Risk Assessment of GM Plants

1. Risk Assessment of GM Plants Assoc. Prof. Dr. Wichai Cherdshewasart Department of Biology, Faculty of Science, Chulalongkorn UniversityTel 02-2185033 Fax 02-2185034

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 methylationanalysis 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

22. 2. Plant testing

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. 2002. Environmental safety assessment for transgenic crops. • Wolf K. 1994. Gene transfer between organelles and the nucleus in lower eukaryotes • Copy P. Bazin C. Anxolabehere D. Langin T. 1994. Horizontal transfer and the evolution of transposable elements • Landmann J. Graser E. Riedel-Preuss A. van der Hoeven C. 1994. Can Agrobacteria be eliminated from transgenic plants? • Hoffmann T. Golz C. Schieder O. 1994. Preliminary findings of DNA transfer from transgenic plants to a wild-type strain of Aspergillus niger • Hansen L. C. Obryeki J.-J. L. 2000 Field deposition of Bt transgeniccorn pollen: lethal effects on the monarch butterfly.