Lectures 20-21, Chapters Regulations and risk assessment Neal Stewart

Discussion questions 1. What are regulations supposed to achieve? 2. With GM crops being used so extensively, how are we assured of their health and environmental safety? 3. How is genetic engineering (biotechnology) regulated? 4. When is plant genetic engineering not regulated? 5. How do the risks posed by products of biotechnology compare to those posed by conventional technologies? 6. How do different countries regulate products of biotechnology?

Plant genetic modification The new plant will pass the transgene to its progeny through seed. Any gene, any organism

Recall… progression of transgenic plants Input traits– commercialized fast from 1996 Output traits—commercialized slowly from early 2000s Third generation– pharma, oral vaccines, phytoremediation, phytosensors— emerging gradually. How might regulating these be more challenging.

Bt maize

Bt cotton

Golden rice Engineered to deliver pro-vitamin A

GFP canola

Plants to detect landmines induction Using inducible promoter/GFP fusions No TNT +TNT

Agriculture and Nature Are farms part of nature? Of the environment? Direct or indirectly? Impacts on nature and agriculture might be inter-related but the endpoints will be different

Big picture—ecological impacts of agriculture Major constraint is agriculture itself Tillage and pesticide practices Crop genetics (of any sort) is miniscule

Tran s gene s Conventiona l breeding Mutagenesi s Half genomes, e.g., wide crosses in hybrids Whole genomes, e.g., horticultural introductions or biological control Amount of genetic information added to ecosystems less more Risk??

Figure 12.1

Domestication of corn TeosinteCorn 9000 years ago?

Domestication of carrot Daucus carota 300 to 1000 years ago? Queen Anne’s Lace 1700s orange carrots appear in Holland

Brassica oleracea Wild cabbage Kohlrabi Germany 100 AD Kale 500 BC Cabbage 100 AD Cauliflower 1400s Broccoli Italy 1500s Brussel sprouts Belgium 1700s Ornamental kale Late 1900s

Regulations

What/why regulate Biosafety– human and environmental welfare Recombinant DNA (rDNA) triggers regulation in most countries Transgenic plants and their products are pound for pound the most regulated organisms on earth “Protect” organic agriculture “Precautionary principle”

US history of regulating biotechnology Early 1970s recombinant organisms are possible (microbes)—plants in 1980s Asilomar conference 1975 NIH Guidelines 1976—regulating lab use OSTP Coordinated Framework—1986 Set up the USDA, EPA and FDA to regulate aspects of transgenic plants Regulatory agencies provide safeguards and requirements to assure safety— determination and mitigation of risks.

Roles of agencies in US regulation of transgenic plants USDA: Gene flow, agronomic effects EPA: Gene flow, environmental/non- target, toxicity when plants harbor transgenes for pest control FDA: human toxicity/allergenicity

Ecological Risk Assessment of Transgenic Plants Problem formulation—assessment and measurement endpoints exposure assessment hazard assessment

Objectives At the end of this lecture students should… Understand framework for assessing risks Be able to define short-term and long-term risks for a transgenic plant application—i.e., define ecological endpoints Understand exposure assessment and hazard assessments for today’s GM plants Critically think about exposure and hazard assessments for upcoming GM plants

Methods of risk analysis Experimental approach (toxicology or ecology) –Controlled experiments with hypothesis testing –Cause and effect Theoretical modeling Epidemiological approach—association of effects with potential causes Expert opinion Adapted from 2002 NRC report: Environmental Effects of Transgenic Plants

Risk vLikelihood of harm to be manifested under environmentally relevant conditions vJoint probability of exposure and effect vQualitative is more reasonable than quantitative

Risk analysis Johnson et al Trends Plant Sci 12:1360

Ecological Risks Risk = exposure x hazard Risk = Pr(event) x Pr(harm|event) The example gene flow Exposure = probability hybridization Hazard = consequences of ecological or agricultural change--severity of negative impact

Ecological Risks Risk = exposure x hazard Risk = Pr(event) x Pr(harm|event) Transgene persistence in the environment– gene flow –Increased weediness –Increased invasiveness Non-target effects– killing the good insects by accident Resistance management– insects and weeds Virus recombination Horizontal gene flow Public perception: Risk = visibility x hysteria

Risk = Pr(GM spread) x Pr(harm|GM spread) Stated another way and with terms: ExposureImpact FrequencyHazard Consequence

Experimental endpoints Hypothesis testing Tiered experiments– lab, greenhouse, field Critical P value Relevancy Comparisons– ideal vs pragmatic world HYPOTHESES MUST BE MADE— WE CANNOT SIMPLY TAKE DATA AND LOOK FOR PROBLEMS!

Example endpoints H, insect death: toxicology of insect resistance genes E, hybridization frequency: gene flow What are some ideal features of end points?

Risk analysis Johnson et al Trends Plant Sci 12:1360

Balancing exposure and hazard R = E x H: an example from the world of gene flow R= E x H : an example from the world on non-targets Johnson et al Trends Plant Sci 12:1360

Gene flow model: Bt Cry1Ac + canola and wild relatives Diamondback moth larvae. Brassica napus – canola contains Bt Brassica rapa – wild turnip wild relative

Brassica relationships Triangle of U

Bt Brassica gene flow risk assessment Is it needed? What kind of experiments? At what scale?

Tiered approach—mainly non- targets Wilkinson et al Trends Plant Sci 8: 208

Ecological concerns Damage to non-target organisms Acquired resistance to insecticidal protein Intraspecific hybridization Crop volunteers Interspecific hybridization Increased hybrid fitness and competitiveness Hybrid invasiveness

Brassica napus, hybrid, BC1, BC2, B. rapa

Hybridization frequencies— Hand crosses– lab and greenhouse F 1 Hybrids BC 1 Hybrids CAQB1QB2TotalCAQB1QB2Total GT 169%81%38%62%34%25%41%33% GT 263%88%81%77%23%35%31%30% GT 381%50%63%65%24%10%30%20% GT 438%56% 50%7%30%36%26% GT 581%75%81%79%39%17%39%31% GT 650% 54%51%26%12%26%21% GT 731%75%63%56%30%19%31%26% GT 856%75%69%67%22% 21%22% GT 981%31% 48%27%28%23%26% GFP 150%88%75%71%18%33%32%27% GFP 269%88%100%86%26%20%57%34% GFP 319%38%19%25%10%22%11%15%

Gene flow model with insecticidal gene Wilkinson et al Trends Plant Sci 8: 208

In the UK, Wilkinson and colleagues predict each year… 32,000 B. napus x B. rapa waterside populations hybrids are produced 16,000 B. napus x B. rapa dry populations hybrids are produced But where are the backcrossed hybrids?

Field level backcrossing Maternal Parent F 1 hybridTransgenic/germinatedHybridization rate per plant Location 1983/ % Location 2939/ % F 1 total1922/ % Maternal Parent B. rapaTransgenic/germinatedHybridization rate per plant Location 134/56, % Location 244/50, % B. rapa total78/107, % Halfhill et al Environmental Biosafety Research 3:73

Genetic Load  Negative effects of genetic load may hinder a hybrid’s ability to compete and survive  Negative epistatic effects of genetic load could trump any fitness benefits conferred by a fitness enhancing transgene GM CropWeed F 1 Hybrid BC X weed

Field level hybridization Third-tier Risk = Pr(GM spread) x Pr(harm|GM spread) Exposure Frequency

Genetic introgression Halfhill et al Theor Appl Genet 107:1533 AFLPs

Generating transgenic “weeds” testing the consequences Brassica napus (AACC, 2n=38) Brassica rapa (AA, 2n=20) F 1 Generation (AAC, 2n=29) B. rapa BC 1 F 1 Generation (AAc, 2n= or 2) BC 2 F 1 Generation (AA, 2n=20) B. rapa BC 2 F 2 Generation (AA, 2n=20)     BC 2 F 1 Generation (AA, 2n=20)

Competition field design

Competition results NC GA Halfhill et al 2005 Mol Ecol 14:3177

Figure 1.Figure 1. Genetic Load Study: Productivity. Average vegetative dry weight and seed yield (2e +4 = 20,000 seeds, 1e + 5 = 100,000 seeds, etc.) of non-transgenic Brassica napus (BN), Brassica rapa (BR) and transgenic BC1/F2 hybrid lines (GT1, GT5 and GT9) grown under non-competitive (A and C) and competitive field conditions (B and D). Columns with the same letter do not differ statistically (P < ). Error bars represent ± standard error of the means. Note that different Y-axis scales are used among figure panels. BMC Biotechnol :83

Discussion question Which is more important: that a field test be performed for grain yield or environmental biosafety?

Monarch butterfly exposure to Bt cry1Ac

Monarch butterfly In October 2001 PNAS– 6 papers delineated the risk for monarchs. Exposure assumptions made by Losey were far off. What’s riskier? Broad spectrum pesticides or non-target effects?

Tiered approach—mainly non- targets Wilkinson et al Trends Plant Sci 8: 208

Tier 1: Lab Based Experiments Bioassays to determine the resistance of the two-spotted spider mite to various chemicals A healthy armyworm (right) next to two that were killed and overgrown by B. bassiana strain Mycotech BB (K9122-1) Examples of insect bioassays

Tier 3: Field Studies Tier 2: Semi-Field/Greenhouse Greenhouse Study: Transgenic Tobacco Field Trials: Transgenic Canola Photo courtesy of C. Rose Photo courtesy of R. Millwood

Goals of Field Research 1.Hypothesis testing 2.Assess potential ecological and biosafety risks (must be environmentally benign) 3.Determine performance under real agronomic conditions (economic benefits)

Tiers of assessment & tiers of testing  level of concern  degree of uncertainty … arising from a lower tier of assessment drives the need to move toward a higher tier of data generation and assessment Tier I Tier II Tier III Tier IV Lab Microbial protein High dose Lab PIP diet Expected dose Long-term Lab Semi-field Field Assessment Testing Jeff Wolt

Non-target insect model Wilkinson et al Trends Plant Sci 8: 208

Examples…identifying Endpoints for Risks, Exposure, Hazards Plant system (crop, weeds, communities, etc) Phenotype Biotic interactions Abiotic interactions Class to give examples—discussion—setting up experiments

Expert knowledge is important Biotechnology –Transformation methods –Transgene –Regulation of expression Ecology –Plant –Insect –Microbial –Populations –Communities –Ecosystems Agriculture –Agronomy –Entomology Regulator acceptance –Developed world –Developing world Public acceptance –Finland and EU –Where GM crops are widely grown –New markets

Features of good risk assessment experiments Gene and gene expression (dose) –Relevant genes –Relevant exposure Whole plants Proper controls for plants Choose species Environmental effects Experimental design and replicates Andow and Hilbeck 2004 BioScience 54:637.

Risk assessment links research to risk management Problem Formulation Exposure & effects characterization Risk Characterization Risk Management Risk Assessment Data Acquisition, Verification, & Monitoring Jeff Wolt

An example of agricultural risk that is not regulated The evolution of weed resistance to herbicides

Marestail or horseweed—found widely throughout North America and the world Compositae First eudicot to evolve glyphosate resistance Resistant biotypes appeared in 2000, Delaware—resistant Conyza in 20+ US states and four continents, e.g. in countries such as Brazil, China, and Poland 2N = 18; true diploid; selfer Conyza canadensis

Spread of glyphosate resistance in Conyza

Copyright ©2004 by the National Academy of Sciences Baucom, Regina S. and Mauricio, Rodney (2004) Proc. Natl. Acad. Sci. USA 101, Fig. 1. The proportion of soybean acreage sprayed with glyphosate from 1991 to 2002 relative to other herbicides

Resistant biotype 1 Susceptible biotype 14 DAT rate in lbs ae/Ac C.L. Main UTC

RR weed risk assessment research Is it needed? What kind of experiments? At what scale? Other weeds?

Environmental benefits of transgenic plants

Big environmental benefits Herbicide tolerant crops have increased and encouraged no-till agriculture– less soil erosion. Over 1 million gallons of unsprayed insecticide per year.

When transgenic plants are not regulated The case of the ancient regulations

USDA APHIS BRS 7 CFR Part Restrictions on the Introduction of Regulated Articles (a) No person shall introduce any regulated article unless the Administrator is: (1) Notified of the introduction in accordance with 340.3, or such introduction is authorized by permit in accordance with 340.4, or such introduction is conditionally exempt from permit requirements under 340.2(b); and (2) Such introduction is in conformity with all other applicable restrictions in this part. 1 1 Part 340 regulates, among other things, the introduction of organisms and products altered or produced through genetic engineering which are plant pests or which there is reason to believe are plant pests. The introduction into the United States of such articles may be subject to other regulations promulgated under the Federal Plant Pest Act (7 U.S.C. 150aa et seq.), the Plant Quarantine Act (7 U.S.C. 151 et seq.) and the Federal Noxious Weed Act (7 U.S.C et seq.) and found in 7 CFR parts 319, 321, 330, and 360.

Transgenic plants would be regulated by the USDA if they contain some of these vectors

Not regulated by USDA

What factors should trigger regulation?