Using genetic engineering for disease control

Question 1

How does genetic engineering technology differ from previous technologies used to create resistant crops for agricultural ecosystems? Describe three other technologies that were used to create resistant crops during the last 100 years.

Answer 1

Obtain sources of resistance which are not otherwise available, to accelerate breeding process, transfer

interspecific hybridization
direct chromosome manipulation
mutagenesis
somatic cell crosses

Question 2

Describe two risks involved in genetic engineering of crop plants. How do these risks compare with risks involved in traditional plant breeding?

Answer 2

environmental risk: exotic genes in native ecosystems, through colonialization many foreign plants were introduced, so compared to that number it is not as much

Human health: secondary metabolites that are toxic to pathogens also could be toxic to people

Question 3

Describe in general terms the steps involved in creating transgenic plants.

Answer 3

1. Transformation: foreign gene is introduced onto the plant
2. Gene expression: introduced gene is expressed, so its protein product is produced
3. Selection and regeneration: plant cells expressing the gene are selected and regenerated to become whole plants

Question 4

Describe five strategies that can be used to genetically engineer resistance into crop plants. Give an example for each strategy.

Answer 4

Add more NBS-LRR receptors to plant cells
Add antimicrobial enzymes that attack pathogen cellular infrastructure (chitinases genes from beans to tobacco)
Add antimicrobial toxins that attack pathogen metabolic pathways or proteins (ribosome inhibiting protein from barley in tobacco)
Add pathogen genes to activate RNA-mediated gene silencing (virus-coat proteins)

Question 5

Which strategy for genetic engineering of disease resistance has led to the greatest commercial success thus far?

Answer 5

Papaya ring spot virus resistance by virus coat protein