.html

Plant Iron Deficiency

Fe3+ Fe2+

H 7

Fe(OH)3 insoluble

pH > 7

3

I b d t i il BUT l il bl f-Iron abundant in soils, BUT poorly available foplants (10-10M soluble/ 10-8M required)

- Iron fertilization expensive and poorly effici- Iron fertilization expensive and poorly effici

- Phenotype of iron deficient plants

Gro

HePhenotype of iron deficient plants

Dec

He

or

ientient

owth decrease and lower yields

avy metals (Zn Mn Cd ) accumulation

creased chlorophyll content

avy metals (Zn, Mn, Cd…) accumulation

Iron Deficiency Alters and Fun

Chloroplasts = plant leaf specific o+ photosynthesis : CO2 ass

and Fun

+ photosynthesis : CO2 assmolecules

+ N and S assimilation ---

These reactions depend upon iron pr(electron transfert chain, nitrite and

+ Fe

Chloroplast Structure nctions

organelles containing chlorophyllsimilation > C skeleton of organic

nctions

similation ---> C skeleton of organic

>Amino Acid and Vitamin synthesis

roteins d sulfite reductases…etc)

- Fe

Iron within the chloroplast

stroma

D2 D1

FLHN

CP47CP43

IJK WMXLhcbiLhcbiLhcbi

PQ

PQ

PQ

IV-cyt b6 GMQA

S E

H+

PC

CP47CP43

OTPR

QRieske

cyt f2 H2O

4H+ + O2

H+LHC

PC

cyt b6fPSIILumen

2 Fe 6 Fe

photosynthetic apparatus

ADP + Pi ATP

II I

FNR

NADP++H+ NADPH

Fd

L

L IKMH G

CE D

JA1 A1’ IIIIII IIIIIIIV

A B

PC 3 H+

NF

LHC

f PSI ATPsynthétasey

14 Fe(from FA Wollman)

Iron is essenti

Fenton Reaction Fe2+ + O Fe3+ + O •-

Fe2+ + H2O2 Fe3+ + HO• + HO-

Fe2 + O2 Fe3 + O2

(Superoxide ion )

(Hydroxyl radical)

Humans :Humans :Hemachromatosis

Plants:Rice « bronzing »

al …but toxic

Oxidative Stress

Molecular principle to coeukaryoy

Uptake : Iron

Storage : FIron excess

U

Iron deficiency

ontrol iron homeostasis in tic cells

n transporters

erritin

Uptake : Iron transporters

Storage : Ferritin

Two different iron uptgraminaceous and non-grai h diff i l iwith a differential sensit

calcarac

N

Picture from V. Rohmeld

take strategies between aminaceous plants correlate i i i il ibili i tivity to iron availaibility in

ceous soils

SOIL ROOTS

H+ HP

FRO2Fe3+

F 2

H+ H+ATPase

2R 1

NON-GRAMINACEOUS

Fe2+ Fe2+IRT1

Phytosiderophores

3

PS PS

GRAMINACEOUS

Fe3+-PSYS1Fe3+-PS

Arabidopsis (non graminaceous

ZIP9

IRT3ZIP6

IRT3ZIP4 ZIP2

ZIP12

ZIP11

ZIP5

ZIP1

Ei ht IRT1ZIP8

IRT2

ZIP3

ZIP5 - Eight pre- WT trans- E103 (red- D100 (blu- D136 (grIRT2

ZIP10ZIP7(g

- H96, H19activity- C109, Y2

(f

s) IRT1 from the ZIP family

di t d t m mb d m i (I VIII)edicted trans-membrane domains (I-VIII)sports Fe, Zn, Cd and Mnd) -->Ala = transports Fe, Cd, Mn but not Znue) -->Ala = transports Zn, Cd but not Fe and Mneen) -->Ala = transports Zn and reduced level of Cd) p97, S198, H224 and E228 (grey) -->Ala = no transport

295, D300 and E305 (yellow) -->Ala = no change with WT

from Rogers et al �[2000] PNAS 97 : 12356-12360)

Localisation of IRT1

pIRT1::GUS fusions expressed at the rooperiphery in the epidermal cell layer in re

+ Fe - Fe

periphery in the epidermal cell layer in reto iron deficiency

IRT1 RNA d t t d i th t IRT1 mRNA detected in the root periphery by in situ hybridization

expression territories

C Dp35S::GFP

C D

ot esponse

p35S:: IRT1-GFPesponse

B

IRT1-GFP fusion localized IRT1-GFP fusion localized at the plasma membrane

IRT1 is involved

WT irt1-1

R LRL+ - + + +- - -Fe :

121.368.840 040.028.4

16.8

WT iIRT1-KO mutant is chlorotic and altin its development.

Vert et al (2002) The Plant Cell 14 : 1223-1233

d in iron uptake

30DW

10

20

e 55

Fe/m

g D

1 1

0

10

pmol

e

+Fe -Fe +Fe -Feirt 1-1 tered

WT Irt1-/-

55Fe feeding for 48 hours i di h i 1 / i indicates that irt1 - / - is deficient in iron uptake

ConcluConclu

IRT1 is the Major Transporter in Dicots to

ConcluConclu

Transporter in Dicots toSoil in case o

Vert et al (2002) The P( )Varotto et al (2002)

Henriques et al (2002) Pl

IRT2 shares the same but its function is nobut its function is noVert et al (2001) The

Vert et al (2009) PlVert et al (2009) Pl

usionusion

Essential Root Iron o Take Up Iron from the

usionusion

o Take Up Iron from the of Deficiency

Plant Cell 14 : 1223-1233 Plant J 31 : 589-599ant Mol Biol 50 :587-597

territories than IRT1, ot redundant to IRT1ot redundant to IRT1e Plant J, 26 : 181-189lanta 229:1171-1179 lanta 229 1171 1179

Maize (grami

WT

YS1 f

ys1

YS1 f

Interv

DeficiDeficiuptake106 :

Ac transposon tagging of ys1 byMassachussets at Ahmerst)

2.8 kb ys1 cDNA cloned from ostarved plants

naceous) YS1

WT

ys1

for Yellow Stripe 1 (Beadle, 1929)for Yellow Stripe 1 (Beadle, 1929)

veinal leaf yellowing

ient in Fe(III)-mugineic acid root ient in Fe(III)-mugineic acid root e (von Wiren et al., 1994, Plant Physiol 71-77)

y Elsbeth Walker (University of

our root library originated from iron-

Maize YS1 and 8 YS-are ver

NHER GLE

Arabidopsis YSL are highly conserved

NH2E

Arabidopsis YSL are highly conservedmaize YS1 :

- 70 to 80 % similarities- 12 putative transmembrane do12 putative transmembrane do- E residues enrichment at the

terminal extremity- REGLE-like motif conservation

NH2-terminal extremity - both belongs to the Oligo Pept

Transporter (OPT) family

-Like from Arabidopsisry similar

COOH

d with

COOH

d with

omains YSL1

ZmYS1YSL2 YSL3

omainsNH2-

n at the YSL6YSL8

YSL4

tide

YSL6

YSL7YSL5

Curie et al (2001) Nature 409 : 346-349

ConcluConclu-YS1 is the major graminaceous Fuptake transporter

YS1 i l bl t t t F-YS1 is also able to transport Feheterologous systems (yeast ans

EightArabidopsis thaliana genes- EightArabidopsis thaliana genesmaize Ys1, raising the questions plants, and of the nature of the (Iron-Nicotianamine?)(Iron Nicotianamine?)

Curie et al (20

Electrophysiology of YS1 = protosymporter

Schaff et al (2004

usionsusionsFe(III)-phytosiderophores

(II) NA h d i e(II)-NA when expressed in Xenopus oocytes)

s (ysl 1 8) are homologous to s (ysl 1-8) are homologous to of their role in non graminaceous substrate they could transport

001) Nature 409 : 346-349

on coupled phytosiderophore

4) J Biol Chem 279 : 9091-9096

bHLH trancription regulation of iron upt

factor networks for take transport systems

Colangelo and Guerinot (2004) Plant Cell 16: 3400-3412

Jakoby et al. (2004) FEBS Lett 577 : 528-534

Yuan et al (2005) Cell Research 15 : 613-621

O t l (2007) Pl t J l 51 Ogo et al (2007) Plant Journal 51: 366-377

Ogo et al (2008) J Biol Chem. 283 Ogo t a ( ) J o h m. : 13407-13417.

Kobayashi et al (2007) PNAS 104: 19150 19155

From Lemanceau et al (2009) Plant Soil 321: 513-535

19150-19155

Iron circulation withinth l tthe plant

Fe(III)-citrate and Fe(II) NA are two major chelates for iron distribution throughout the plant via xylem (blue) and phloem (pink) saps

Frd3 (MATE type) involved in citrate loading of xylem

YS1IRT1

Fe(II)-NA is transported by YSLs

IRT1Nicotianamine (NA)

structure

YSL transportersBriat et al (2007) Curr Op Plant Biol 10 : 276-282Curie et al (2009) Ann Bot 103 : 1-11

Overview of sub-cellular

Vacuole iron influxer (VIT1) and effluxerVacuole iron influxer (VIT1) and effluxer(Naramp3 / Nramp4) have been identifi

Tranporters for mitochondria and Chloroplasts iron uptake are still uncharacterized

Both mitochondria and chloroplastsare able to synthesize heme and Fe-Sl

B i t t l (2007) C O Pl t Bi l 10 276

clusters

Briat et al (2007) Curr Op Plant Biol 10 : 276-

iron utilisation in plant cells

YSL4rs YSL4YSL6 ?

rsed

282-282

Arabidopsis thaliana ferri

. Ferritins are located in plastids

. 4 genes in Arabidopsis AtFer1 to -4Gaymard et al., 1996 Biochem. J. Petit et al., 2001 Biochem. J. 359

AtFer1

shoots0h 3h 6h 12h+ Iron

AtFer1AtFer2AtFer3AtFer4

AtFeregu

AtFer1 = most expres

AtFer425 S

response to iron excess homeostasis r

tins

318, 67-739, 575-582

Fer1, -3 and -4 transcriptional ulation in response to iron excess

ssed ferritin gene in model to study iron

regulation

WORKING MODEL Arnaud etBriat et al

IDT

REPRA- Low iron

B- High iron

ID

AtFer1 promoter5’

FeB H gh ron

PlastidNOS activity

enzymeym

NO

7mproteasome d d t

PPdependent

degradation REPRESSOR

Ub

IDRS

AtFer1 promoter5’

UbTF

t al (2006) J Biol Chem 281 : 23579-23588(2009) Ann Bot (in press)

AtFer1DRSTF

ESSOR

AtFer1DRS 3’

mGpppGAUG

PolyAAtFer1 mRNA

P2A

AtFer1 3’

Ferritin gene exArabidopp

A bid i AtF 2 d iArabidopsis AtFer2 expressed speci

Arabidopsis AtFer1-3-4 expresseroots floral stalk) in flowers anroots, floral stalk), in flowers, an

pression in various opsis organsp g

ifi ll i t difically in mature seeds

ed in vegetative organs (leaves, nd in germinating seeds

Petit et al., 2001 Biochem. J. 359, 575-582

nd in germinating seeds.

What do we learn cfunction in planta usifunction in planta, usi

approach in A

Ravet et al., 2009 Pla

- Ferritin function in seeds- Ferritin function in leaves- Lack of ferritins and flowe- Role of ferritins in iron me

concerning ferritin ing a reverse genetic ing a reverse genetic Arabidopsis ?

ant. J. 57 : 400-412

er developmentediated oxidative stress

T-DNA insertiAtFer2 F

fer2

Seed Col fer2

LB LBT-DNA

Seed Ferritins

Coomassie

T-DNA insertion in the AtFer2 gene l d t m t t d l ki f itileads to mutant seeds lacking ferritin

Iron content is unchanged in ferritin

Seed ferritins are not a ma(Iron ferritin = 5%

on mutant in the Ferritin Gene

Col fer20 12 24

Time (h) after seed imbibition 0 12 240 12 24

Ferritins

Coomassie

after seed imbibition 0 12 24

7575

Fe c

onte

ntµg

.g-1

DW

)

25

50

0

25

50

75

F (µ

0

1 2

0

Col fer2 ns

nless fer2 seeds

ajor iron store in Arabidopsis% of total seed iron)

Role of Fer2 seed against oxg

80

100

on(%

)

40

60

erm

inat

i

Colf 2

0

20

0 2 4 6 8 10

G fer2fer2 x 35S::AtFer1

0 2 4 6 8 10

Methylviologene (µM)

S d f i i i i Seed ferritins participate to prduring the ger

ferritin in protectionxidative stress

Germination of Germination of ferritinless fer2 seeds is more sensitive to methylviologen treatment

12

methylviologen treatment than wild type Col seeds

12

i i id i rotection against oxidative stressrmination process

Iron storage subcellular

VofofS

Nfovaet

Sst20

Hobetest

compartmentation in seeds

VIT1 is necessary for iron loading f vacuoles in seeds (Kim et al 2006 f vacuoles in seeds (Kim et al 2006 cience 314:1295-1298)

NRAMP3and NRAMP4 are required or Fe remobilization from acuoles during germination (Lanquar t al 2005 EMBO J 24 :4041-4051

Seed ferritin FER2 not a major torage form in plastids (Ravet et al, g p009 Plant. J. 57:400-412)

owever, is there any crosstalk tween vacuoles and plastids to tablish seed iron homesotasis?

Vacuoles / Plastids croIron Ho

2 2

Iron Hom

p3-4

#2

mp3

-4#

1

:NRa

mp3

#1

:NRa

mp3

#2

:NRa

mp4

#1

:NRa

mp4

#2

Col

nram

WS

nram

35S:

35S:

35S:

35S:FERRITI

Coomassblue stain

Seed ferritin Fer2 pronramp3nramp4 KO mut

(Ra

osstalk to establish Seedomeostasisomeostasis

:Vit

1#10

:vit

1#17

Col

vit1

35S:

:

35S:

:

NS

siening

otein abundance decreased in tants and in VIT1 overexpressors

avet et al, 2009 Molecular Plant, in press)

Vacuoles / Plastids croIron HoIron Ho

2,5

1,5

2

RNA

leve

lL) N

A le

vel

0,5

1

AtFe

r2m

R(R

TL

tFer

2m

RN

0

A

1 2 3 4 5 6 7 8 9

Col nramp3-4#21 2 3 4 5 6 7 8 9

At

Seed ferritin Fer2 tranramp3nramp4 KO mut

Post-transcriptional regulation of

(Ra

Post-transcriptional regulation ofa functional iron storag

osstalk to establish Seedomeostasis omeostasis

NA

leve

lL)

10000

150003

2 10000

150003

2

tFer

2m

RN(R

TL

0

50001

0 0

50001

0

AtWS nramp3-4

#1

0

1 2

0

Col nramp3-4#2

0

1 2

0

anscript abundance unaffected tants

f ferritin AtFer2 in seeds requires

avet et al, 2009 Molecular Plant, in press)

f ferritin AtFer2 in seeds requiresge vacuolar compartment


approach in A




ant. J. 57 : 400-412


T-DNA insertiAtFer1-3 and

fer1

fer4 T-DN

AtF 4Col

LB RBT-DNA fer4

genesand f

T DNAtFer4

EF1�

T-DNAtFermutan

Obtention of the triple fercrossing using single fer1,

on mutant in the -4 Ferritin Genes

fer3

AtFer3

Col fer3- + - + FeLB

T-DNA

EF1�

NA insertion in AtFer1 and AtFer4s leads to knock-out null single fer1fer4 mutants

NA insertion in promoter region of NA insertion in promoter region of er3 leads to knock-down single fer3nt

er1-3-4 mutants by succesive fer3 and fer4 mutants give

Ferritin protein subuvarious fevarious fe

2

- +

Col

- +

fer

2

+ +

28kDa26.5kDa

Confirmation that Fer2 protein is

Fer1 is the major ferritin proteisubunit whereas Fer3/4 are subusubunit, whereas Fer3/4 are subu

No ferritin subunits are detected

unit content in leaves oferritin mutantserritin mutants

3-4

+ - + - +

fer

1

fer

1-3

Fe

Ferritins

+ + + Fe

Coomassie

absent in leaves

in in leaves present as a 28 kDa units of 26 5 kDaunits of 26.5 kDa

in leaves of the fer1-3-4 triple mutant

Arabidopsis rosette biomassand in the fer1-3-4 triple m

C l fer1 3 4F

and in the fer1 3 4 triple m

-

Col fer1-3-4Fe

(

+

D M

ttNo biomass difference between Col (No biomass difference between Col (mutant devoided of leaf ferritin whe

Irrigating Col with a Fe-EDDHA solu

Irrigating fer1-3-4 with a Fe-EDDH

s in wild type Arabidopsismutant lacking leaf ferritinsmutant lacking leaf ferritins

er(m

g.

-1)

400

600

800

fer1-3-4/H2O

800

600

400

Col/FeCol/H2O

35S::AtFer1-fer1-3-4 /Fe

Dry

Mat

tepl

ant-

0

200

400

20 25 30 35 40 45 5020 30 40 50

400

200

0

fer1-3-4/Fe

Time after sowing(days)

(wild type plants) and the fer1-3-4

20 30 40 50

(wild type plants) and the fer1 3 4en irrigated with tap water

ution increases its biomass

HA solution decreases its biomass

Analysis of variouthe fer1 3 4 mutant phthe fer1-3-4 mutant phCol fer1-3-4

F ein

PsaD

- + Fe- +

300

400

500

hyll

/ pr

ote

300

400

500

PsbA

b6f

100

200

300

io C

hlor

oph

100

200

300

PsbA

Fdx

0Rati

0

NFU2 Amounand phhlCoomassie chloro

fer1-3

us components of hotosynthetic apparatushotosynthetic apparatus

Col

0

0

0

Colfer1-3-4

0

0

0

1 2 3 4 5 6 7- +Fe

nts of plastidial electron transfert chain hotosynthesis related polypeptides, and h ll h d i h phyll content are unchanged in the

3-4 mutant.

Photosynthesis activity

0,8

0,6

SII

0,2

0,4

0 200 400 600 800 1000

PS

0 200 400 600 800 1000PAR(µE.m-2.s-1)

Quantum yield of PSII (PSII) is ufer1-3-4 mutant under Fe or water

N Ph h d dNet Photosynthesis rate is decreade4 mutant when irrigated with 2 mM

in the fer1-3-4 mutant

20

esis

)

10

15

hoto

synt

hCO

2.m-2

.s-1

0

5

0 200 400 600 800 1000Rate

of

Ph(µ

mol

C

0 200 400 600 800 1000R

PAR(µE.m-2.s-1)

Col / H2OCol / H2Ofer1-3-4 / H2OCol / Fefer1-3-4 / Fe

unaffected in the r irrigation

d h f 1 3ed in the fer1-3-Fe-EDDHA


approach in A




ant. J. 57 : 400-412


Pleiotropic alterationsin the fer1

Col fer1-3-4

f

1000

g.pl

ant-

1 )500

750

d yi

eld(

mg

0

250Se

ed

Impaired flower and silique developm

Seed production decreases in the fe

p q p

during fruit formation -3-4 mutant m

Col fer1-3-435S::AtFer1 fer1-3-4

## #

*

*

#1

#4

#10

0 0 5 1 2

*

0 0.5 1 2 Fe (mM)

ment in Fe-irrigated fer1-3-4 mutant

fer1-3-4 mutant irrigated with iron

g

Reciprocal graftinfer1-3-4 bf

fer1-3-4Col fe

ng between Col and bolted plants p

fer1-3-4 flowers phenotype is

Coler1-3-4

ph notyp s independent of leaves.

Iron content in Col and

400 1000Colfer1-3-4

e co

nten

tµg

.g-1

DW

)

200

*

500

1000

Fe (µ

0 0+

stem

+-

Under water irrigation conditions F

Under iron irrigation conditions Fe

Under water irrigation conditions, Ffer1-3-4 plants in floral stem, and

Under iron irrigation conditions, Fe fer1-3-4, and increases in unfertilito Col

d fer1-3-4 floral stalks

Colfer1-3-4 *

*

++

unfertilizedflower

fertilizedflower

++- -

e content is unchanged between Col and

content decreases in floral stems of

e content is unchanged between Col and in unfertilized or fertilized flowers

content decreases in floral stems of zed or fertilized flowers, comparatively

Metal transporters expres

Fold change of the expression of varmetal transporter genes betweenmetal transporter genes betweeniron irrigated or water irrigated planare altered in fer1-3-4 comparative

Alteration of iron allocation betflowers in fer1-3-4 plants coul

of expression of various

ssion in Col and fer1-3-4

Gene AGI Col fer1-3-4 Col fer1-3-4NRamp1 At1g80830 -3,7 -1,5 -1,6 2,2NRamp2 At1g47240 -2,1 -2,5 -1,1 1,0NRamp3 At2g23150 20 2,0 4,4 -1,2NRamp4 At5g67330 1 5 -1 5 2 2 2 1

Stem Flowers

NRamp4 At5g67330 1,5 -1,5 2,2 2,1NRamp5 At4g18790 43 30 9,6 2,7NRamp6 At1g15960 2,0 6,0 37 6,2

YSL1 At4g24120 2,4 1,3 1,3 -2,3YSL2 At5g24380 -2,2 -4,9 -130 -281YSL3 At5g53550 1,6 8,9 3,9 4,0YSL4 At5g41000 7,5 1,8 2,7 -6,6YSL5 At3g17650 1 3 2 1 1 1 4 0

riousYSL5 At3g17650 -1,3 2,1 1,1 4,0YSL6 At3g27020 1,2 -1,2 1,5 1,2YSL7 At1g65730 8,1 1,1 2,7 -6,0YSL8 At1g48370 -1,3 -2,2 -1,7 -2,9IRT1 At4g19690 1,4 -40 2,1 -468IRT2 At4g19680 1,2 -104 1,5 -9,4ZIP1 At3g12750 -1,4 -2,0 1,9 1,3ZIP4 At1 10970 1 3 3 1 1 2 1 8

ntsely to Col

ZIP4 At1g10970 1,3 3,1 1,2 1,8ZIP5 At1g05300 13 3,6 -2,5 -1,4ZIP6 At2g30080 -1,4 -1,6 -2,2 -1,9ZIP9 At4g33020 7,6 6,9 2,0 1,3ZIP12 At5g62160 7,2 18 1,7 -2,1Pic1 At2g15290 1,6 1,8 6,7 14Vit1 At2g01770 -1,5 1,4 1,1 1,0

Induction � 20 20 > Repression � 2

20 > Induction � 2 Repression � 20

tween stems of floral stalks and ld be related to the deregulations metal transporter genes


approach in A




ant. J. 57 : 400-412


ROS imaging in Arabid pArabidop

GUS stainingRO i

Col fer1-3-4 Col fer1

gCol Fe

pAtFer1:GUS

- +ROS im

pAtFer3:GUS

pAtFer4:GUS

DCFDA ROSi i

Chlorop

GUS

imaging

Reactive Oxygen Species (3 4 flowers from water ir3-4 flowers from water irfrom iron irrigated plants,

Col and fer1-3-4psis fl ers psis flowers

i

r1-3-4 Col fer1-3-4

aging

ROS qu ntific ti n

200

200

(a.u

.) *Colfer1-3-4

quantification

hyll Overlay50

100

150

100

0ores

cenc

e

069

0

Flu

(ROS) overaccumulate in fer1-rrigated plants (and even more rrigated plants (and even more , not shown)

ROS detoxyfying enzyand fer1 3 4 Arabid pand fer1-3-4 Arabidop

A

y min

-1)

60*

Catalase

C lfer1-3-4

1500y min

-1)

pe

AT

acti

vity

.g-1pr

otei

n.

20

40 *

Col

1000

1500

PX a

ctiv

ity

.g-1pr

otei

n.

CA(µ

mol

e.

0

20

1 2 3 4 5leaf flower 0

500

1

AP

(µm

ole.

le

ROS detoxyfying enzyme fer1-3-4 leaves and flowe(and even more from iron

yme activities in Col psis leaves and fl ers opsis leaves and flowers

Glutathioned

Ascorbateid

min

-1)

reductaseeroxidase

*l

fer1-3-490

*fer1-3-4

R ac

tivi

ty-1pr

otei

n.m

*

Col

60

90

*

Col

GR(µ

mol

e.g-

2 3 4 5eaf flower 0

30

1 2 3 4 5leaf flower

activities are enhanced in ers from water irrigated plants g pirrigated plants, not shown)

Conclus

Fer2 is the only seed ferritin- limited function in iro- role for protecting grole for protecting g

oxidative stress

A f 1 3 4 t t h lA fer1-3-4 mutant has no le- its biomass is affect- its CO2 fixation is de

the thylakoid electron transf

fer1 3 4 mutant has pleiotrofer1-3-4 mutant has pleiotroirrigated with iron

- independently of the l d d ld - leading to seed yield

ions (I)

n in Arabidopsis with a :on storageerminating seedlings against erminating seedlings against

f f iti d tleaf ferritin and consequentlyed when irrigated with ironecreased, without alteration of fer chain

opic flower defects when opic flower defects when

lack of ferritins in leaves d decrease

Conclusi

Expression of various metal tfer1-3-4, consistent with anbetween stems of floral stalk

ROS scavenging mechanisms a- sufficient to avoid ox

irrigationirrigation- unsufficient under Fe

(decreased biomass, flower athese conditionsthese conditions

ons (II)

transporters is deregulated in n alteration of iron allocation k and flowers

are enhanced in fer1-3-4 plantsxidative damages under water

e excess, explaining phenotypes and siliques alterations) under

Iron nutrition and homeostasis is aIron nutrition and homeostasis is a

many molecular actors which are in

through complex regulatory pathwa

signaling, transcription factor netw

controls etc) controls …etc) ………………..

…. It is another story w

Than you foy u f

a very dynamic process involvinga very dynamic process involving

ntegrated at the whole plant level

ays (hormones, long distance

works, post-transcriptonal

which is starting to emerge ….

or your attention ! y u

Physiologia Plantarum lecturee + IRT1 Fe + Phytosiderophores 3 PS PS GRAMINACEOUS Fe +-PS YS1...

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Transcript of Physiologia Plantarum lecturee + IRT1 Fe + Phytosiderophores 3 PS PS GRAMINACEOUS Fe +-PS YS1...