Transcript Genetically Modified Organisms

GoldenRiceTM - a success story
Vitamin A deficiency in
developing countries
• Lack of vitamin A is the leading cause
of blindness among children in
developing countries
– 250,000 children per year go blind
– 124 million children worldwide are
deficient in vitamin A
• Oral delivery is difficult because of
lack of infrastructure
GoldenRice
• Rice is a major staple food in Asia
• The outer oil-rich, nutritious
aleurone layer is usually milled
because it turns rancid upon storage
in tropical areas
• The remaining endosperm lacks
provitamin A (b carotene)
b-carotene
biosynthetic
pathway
The problem with rice:
• Does not express
phytoene synthase in
endosperm
• Does not express
phytoene desaturase
or z-carotene
desaturase
The solution
• Ingo Potrykus and colleagues engineered
rice to contain genes for two enzymes
 phytoene synthase from daffodil
 carotene desaturase from Erwinia
• The resulting rice endosperm can yield
100 mg retinol equivalent / 300 g rice
– 1.3 µg b-carotene / g rice
– U.S. RDA for 1- to 3-year-old children is 300 µg
Ye et al. (2000) Science 287: 303-309
What’s new?
• Golden Rice does not meet the minimum
RDA for vitamin A
• New version--Golden Rice 2--has been
made by adding the maize phytoene
synthase gene
Paine et al., 2005. Nature Biotechnology 23:482.
Golden Rice 2
• Supplies 50% of the
300 µg vitamin A RDA
in 72 g of dry rice
– Typical child’s portion of
rice is 60 g
– This amount of rice is
eaten twice a day in
many countries
What’s next?
• Use traditional breeding to introduce the
b-carotene production into strains of rice
that grow well in developing countries
– India
– China
– Africa
– Latin America
• Overcome the GMO opposition
Overcoming the GMO opposition
• Golden rice fulfills the wishes of the GMO opposition
• It was not developed by industry, and industry does not
benefit from it
• It presents a sustainable, cost-free solution, not
requiring other resources
• It is given free of charge and it benefits the poor and
disadvantaged
• It does not create new dependencies on, or
advantages for, rich landowners
• It can be resown every year from saved seed
• It does not reduce agricultural or natural biodiversity
• It does not present any negative impact on the
environment or risk to human health
Golden Rice is a success