Molecular breeding for Molecular breeding for enhancing tolerance to enhancing tolerance to

low iron availability low iron availability in in CalcariousCalcarious Soils Soils

Naoko K. Naoko K. NishizawaNishizawaThe University of Tokyo, JapanThe University of Tokyo, Japan

March 14, 2008, GIES 2008

順序かえた連

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Environment

C

FeZn

Cu

Mn

MoN

Ni

PK

S

Cl

B

MgCa

H

O

Food

Crop production is critical for our life Crop production is critical for our life

Distribution of calcareous soils (high soil pH) Distribution of calcareous soils (high soil pH) Distribution of calcareous soils (high soil pH)

Distribution of CALCISOLSBased on WRB and the FAO/Unesco Soil Map of the World

- Fe

Iron is not available in Iron is not available in alkaline soilsalkaline soils

Fe

FeFe

Fe

Fe Plants diePlants die in alkalinein alkalinesoilssoils due to iron deficiencydue to iron deficiency

Iron is the essential elementIron is the essential elementfor plant growthfor plant growth

Fe deficiency in peach tree (Israel)Fe deficiency in peach tree (Israel)

Maize suffered from Fe deficiencyMaize suffered from Fe deficiency ((UthaUtha, USA), USA)

Fe deficient grape (Israel)

Mugineic Mugineic AcidAcid

細胞膜 細胞壁 土壌

細胞質

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

FeFe

Fe

Fe

Fe

Fe

FeFe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

FeFeFe

Fe

FeFe

Fe

Soil

FeFe

FeFe

Fe

Fe

Fe

Fe Fe

Fe

Fe

Fe

Fe

Fe

CO2H

OH

CO2HCO2H

OH

N NH

Fe YS1

Cell WallCell MembraneCell Membrane

CytoplasmCytoplasm

Iron Acquisition in Graminaceous plantsIron Acquisition in Iron Acquisition in Graminaceous Graminaceous plantsplants

NH

NH2

COOH COOH COOH

N

Nicotianamine

S-adenosyl Methionine (SAM)

COOH

H3CS NH2

Methionine

NH

O

COOH COOH COOH

N

3”-oxo acidNH

OH

COOH COOH COOH

N

2’-deoxymugineic acid

NH

OH

COOH COOH COOH

N

Mugineic acid

NH

OH

COOH COOH COOH

N

3-hydroxymugineic acid

NH

OH

COOH COOH COOH

N

3-epi-hydroxy-2’-deoxymugineic acid

NH

OH

COOH COOH COOH

N

3-epi-hydroxymugineic acid

OH

OH OH

HO HO

HO

IDS3

IDS3IDS2

IDS2

Deoxymugineic acid synthase

SAM synthetase

Nicotianamine synthase

Nicotianamine aminotransferase

Mugineic Mugineic acid familyacid family phytosiderophoresphytosiderophores

Biosynthetic Pathway of MAs Biosynthetic Pathway of MAs Biosynthetic Pathway of MAs

high

low0 1 2 3 4 5 6 (h) -Fe +Fe

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5252FeFe3+3+--DMA absorption from the barley roots DMA absorption from the barley roots

Rice Suffered From Iron Deficiency Rice Suffered From Iron Deficiency Rice Suffered From Iron Deficiency

Fe deficiency rice field in India

Rice Plants Uptake Iron as Rice Plants Uptake Iron as FeFe3+3+--phytosiderophore phytosiderophore and Feand Fe2+2+

OsYSLOsYSL OsIRTOsIRT

FeFe3+3+--DMADMA

FeFe3+3+

DMADMA

FeFe2+2+

FeFe2+2+

cytoplasm soil cytoplasm

Ishimaru et al, Plant J, 2006

soil

Takahashi et al,Takahashi et al,Nature Biotech, Nature Biotech, 20012001

Transgenic rice Transgenic rice tolerant to Fe tolerant to Fe deficiencydeficiency

TransformantNT

OsIRTOsIRT

FeFe2+2+

FeFe2+2+

FeFe3+3+

FeFe3+3+

Introduction ofIntroduction ofFeFe3+ 3+ Reduction Activity intoReduction Activity into Rice Rice

cytoplasm soilFeFe2+2+

Refre1-372

Mutational reconstructedMutational reconstructedferric ferric chelate reductasechelate reductase

Refre1-372Vector control Vector control

Transgenic riceTransgenic rice shows enhancedshows enhanced tolerancetolerance totolow Fe availability in a calcareous soillow Fe availability in a calcareous soil

Alkaline soilNormal soil

CACGTGG OsNAS1OsFDHOsAPT1

MTN

CACGTGG NACprotein

NAC

unknowncis-element

Fedeficiency

CACGTGG AP2 domainprotein

AP2

unknowncis-element

Fedeficiency

Fe deficiency stress

IDE-like

IDEs binding transcription factor

OsIRO2

OsIRO2

Model of gene regulation, including OsIRO2 Model of gene regulation, including OsIRO2 Model of gene regulation, including OsIRO2 Ogo et al, Plant J, 2007

Field evaluation of transgenic rice with enhanced tolerance to alkaline soils

Field evaluation of transgenic rice with Field evaluation of transgenic rice with enhanced tolerance to alkaline soils enhanced tolerance to alkaline soils

Wild typeWild typeTransgenic riceTransgenic rice

Suzuki et alSuzuki et al, Soil, Soil Sci Sci Plant Plant NutrNutr,, 20082008

Nakanishi et al, Japanese Patent 2005-9600 (2005)

New System forMarker Free Transgenic Crops

New System forNew System forMarker Free TransgenicMarker Free Transgenic CropsCrops

Flower

spw1-cls

Mutant, spw1-cls

WT spw1-clsWT

Thank you for your attention !