Bao-Rong Lu Dept. Ecology & Evolutionary Biology School of Life Sciences, Fudan University...

Bao-Rong Lu

Dept. Ecology & Evolutionary Biology School of Life Sciences, Fudan University

Bao-Rong Lu

Dept. Ecology & Evolutionary Biology School of Life Sciences, Fudan University

Assessing Environmental Assessing Environmental risks caused by risks caused by

transgene escape from transgene escape from GM plantsGM plants

Biosafety concernsBiosafety concerns Biosafety concernsBiosafety concerns

Food & health safety Environmental safety Labeling & detection Socio-economic & ethic

concerns Regulatory procedures Public perception Biosafety assessment

Food & health safety Environmental safety Labeling & detection Socio-economic & ethic

concerns Regulatory procedures Public perception Biosafety assessment

Environmental Environmental safetysafety Environmental Environmental safetysafety

Environmental safetyEnvironmental safety

Effect on non-target organisms: direct & indirect

Transgene escape & its ecological consequences

Changes of biodiversity: agricultural ecosystem

Pest resistance development

Impact of transgenes on soil microbe

Effect on non-target organisms: direct & indirect

Transgene escape & its ecological consequences

Changes of biodiversity: agricultural ecosystem

Pest resistance development

Impact of transgenes on soil microbe

Transgene escape & its ecological Transgene escape & its ecological consequencesconsequencesTransgene escape & its ecological Transgene escape & its ecological consequencesconsequences

Transgenes escape Transgenes escape viavia ggene flowene flow

Transgenes escape Transgenes escape viavia ggene flowene flow

Gene flow: movement of genes from one population to another

Pollen – Seed – Vegetative organs

Crop-to-crop Crop-to-wild relatives

Gene flow: movement of genes from one population to another

Pollen – Seed – Vegetative organs

Crop-to-crop Crop-to-wild relatives

Risk = hazard × exposureRisk = hazard × exposure Risk = hazard × exposureRisk = hazard × exposure

Risk: probability that any adverse effect occurs from a hazard (%)

Hazard: intrinsic properties of a substance or object with potential adverse or harmful effects

Exposure: measurement of the extent to which a given hazard is present in a particular dimension

Risk: probability that any adverse effect occurs from a hazard (%)

Hazard: intrinsic properties of a substance or object with potential adverse or harmful effects

Exposure: measurement of the extent to which a given hazard is present in a particular dimension

Science 2004, 306: 1458–1459. Science 2004, 306: 1458–1459.

Impacts of transgene Impacts of transgene

escape via gene flowescape via gene flow——A A case study in ricecase study in rice

1. Crop-to-crop gene flow: potential risks

1. Crop-to-crop gene flow: potential risks

Unintended “contamination” of non-GM rice

Food & feed safety issues

Legal or trade problems

Non-target organisms

Changes in genetic diversity

Unintended “contamination” of non-GM rice

Food & feed safety issues

Legal or trade problems

Non-target organisms

Changes in genetic diversity

Pollen-mediated gene flowPollen-mediated gene flow：： ImportImportant to know pollen dynamics with spant to know pollen dynamics with spatial distancesatial distances

Parameters affect pollen flowParameters affect pollen flow Maximum pollen flow of MH-63: 110Maximum pollen flow of MH-63: 110

m (wind speed 10m/s)m (wind speed 10m/s)

Pollen-mediated gene flowPollen-mediated gene flow：： ImportImportant to know pollen dynamics with spant to know pollen dynamics with spatial distancesatial distances

Parameters affect pollen flowParameters affect pollen flow Maximum pollen flow of MH-63: 110Maximum pollen flow of MH-63: 110

m (wind speed 10m/s)m (wind speed 10m/s)

(1) Pollen flow & its (1) Pollen flow & its modelingmodeling

Lu et al. 2003

花粉密度随距离增加呈指数衰减花粉密度随距离增加呈指数衰减

xax eDD 0

• 湍流系数估计：湍流系数估计： nn = 1 = 1• 衰减系数估计：衰减系数估计： aa 0. 0.3434

(2) Gene flow & its modeling(2) Gene flow & its modeling

杂交稻 x 农家稻 杂交稻 x 农家稻

Gene flow between traditional and hybrid rice

Gene flow between traditional and hybrid rice

Gene flow frequencies between traditional rice &

hybrid rice

Gene flow frequencies between traditional rice &

hybrid rice

HR vs. TR

TR HR: 0.11%

HR TR: 0.04%

HR vs. TR

TR HR: 0.11%

HR TR: 0.04%

Gene flow of transgenic （ Bt/CpTI） rice Gene flow of transgenic （ Bt/CpTI） rice Exp. 1Exp. 1 GM riceGM rice Non-GM riceNon-GM riceExp. 2Exp. 2

Exp. 3Exp. 3 Exp. 4Exp. 4

Gene flow between adjacent Bt/CpTI rice lines & non-transgenic controls

Gene flow between adjacent Bt/CpTI rice lines & non-transgenic controls

20 m

32 m20 m

The prevalent wind direction

A C

20 m

10 m

B

32 m

D

38 m

10 m 32 m

20 m5 m 32 m

Distance effect: transgene flow from Bt/CpTI rice

Distance effect: transgene flow from Bt/CpTI rice

Rong et al. 2007 New PhytologistRong et al. 2007 New Phytologist

Determinants of gene flowDeterminants of gene flow

Biological: Outcrossing rate of pollen

recipients

Pollen density around pollen recipients (pollen competition)

Physical: Climate conditions

Biological: Outcrossing rate of pollen

recipients

Pollen density around pollen recipients (pollen competition)

Physical: Climate conditions

Model predicted maximum frequencies Model predicted maximum frequencies of gene flow in riceof gene flow in rice

Model predicted maximum frequencies Model predicted maximum frequencies of gene flow in riceof gene flow in rice

5 m 30 m 50 m 70 m 85 m

xaO exaFF )1(

Scale effect of gene flowScale effect of gene flowExperiment of 3 GM rice & parentsExperiment of 3 GM rice & parentsScale effect of gene flowScale effect of gene flow

Experiment of 3 GM rice & parentsExperiment of 3 GM rice & parents

GM vs nonGMMSR+ vs MSR-HY1+ vs HY2-Hy2+ vs HY2-

Gene flow frequencies not positively correlate with the increase of plot size

Overall gene flow frequency is <1%

Gene flow frequencies not positively correlate with the increase of plot size

Overall gene flow frequency is <1%

Pollen-mediated transgene flow is neglectable in rice

Spatial isolation can reduce “contamination”

Seed-mediated transgene flow may pose significant “contamination”

Seed production & distribution control

Pollen-mediated transgene flow is neglectable in rice

Spatial isolation can reduce “contamination”

Seed-mediated transgene flow may pose significant “contamination”

Seed production & distribution control

General conclusion:General conclusion:General conclusion:General conclusion:

2. Crop-to-wild gene flow: potential risks

2. Crop-to-wild gene flow: potential risks

Pollen-mediated crop-wild transgene flow posing environmental risks

Transgene in wild-rice populations may change fitness of wild plants

Enhance/reduce competitive ability of wild rice with transgene

Pollen-mediated crop-wild transgene flow posing environmental risks

Transgene in wild-rice populations may change fitness of wild plants

Enhance/reduce competitive ability of wild rice with transgene

Wild O. rufipogon is distributed in southern China

Hazards: Turning it into an invasive weed

Bringing endangered populations into extinction by demographic swamping

Wild O. rufipogon is distributed in southern China

Hazards: Turning it into an invasive weed

Bringing endangered populations into extinction by demographic swamping

Oryza rufipogon

Assessment of transgene escape & its ecological consequences

Assessment of transgene escape & its ecological consequences

Transgene flow to

wild rice

Transgene flow to

wild rice

Transgene express in wild rice

Transgene express in wild rice

Transgene persist & spread in natural

population

Transgene persist & spread in natural

populationEcological

consequenceEcological

consequence

Exposure (%)Exposure (%)HazardHazard

O. sativaO. sativa O. rufipogonO. rufipogon

Design ADesign A Design BDesign B

Design CDesign C

Screening of molecular markersScreening of molecular markers

Electrophoretogram of ESTElectrophoretogram of EST PCR amplified products generated using SSR primer RM44

PCR amplified products generated using SSR primer RM44

RAPD amplification products generated with primer S107RAPD amplification products generated with primer S107

RAPD amplification products generated with primer S358RAPD amplification products generated with primer S358

Gene flow from rice to Gene flow from rice to common wild rice: common wild rice:

up to 3%up to 3%

Gene flow from rice to Gene flow from rice to common wild rice: common wild rice:

up to 3%up to 3%

Modeling gene flow to wild relativesModeling gene flow to wild relativesModeling gene flow to wild relativesModeling gene flow to wild relatives

Frequency of crop-to-wild gene flow is high

3. Crop-to-weedy gene flow: potential risks

3. Crop-to-weedy gene flow: potential risks

Weedy rice is a bad weed occurring widely in tropic & temperate regions

Asia, America, Africa & Europe

In Asia, weedy rice was mainly found in S & SE Asian countries

NE China, associated with direct seeding

Weedy rice is a bad weed occurring widely in tropic & temperate regions

Asia, America, Africa & Europe

In Asia, weedy rice was mainly found in S & SE Asian countries

NE China, associated with direct seeding

Ca. 0.5% gene flow from rice to its weedy type in

generation

Ca. 0.5% gene flow from rice to its weedy type in

generation

500 bp500 bp

Cultivated-weedy-wild rice mixtureCultivated-weedy-wild rice mixture

Bt gene expression in wild rice

Bt gene expression in wild rice

Hybrids between Bt-O. sativa & O. rufipogon

Gene expression by ELISA test

Transgene expression level (%) is similar in hybrids compared with GM rice

Hybrids between Bt-O. sativa & O. rufipogon

Gene expression by ELISA test

Transgene expression level (%) is similar in hybrids compared with GM rice

Xia et al. 2008, J. Plant Biotech.Xia et al. 2008, J. Plant Biotech.

A cost-benefit experiment involving Bt, CpTI & Bt/CpTI rice & their non-GM controls

The results showed different benefit-cost patterns for various characters

E.g. good seed production

A cost-benefit experiment involving Bt, CpTI & Bt/CpTI rice & their non-GM controls

The results showed different benefit-cost patterns for various characters

E.g. good seed production

Fitness performanceFitness performance

Performance of O. sativa, O. rufipogon & hybrids

Hybrids: lowest value: seedling survival ability,

pollen viability & seed production

Medium value: seed germination, spikelet production & flag-leaf areas

High value: plant height, number of tillers & panicles

Performance of O. sativa, O. rufipogon & hybrids

Hybrids: lowest value: seedling survival ability,

pollen viability & seed production

Medium value: seed germination, spikelet production & flag-leaf areas

High value: plant height, number of tillers & panicles

Hybrids: Poor sexual reproduction High hybrid vigor & tillering

ability No significant differences in

composite fitness across whole life-history

Rice genes may persist in wild populations through vegetative & sexual reproduction

Hybrids: Poor sexual reproduction High hybrid vigor & tillering

ability No significant differences in

composite fitness across whole life-history

Rice genes may persist in wild populations through vegetative & sexual reproduction

General conclusionsGeneral conclusions

Rice & its close wild relatives co-exist in many areas worldwide

Crop-wild gene flow in rice is commonly found in nature

High probability of transgene escape to weedy/wild rice through gene flow

Rice & its close wild relatives co-exist in many areas worldwide

Crop-wild gene flow in rice is commonly found in nature

High probability of transgene escape to weedy/wild rice through gene flow

Confinement of crop-to-wild gene flow is difficult in many places

Crop gene can persist in wild population via introgression

Consequences of transgene escape to wild & weedy rice should be thoroughly assessed

Confinement of crop-to-wild gene flow is difficult in many places

Crop gene can persist in wild population via introgression

Consequences of transgene escape to wild & weedy rice should be thoroughly assessed

Assessment of transgene escape & its ecological consequences

Assessment of transgene escape & its ecological consequences

Transgene flow to

wild rice

Transgene flow to

wild rice

Transgene express in wild rice

Transgene express in wild rice

Transgene persist & spread in natural

population

Transgene persist & spread in natural

populationEcological

consequenceEcological

consequence

Exposure (%)Exposure (%)HazardHazard

?

BioScience 2005BioScience 2005

Acknowledgement:Acknowledgement:Fudan University, ShanghaiFudan University, ShanghaiDr. Song Zhiping; Mr. Rong Jun; Ms. Chen Liangyan; Ms. Cao Qianjin; Dr. Song Zhiping; Mr. Rong Jun; Ms. Chen Liangyan; Ms. Cao Qianjin; Mr. Xia HuiMr. Xia HuiFujian Academy of Agricultural Science, FuzhouFujian Academy of Agricultural Science, FuzhouDr. Wang Feng; Dr. Shu JunDr. Wang Feng; Dr. Shu JunYunnan Agricultural University, KunmingYunnan Agricultural University, KunmingDr. Chen Lijuan; Dr. Zhu Youyong, Dr. Wang YunyueDr. Chen Lijuan; Dr. Zhu Youyong, Dr. Wang YunyueOhio State University, USAOhio State University, USADr. A. A. SlowDr. A. A. Slow

Nature Science Foundation of ChinaNature Science Foundation of China (NSFC)(NSFC) for Distinguished Young for Distinguished Young Scholars (30125029 & Scholars (30125029 & 2007ZD0012007ZD001) ) National High Science and Technology ProgramNational High Science and Technology Program (2001AA212031 & 20 (2001AA212031 & 2001AA212041) 01AA212041) Science & Technology Commission of ShanghaiScience & Technology Commission of Shanghai (02JC14022 & 03dz19(02JC14022 & 03dz19309)309)

Acknowledgement:Acknowledgement:Fudan University, ShanghaiFudan University, ShanghaiDr. Song Zhiping; Mr. Rong Jun; Ms. Chen Liangyan; Ms. Cao Qianjin; Dr. Song Zhiping; Mr. Rong Jun; Ms. Chen Liangyan; Ms. Cao Qianjin; Mr. Xia HuiMr. Xia HuiFujian Academy of Agricultural Science, FuzhouFujian Academy of Agricultural Science, FuzhouDr. Wang Feng; Dr. Shu JunDr. Wang Feng; Dr. Shu JunYunnan Agricultural University, KunmingYunnan Agricultural University, KunmingDr. Chen Lijuan; Dr. Zhu Youyong, Dr. Wang YunyueDr. Chen Lijuan; Dr. Zhu Youyong, Dr. Wang YunyueOhio State University, USAOhio State University, USADr. A. A. SlowDr. A. A. Slow

Nature Science Foundation of ChinaNature Science Foundation of China (NSFC)(NSFC) for Distinguished Young for Distinguished Young Scholars (30125029 & Scholars (30125029 & 2007ZD0012007ZD001) ) National High Science and Technology ProgramNational High Science and Technology Program (2001AA212031 & 20 (2001AA212031 & 2001AA212041) 01AA212041) Science & Technology Commission of ShanghaiScience & Technology Commission of Shanghai (02JC14022 & 03dz19(02JC14022 & 03dz19309)309)

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