1. Types of genetic modifications in plants

2. GM Plants
Genetic modification can be employed to achieve the following outcomes
Agronomic Traits
Herbicides; insecticides; viral and disease resistance
Quality traits
Texture; colour; ripening; flavour; removal of undesirable traits
Novel Products
Pharmaceuticals; vaccines; plastics etc

3. Characteristics of Herbicides
Characteristics of ideal herbicide
Not harmful to animals
Be biodegradable
Specifically target weeds and not harm crops
Most herbicides target the basic functions of plants (photosynthesis or amino acid biosynthesis etc)
Mainly used to target “undesirable competitive plants”
Glyphosate (Round-up Ready)

4. Glyphosate
Highly effective
Rapidly biodegradable

5. GM Herbicide resistant plants
Crop plant is made resistant to the herbicide
Two main strategies
Changing properties of target protein
Introducing detoxifying enzyme
EPSPS (5-enolpyruvyl-shikimate-3-phosphate synthetase)

6. Changing properties of target protein

7. Introduction of detoxifying enzyme

8. Pest Resistance Bacillus thuringiensis (Bt) spores
Production of large crystal-like proteins structures
Insecticidal activity
Bt toxin

9. Viral Resistance “Cross Protection” or “pathogen derived resistance”
Virus coat protein is used
Strengthens immunity
against specific viruses
Melon, papaya, rice, sugar beet

10. Overcoming drought stress
In warm regions, crop yields can drop ~3 – 5% with every 1°C increase in temperature
Drought stress is compounded by increasing global temperatures and reduces the rate of photosynthesis and growth, whereas extreme drought stress is lethal

11. Introduction of single drought resistant gene in Arabidopsis
After re-watering
Well-watered
10 days drought
20 days drought
Drought-resistant
Wild-type
Yu, H., et al., (2008) Activated expression of an Arabidopsis HD-START protein confers drought tolerance with improved root system and reduced stomatal density. Plant Cell 20:

12. Quality Traits Improvement in taste, colour, texture, shelf life etc
Commercially available tomatoes (FLAVR SAVR)
Suppression of cell-wall degrading enzyme (polygalactouronase)
Enhanced shelf-life
Resistance to mechanical
damage

13. Other quality traits Elimination of unwanted characteristics
Switching off problematic genes
Example: pollen, allergens etc
Addition of desired nutrients for malnourished populations
Vitamin A (Golden Rice)
Supplementation of minerals like Fe, Zn etc
Introduction of antioxidants
Post-harvest spoilage prevention

14. Post-Harvest Spoilage Prevention
Greening along with solanine production can occur in improperly stored potatoes. Solanine (Glycoalkaloid) is harmful and can be toxic in large quantities.
Source: Dr. C.M. Christensen, Univ. of Minnesota.; WSU; Pavalista, A.D. 2001

15. Overview of the current progress in Pakistan
Crop
Feature
Cotton
Diamondback moth resistance with Bt gene
- Virus (CLCuV) resistance with RNA
interference (RNAi)
Rice
Salt tolerance with Yeast and Arabidopsis Na+/H+ antiporter genes
- Bacterial blight resistance with Xa21 gene
Potato
Virus resistance
Sugarcane
Insect resistance with Cry gene
- chloroplast transformation
Tomato
Male sterility through RNAi
- Virus (TLCV) resistance through RNAi
Source: Malik, Dr. Kauser. “Agricultural in Biotechnology potential for economic Pakistan: potential for economic development”