Lecture 13 Chapter 8

Genes and traits of interest II

Neal Stewart

Discussion questions1. Other than the products discussed in this chapter, what other sorts of

genes or strategies might be useful in engineering transgenic plants resistant to insects or pathogens?

2. Golden Rice producing provitamin A has the potential to help many impoverished people who might benefit from eating it. Although application of this technology is supported by many people and organizations, there are also some who oppose the technology. Considering their possible motivations and potential biases, discuss some of the reasons that groups have come out in favor or in opposition to Golden Rice.

3. What are the potential benefits of producing pharmaceutical proteins in plants? What are some of the disadvantages or potential dangers?

4. Animal genes can be inserted into plants and expressed. Would you be opposed to eating foods from plants expressing proteins encoded by animal genes? By human genes? Discuss the reasons for your answers.

Insect resistance

Controlling Colorado potato beetle is not easy

Bt corn

Bt cotton

Stewart, 2004. Genetically Modified Planet 2004

Bacillus thuringiensis

Bt Cry structure

IIII

II

Stewart, 2004. Genetically Modified Planet 2004

Figure 8.3

Insect midgut cells that have bound Bt toxin.

Same gut cells a few hours later– note the damage and leakage.

Bt toxin

Stewart, 2004. Genetically Modified Planet 2004

Insect midgut cells that have bound Bt toxin.

Bt

Mutated receptors cannot bind Bt toxin.

Receptors are not present– cells cannot bind Bt Stewart, 2004. Genetically Modified Planet 2004

Different Bt Crys

• Cry 1s—kills caterpillars (lepidoptera)

• Cry 2s—kills caterpillars (lepidoptera)

• Cry 3s—kills beetles (coleoptera)

Canola plant expresses a Bt cry1Ac gene

Transgenic disease resistance

• Viruses (yes)

• Bacteria (no)

• Fungi (no)

• Nematodes (no)

Figure 8.4

Stewart, 2004. Genetically Modified Planet 2004

RNA virus structure

Discussion question

Other than the products discussed in this chapter, what other sorts of genes or strategies might be useful in engineering transgenic plants resistant to insects or pathogens?

Figure 8.5

Second generation

Output traits

Improved nutrition, better foods

• Golden rice

• Modified oils from oilseeds

• Vitamin E enhancements

Golden rice: producing provitamin A

www.goldenrice.org

Biotechnologist of the day:

Ingo Potrykus

Figure 8.6

Golden Rice producing provitamin A has the potential to help many impoverished people who might benefit from eating it.

Although application of this technology is supported by many people and organizations, there are also some who oppose the technology.

Considering their possible motivations and potential biases, discuss some of the reasons that groups have come out in favor or in opposition to Golden Rice.

Third generation

Non-traditional products

Examples

• Pharmaceuticals

• Oral vaccines

• Phytoremediation

• Phytosensors

• Biofuels

Plant-made pharmaceuticalsaka

Molecular pharming

Duckweed

Corn

GeneticEngineering

Protein Purification

Grow in lab

Or field

Oral vaccine– eat the fruit, or purify the vaccine pill or injection

Fraunhofer USA: one plant-based platform to produce

pharmaceutical proteins: vaccines

http://www.youtube.com/watch?v=oCGFW1WOFTY

What are the potential benefits of producing pharmaceutical proteins in plants? What are some of the disadvantages or potential dangers?

Phytorediation exampleHow to remediate mercury in soil

www.uga.genetics.edu/rmblab

Phytosensor example:plants to detect landmines

induction

Using induciblepromoter/GFP fusions

No TNT +TNT

Phytosensor example:plants to detect landmines

So, transgenic plants could be used in a lot of applications…

Are there any we should avoid?