“If you desire peace, cultivate justice, but at the same time cultivate the fields to produce more bread; otherwise there will be no peace.” Norman Borlaug GM Crops, from Science to Politics L. Andrew Staehelin Department of Molecular, Cellular and Developmental Biology University of Colorado, Boulder Food and Environment lecture 2013 Scientific Challenge Eurobarometer 2003 Study Is the following statement true? “Ordinary tomatoes do not contain genes, while genetically modified tomatoes do.” Only 36% of 17,000 respondents across 17 EU countries correctly identified this statement as false. Agriculture - The cultivation of land to produce crops for human consumption and use • Foods Proteins, Starch, Oils • Industrial materials Starch, Fibers, Oils • Pharmaceuticals Natural Chemicals (vitamins, omega-3 fatty acids), Vaccines, Antibodies, Protein Drugs (insulin) The big problem my birth Industrial revolution Can organic farming feed the world? NO! • Why? • Organic farming is between 3% and 55% less productive than traditional farming. It could not even feed the current world population. • Organic farming is also much more sensitive to environmental challenges (insects, pathogens, drought). Thus, its productivity is more variable than traditional agriculture. • Conclusion: organic farming does not provide an option for feeding the world in the future. How will we feed the growing world population? Agricultural challenges • less agricultural land (urbanization, salination, desertification) • less water (competing uses, contamination) • global warming • the GREEN REVOLUTION has run its course wheat The Green Revolution was driven in part by the introduction of genes for dwarfism: shorter stems -> more seeds/fruits. How can we produce more food? Agricultural changes • improve cultivation methods (fertilizer and water use) • improve storage and transport Biological improvements • reduce crop losses during/after cultivation due to insect pests, pathogens, heat, water and salinity stresses • increase productivity of plants (more seeds, bigger fruit) • improve nutrient value (increased content of desired products, e.g. protein to reduce need for meat) Biological improvements require changes in genetic makeup! Methods for changing genetic makeup of crop plants Traditional breeding • limited in scope to gene pool of given plant • time consuming (~10 years) due to long generation times Mutagenesis – radiation, chemical, tissue culture growth • results unpredictable; limited in scope Genetic engineering • can utilize genes of all organisms (cis-genic, trans-genic) • can add new genes or suppress the expression of existing genes (silencing) • more precise and faster than traditional breeding Agrobacterium tumefasciens – a soil bacterium DNA Ti plasmid Ti plasmid contains 25 vir genes, which can be injected into plant cells by bacterium T-DNA sequences in plasmid allow for the insertion of plasmid genes into plant cell DNA Vir genes code for enzymes for producing • plant hormones (auxin, cytokinins) that promote uncontrolled cell divisions (tumors) • unusual amino acids (opins) that provide N- and C-sources for the bacteria The Agrobacterium transformation system Modification of Ti plasmids for transformation experiments • removal of genes coding for opin synthesis enzymes • removal of genes coding for hormone synthesis enzymes (no tumor formation) • insertion of desired gene plus selection marker gene into emasculated Ti plasmid Production of a transgenic plant Plant cell 29 countries grew GE crops in 2010 (40 countries predicted to plant GM crops by 2015) Clive James, ISAAA, 2011 2011: 160 million hectares (400 million acres) of GM crops – 8% increase over 2010 16.7 million farmers, 15 million in developing countries GM crops permitted for planting Bt crops expressing insecticidal Cry proteins: corn, cotton, soybeans, potato, tomato Roundup Ready crops resistant to the herbicide glyphosate: soybeans, sugarbeets, rapeseed (canola), alfalfa Virus-resistant crops: papaya, squash Bionutrient-enhanced crops: Golden Rice Drought-resistant crops: corn European corn borer protection by Bt cry-protein Bt Corn Non-Bt Corn European corn borer Sources: Monsanto, Clemson University European corn borer European corn borer damage to corn kernels: Bt-Maize v. non-Bt-Maize Fusarium molds (arrow) produce fumonisins, highly toxic chemicals, that cause cancer and spina bifida babies Damage from corn rootworm feeding - can be controlled with Bt protein expression Sources: USDA, Iowa State Univ. Bt crops Crops: corn, cotton, soybeans, potato, tomato Mode of action of Cry proteins • Insect guts have alkaline pH, which converts the Cry protein to a membrane pore-forming toxin • In acidic intestines (mammals, birds, fish) the Cry proteins remain inactive and are digested Benefits of Bt crops • Very effective for combating European corn borer, cotton bollworm, and corn rootworm • Farmers planting Bt corn and Bt cotton report using 30-70% fewer pesticides, and having a 10-30% increase in yield Methods for reducing the development of resistance to Bt toxins Crop rotation Refuge plus high dose strategy • planting of non-Bt refuges (~20% of acreage) • use of crops with combinations of transgenes (e.g. 3 Cry genes for Lepidopteran pests and 3 Cry genes for Coleopteran pests Integrated pest management systems • use refuges, crop rotation and multitoxin Bt crops • monitor crops for pests • release of sterile insects • apply specific insect growth regulators, feeding inhibitors • apply narrow-spectrum chemical pesticides Roundup Ready crops Control soybeans Roundup Ready soybeans Source: Monsanto Roundup Ready crops are resistant to the herbicide glyphosate, which enables farmers to kill weeds without affecting the crop plants. Roundup Ready crops Crops • corn, soybeans, sugar beets, canola, alfalfa Mode of action of Roundup (glyphosate) • glyphosphate inhibits the activity of the plant EPSPS enzyme needed for the synthesis of aromatic amino acids • this enzyme is also found in many bacteria, but not in humans and animals (glyphosate is non-toxic) • Roundup Ready plants contain bacterial EPSPS that is not inhibited by glyphosate Roundup Ready crop benefits • Excellent weed control • Rapid degradation of herbicide in soil -> no groundwater contamination • Increased productivity (less competition by weeds; Boulder County sugar beet farmer: same yield on 80 acres as previously with 130 acres) • Allows for no-till farming, which conserves water and soil (soybean farmers report a 90% reduction in soil erosion) • Emerging problem: development of RoundupReady resistant weeds Papaya Ringspot Virus Fig. 38.18 GM-papaya - protected from the virus by the expression of a viral coat protein in the papaya plants, which causes gene silencing. Developed by University of Hawaii scientists. Papaya farming in Hawaii was saved from extinction by these GM fruits. GM-papaya control Countries, where vitamin A-deficiency is a severe public health problem WHO 2008 Vitamin A deficiency causes child blindness (~500,000 cases per year) and immune deficiency problems (~2 million deaths per year). Golden Rice produces beta-carotene, a precursor of vitamin A One bowl (3 to 5 oz) of cooked Golden Rice 2 per day can provide 60% of needed vitamin A for young people. Poor farmers in Bangladesh, Indonesia, Philippines, India(?) will be receiving free Golden Rice seeds starting late 2013. Examples of GM crops soon to be released • • • drought resistant corn (several companies) – now released golden rice (Int. Rice Institute, Philippines) – now released blight resistant peanut (Virginia Tech) • • • • non-browning apple (Okanagan Speciality Fruits) higher yielding soybean (Monsanto) cold tolerant eucalyptus (Arbor Gene) new herbicide resistant crops (Bayer, BASF, Dow, DuPont, Monsanto, Syngenta) By 2015 – 120 GM crops worldwide (50% will be crops developed for local use in Asia and Latin America) Greenpeace Demonstration Side Note: Patrick Moore, co-founder of Greenpeace, has recently become a vocal supporter of GM crops. He now accuses Greenpeace of crimes against humanity for opposing the planting of Golden Rice. GM Food Hysteria Which federal entity regulates GE crops in the U.S.? U.S. Dept. of Agriculture Environmental Protection Agency Food and Drug Administration Cost of going through the regulatory process is estimated at $10-20 million. Some concerns with GM crops Ethical: Is GE technology playing God? Economic: • cross pollination introduces GE material into organic food products • concentration of seed business in the hands of a few companies is risky Food safety: • do GE foods have adverse health effects? • will GE foods provoke allergic reactions? Environmental: • development of Bt resistant insects and RR resistant weeds • transfer of transgenes to relatives of crops Why have genetically modified organisms (GMOs) remained so controversial? Genetically modified abominations Jakub Kwiecinski - EMBO reports 10:1187-1190, 2009 A central function of society and culture is to impose order on the natural world by projecting categories to classify and structure nature. Societies like clear divisions: human and nonhuman, female and male, etc. Scientists perceive genes as information that is readily exchanged between organisms. Many non-scientists regard genes as things that maintain boundaries between species. GMOs break the classical boundaries of fixed categories and are therefore viewed as polluting the human system of ordering the universe. Cross-pollination from GE to organic fields A major point of contention is that pollen from GE fields will pollinate neighboring organic fields, resulting in some level of transgenic material in the organic seed. ♂ ♀ In corn, separate male and female flowers and pollen dissemination by wind strongly promote cross-pollination. How far does corn pollen travel in Colorado? Blue corn trial, Boulder County, 2002-2006 North West East Blue Corn Yellow corn = sample of 10 ears Sampling distances up to 1000 ft. South Byrne and Fromherz (2003) Food, Agric. & Envir. 1:258-261 Blue corn trial, south side, 2002 2.5 ft: 46% 150 ft: 0.53% 300 ft: 0.18% 30 ft: 14% 600 ft: 0.06% Byrne and Fromherz (2003) Food, Agric. & Envir. 1:258-261 Percent cross-pollination vs. distance from pollen source, blue corn trial, Boulder Co., 2004 14.00 % cross-pollination 12.00 10.00 most distant blue kernels: 918 ft SW, 0.05% 8.00 SE SW NE 6.00 NW 4.00 W 150 ft: 0.07 – 0.42% 2.00 0.00 0 150 300 450 600 750 900 Distance (ft) Byrne and Fromherz (2003) Food, Agric. & Envir. 1:258-261 Challenges associated with the design and execution of studies of GM food safety European Union has developed strict guidelines for studies Obtaining equivalent GM and non-GM foods is critical • plants are masters of adaption to local growth conditions (a plant has to be able to survive and reproduce wherever it germinates) • good-bad wine vintages (precipitation and temperature affect composition) • local growth conditions affect composition: isoflavone (hormonelike compounds) levels of soybeans grown in different parts of Illinois varied from 47mg/10g to 171mg/10g in same year • natural toxin (aflatoxin, fumonisin) levels fluctuate • feeding studies should use “isolines” grown in same place at same time – complete chemical analysis needed Challenges associated with the design and execution of studies of GM food safety (continued) Experimental design questions • animal species? animal age? animal sex? • animals need a balanced diet; what is an appropriate amount of experimental food in diet (alfalfa, corn, potatoes, papaya)? • diets should include multiple concentrations of experimental food -> concentration-dependent response • duration of study? • which health parameters should be tested? Assessment of health impacts of GM diets using feeding trials by Chelsea et al. Food Chem Toxicol. 50:1134-1148, 2012 Review of 12 long-term studies of 90 days to 2 years, and of 12 multigenerational studies (2-5 generations). Animal types: mice, rats, cows, pigs, sheep, goats, hens, salmon. High degree of compliance with European Union guidelines. Conclusion: GM plants/foods are nutritionally equivalent to their non-GM counterparts and can be safely used for food and feed. Effects of ratio of organic to conventional agriculture on pest levels by Adl et al. Sci. Total Envir. 409-2192-2197, 2011 Organic agriculture benefits greatly from the low levels of pests maintained by the use of GM crops and pesticides by conventional farmers. Above a threshold level of organic to conventional farms the pest population in organic plots grows rapidly causing epidemics of pest outbreaks, a major reduction in organic farm output and in food security. Conclusion: Too many organic farms are bad for organic farming! Summary: Some benefits of GE crops • Better insect pest control, reduced chemical insecticide applications -> greater yield • Better weed control -> greater yield • Drought tolerance -> greater yield • Facilitates no-till farming for soil and water conservation. • Effective viral, bacterial and fungal disease control • Improved nutritional properties (Golden rice); pharmaceuticals • Greater profitability, shared throughout the agricultural system Comparison of timelines for producing plantmade and egg-based vaccines DAY 0 21 75 96 150 A: pre-production (plants: cloning and transformation; egg-based system: preparation of vaccine strain) B: Production time for first batch C: Estimated 2.5 months for testing and regulatory approval Penney et al. (2011) Plant Cell Rep. 30:789-798 Experiment to gage consumer attitudes towards GM foods via fruit stand sales (Countries: New Zealand, Sweden, France, Belgium, UK, Germany) Fruit “types”: • Organic (certified) • Conventional (low spray) • GM spray-free Price levels: prevailing market price +/-15% (combinations) Note: customers were informed of the experiment after they had made their selection, but before money had changed hands (ethics rule) (Nature Biotechnology 25:507-508, 2007) Market share simulation comparing revealed versus preferences stated in surveys Price level: 15% ORGANIC ORDINARY SPRAY-FREE premium for organic; 15% discount for sprayfree GM “Biogrow certified” “Low residue” “Genetically Modified” NZ: Revealed Stated 20% 38% 20% 32% 60% 30% Sweden: Revealed Stated 20% 39% 38% 30% 43% 31% Germany: Revealed Stated 33% 28% 31% 59% 36% 12% Fruit stands were visited by 2,736 customers in six countries (Nature Biotechnology 25:507-508, 2007) Findings • Across 6 countries it appears that 30-40% of consumers either don’t care, don’t notice, or like the idea of spray-free GM fruit • This proportion goes higher at discount prices • Revealed preferences do not match stated preferences (Nature Biotechnology 25:507-508, 2007) Golden Rice – development time and costs PP IPP PP DMAPP PP GGPP Phytoene Phytofluene -Carotene Neurosporene It took a total of 9 years of basic research and engineering in the complementing teams of Ingo Potrykus and Peter Beyer and $ 2.4 million to establish the biochemical pathway. It took, however, additional 13 years and $ 22 million to develop a GMO-product and pass it through regulation. Lycopene Golden rice seeds developed by the International Rice Institute are being made available to poor farmers free of charge in Asia. U.S. adoption of genetically engineered crops Percent of acreage 100 91 88 85 Cotton 80 Soybean 60 40 Corn 20 1996 1998 2000 2002 2004 2007 Compiled from USDA annual estimates 2009 Cotton bollworm Cotton bollworm damage Cotton bollworm Photos: USDA