1. Risk Assessment of GM Plants
Assoc. Prof. Dr. Wichai Cherdshewasart  
Department of Biology, Faculty of Science, Chulalongkorn University Tel Fax

2. Modes of plant gene modification
1. Classical breeding (wild crossing)
2. Mutation
3. Somaclonal variation
4. Protoplast fusion
5. Embryo rescue
6. Gene transfer

3. 1. Classical breeding (wild crossing)
Advantage:
practical, low cost, stable, effective within species
Disadvantage:
time-consumed, ineffective within different species

4. 2. Mutation Advantage: practical, low cost Disadvantage:
randomized, needs long selection procedure, not totally stable, may initiate revertant

5. 3. Somaclonal variation Advantage: in vitro manipulation Disadvantage:
takes time, randomized, needs long selection procedure

6. 4. Protoplast fusion Advantage: across species barrier Disadvantage:
randomized, remote species may success but fail for further development

7. 5. Embryo rescue Advantage:
cross between different species is possible to initiate embryonic development.
Disadvantage:
transfer pre-mature embryo to new environment could initiate fully developed plants, but sterile

8. 6. Gene transfer Advantage:
precise genotype obtained, laboratory and industry practical
Disadvantage:
Not possible for all species, especially monocot

9. Mode of gene transfer: 1. Vector-mediated gene transfer
Agrobacterium-mediated
Virus-mediated
2. Vectorless-mediated gene transfer (Direct gene transfer)
Mechanical
Physical
Electrical
Chemical

10. Analysis of transgenic plants
1. Phenotypic analysis
2. Genotypic analysis
3. Greenhouse condition analysis
4. Field trial condition analysis

11. Genotypic analysis PCR for rapid screening
Southern blot for precise gene detection
Northern blot for transcription analysis
Western blot for translation analysis, together with Ab-binding or enzymatic analysis
Mendelian analysis for insertion locus and linkage analysis
In situ hybridization for precise insertion locus analysis
DNA methylation analysis for silencing potential analysis

12. A generally accepted risk assessment method*,**,***
1. Identify potential adverse effects on human health and/or the environment
2. Estimate the likelihood of these adverse effects being realized
3. Evaluate the consequence should be identified effects be realized (the risk)
4. Consider appropriate risk-management strategies
5. Estimate the overall potential impact, including a consideration of potential impacts that may be beneficial to human health or the environment
* UNEP International Technical Guideline for Safety in Biotechnology
** The Cartegena Protocol
*** EC Directive 2001/18/EEC

13. Approaches to risk assessment
1. Trait analysis
characteristics of the modified organism; transgene, parental organisms, receiving environment
less problem, if small scale
more problem, if large scale
2. Familarity
comparison of transgenic to similar organism(s) derived from classical genetic methods
assume that small genetic changes (1-4 genes) exhibits no significant change in well-known organism, phenotype is still the same

14. 3.  Formulaic
possible adverse effects; to human health or the environment
R = H x E
R; Risk, H; Hazard, E; Exposure
facilitates consideration of risk-management options
4. Intuitive Reasoning
use education, experience and reason to promote knowledge for making decision with complete information
depends on what should be considered
use of expert committees, independent reviewers/assessors without a conflict of interest

15. Environment Safety Assessment For Transgenic Crops:

16. Needs:
1. Environmental friendly products
2. Tight global regulatory requirements
3. Trade barrier
Methods:
1. Product and country specification
2. Science-based assessment
3. Multi-tiered, complementary approaches

17. Plant assessment:
1. Survival against wild type plants
2. Stability of gene expression, especially in
the field vs. laboratory / greenhouse
3. Distinct genotype over wild type plant
4. Invasiveness of transgenic plants, the
possibility to develop into weeds

18. Trait assessment:
1. Toxicity to non-target organisms
2. In case of human consumption,
no allergen / toxic substance
3. Ecological impacts (outcrossing)

19. Guidelines for Plant Testing

20. Field obseravation Emergence
Order of testing relies on degree of possible risk of the plant
Growth measurement
Transgenic plant growth / wild type, not greater than 1
Days of flowering
Transgenic plant days of flowering / wild type, not greater than 1
Length of flowering period
Transgenic plant length of flowering period / wild type, not greater than 1
Pollen dispersal distance
This is the reason why buffer zone has to be set up)

21. Shattering of seed from plant
Distance of seed shattering determines degree of risk
Reproductive success or yield (annual)
Reproductive success determines transmission risk
Reproductive success or yield (perennial)
Perennial risk determines more risk
Qualitative insect
Non-target insects = 0
Qualitative pathogens
Non-target pathogens = 0
Others

22. 2. Plant testing Dormacy/ germination
-shorter dormancy / germination determine front running risk
-longer dormancy / germination determine latent risk
risk
Field seedbank longevity (dormancy x viability)
-increase longevity determines risk
Competition (Replacement or addition series)
-stronger competition determines risk
Replacement capacity
-higher replacement capacity determines risk

23. Gene flow (through pollen movement)
-wider pollen dispersal determines risk
-outcrossing determines risk
Introgression (hybrid weediness)
-hybrid weediness determines long term risk
Alleopathy
-Competitive of survival risk

24. Susceptibility to conventional management
-Competitive of agricultural risk
Genetic stability
-High genetic stability determines risk
Epistasis
-Epistasis determines unexpected genetics
-Horizontal gene transfer
Gene transfer between plant nucleus and organelle
Gene transfer between plant nucleus and genome of consumer, predator, Gene transfer between nucleus and organelle
Other

25. Regulatory principles:
Scientifically based, based on information of organism, used technology and effects to humans and environment
Product-based approach, use existing product-based legislation
Familiarity and substantial equivalence, experience with the use of that species. The determination is based on scientific literature and practical experience with the plant and similar plant varieties.
Case-by case, allow the development of knowledge that could inform criteria and requirement over time.

26. Regulatory principles:
Step-wise fashion, products should be assessed throughout the chain of development : From laboratory to greenhouse and finally large-scale field trial
Transparency
Precautionary principle/approach, derived from Rio Declaration, regulatory groups can make decisions about products based on scientific uncertainty.
Harmonization, sharing of or acceptance of another group’s review

27. Risk management of transgenic plant

28. 1. Good laboratory practice
Tightly control of GM-vectors, plasmids and plant materials
Apply no bacterial antibiotic resistant-derived gene
Apply bioluminescence gene from animal as marker
Apply antisense for pollen developmental gene
Limit level of toxic gene, eg, cry family

29. 2. Good agricultural practice
Controlled plantation area with standard buffer zone and % sharing with wild type plants
Emasculation
Flower bud elimination
Closed-bag control
Net protection of fruits and seeds from insects, birds, bats, rodents
Total fruit and seed collection
Labeling and separation technique for transgenic plant and seed
Whole plant elimination after harvest

30. 3. Good manufacturing practice
Labeling GM-products according to domestic and export regulations
Testing for allergen and toxicity of the products containing GM-materials

31. 4. Good marketing practice
Fully-informed alien gene(s) and awareness of application
Evaluated for allergen and toxic molecule
Labeling
Post marketing record

32. 5. Good consumption practice
For GM-food products: determine animals as primary consumer and human as secondary consumer
Study labeling
Food safety criteria

33. References
Head G. and Duan J Environmental safety assessment for transgenic crops.
Wolf K Gene transfer between organelles and the nucleus in lower eukaryotes
Copy P. Bazin C. Anxolabehere D. Langin T Horizontal transfer and the evolution of transposable elements
Landmann J. Graser E. Riedel-Preuss A. van der Hoeven C Can Agrobacteria be eliminated from transgenic plants?
Hoffmann T. Golz C. Schieder O Preliminary findings of DNA transfer from transgenic plants to a wild-type strain of Aspergillus niger
Hansen L. C. Obryeki J.-J. L Field deposition of Bt transgenic corn pollen: lethal effects on the monarch butterfly.