Lecture 13 Chapter 8
Genes and traits of interest II
Neal Stewart
Discussion questions
1. 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
Bacillus thuringiensis
Stewart, 2004. Genetically Modified Planet 2004
Bt Cry structure
III
I
II
Stewart, 2004. Genetically Modified Planet 2004
Figure 8.3
Bt toxin
Insect midgut cells that have bound Bt toxin.
Same gut cells a few hours later– note the damage and leakage.
Stewart, 2004. Genetically Modified Planet 2004
Bt
Insect midgut cells that have bound Bt toxin.
Mutated receptors cannot bind Bt toxin.
Stewart, 2004. Genetically Modified Planet 2004
Receptors are not present– cells cannot bind Bt
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
RNA virus structure
Stewart, 2004. Genetically Modified Planet 2004
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
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 pharmaceuticals
aka
Molecular pharming
Duckweed
Genetic
Engineering
Grow in lab
Or field
Protein
Purification
Oral vaccine– eat the fruit, or purify the
vaccine pill or injection
Corn
Fraunhofer USA: one plantbased 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 example
How to remediate mercury in soil
www.uga.genetics.edu/rmblab
Phytosensor example:
plants to detect landmines
Phytosensor example:
plants to detect landmines
No TNT
induction
Using inducible
promoter/GFP
fusions
+TNT
So, transgenic plants could be
used in a lot of applications…
Are there any we should avoid?