Golden Rice accumulates -carotene) in the grain - TU Chemnitz

A unique feat: Golden Rice accumulates

provitamin A (β-carotene) in the grain

Claudia LeißnerApril 11, 2007

Do you know that…

… there is the same amount of malnourished people like fat people in the world ?

• Humans require at least 49 nutrients to meet their metabolic needs:

• Water and energy

• Proteins (amino acids)

• Lipids and fats (Linoleic, Linolenic acid)

• Macro-elements (Na, K, Ca, Mg, S, P, Cl)

• Micro-elements (Fe, Zn, Cu, Mn, I, F, B…)

• Vitamins (A, D, E, K, C, B12, Biotin…)

Metabolic Need of Nutrients

Inadequate consumption Diseases

Consequences: Sickness, poor health, impaired development in children (learning ability, growth…), large economic costs to society

Golden Rice

• We need a varied diet, rich in vegetables, fruits and animal products (particularly children)!

• One of the important nutrients is vitamin A

• But some cultures have slightly more to eat than rice.

• Rice plants produce e.g. β-carotene only in the green tissues, not in the endosperm.

Solution: Rice, that accumulates β-caroteneafter biofortification – Golden Rice

Vitamin A Deficiency

Problem

Gene Technology

Golden Rice

Outlook

Outline

Vitamin A Deficiency (VAD)

Vitamin A

Xerophthalmia Immune response

Vision (night, day, colour)

Haemopoiesis Skeletal growth

Fertility Embryogenesis

Night blindness Xerophthalmia

Vitamin A Deficiency Problem Gene Technology Golden Rice Outlook



• Dietary vitamin A deficiency(VAD) causes more than 250,000to 500,000 children to go blindeach year

• But blindness and otherafflictions are indicators of moreunderlying health problems:more than half of the childrenwho lose their sight die withinone year of becoming blind

Blind: 0.5 million

Xerophthalmia: 3.1 million

Night blind: 13.5 million

Inadequate Vitamin A supply, 231 million

23% greater

risk of death

Children with Vitamin A Deficiency

The Rice Grain


The outer coat of the dehusked grains – the hull –contains a number of valuable nutrients, e.g. vitamin Band nutrients fats, but also no vitamin A.

The endosperm (also known as white rice) does notcontain vitamin A.

Only the leaves of the plant contain vitamin A because it is vital for photosynthesis.



Vitamin A is produced of provitamin A (β-carotene) directly in the body

Rice does not contain any β-carotene (provitamin A) in the endosperm, only in leaves.

Biofortification: the creation of plants that make or accumulate micronutrients

β-carotene (provitamin A) vitamin A

Solution for the Rice Grain


All required genes are present in the grains, but some of them have been turned off.

Genetically modification (GM) of the rice DNA. Three genes have been inserted into the rice genome by genetic engineering.

Production and accumulation of β-carotene in the endosperm.

Gene Technology - Evolution

DNA (desoxyribonuclein acid) is a nucleicacid that contains the genetic instructionsfor the development and functioning ofliving organisms.

Evolution is the natural rearrangement ofDNA –> new characteristics


Gene Technology - Evolution

The DNA is stored in the chromosomes anddifferent types of chromosomes arephysically separated because of theirdifferent functions.


Recombination of DNA allowschromosomes to exchangegenetic information andproduces new combinationsof genes.

Gene Technology – Transgenetic Plants

Transgenetic plants are plants that possess one or moregenes, that have been transferred from differentspecies

– May be performed through ordinary hybridization(since the 1930´s)

– Use of recombinant DNA technology: artificialinsertion of genes from other species to achievespecific characteristics

Examples: transgenic tomato, maize, soy bean, …


Gene Technology – Development of Golden Rice

First recombination of DNA was discovered in 1973with a transgenic bacteria, since then the techniquewas improved and applied to other topics.

Since the beginning of the 80s fundamental researchfor gene technology like it was used for Golden Ricewas done.


Gene Technology – Development of Golden Rice


1992 : Start of the Golden Rice research project

1992-1999 : Introduction of specific genes for provitamin A biosynthesis into the seed

1999: First Golden Rice!

Golden Rice - The Inventors


Professors Ingo Potrykus (ETH Zurich) and Peter Beyer (University of Freiburg), inventors of Golden Rice (GR)

The specific details were first published in Science in 2000.

Scientific breakthrough in biotechnology – engineering of a complete biosynthetic pathway

Golden Rice – Biosynthesis of β-Carotene


Carotenoid biosynthesis pathway in golden rice:

PPPP

Geranylgeranyl diphosphate (C20)(exists in the endosperm naturally)

Phytoene (C40)

ζ-carotene

Lycopene

β-carotene/provitamin A (productioncatalysed by the three additional genes)

Crt 1

Crt 1

Lyc

Psy

Golden Rice – Insertion of the New Genes


Three β-carotene biosynthesis genes:

1.) Psy (phytoene synthase), from daffodil

Peptid sequence for transformation of geranylgenanyl diphosphate to phytoene

2.) Crt1 from the soil bacterium Introduces conjugation by adding four double bonds

3.) Lyc (lycophene cyclase), from daffodil

Transformation of lycopeneto β-carotene

Golden Rice – Insertion of the New Genes


daffodil(Narcissus pseudonarcissus)

genes

bacterium (Erwinia uredovora)

plasmide

soil bacterium

seedhull

embryo

rice embryo

The gene transformation process:

Golden Rice – Breeding


All a farmer needs is one seed of Golden Rice:

1 seed -> 1 plant -> 1000 seeds / 20 g

Within two years:

-> 1 000 000 seeds /20 kg

-> 1 000 000 000 seeds / 20 t

-> 1 000 000 000 000 seeds / 20 000 t

Golden Rice – Green House Conditions


First official bred rice with 1.6 μg/g β-carotene was obtained in 2003.

Bioavailability (ability to incorporate the provitamin A to the body) is high, because of the natural fats in the ricegrain.

Golden Rice – Green House Conditions


First regulatory clean line with 1.6 μg/g β-carotene was obtained in 2003

Golden Rice – First Field Trial


First small-scale field trial in the USA, Louisiana, 2004

An average of 6 μg/g β-carotene was obtained from the 2004 field trial-> Four times higher β-carotene content than under green houseconditions

The field test with 6 lines did, so far, not indicate any agronomic orecological problem and the content of provitamin A was at least as highas in the glass house or even higher.

Golden Rice – Syngenta


After the publication of Golden Rice 1 (end of public funding of theproject) Syngenta, a biotechnology company was involved into thefurther development of Golden Rice.

Establishing of free licences for all these techniques, so thatSyngenta and humanitarian partners could use Golden Rice inbreeding programs and develop new crops.

There is no fee for the humanitarian use of Golden Rice!

Golden Rice – 2nd Generation


• A second generation of Golden Rice was first published in 2005and produced by a team of researchers of Syngenta

• Under green house conditions it produces 23 times morecaroteniods, which preferentially accumulate β-carotene (up to31 μg/g)

Golden Rice – 2nd Generation


• To receive the Recommended Dietary Allowance (RDA), it is

estimated that 144 g of this rice would have to be eaten.

• Golden Rice 2 have not yet undergone nutritional testing.

Golden Rice – Acceptance


Color:

• Color of the rice is in accordance to the amount of β-carotene

• In many cultures rice is mixed with yellow spices (safran, curry, …)

• A lot of educational work has to be done

Picture:

• a) Freshly harvested Golden Rice grains

• b) Dehusked rice grains

• c) Polished rice grains

a)

b)

c)

Golden Rice – Risks


2- Environmental Risks

What are the most important risks of Golden Rice ?

1- Risks concerning human health



1 - Eventual Risks concerning human health

- Overdose of proteins

- No significant impact of micronutrient levels on health or low bioavailability

- Introduction of allergenic proteins

Solution: GR2 with high content

Solution: β-carotene is already in our diet



2 - Environmental risks

Genetic contamination of wild population by:

• Seed dispersal by natural vectors or humans

• Horizontal transfer

• Pollen dispersal by wind or animals

Increased weediness of crop plantsLoss of Biodiversity

Risks associated with gene flow and recombination

Golden Rice – Biodiversity


Golden Rice techniques shall be applied to all local rice varieties – free use of the patents and free of charge for humanitarian use!

No loss of biodiversity = genetic difference between species

This is possible because of the assumption of safety: Lot of tests on health and environment risks have to be done only one time for all varieties.

Golden Rice – Summary


Most important problems of Golden Rice:

• Acceptance of the golden color

• Acceptance of genetically modified food (GMO)

• Reduction of over-regulating GMO

• Adoption of the new technology to local rice

varieties

• Impact to the human body and the nature

Golden Rice – Outlook


• Golden Rice will not solve the problem of the developing countries

• A lot of work has to be done in politics and economics

There is enough food in the world - problemswith food distribution, not production, have tobe solved!

Think about it!

Thank you for your attention.

Do you have questions?

References


• www.goldenrice.org

• The Golden Rice “Tale”, Ingo Pytrokus

• Kurzlehrbuch Biochemie, Thomas Kreutzig

• Ingo Potrykus; Golden Rice, vitamin A and blindness – public responsibility and failure; March 18, 2005; Zurich.

• Ingo Potrykus; Is GMO over-regulating costing lives; April 11-15, 2005; Lyon.

• P. Schaub, S. Al-Babili, R. Drake, P. Beyer; Why is Golden Rice (Yellow) instead of Red?; Am. Soc. of Plant Biologists; 1-10 ; 2005.

• S. Al-Babili, P. Beyer; Golden Rice – five years on the road – five years to go?; Elsevier; 565-573 ; 2005.

• R. M. Welch, R.D. Graham; Breeding for micronutrients in staple food crops from a human nutrition perspective; J. Exp. Botany; 55, 396; 353-364; 2004.

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Golden Rice accumulates -carotene) in the grain - TU Chemnitz