Ch 8 Agricultural Biotechnology
Examples of microbial biotechnology employed in agriculture
1. Frostban bacteria were a strain of Pseudomonas syringe with a transgene for an "ice-minus" protein. The recombinant strain prevented frost damage when applied to crop fields, but due to its negative public image the product was not marketed. 2. Bacillus thuringiensis (Bt) is applied to crops as a natural insecticide. Bt expresses the Cry protein.
Ti plasmid
Agrobacterium species naturally infect the roots of many plants and contain a tumor-inducing plasmid called Ti. A segment of the Ti plasmid (aka T-DNA) enters the plant cells. By constructing a T-DNA region with a selected transgene, bioengineers can insert the desired genetic information into a plant species, thus creating a GM variety.
Floral dip method
Allows plants to grow until they produce floral buds, which are removed. When the floral buds start to reappear, they are dipped in a solution including surfactant molecules and recombinant Agrobacterium spp. containing an engineered Ti plasmid. Then, transfection occurs which introduces the transgene into germline tissues. The conferred trait is then passed on to future offspring.
Utility of Cre/lox P system
Because of concern that inserted antibiotic resistance genes could transfer to other species and lead to increased resistance, the Cre/lox P system helps alleviate the fear of reduced effectiveness of our existing antibiotics. The Cre/lox P technique removes antibiotic resistance genes from GM plant species.
Contextualize food biotechnology throughout human history
For thousands of years, humans have used organisms as living factories in the production of food. For example, the production of bread, beer, wine and cheese. We have also engaged in selective breeding to select desirable traits for plants and animals. After selective breeding, we developed molecular biotechnology techniques that have enabled us to produce GM food. Additionally, we use GM bacteria downstream in food processing. Production and preservation methods utilize biotechnology, and some ingredients (e.g. vitamins) added to processed food are the products of biotechnology.
Biolistics
Gene guns are used to blast transgenes into plant cells, where they either enter the cytoplasm or become incorporated into the plant DNA.
Agricultural products obtained through Molecular Biotechnology
Genetically modified plants, farmed seafood, and potentially, livestock.
Summarize the process of plant tissue culture
Plant tissue culture produces an entire plant from a single totipotent plant cell. The first step is to remove the portion of the plant to be cultured, which is called the explant. Next, the explant is treated with plant hormones that will yield a predetermined pattern of growth. When solid media is used, a mass of undifferentiated cells called callus will form. The callus is treated with additional hormones, first to initiate shoot formation and then to initiate root growth. Now the cultured plants can be transferred to soil for for its final growth period. In the case of suspension culture, shoot and root formation occurs simultaneously.
Role of Molecular Biotechnology in aquaculture and livestock production
Some fish are genetically modified for faster growth rates or increased tolerance to freezing temperatures. Currently no GM livestock are available for sale, but several examples are currently in research and development phases.
Identify genetic modifications used in crop plants
Some of the genetic modifications used in crop plants are herbicide, pathogen, and insect resistance. Plants can be modified for increase tolerance to environmental stress (e.g. drought or high salinity).
Methods of introducing transgenes into plant species
Ti plasmid The floral dip method Biolistics