5. Plant Transformation The introduction and expression of genes into plants is a three step process: DNA Delivery to Target Cells Selection and Regeneration Event Selection
6. Plant Transformation – DNA Delivery microprojectile bombardment “ biolistics” or “gene gun” tiny DNA-coated particles are shot into plant cells versatile method complex DNA integration patterns: tandem arrays of fragmented molecules Agrobacterium tumefaciens natural property of Agrobacterium to transfer DNA to host plant cells is exploited to introduce genes of interest difficult with cereal crops simple DNA integration patterns
7. Plant Transformation – Target Cells All Crop Transformation Protocols Deliver DNA to Plant Cells in Tissue Culture Tissue cultures allow regeneration of fertile plants from single cells Large number of target cells available for DNA delivery in a compact form (callus) Establishment, maintenance and plant regeneration is labor intensive Methods limited to a few genotypes, usually not commercial varieties Can introduce undesirable mutations
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10. THE MAKING OF A GMO CROP VARIETY Backcrossing and selection (6- 8 generations) Transgenic line Commercial variety x x x Commercial Transgenic Line Biotechnology
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12. GMOs: Why the Controversy? Genetic engineering is a powerful new technology that is in general poorly understood and whose long term effects are unknown. GMOs are an innovation that have and will continue to impact all facets of the global agricultural economy. Production Consumer Products Processing Commodity Handling
13. GMO Crops: Three Major Issues 1. Food safety and environmental impacts 2. Global trade 3. Increased corporate control of agriculture