Golden Rice was created in 1999 to address vitamin A deficiency in rice-dependent populations. Scientists added two genes (psy and crtI) to rice to produce beta-carotene, a precursor to vitamin A. Golden Rice-1 did not produce enough beta-carotene. In 2005, Golden Rice-2 was developed by using a maize psy gene and seed-specific promoter, producing higher beta-carotene levels. Golden Rice is considered safe as beta-carotene is converted to vitamin A only as needed. However, some have raised concerns about allergies, genetic contamination, and impacts on local cultures and biodiversity. Supporters argue it could reduce medical costs and increase productivity compared to alternative

1. Golden Rice

2. Why....Rice?
 Milled rice is provitamin-A-free.
 Symptoms of a provitamin-A-free diet
• Night-blindness
• Xerophthalmia
• Fatal susceptibility to childhood diseases (e.g.
measles) and general infections (diarrhea, respiratory
diseases).
For many countries, the infrastructure doesn’t exist to
deliver vitamin pills.
•Improved vitamin-A content in major staple consumed
crops is an attractive alternative to fight micronutrient
deficiencies
 Solution

3. Golden Rice… Project?
• 1999 Team of scientists, including Ingo
Potrykus, successfully genetically
engineer rice to produce carotenoids,
precursors to Vitamin-A.
• The hype begins:2000 Time magazine
cover story:
“This rice could save a million kids a
year.”
• June, 2000 US special Congressional
Forum, “Can Biotechnology Solve
World Hunger?”

5. -Carotene Pathway: Problem in
Plants IPP
 -carotene
(vitamin Aprecursor)
Geranylgeranyl diphosphate
Phytoene synthase
Phytoene
Phytoene desaturase
ξ-carotene desaturase
Lycopene
Lycopene-beta-cyclase
Problem:
Rice lacks
these enzymes
Normal
Vitamin A
“Deficient”
Rice

6. Production of Golden rice: Genetic
modification
• Rice plants possess the whole machinery for
synthesis of β-carotene, and while this
machinery is fully active in leaves, parts of it
are turned off in the grain endosperm.
• By adding only two genes, a plant phytoene
synthase (psy) and a bacterial carotene
desaturase (crt I), the pathway is turned back
on and β-carotene consequently accumulates
in the grain.

7. • Golden rice wascreated by transforming rice
with β-carotene biosynthesis genes:
1)psy (Phytoene synthase) from
daffodil (Narcissus pseudonarcissus)
2)crtI (Carotene desaturase) from the
soil bacterium Erwinia uredovora
Production of Golden rice: Genetic
modification

8. The Golden Rice: Solution
IPP
 -carotene
(vitamin Aprecursor)
Lycopene-beta-cyclase
Geranylgeranyl diphosphate
Daffodil gene Phytoene synthase
Phytoene
Phytoene desaturase
Single bacterial gene;
performs both functions
ξ-carotene desaturase
Lycopene
Daffodil gene
-Carotene Pathway GenesAdded
VitaminA
Pathway
is complete
and functional
Golden Rice
Presence of pro-vitamin -A gives rice grains a yellowish-orange color, thus, thename
‘GoldenRice.’

10. Golden Rice-1: limits
• Originial Golden Rice (GR1) does not produce enough ß-
carotene (Provitamin A); it produces “only 1.6 μg/gm of
carotenoids; a child would have to eat more than
10kg/day to get sufficient dose”.
• Unexpected effect: GR1 was supposed to produce
lycopene (as in tomatoes) and so be bright red; instead, it
produced ß-carotene due to unexpected metabolic pathway.

11. Agriculture Biotechnology
Known information about rice
It was known that rice plants produced β-carotene in the green tissues,
but not in the edible part of the plant (the endosperm).
And also the rice endosperm produce gernanylgernayl diphosphate (a
precursor of β-carotene).

12. Agriculture Biotechnology
How was Golden rice made?
The original golden rice was created in 1999 by a collaboration
between Peter Beyer and Ingo Potrykus .
To do this, they added three genes to rice: phytoene synthase (psy)
and lycopene β-cyclase from daffodil (Narcissus pseudonarcissus)
and phytoene desaturase (crt I) from the soil bacterium Erwinia
uredovora.
Agrobacterium transformation was used to introduce three different
plasmids into the rice genome.

13. Golden Rice 2
• In 2005, Syngenta, produced a variety of golden rice called
"Golden Rice 2".
• They combined the phytoene synthase(psy) gene from maize
with carotene desaturase (crt1) from the original Golden rice-1.
• Both genes are under endosperm specific promoter control
and the mannose act as selectable marker.
• Golden rice 2 produces 23 times more carotenoids than golden
rice1 and preferentially accumulates β-carotene. To receive the
Recommended Dietary Allowance (RDA), it is estimated that
people have to eat about 75g of golden rice per day.

14. Figure: Gene construct used to generate Golden Rice
RB, T-DNA right border sequence;
Glu, rice endosperm-specific glutelin promoter;
tpSSU, pea ribulose bis-phosphate carboxylase small subunit transit peptide
for chloroplast localisation;
crtI Carotene desaturase from the soil bacterium Erwinia uredovora;
nos, nopaline synthase terminator;
Psy, phytoene synthase gene from Narcissus pseudonarcissus (GR1) or Zea
mays (GR2);
Ubi1, maize polyubiquitin promoter;
Pmi, phosphomannose isomerase gene from E. coli for positive selection
(GR2);
LB, T-DNA left border sequence.

15. Agriculture Biotechnology
How was Golden rice made?
To determine which plants had taken up the appropriate plasmids, the plants were tested for hygromycin resistance,
and were analyzed using southern hybridization and restriction digests.
From these, plants showing all four introduced genes were planted, and the seeds were analyzed.
The most successful plant produced ~1.6µg/g of β-carotene in the endosperm.
This would not be enough to meet the vitamin A requirement in children (the recommended daily allowance is
300µg, but 150µg would be sufficient).

16. Agriculture Biotechnology
How was Golden rice made?
It was also discovered that none of the plants accumulated detectable
amounts of lycopene, which meant that lycopene β-cyclase was either
produced in the endosperm constitutively or was turned on when
lycopene was present.
This meant that this gene did not need to be added to the rice to form
β-carotene.

17. Agriculture Biotechnology
Further experiments showed that the rate-limiting step in this reaction was the enzymatic
activity of psy.
In 2005, researchers (Paine et.al, 2005) discovered that using a psy gene and new
promoter from maize instead of daffodil and using a seed-specific promoter, instead of a
constitutive promoter for the crtI gene, produced ~31µg/g of β-carotene. They referred to
this rice as Golden Rice 2.72g of this rice would provide the 150µg of vitamin A that is
needed daily in children. Most children in countries where rice is a staple food consume
more than 72g of rice a day.

18. Agriculture Biotechnology
Concerns with Golden rice: is it safe?
Golden rice is safe, because it contains β-carotene, which is a
precursor to vitamin A and not vitamin A itself.
The body will only make vitamin A if it needs it. If it does not need it
then the excess β-carotene will either be stored or excreted.
There has been no information to show that carotenoids have any
ill-effects on humans.

19. Agriculture Biotechnology
Concerns with Golden rice: Gene flow
The chances of the introduced genes escaping are very low due to the fact that rice
pollen is only viable for 3-5 minutes.
Also, these genes confer no advantage to other plants, since other plants produce
carotenoids.
In order to lower the chances of the genes escaping even further, the crops could be
planted by having staggered flowering days and by having a certain distance
between fields.
Since the two genes do not give a selective advantage, they will probably be diluted
out of a population, instead of incorporated into one.

20. Agriculture Biotechnology
Concerns with Golden rice: the antibiotic resistant marker
Some people are wary of having a hygromycin resistance marker
included in the transformed rice, but the marker was not included in
the final product through the process of co-transformation.
Also, it was found that hygromycin does not pose a threat to humans
or the environment.
An alternative technology has been created by Syngenta called
Positech® that identifies transformants using a non-metabolizable
sugar instead of antibiotic resistance.

21. Agriculture Biotechnology
Concerns with Golden rice: economics
Disadvantages:-
Some countries refuse to import transgenic crops.-People may be
unwilling to by golden rice.
Advantages:-
Medical costs related to VAD would decrease.-Worker productivity
would increase.

22. Controversy: Golden Rice…..Is it
worth the risks?
Critics of genetically engineered crops have raised
various concerns.
 Health
• May cause allergies or fail to perform desired effect.
• Supply does not provide a substantial quantity as the recommended
daily intake.
 Environment
• Loss of Biodiversity. May become a super weed and endanger the
existence of natural rice plants.
• Genetic contamination of natural, global staple foods.
• Gene flow from GM to non- GM field crops.
 Culture
• Some people prefer to cultivate and eat only white rice based on
traditional values and spiritual beliefs on Veg. or Non-Veg.
• Intervention in “Gods creation”.

23. • An early issue was that “golden rice originally did not have
sufficient vitaminA”.
• “The speed at which vitamin A degrades once the rice is
harvested”, and “how much remains after cooking are
contested.”
• Greenpeace opposes the use of any patented genetically
modified organisms in agriculture and opposes the cultivation
of golden rice, claiming “it will open the door to more wide
spread use of GMOs’’
Golden Rice: A boom or Bane?

24. • Other groups argued that a varied diet containing foods rich in
beta carotene such as sweet potato, leafy green vegetables
and fruit would provide children with sufficient vitamin A.
• But the “foodstuffs containing vitamin A are either unavailable,
or only available at certain seasons, or that they are too
expensive for poor families in underdeveloped countries”.
Golden Rice: A boom or Bane?