Genetic Engineering In Action

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Golden Rice

LO: Principle of genetic engineering and the techniques.

Key words: Golden rice, transgenic plant and vector.

It is genetically engineered with chemical beta-carotene inserted into the plant.

It is a precursor in vitamin A.

Vitamin A deficiency common in developing countries.

E.g. for vision and the immune system.

Providing food with enough vitamin A is difficult in these countries.

The basic methodology used to create golden rice

The tumour forming Agrobacterium is modified by removing the DNA ligase. The PSY and CRT1 genes are sequenced and inserted into the T1 plasmid. Endosperm are synthesised with the genes to ensure the desired gene is only produced in the edible part (endosperm). Hygromycin is also inserted into the T1 plasmid so the modified plants can be identified. The plasmid is inserted into the bacterium and is incubated with rice plant embryo.

How do scientists ensure Beta-carotene is produced in the endosperm?

Endosperm specific promotors are synthesised into packages with the genes so the expression of the gene is only in the edible parts.

What property of Agrobacterium tumefaciens makes it an ideal vector for introducing new genes into the plants?

Agrobacterium has the ability to transfer genes. It is a pathogen.

How could this new variety of rice reduce disease in developing countries?

It could reduce vitamin A deficiency which causes blindness and death by improving immunity.

Absorption of vitamin A requires sufficient dietary fat. Explain how this could be problematic for the targeted use of golden rice in developing countries.

They have poor dietary fat so they can't absorb vitamin A.