Genetically Modified Crops

1. Genetically Modified Crops Thomas L Sims, Ph.D. Department of Biological Sciences & Plant Molecular Biology Center, Northern Illinois University Miracle Crops or Frankenfoods? Summer Ag Institute: DeKalb County Farm Bureau, June 17, 2014

2. My Background • Mother’s family were dairy farmers in Wisconsin • B.S. University of Wisconsin, Ph.D. University of Oregon, Post-doctoral research fellow at UCLA • While at UCLA, part of a team that was the first group in the U.S. to make “transgenic” (GMO) plants, by putting a gene from soybean into tobacco • Came to NIU in 1992. Current research on Plant reproduction & Petunia Genome Project + Petunia integrifolia Petunia axillaris Petunia hybrida

3. Challenges • Human population growth • Increased economic prosperity in developing countries • Loss of arable land & urbanization • Global climate change • How do we feed a larger population, on less land, with fewer inputs, while facing the challenges of reductions in yield because of climate change?

4. Knowledge-Based Approaches • Molecular Genetics • Plant genomic sequencing (rice, corn, soybean, tomato, pepper, tobacco, petunia, Arabidopsis thaliana) • Plant Biochemistry, Plant Physiology Limitations • Over 250,000 species of flowering plants, but all of agriculture is based on ~30 species and just a few of these provide the vast majority of calories

5. GMO • Genetically-modified organism • Genetically-modified crops • Genetically-modified food • What are GMOs? • How do you make them? • Why make them? • Are there legitimate concerns about GMOs? • What’s in the future?

7. Genetic Modification • Ruby-Red Grapefruit (ionizing radiation) • Golden Raisins/Sultanas (processing mutant) • Seedless fruits (ionizing radiation) • Cultivated tomato (mutations in HT-B, S-RNase, uniform-ripening) • Cultivated potato (tetraploid) • Modern (non-transgenic) rice • Modern maize (from teosinte)

8. Transgenic Plants • DNA encodes genetic information • Can physically isolate and clone DNA sequences encoding specific genes • Transgenic organisms are those where: • A NEW gene has been inserted and is expressed or • An EXISTING gene has been turned off • Insert cloned genes into plant cells and re-generate whole transgenic plants • Transgenic plants = GMO plants

9. Agrobacterium tumefaciens, a natural soil bacterium, causes crown galls

10. Plant Regeneration from Tissue Culture Fertile plants can be regenerated from single cells

11. Just replace the T-DNA in Agrobacterium with gene of interest, let the bacterium transfer the gene to the plant & regenerate

12. Expressing “Transgenes” • Source of expressed gene of interest can be anything: • A gene from a different plant (Golden Rice) • A gene from a bacterium (Bt-corn, Round-Up Ready Soybeans) • A gene from an animal (drug production) • A gene-construct that turns-off a gene target (Flavr-Savr, Arctic apple) • Must have plant-specific “switch” or promoter

14. RNA interference (RNAi) • Inhibition of Gene Expression by RNA degradation, translational inhibition or chromatin modification • Present in all higher eukaryotic organisms. • Much of human genome is regulatory miRNA genes • Anti-virus defense mechanism in plants • Based on sequence complementarity to target mRNA

15. Types of Transgenic Modifications in GMOs • Transfer of bacterial protein-coding gene (HT, Bt, Golden Rice, drought-tolerant corn, cold-tolerant Eucalyptus) • Transfer of non-coding viral gene (GM Papaya in Hawaii) • Transfer of a gene from a different plant species (Golden Rice, Green-Blight tolerant oranges, yield-enhanced soybean) • Down-regulation of endogenous plant gene (Arctic apples, InnateTM potatoes, reduced CN Cassava) • Down-regulation of insect-pest gene (Corn rootworm III)

17. GMO Regulation in United States • USDA-APHIS • Regulates “environmental risk” • In practice, regulates all GMO products • EPA • Regulates any GMO product involving a pesticide (e.g. herbicide-tolerance, Bt corn/cotton) • FDA • Regulates Food and Feed Safety • Potential allergens? New toxic substances? Altered Nutritional Composition?

18. GMO Regulation in Europe • European Food Safety Authority • Scientific Panel, founded 2002 • Broad-based European authority for food safety • GMO Panel • Has approved every GMO application it has reviewed • Recommendations go to EC Standing Committee on Food Chain and Animal Health • Luxembourg & Austria 100% “No” to approval • Sweden, Finland, Czech, Netherlands, 100% “Yes” • EFSA also rejected ‘health-claim’ benefits of food additives and other foods

19. Some Brief Examples • Flavr-Savr tomato (first transgenic, 1994) • Bt-corn (insect resistance) • ArcticTM apple (non-browning, scheduled for release soon) • Golden Rice

20. Flavr-Savr Tomato (1994) • Conventional tomatoes have a mutation in uniform ripening that also reduces flavor • Conventional tomatoes harvested green, stored, exposed to ethylene gas • Flavr-Savr tomato engineered to turn-off “polygalacturonase” (PG) gene involved in rotting • Leave on the vine to ripen, then pick • Better taste, flavor & color • Marketed in DeKalb but no longer in production

21. Genetic engineering for resistance to European Corn borer or related pests • Conventional chemical sprays don’t work on corn borer • Huge amounts of chemical sprays used on cotton • Genetic engineering of ‘crystal-toxin’ (Cry) gene from Bacillus thuringiensis Bt CornBt Cotton • Solution of Bt bacterium sold off the shelf as insecticide for organic gardening • Non-toxic to humans & animals • Non-toxic to non-target insects

22. Bt protein Mode of Action Only in specific insects. Not in animals or other insects.

23. Adoption of Bt cotton has resulted in large decrease in use of chemical insecticides National Research Council Report 2011, on the Environmental Effects of Transgenic Crops

24. Enzymatic Browning (Polyphenoloxidase) apples Potatoes

25. RNAi: Polyphenoloxidase (PPO)

26. Arctic Apple • Onkanagon Specialty Fruits, British Columbia, CA • Non-browning apple • RNAi of four members of polyphenoloxidase gene family • In last phases of regulatory process for unregulated release in U.S. and Canada • www.arcticapples.com

27. Intention of the company is to label the individual apples as GMO, once they are approved for release

28. “Natural” PPO Mutant • 1962: “Bruce’s Sport” mutation of Sultana grape variety. Lacked PPO. • Used to produce “Golden Raisins” Completely unregulated process • Mutation deciphered 1992 PPO protein precursor, 67 kDa protein 40.2 kDa active enzyme 10.6 kDa transit peptide 16.2 kDa C-terminal peptide • In “Bruce’s Sport”, mutation eliminates cleavage of C-terminal peptide • “New” protein of 60 kDa without PPO activity

29. Peter Beyer, Freiburg Ingo Potrykus, Zurich

30. Vitamin A deficiency • Important for vision • Important for immune system • -carotene (provitamin-A) cleaved to Vitamin A • 400 million people at risk, 100-140 million children • 250,000 - 500,000 cases of blindness. 50% of these die within one year

31. Global Vitamin-A Deficiency Patterns Vitamin-A deficiency largely due to poor diet, subsidence diet, especially of rice (Asia) or Cassava (Africa) which lack Vitamin-A

32. Steps shown in GREEN are present in rice, others are not

33. Gene construct for Golden-Rice-2 Glu= Rice glutelin promoter (endosperm specific) tpSSU = transit peptide Rubisco small-subunit (pea) CrtI = Bacterial desaturase CRTI Nos = nopalinesynthase terminator Psy = Phyotenesynthase (daffodil) Ubi1= maze polyubiquitin promoter Pmi = Phosphomannoseisomerase (E. coli)

35. Long Road in Development to Public Release Potrykus “Regulation must be revolutionized” Nature 466: 561 (2010) 2014?

36. Future Developments? • Marker-free & vector-free GMOs (e.g. InnateTM potatoes, uses only modified potato DNA) • Reduction of antinutritional compounds (reduced CN/enhanced Fe Cassava) • Improved Nitrogen utilization (less fertilizer input) • Golden Rice II release?

37. Resistance to GMOs • Organized and effective political opposition • Fears/concerns about corporate control of food (March Against Monsanto) • Safety concerns, Environmental concerns • Philosophical concerns • How legitimate are the issues raised? • Some problems do exist, but these can (and will) be addressed because of an understanding of the underlying scientific cause • Many are blown out of proportion, either deliberately or because of a lack of understanding

38. Example: herbicide resistant weeds • Fears/accusations of GMO “superweeds” • Requirements for genetic transfer of resistance • Sexually-compatible weedy relative in geographic proximity • Overlap in flowering time • Pollinator • Positive Selection • Canola, sugar beet most problematic • Soybean, corn less so • Real problem is not cross-pollination but conventional natural-selection & population genetics

39. Evolution of weeds resistant to Glyphosate All of these are due to natural selection on existing weeds, not pollen transfer Also: use of glyphosatehas increased total amount or herbicide used (lbs/acre) BUT glyphosate is far LESS toxic than previous herbicides, so its use is a environmental plus compared to prior practice

40. Addressing Herbicide Resistance • No “super” weeds; still susceptible to other herbicides • “Stacking” two or more resistance genes (glyphosate, glufosinate, dicamba, 2,4-D) will greatly slow or eliminate development of resistance because resistance required simultaneous mutations in two different genes • More attention to crop rotation (don’t use the same trait in all crops, all the time)

41. Anti-GMO Headline ‘Agent Orange’ Crops Would Trigger Massive Increase in Use of Toxic Pesticide 2,4-D (Jan 2014) • Misleading: 2,4-D (synthetic plant hormone) was one ingredient of “Agent-Orange”, but NOT the dangerous one (2,4,5-T, whose synthesis produced dioxin as a by-product. Dioxin was the real culprit) • 2,4,5-T is no longer manufactured or used • 2,4-D is in >1500 herbicides and has been used since the 1940’s

42. GMO Labeling • Passed in Vermont, Connecticut • Defeated in Washington, California • Under consideration elsewhere, including Illinois • How food is produced versus what it contains • USDA doctrine of “Substantial equivalence” • Inconsistencies: (crops sprayed with Bt bacteria, expressing the Bt protein, would not have to be labeled, but those expressing transgenic Bt protein would have to be labeled)

43. Two web sites with objective information http://www.geneticliteracyproject.org/ Stronger life, stronger science, and stronger communication. http://www.biofortified.org/

44. Questions? GRII in cultivation