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Chapter 6 Plant Biotechnology Agriculture: The Next Revolution Biggest industry in the world ($1.3 trillion of products per year) Plant transgenesis allows innovations that are impossible to achieve with conventional hybridization methods • Resistant to herbicides • Pest resistant • Vaccines Methods Used in Plant Transgenesis Unique advantages of plants: • The long history of plant breeding provides plant geneticists with a wealth of strains that can be exploited at the molecular level • Plants produce large numbers of progeny; so rare mutations and recombinations can be found more easily • Plants have been regenerative capabilities, even from one cell • Species boundaries and sexual compatibility are no longer an issue Methods Used in Plant Transgenesis Selective Breeding • Farmers cross plants with desirable traits to increase the likelihood of producing offspring with that trait. selective breeding animation Methods Used in Plant Transgenesis Protoplast Fusion to create plant hybrids • Degrade cell wall with cellulase • A cell lacking a cell wall is called a protoplast • The protoplasts from different species of plants can be fused together to create a hybrid • The fused protoplasts grow in nutrient agar for a few weeks • The colonies are then transferred to media to induce root and shoot growth Methods Used in Plant Transgenesis Selective Breeding vs. Biotechnology Traditional selective breeding vs. biotechnology Methods Used in Plant Transgenesis Transgene – gene for a desirable trait introduced into a novel organism • Transgene construct contains a promoter, terminator, and selectable marker gene Methods Used in Plant Transgenesis Transformation by Agrobacterium Method • Ti plasmid integrates into the DNA of the host cell, making it an ideal vehicle for transferring recombinant DNA to plant cells Animation: Gene Transfer in Plants Using Ti Plasmid Methods Used in Plant Transgenesis Leaf Fragment Technique • Small discs of leaf incubated with genetically modified Agrobacterium Ti plasmid • Treat with hormones to stimulate shoot and root development Animation: Engineer a Crop Methods Used in Plant Transgenesis Transformation by Gene Gun Method • Blast tiny metal beads coated with DNA into an embryonic plant cell Gene Gun animation Methods Used in Plant Transgenesis Chloroplast Engineering • More genes can be inserted at one time • Genes are more likely to be expressed • DNA is separate from the nucleus Methods Used in Plant Transgenesis Plant Breeding and Testing Overview of crop genetic engineering Methods Used in Plant Transgenesis Antisense Technology • Flavr SavrTM tomato introduced in 1994 • Ripe tomatoes normally produce the enzyme, polyglacturonase (PG) which digests pectin • Scientists isolated the PG gene, produced a complementary gene which produces a complementary mRNA that binds to the normal mRNA inactivating the normal mRNA for this enzyme Antisense technology Methods Used in Plant Transgenesis RNA Interference (RNAi) • Inhibits gene expression by interfering with transcription or translation of RNA molecules Active protein expression Protein expression silenced by RNAi RNAi video and animations Practical Applications in the Field Disease Resistance • Vaccines for plants contain dead or weakened strains of plant viruses to turn on the plant’s immune system • Transgenic plants express viral proteins to confer immunity Practical Applications in the Field Insect Control • Bacillus thuringiensis (Bt) produces a protein that is toxic to plant pests • Transgenic plants contain the gene for the Bt toxin and have a built-in defense against these plant pests Animation: How Bt Affects Insects Practical Applications in the Field Weed Management • Herbicide resistance Weed-infested soybean plot Transgenic soybean plot after Roundup treatment Practical Applications in the Field Safe Storage • avidin-blocks the availability of biotin for insects Stronger fibers • Increase strength of cotton fiber by 60% Practical Applications in the Field Enhanced Nutrition • Golden rice that is genetically modified to produce large amounts of beta carotene • QPM: Maize with increased nutritive value QPM program in Haiti Practical Applications in the Field Future Transgenic Products • RNAi to generate caffeine free coffee beans. • Biotech Crop Database Animation: Future GMOs Practical Applications in the Field The Future: From Pharmaceuticals to Fuel • Plant-based petroleum for fuels • Biofuel – fuel derived from biomass Types of Biofuels Bioethanol – alcohol made by fermenting plant based sugar compounds Video tour of an Ethanol Plant Types of Biofuels Biodiesel-vegetable oil or animal fat derived diesel fuel Comparison of biodiesel output for different feed stocks Biofuel Production Generation 1 Biofuels: Food Sources Biofuel Production Corn Used for Ethanol production 1985-2008 4,000 3,600 3,500 3,026 2,500 2,120 2,000 1,603 1,500 1,323 1,168 996 1,000 398 426 458 500 271 279 287 321 349 533 566 628 481 526 429 396 706 2008a 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 0 1985 Million Bushels 3,000 Biofuel Production Biotechnology Solutions for Generation 1 • The soybean Biofuel Production Generation 2 Biofuels: Non-Food Sources Biofuel Production Biotechnology Solutions for Generation 2 • GM Jatropha doubles oil yield Practical Applications in the Field Metabolic Engineering • Manipulation of plant biochemistry to produce nonprotein products or to alter cellular properties Health and Environmental Concerns Human Health • Allergens • Antibiotic resistance Health and Environmental Concerns Environmental Impact • Effect on non-target species • Super weeds Health and Environmental Concerns Regulations • US Department of Agriculture (USDA) • Safe to grow • Food and Drug Administration (FDA) • Safe to consume • Environmental Protection Agency (EPA) • Poses little or no environmental risk Plant Biotechnology