Methods of GM crops Flashcards
2 types of delivery systems
gene gun: coat gold particles with DNA and then shoot them onto a disc, DNA enters the plant tissue, hope that some of it enters the nucleus
agrobacterium-mediated transformation
Ti plasmid
T-DNA region that contains auxin and cytokinin which speeds up replication process, and opine that is used for the bacteria
Outside: vir genes that are essential for the transfer of the T-DNA region
How to use agrobacterium plasmid for genetic engineering
take out oncogenes and opine synthesis and replace with GOI + selectable marker
How does agrobacterium invade plant cell
agrobacterium senses phenolic compounds released by a damaged plant
induces the activity of virulence genes
single stranded copy of T-DNA produced, protected by ssDNA binding protein
travels to plant cell by pore
How are transformed plant genes selected for
antibiotics such as kanamycin and hydromycin
Why do we use Arabidopsis as a model organism
rapid life cycle, small genome, self-fertilizing, fully sequenced genome, makes thousands of seeds, not fussy about growth conditions
Floral dip method
- Dip flowering buds into a solution of transformed Agrobacterium
- Agrobacterium can pass through the vascular system into the ovules
- Let plant grow and go to seed, collect the seed and use the selectable marker in the next generation
Only seedlings with T-DNA integrated into their own DNA can survive in the presence of herbicide
Genetic approaches: forward, backwards and functional
The difference between forward and reverse genetic studies is the focus of the studies. In forward genetics, scientists select the phenotype of interest and try to identify the gene that is responsible, whereas in reverse genetics, the scientists try to find the function of a specific gene, and observe the trait associated by mutating or removing this gene.
functional: use sequence as a tool to discover the functions of all genes in an organism
Callus
undifferentiated mass of plant cells
